Underwriting Agreement dated April 1, 2008 by and among Hansen Medical, Inc. and Morgan Stanley & Co. Incorporated

Exhibit 1.1

3,000,000 Shares

HANSEN MEDICAL, INC.

COMMON STOCK, PAR VALUE $0.0001 PER SHARE

UNDERWRITING AGREEMENT

April 1, 2008

April 1, 2008

Morgan Stanley & Co. Incorporated
1585 Broadway
New York, New York 10036

Ladies and Gentlemen:

     Hansen Medical, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to Morgan Stanley & Co. Incorporated (the “Underwriter”) 3,000,000 shares of its Common Stock, par value $0.0001 per share (the “Shares”). The shares of Common Stock, par value $0.0001 per share of the Company to be outstanding after giving effect to the sales contemplated hereby are hereinafter referred to as the “Common Stock.”

     The Company has filed with the Securities and Exchange Commission (the “Commission”) a registration statement, including a prospectus, (the file number of which is set forth in Schedule I hereto) on Form S-3, relating to the securities (the “Shelf Securities”), including the Shares, to be issued from time to time by the Company. The registration statement as amended to the date of this Agreement, including the information (if any) deemed to be part of the registration statement at the time of effectiveness pursuant to Rule 430A or Rule 430B under the Securities Act of 1933, as amended (the “Securities Act”), is hereinafter referred to as the “Registration Statement”, and the related prospectus covering the Shelf Securities dated March 17, 2008 in the form first used to confirm sales of the Shares (or in the form first made available to the Underwriter by the Company to meet requests of purchasers pursuant to Rule 173 under the Securities Act) is hereinafter referred to as the “Basic Prospectus.” The Basic Prospectus, as supplemented by the prospectus supplement specifically relating to the Shares in the form first used to confirm sales of the Shares (or in the form first made available to the Underwriter by the Company to meet requests of purchasers pursuant to Rule 173 under the Securities Act) is hereinafter referred to as the “Prospectus,” and the term “preliminary prospectus” means any preliminary form of the Prospectus. If the Company has filed an abbreviated registration statement to register additional shares of Common Stock pursuant to Rule 462(b) under the Securities Act (the “Rule 462 Registration Statement”), then any reference herein to the term “Registration Statement” shall be deemed to include such Rule 462 Registration Statement.

     For purposes of this Agreement, “free writing prospectus” has the meaning set forth in Rule 405 under the Securities Act, “issuer free writing

prospectus” has the meaning set forth in Rule 433 of the Securities Act, relating to the Shares that (i) is required to be filed with the Commission by the Company, (ii) is a “road show that is a written communication” within the meaning of Rule 433(d)(8)(i) whether or not required to be filed with the Commission or (iii) is exempt from filing pursuant to Rule 433(d)(5)(i) because it contains a description of the Shares or of the offering that does not reflect the final terms, in each case in the form filed or required to be filed with the Commission or, if not required to be filed, in the form retained in the Company’s records pursuant to Rule 433(g), “Time of Sale Prospectus” means the Basic Prospectus and the preliminary prospectus together with the free writing prospectuses, if any, each identified in Schedule II hereto, and "broadly available road show” means a “bona fide electronic road show” as defined in Rule 433(h)(5) under the Securities Act that has been made available without restriction to any person. As used herein, the terms “Registration Statement,” “Basic Prospectus,” “preliminary prospectus,” “Time of Sale Prospectus” and “Prospectus” shall include the documents, if any, incorporated by reference therein. The terms “supplement,” “amendment,” and “amend” as used herein with respect to the Registration Statement, the Basic Prospectus, the Time of Sale Prospectus, any preliminary prospectus or free writing prospectus shall include all documents subsequently filed by the Company with the Commission pursuant to the Securities Exchange Act of 1934, as amended (the “Exchange Act”), that are deemed to be incorporated by reference therein.

     1. Representations and Warranties. The Company represents and warrants to and agrees with the Underwriter that:

     (a) The Registration Statement has become effective; no stop order suspending the effectiveness of the Registration Statement is in effect, and no proceedings for such purpose are pending before or, to the knowledge of the Company and its subsidiaries, threatened by the Commission.

     (b) (i) Each document, if any, filed or to be filed pursuant to the Exchange Act and incorporated by reference in the Time of Sale Prospectus or the Prospectus complied or will comply when so filed in all material respects with the Exchange Act and the applicable rules and regulations of the Commission thereunder; (ii) each part of the Registration Statement, when such part became effective, did not contain, and each such part, as amended or supplemented, if applicable, will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading, (iii) the Registration Statement as of the date hereof does not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading, (iv) the Registration Statement and the Prospectus comply, and as

amended or supplemented, if applicable, will comply in all material respects with the Securities Act and the applicable rules and regulations of the Commission thereunder, (v) the Time of Sale Prospectus does not, and at the time of each sale of the Shares in connection with the offering when the Prospectus is not yet available to prospective purchasers and at the Closing Date (as defined in Section 4), the Time of Sale Prospectus, as then amended or supplemented by the Company, if applicable, will not, contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading, (vi) each broadly available road show, if any, when considered together with the Time of Sale Prospectus, does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading and (vii) the Prospectus does not contain and, as amended or supplemented, if applicable, will not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading, except that the representations and warranties set forth in this paragraph do not apply to statements or omissions in the Registration Statement, the Time of Sale Prospectus or the Prospectus based upon information relating to the Underwriter furnished to the Company in writing by the Underwriter expressly for use therein.

     (c) The Company is not an “ineligible issuer” in connection with the offering pursuant to Rules 164, 405 and 433 under the Securities Act. Any free writing prospectus that the Company is required to file pursuant to Rule 433(d) under the Securities Act has been, or will be, filed with the Commission in accordance with the requirements of the Securities Act and the applicable rules and regulations of the Commission thereunder. Each free writing prospectus that the Company has filed, or is required to file, pursuant to Rule 433(d) under the Securities Act or that was prepared by or behalf of or used or referred to by the Company complies or will comply in all material respects with the requirements of the Securities Act and the applicable rules and regulations of the Commission thereunder. Except for the free writing prospectuses, if any, identified in Schedule II hereto forming part of the Time of Sale Prospectus, and electronic road shows, if any, each furnished to you before first use, the Company has not prepared, used or referred to, and will not, without your prior consent, prepare, use or refer to, any free writing prospectus.

     (d) The Company has been duly incorporated, is validly existing as a corporation in good standing under the laws of the jurisdiction of its incorporation, has the corporate power and authority to own its property and to conduct its business as described in the Time of Sale Prospectus and is duly qualified to transact business and is in good standing in each jurisdiction in which

the conduct of its business or its ownership or leasing of property requires such qualification, except to the extent that the failure to be so qualified or be in good standing would not have a material adverse effect on the Company and its subsidiaries, taken as a whole.

     (e) Each subsidiary of the Company has been duly incorporated, is validly existing as a corporation in good standing under the laws of the jurisdiction of its incorporation, has the corporate power and authority to own its property and to conduct its business as described in the Time of Sale Prospectus and is duly qualified to transact business and is in good standing in each jurisdiction in which the conduct of its business or its ownership or leasing of property requires such qualification, except to the extent that the failure to be so qualified or be in good standing would not have a material adverse effect on the Company and its subsidiaries, taken as a whole; all of the issued shares of capital stock of each subsidiary of the Company have been duly and validly authorized and issued, are fully paid and non-assessable and are owned directly by the Company, free and clear of all liens, encumbrances, equities or claims.

     (f) This Agreement has been duly authorized, executed and delivered by the Company.

     (g) The authorized capital stock of the Company conforms as to legal matters to the description thereof contained in each of the Time of Sale Prospectus and the Prospectus.

     (h) The shares of Common Stock outstanding prior to the issuance of the Shares have been duly authorized and are validly issued, fully paid and non-assessable.

     (i) The Shares have been duly authorized and, when issued and delivered in accordance with the terms of this Agreement, will be validly issued, fully paid and non-assessable, and the issuance of such Shares will not be subject to any preemptive or similar rights.

     (j) Except as disclosed in the questionnaires delivered by the Company to the Underwriter or its counsel, to the Company’s and its subsidiaries’ knowledge, none of the Company’s officers or directors are affiliated with any member firm of the Financial Industry Regulatory Authority, Inc. (the “FINRA”).

     (k) The execution and delivery by the Company of, and the performance by the Company of its obligations under, this Agreement will not (i) conflict with or result in a breach or violation of any of the terms or provisions of, or constitute a default under, or result in the creation or imposition of any lien,

charge or encumbrance upon any property or assets of the Company or any of its subsidiaries pursuant to, any indenture, mortgage, deed of trust, loan agreement or other agreement or instrument to which the Company or any of its subsidiaries is a party or by which the Company or any of its subsidiaries is bound or to which any of the property or assets of the Company or any of its subsidiaries is subject, (ii) result in any violation of the provisions of the certificate of incorporation or bylaws of the Company or (iii) result in the violation of any law or statute or any judgment, order, rule or regulation of any court or arbitrator or federal, state, local or foreign governmental or regulatory authority (each a, “Governmental Authority”), except, in the case of clause (i), for any such contravention, conflict, violation, breach, default or imposition of a lien, charge or encumbrance that would not, individually or in the aggregate, reasonably be expected to have a material adverse effect on the Company and its subsidiaries, taken as a whole; and no consent, approval, authorization or order of, or qualification with, any governmental body or agency is required for the execution and delivery of this Agreement by the Company and the performance by the Company of its obligations under this Agreement, except such as may be required under applicable state securities laws or the bylaws, rules and regulations of the FINRA in connection with the purchase and distribution of the Shares by the Underwriter.

     (l) There has not occurred any material adverse change, or any development involving a prospective material adverse change, in the condition, financial or otherwise, or in the earnings, business or operations of the Company and its subsidiaries, taken as a whole, from that set forth in the Time of Sale Prospectus.

     (m) There are no legal or governmental proceedings pending or, to the knowledge of the Company and its subsidiaries, threatened to which the Company or any of its subsidiaries is a party or to which any of the properties of the Company or any of its subsidiaries is subject (i) other than proceedings accurately described in the Time of Sale Prospectus or proceedings that would not have a material adverse effect on the Company and its subsidiaries, taken as a whole, or on the power or ability of the Company to perform its obligations under this Agreement or to consummate the transactions contemplated by the Time of Sale Prospectus or (ii) that are required to be described in the Registration Statement or the Prospectus that are not so described in the Registration Statement, the Time of Sale Prospectus and the Prospectus; and there are no statutes, regulations, contracts or other documents that are required to be described in the Registration Statement or the Prospectus or to be filed as exhibits to the Registration Statement that are not described in the Registration Statement, the Time of Sale Prospectus and the Prospectus or filed as required.

     (n) No order preventing or suspending the use of any preliminary prospectus has been issued to the Company, and each preliminary prospectus filed as part of the Registration Statement as originally filed or as part of any amendment thereto, or filed pursuant to Rule 424 under the Securities Act, complied when so filed in all material respects with the Securities Act and the applicable rules and regulations of the Commission thereunder.

     (o) The Company is not, and after giving effect to the offering and sale of the Shares and the application of the proceeds thereof as described in the Prospectus will not be, required to register as an “investment company” as such term is defined in the Investment Company Act of 1940, as amended.

     (p) Except as described in the Registration Statement, the Time of Sale Prospectus and the Prospectus, the Company and its subsidiaries: (A) are and at all times have been in material compliance with all statutes, rules, regulations, or guidances applicable to the ownership, testing, development, manufacture, packaging, processing, use, distribution, marketing, labeling, promotion, sale, offer for sale, storage, import, export or disposal of any product manufactured or distributed by the Company or such subsidiary (“Applicable Laws”); (B) have not received any FDA Form 483, notice of adverse finding, warning letter, untitled letter or other correspondence or notice from the U.S. Food and Drug Administration or any other Governmental Authority alleging or asserting noncompliance with any Applicable Laws or any licenses, certificates, approvals, authorizations, permits and supplements or amendments thereto required by any such Applicable Laws necessary for the conduct of the Company’s business as described in the Time of Sale Prospectus (“Authorizations”); (C) possess all Authorizations and such Authorizations are valid and in full force and effect and are not in violation of any term of any such Authorizations; (D) have not received notice of any claim, action, suit, proceeding, hearing, enforcement, investigation, arbitration or other action from any Governmental Authority or third party alleging that any product operation or activity is in violation of any Applicable Laws or Authorizations and have no knowledge that any such Governmental Authority or third party is considering any such claim, litigation, arbitration, action, suit, investigation or proceeding; (E) have not received notice that any Governmental Authority has taken, is taking or intends to take action to limit, suspend, modify or revoke any Authorizations and have no knowledge that any such Governmental Authority is considering such action; (F) have filed, obtained, maintained or submitted all reports, documents, forms, notices, applications, records, claims, submissions and supplements or amendments as required by any Applicable Laws or Authorizations and that all such reports, documents, forms, notices, applications, records, claims, submissions and supplements or amendments were complete and correct, in all material respects, on the date filed (or were corrected or supplemented by a subsequent submission); and (G) have

not, either voluntarily or involuntarily, initiated, conducted, or issued or caused to be initiated, conducted or issued, any recall, market withdrawal or replacement, safety alert, post sale warning, “dear doctor” letter, or other notice or action relating to the alleged lack of safety or efficacy of any product or any alleged product defect or violation and, to the Company’s and its subsidiaries’ knowledge, no third party has initiated, conducted or intends to initiate any such notice or action.

     (q) The studies, tests and preclinical and clinical trials conducted by or on behalf of the Company or any of its subsidiaries were and, if still pending, are being conducted in material accordance with experimental protocols, procedures and controls pursuant to accepted professional scientific standards and all Applicable Laws and Authorizations, including, without limitation, the Federal Food, Drug and Cosmetic Act and the rules and regulations promulgated thereunder (collectively, “FFDCA”); the descriptions of the results of such studies, tests and trials contained in the Registration Statement, the Time of Sale Prospectus and the Prospectus are accurate and complete in all material respects and fairly present the data derived from such studies, tests and trials; except to the extent disclosed in the Registration Statement, the Time of Sale Prospectus and the Prospectus, the Company is not aware of any studies, tests or trials, the results of which the Company believes reasonably call into question the study, test, or trial results described or referred to in the Registration Statement, the Time of Sale Prospectus and the Prospectus when viewed in the context in which such results are described and the clinical state of development; and neither the Company nor any of its subsidiaries have received any notices or correspondence from any Governmental Authority requiring the termination, suspension or material modification of any studies, tests or preclinical or clinical trials conducted by or on behalf of the Company or any of its subsidiaries.

     (r) The Company and its subsidiaries (A) are in compliance with any and all applicable foreign, federal, state and local laws, rules, regulations, treaties, statutes and codes promulgated by any and all Governmental Authorities (including pursuant to the Occupational Health and Safety Act) relating to the protection of human health and safety in the workplace (“Occupational Laws”); (B) have received all material permits, licenses or other approvals required of it under applicable Occupational Laws to conduct its business as currently conducted; and (C) are in compliance with all material terms and conditions of such permits, licenses or approvals. No action, proceeding, revocation proceeding, writ, injunction or claim is pending or, to the Company’s and its subsidiaries’ knowledge, threatened against the Company or any of its subsidiaries relating to Occupational Laws, and neither the Company nor its subsidiaries have knowledge of any facts, circumstances or developments relating to its or its subsidiaries’ operations or cost accounting practices that could

reasonably be expected to form the basis for or give rise to such actions, suits, investigations or proceedings.

     (s) Each employee benefit plan, within the meaning of Section 3(3) of the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), that is maintained, administered or contributed to by the Company or any of its affiliates for employees or former employees of the Company and its subsidiaries has been maintained in compliance with its terms and the requirements of any applicable statutes, orders, rules and regulations, including ERISA and the Internal Revenue Code of 1986, as amended (the "Code”). No prohibited transaction, within the meaning of Section 406 of ERISA or Section 4975 of the Code, has occurred with respect to any such plan excluding transactions effected pursuant to a statutory or administrative exemption; and for each such plan that is subject to the funding rules of Section 412 of the Code or Section 302 of ERISA, no “accumulated funding deficiency” as defined in Section 412 of the Code has been incurred, whether or not waived, and the fair market value of the assets of each such plan (excluding for these purposes accrued but unpaid contributions) exceeds the present value of all benefits accrued under such plan determined using reasonable actuarial assumptions.

     (t) Nothing has come to the attention of the Company that has caused the Company to believe that the statistical and market-related data included in the Registration Statement, the Time of Sale Prospectus and the Prospectus is not based on or derived from sources that are reliable and accurate in all material respects.

     (u) The Company and its subsidiaries (i) are in compliance with any and all applicable foreign, federal, state and local laws and regulations relating to the protection of human health and safety, the environment or hazardous or toxic substances or wastes, pollutants or contaminants (“Environmental Laws”), (ii) have received all permits, licenses or other approvals required of them under applicable Environmental Laws to conduct their respective businesses and (iii) are in compliance with all terms and conditions of any such permit, license or approval, except where such noncompliance with Environmental Laws, failure to receive required permits, licenses or other approvals or failure to comply with the terms and conditions of such permits, licenses or approvals would not, singly or in the aggregate, have a material adverse effect on the Company and its subsidiaries, taken as a whole.

     (v) There are no costs or liabilities associated with Environmental Laws (including, without limitation, any capital or operating expenditures required for clean-up, closure of properties or compliance with Environmental Laws or any permit, license or approval, any related constraints on operating

activities and any potential liabilities to third parties) which would, singly or in the aggregate, have a material adverse effect on the Company and its subsidiaries, taken as a whole.

     (w) Except as described in the Time of Sale Prospectus, there are no contracts, agreements or understandings between the Company and any person granting such person the right to require the Company to file a registration statement under the Securities Act with respect to any securities of the Company or to require the Company to include such securities with the Shares registered pursuant to the Registration Statement.

     (x) Subsequent to the respective dates as of which information is given in each of the Registration Statement, the Time of Sale Prospectus and the Prospectus, except as described in the Registration Statement, the Time of Sale Prospectus or the Prospectus collectively, (i) neither the Company nor any of its subsidiaries has incurred any material liability or obligation, direct or contingent, nor entered into any material transaction; (ii) neither the Company nor any of its subsidiaries has purchased any of its outstanding capital stock (other than from its employees or service providers in connection with the termination of their service to the Company or such subsidiary), nor declared, paid or otherwise made any dividend or distribution of any kind on its capital stock other than ordinary and customary dividends; and (iii) there has not been any material change in the capital stock, short-term debt or long-term debt of the Company or any of its subsidiaries.

     (y) Neither the Company nor any of its subsidiaries owns any real property. The Company and each of its subsidiaries has good and marketable title to all personal property owned by it which is material to the business of the Company and its subsidiaries, taken as a whole, free and clear of all liens, encumbrances and defects of title except such as are described in the Time of Sale Prospectus or such as do not materially affect the value of such property and do not interfere with the use made and proposed to be made of such property by the Company or such subsidiary and any real property and buildings held under lease by the Company or such subsidiary are held by it under valid, subsisting and enforceable leases with such exceptions as are not material and do not interfere with the use made and proposed to be made of such property and buildings by the Company or such subsidiary, in each case except as described in the Time of Sale Prospectus.

     (z) Except as disclosed in the Time of Sale Prospectus, the Company and each of its subsidiaries owns, possesses rights to use, or can acquire on reasonable terms rights to use all Intellectual Property (as defined below) necessary for the conduct of the business of the Company or such subsidiary as

described in the Registration Statement, the Time of Sale Prospectus and the Prospectus as now conducted or now proposed to be conducted, and except as would not, individually or in the aggregate, reasonably be expected to have a material adverse effect on the Company and its subsidiaries, taken as a whole, or except as described in the Time of Sale Prospectus, (i) to the knowledge of the Company or its subsidiaries, there is no infringement, misappropriation or violation by third parties of any such Intellectual Property; (ii) there is no pending or, to the knowledge of the Company or its subsidiaries, threatened action, suit, proceeding or claim by others challenging the rights of the Company or any of its subsidiaries in or to any such Intellectual Property, and the Company is unaware of any facts which would form a reasonable basis for any such claim; (iii) the Intellectual Property owned by the Company and each of its subsidiaries and, to the knowledge of the Company or its subsidiaries, the Intellectual Property licensed to the Company and its subsidiaries have not been adjudged invalid or unenforceable, in whole or in part, and there is no pending or threatened action, suit, proceeding or claim by others challenging the validity or scope of any such Intellectual Property, and the Company is unaware of any facts which would be reasonably likely to form a basis for any such claim; (iv) there is no pending or, to the knowledge of the Company or its subsidiaries, threatened action, suit, proceeding or claim by others that the Company or any of its subsidiaries infringes, misappropriates or otherwise violates any Intellectual Property or other proprietary rights of others, the Company has not received any written notice of such claim that has not been resolved and the Company is unaware of any other facts which would form a reasonable basis for any other such claim; and (v) to the Company’s or its subsidiaries’ knowledge, no current employee of the Company or any of its subsidiaries is in or has ever been in violation of any term of any employment contract, patent disclosure agreement, invention assignment agreement, non-competition agreement, non-solicitation agreement, nondisclosure agreement or any restrictive covenant to or with a former employer where the basis of such violation relates to such employee’s employment with the Company or such subsidiary, or actions undertaken by the employee while employed with the Company or such subsidiary. The term “Intellectual Property” as used herein means all patents, patent applications, trade and service marks, trade and service mark registrations, trade names, copyrights, licenses, inventions, trade secrets, know-how and other intellectual property.

     (aa) No material labor dispute with the employees of the Company or any of its subsidiaries exists, except as described in the Time of Sale Prospectus, or, to the knowledge of the Company or its subsidiaries, is imminent; and neither the Company nor any of its subsidiaries have received any notice of any existing, threatened or imminent labor disturbance by the employees of any of their respective principal suppliers, manufacturers or contractors that could be

reasonably likely to have a material adverse effect on the Company and its subsidiaries, taken as a whole.

     (bb) The Company and its subsidiaries are insured by insurers of recognized financial responsibility against such losses and risks and in such amounts as are prudent and customary in the businesses in which they are engaged; neither the Company nor any of its subsidiaries has been refused any insurance coverage sought or applied for; and the Company has no reason to believe that it or its subsidiaries will not be able to renew their respective existing insurance coverage as and when such coverage expires or to obtain similar coverage from similar insurers as may be necessary to continue their respective businesses at a cost that would not have a material adverse effect on the Company and its subsidiaries, taken as a whole, except as described in the Time of Sale Prospectus.

     (cc) The Company and its subsidiaries possess all certificates, authorizations and permits issued by the appropriate federal, state or foreign regulatory authorities necessary to conduct their respective businesses, except where the failure to obtain such certificate, authorization or permit would not, singly or in the aggregate, have a material adverse effect on the Company and its subsidiaries, taken as a whole, and neither the Company nor any of its subsidiaries has received any notice of proceedings relating to the revocation or modification of any such certificate, authorization or permit which, singly or in the aggregate, if the subject of an unfavorable decision, ruling or finding, would have a material adverse effect on the Company and its subsidiaries, taken as a whole, except as described in the Time of Sale Prospectus.

     (dd) The Company maintains a system of internal accounting controls sufficient to provide reasonable assurance that (i) transactions are executed in accordance with management’s general or specific authorizations; (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles and to maintain asset accountability; (iii) access to assets is permitted only in accordance with management’s general or specific authorization; and (iv) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences. Except as described in the Time of Sale Prospectus, since the end of the Company’s most recent audited fiscal year, there has been (i) no material weakness in the Company’s internal control over financial reporting (whether or not remediated) and (ii) no change in the Company’s internal control over financial reporting that has materially affected, or is reasonably likely to materially affect, the Company’s internal control over financial reporting.

     (ee) Except as described in the Time of Sale Prospectus, the Company has not sold, issued or distributed any shares of Common Stock during the six-month period preceding the date hereof, including any sales pursuant to Rule 144A under, or Regulation D or S of, the Securities Act, other than shares issued pursuant to employee benefit plans, qualified stock option plans or other employee compensation plans or pursuant to outstanding options, rights or warrants.

     (ff) The Company maintains a system of “disclosure controls and procedures” (as defined in Rule 13a-15(e) of the Exchange Act) that is designed to ensure that information required to be disclosed by the Company in reports that it files or submits under the Exchange Act is recorded, processed, summarized and controls and procedures designed to ensure that such information is accumulated and communicated to the Company’s management as appropriate to allow timely decision regarding required disclosure. The Company has utilized such controls and procedures in preparing and evaluating the disclosures in the Registration Statement, the Time of Sale Prospectus and the Prospectus.

     (gg) Neither the Company, any of its subsidiaries, nor any director, officer, agent, employee, other person acting on behalf of the Company or any of its subsidiaries or, to the Company’s or its subsidiaries knowledge, other person associated with the Company or its subsidiaries has (i) used any corporate funds for any unlawful contribution, gift, entertainment or other unlawful expense relating to political activity; (ii) made any direct or indirect unlawful payment to any foreign or domestic government official or employee from corporate funds; (iii) violated or is in violation of any provision of the Foreign Corrupt Practices Act of 1977; or (iv) made any bribe, rebate, payoff, influence payment, kickback or other unlawful payment.

     (hh) None of the Company or any director, officer, agent, employee, controlled affiliate of the Company or, to the Company’s or its subsidiaries’ knowledge, non-controlled affiliate of the Company is currently subject to any U.S. sanctions administered by the Office of Foreign Assets Control of the U.S. Department of the Treasury (“OFAC”); and the Company will not directly or indirectly use the proceeds of the offering of the Shares hereunder, or lend, contribute or otherwise make available such proceeds to any subsidiary, joint venture partner or other person or entity, for the purpose of financing the activities of any person that the Company is aware is currently subject to any U.S. sanctions administered by OFAC.

     (ii) The Company is not a party to any contract, agreement or understanding with any person (other than this Agreement) that would give rise to a valid claim against the Company or the Underwriter for a brokerage

commission, finder’s fee or like payment in connection with the offering and sale of the Shares.

     (jj) The Company has not taken, directly or indirectly, any action designed to or that could reasonably be expected to cause or result in any stabilization or manipulation of the price of the Shares.

     (kk) The Company has complied with all provisions of Section 517.075, Florida Statutes (Chapter 92-198, Laws of Florida) relating to doing business with the Government of Cuba or with any person or affiliate located in Cuba.

     2. Agreements to Sell and Purchase. The Company hereby agrees to sell to the Underwriter, and the Underwriter, upon the basis of the representations and warranties herein contained, but subject to the conditions hereinafter stated, agrees to purchase from the Company the Shares at the price set forth in Schedule I hereto (the “Purchase Price”).

     3. Terms of Public Offering. The Company is advised by you that the Underwriter proposes to make a public offering of the Shares as soon after the Registration Statement and this Agreement have become effective as in your judgment is advisable. The Company is further advised by you that the Shares are to be offered to the public upon the terms set forth in the Prospectus.

     4. Payment and Delivery. Payment for the Shares shall be made to the Company in Federal or other funds immediately available in New York City against delivery of such Shares for the account of the Underwriter on the closing date and time set forth in Schedule I hereto, or at such other time on the same or such other date, not later than the fifth business day thereafter, as shall be designated in writing by you. The time and date of such payment are hereinafter referred to as the “Closing Date.”

     The Shares shall be registered in such names and in such denominations as you shall request in writing not later than one full business day prior to the Closing Date. The Shares shall be delivered to you on the Closing Date for the account of the Underwriter, with any transfer taxes payable in connection with the transfer of the Shares to the Underwriter duly paid, against payment of the Purchase Price therefor.

     5. Conditions to the Company’s and Underwriter’s Obligations. The obligations of the Underwriter are subject to the following further conditions:

     (a) Subsequent to the execution and delivery of this Agreement and prior to the Closing Date:

     (i) there shall not have occurred any downgrading, nor shall any notice have been given of any intended or potential downgrading or of any review for a possible change that does not indicate the direction of the possible change, in the rating accorded any of the securities of the Company or any of its subsidiaries by any “nationally recognized statistical rating organization,” as such term is defined for purposes of Rule 436(g)(2) under the Securities Act; and

     (ii) there shall not have occurred any change, or any development involving a prospective change, in the condition, financial or otherwise, or in the earnings, business or operations of the Company and its subsidiaries, taken as a whole, from that set forth in the Time of Sale Prospectus as of the date of this Agreement that, in your judgment, is material and adverse and that makes it, in your judgment, impracticable to market the Shares on the terms and in the manner contemplated in the Time of Sale Prospectus.

     (b) The Underwriter shall have received on the Closing Date a certificate, dated the Closing Date and signed by the chief financial officer or chief accounting officer of the Company and one additional senior executive officer of the Company, (i) to effect that such officers have carefully reviewed the Registration Statement, the Time of Sale Prospectus and the Prospectus and the representations in Section 1(b) hereof are true and correct as of the Closing Date, (ii) to the effect set forth in Section 5(a)(i) above and (iii) to the effect that the other representations and warranties of the Company contained in this Agreement are true and correct as of the Closing Date and that the Company has complied, in all material respects, with all of the agreements and satisfied all of the conditions on its part to be performed or satisfied hereunder on or before the Closing Date. The officer signing and delivering such certificate may rely upon the best of his or her knowledge as to proceedings threatened.

     (c) The Underwriter shall have received on the Closing Date the opinion and negative assurance letter of Gunderson Dettmer Stough Villeneuve Franklin & Hachigian, LLP, outside counsel for the Company, dated the Closing Date, in the form attached hereto as Exhibit A.

     (d) The Underwriter shall have received on the Closing Date, the opinion and negative assurance letter of Hogan & Hartson LLP, special regulatory counsel for the Company, dated the Closing Date, in the form attached hereto as Exhibits B-1 and B-2, respectively.

     (e) The Underwriter shall have received on the Closing Date, the opinion of VistaIP Law Group, special intellectual property counsel for the Company, dated such Closing Date, in the form attached hereto as Exhibit C.

     (f) The Underwriter shall have received on the Closing Date an opinion of Latham & Watkins LLP, counsel for the Underwriter, dated the Closing Date, with respect to such matters as the Underwriter may reasonably request.

     The opinions described in Section 5(c), 5(d) and 5(e) above shall be rendered to the Underwriter at the request of the Company and shall so state therein.

     (g) The Underwriter shall have received, on each of the date hereof and the Closing Date, a letter dated the date hereof or the Closing Date, as the case may be, in form and substance satisfactory to the Underwriter, from PricewaterhouseCoopers LLP, independent registered public accounting firm, containing statements and information of the type ordinarily included in accountants’ “comfort letters” to underwriters with respect to the financial statements and certain financial information contained in the Registration Statement, the Time of Sale Prospectus and the Prospectus; provided that the letter delivered on the Closing Date shall use a “cut-off date” not earlier than the date hereof.

     (h) The “lock-up” agreements, each substantially in the form of Exhibit D hereto, between you and certain officers, directors and shareholders of the Company identified on Schedule III attached hereto, relating to sales and certain other dispositions of shares of Common Stock or certain other securities, delivered to you on or before the date hereof, shall be in full force and effect on the Closing Date.

     (i) No action shall have been taken and no statute, rule, regulation or order shall have been enacted, adopted or issued by any federal, state or foreign governmental or regulatory authority that would, as of the Closing Date, prevent the issuance or sale of the Shares; and no injunction order of any federal, state or foreign court shall have been issued that would, as of the Closing Date, prevent the issuance or sale of the Shares.

     (j) The Underwriter shall have received on and as of the Closing Date satisfactory evidence of the good standing of the Company and AorTx, Inc. in their respective jurisdictions of organization and their good standing as foreign entities in such other jurisdictions as the Underwriter may reasonably request, in each case in writing or any standard form of telecommunication from the appropriate Governmental Authorities of such jurisdictions.

     (k) The Shares to be delivered on the Closing Date shall have been approved for listing on the Nasdaq Global Market, subject to official notice of issuance.

     (l) No order suspending the effectiveness of the Registration Statement shall be in effect, and no proceeding for such purpose pursuant to Section 8A under the Securities Act shall be pending before or threatened by the Commission; the Prospectus and each issuer free writing prospectus shall have been timely filed with the Commission under the Securities Act (in the case of an issuer free writing prospectus, to the extent required by Rule 433 under the Securities Act) and in accordance with Section 6(d) hereof; and all requests by the Commission for additional information shall have been complied with to the reasonable satisfaction of the Underwriter.

     6. Covenants of the Company. The Company covenants with the Underwriter as follows:

     (a) To furnish to you, without charge, two (2) signed copies of the Registration Statement (including exhibits thereto and documents incorporated by reference) and to furnish to you in New York City, without charge, prior to 10:00 a.m. New York City time on the business day next succeeding the date of this Agreement and during the period mentioned in Section 6(f) and 6(g) below, as many copies of the Time of Sale Prospectus, the Prospectus, any documents incorporated by reference and any supplements and amendments thereto or to the Registration Statement as you may reasonably request.

     (b) The Company will file any issuer free writing prospectus or other free writing prospectus known to the Company to the extent required to be filed by the Company by Rule 433 under the Securities Act.

     (c) Before amending or supplementing the Registration Statement, the Time of Sale Prospectus or the Prospectus, to furnish to you a copy of each such proposed amendment or supplement and not to file any such proposed amendment or supplement to which you reasonably object, and to file with the Commission within the applicable period specified in Rule 424(b) under the Securities Act any prospectus required to be filed pursuant to such rule.

     (d) To furnish to you a copy of each proposed free writing prospectus or press release relating to the Shares to be prepared by or on behalf of, used by, or referred to by the Company and not to use or refer to any proposed free writing prospectus or press release relating to the Shares to which you reasonably object.

     (e) Not to take any action that would result in the Underwriter or the Company being required to file with the Commission pursuant to Rule 433(d) under the Securities Act a free writing prospectus prepared by or on behalf of the Underwriter that the Underwriter otherwise would not have been required to file thereunder.

     (f) If the Time of Sale Prospectus is being used to solicit offers to buy the Shares at a time when the Prospectus is not yet available to prospective purchasers and any event shall occur or condition exist as a result of which it is necessary to amend or supplement the Time of Sale Prospectus in order to make the statements therein, in the light of the circumstances in which they were made, not misleading, or if any event shall occur or condition exist as a result of which the Time of Sale Prospectus conflicts with the information contained in the Registration Statement then on file, or if, in the reasonable opinion of counsel for the Underwriter, it is necessary to amend or supplement the Time of Sale Prospectus to comply with applicable law, forthwith to prepare, file with the Commission and furnish, at its own expense, to the Underwriter and to any dealer upon request, either amendments or supplements to the Time of Sale Prospectus so that the statements in the Time of Sale Prospectus as so amended or supplemented will not, in the light of the circumstances when the Time of Sale Prospectus is delivered to a prospective purchaser, be misleading or so that the Time of Sale Prospectus, as amended or supplemented, will no longer conflict with the Registration Statement, or so that the Time of Sale Prospectus, as amended or supplemented, will comply with applicable law, as the case may be.

     (g) If, during such period after the first date of the public offering of the Shares as in the opinion of counsel for the Underwriter the Prospectus (or in lieu thereof the notice referred to in Rule 173(a) under the Securities Act) is required by law to be delivered in connection with sales by the Underwriter or a dealer, any event shall occur or condition exist as a result of which it is necessary to amend or supplement the Prospectus in order to make the statements therein, in the light of the circumstances when the Prospectus (or in lieu thereof the notice referred to in Rule 173(a) under the Securities Act) is delivered to a purchaser, not misleading, or if, in the opinion of counsel for the Underwriter, it is necessary to amend or supplement the Prospectus to comply with applicable law, forthwith to prepare, file with the Commission and furnish, at its own expense, to the Underwriter and to the dealers (whose names and addresses you will furnish to the Company) to which Shares may have been sold by you and to any other dealers upon request, either amendments or supplements to the Prospectus so that the statements in the Prospectus as so amended or supplemented will not, in the light of the circumstances when the Prospectus (or in lieu thereof the notice referred to in Rule 173(a) under the Securities Act) is delivered to a purchaser, be misleading or so that the Prospectus, as amended or supplemented, will comply with applicable law.

     (h) To endeavor to qualify the Shares for offer, sale and distribution under the securities or Blue Sky laws of such jurisdictions as you shall reasonably request; provided, however, that nothing contained herein shall require the Company to qualify to do business in any jurisdiction, to execute a general

consent to service of process in any state or to subject itself to taxation in any jurisdiction in which it is otherwise not so subject.

     (i) To make generally available to the Company’s security holders and to you as soon as practicable an earning statement covering a period of at least twelve months beginning with the first fiscal quarter of the Company occurring after the date of this Agreement which shall satisfy the provisions of Section 11(a) of the Securities Act and the rules and regulations of the Commission thereunder.

     (j) [intentionally omitted].

     (k) Whether or not the transactions contemplated in this Agreement are consummated or this Agreement is terminated, to pay or cause to be paid all expenses incident to the performance of its obligations under this Agreement, including: (i) the fees, disbursements and expenses of the Company’s counsel and the Company’s accountants in connection with the registration and delivery of the Shares under the Securities Act and all other fees or expenses in connection with the preparation and filing of the Registration Statement, any preliminary prospectus, the Time of Sale Prospectus, the Prospectus, any issuer free writing prospectus and amendments and supplements to any of the foregoing, including all printing costs associated therewith, and the mailing and delivering of copies thereof to the Underwriter and dealers, in the quantities hereinabove specified, (ii) all costs and expenses related to the transfer and delivery of the Shares to the Underwriter, including any transfer or other taxes payable thereon, (iii) the cost of printing or producing any Blue Sky or Legal Investment memorandum in connection with the offer and sale of the Shares under state securities laws and all expenses in connection with the qualification of the Shares for offer and sale under state securities laws as provided in Section 6(h) hereof, including filing fees and the reasonable fees and disbursements of counsel for the Underwriter in connection with such qualification and in connection with the Blue Sky or Legal Investment memorandum, (iv) all filing fees and the reasonable fees and disbursements of counsel to the Underwriter incurred in connection with the review and qualification of the offering of the Shares by the FINRA, (v) all costs and expenses incident to listing the Shares on the Nasdaq Global Market, (vi) the cost of printing certificates representing the Shares, (vii) the costs and charges of any transfer agent, registrar or depositary, (viii) the costs and expenses of the Company relating to investor presentations on any “road show” undertaken in connection with the marketing of the offering of the Shares, including, without limitation, expenses associated with the preparation or dissemination of any electronic road show, expenses associated with the production of road show slides and graphics, fees and expenses of any consultants engaged in connection with the road show presentations with the prior approval of the Company, travel and

lodging expenses of the representatives and officers of the Company and any such consultants, and, with the prior approval of the Company, fifty percent (50%) of the cost of any aircraft chartered in connection with the road show, (ix) the document production charges and expenses associated with printing this Agreement, and (x) all other costs and expenses incident to the performance of the obligations of the Company hereunder for which provision is not otherwise made in this Section. It is understood, however, that except as provided in this Section, Section 8 entitled “Indemnity and Contribution” and the last paragraph of Section 10 below, the Underwriter will pay (i) all of its costs and expenses, including fees and disbursements of its counsel, stock transfer taxes payable on resale of any of the Shares by it and any advertising expenses connected with any offers it may make and (ii) all travel and lodging expenses of the representatives and employees of the Underwriter incurred in connection with the road show, which expenses shall include the cost of any aircraft chartered in connection with the road show, except that with the prior approval of the Company to charter aircraft in connection with the road show, the Underwriter shall only be obligated to pay fifty percent (50%) of the cost of such aircraft.

     (l) The Company also covenants with the Underwriter that, without the prior written consent of the Underwriter, it will not, during the period beginning on the date of this Agreement and ending 60 days after the date of the Prospectus, (1) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock or (2) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of the Common Stock, whether any such transaction described in clause (1) or (2) above is to be settled by delivery of Common Stock or such other securities, in cash or otherwise or (3) file any registration statement with the Commission relating to the offering of any shares of Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock (other than on Form S-8).

     The restrictions contained in the preceding paragraph shall not apply to (a) the Shares to be sold hereunder, (b) the issuance by the Company of shares of Common Stock upon the exercise of an option or warrant or the conversion of a security outstanding on the date hereof and described in the Registration Statement, (c) the grant of options or the issuance of shares of Common Stock by the Company pursuant to equity incentive plans described in the Time of Sale Prospectus, (d) the issuance by the Company of shares of Common Stock in connection with any strategic transaction that includes a commercial relationship involving the Company and other entities (including but not limited to joint

ventures, marketing or distribution arrangements, collaboration agreements or intellectual property license agreements), (e) the issuance by the Company of shares of Common Stock in connection with any equipment loan or leasing arrangement, real property leasing arrangement or debt financing from a bank or similar financial institution, (f) the issuance of shares of Common Stock by the Company pursuant to the Company’s acquisition of AorTx, Inc. and the filing of a registration statement relating to the resale of such shares, each as described in the Time of Sale Prospectus or (g) the establishment of a trading plan pursuant to Rule 10b5-1 under the Exchange Act for the transfer of shares of Common Stock, provided that such plan does not provide for the transfer of Common Stock during the 60 day restricted period; provided, however, that, in the case of issuances pursuant to clauses (d) and (e), the total aggregate number of shares issued pursuant such clauses shall not exceed three percent (3%) of the total shares of Common Stock outstanding immediately following the Closing Date and any recipients of such shares shall execute a lock-up agreement in substantially the form set forth in Exhibit D hereto. Notwithstanding the foregoing, if (1) during the last 17 days of the 60-day restricted period the Company issues an earnings release or material news or a material event relating to the Company occurs; or (2) prior to the expiration of the 60-day restricted period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the 60-day period, the restrictions imposed by this Section 6(1) shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event. The Company shall promptly notify the Underwriter of any earnings release, news or event that may give rise to an extension of the initial 60-day restricted period.

     (m) The Company will apply the net proceeds from the sale of the Shares as described in the Time of Sale Prospectus under the heading “Use of Proceeds”.

     (n) The Company will not take, directly or indirectly, any action designed to or that could reasonably be expected to cause or result in any stabilization or manipulation of the price of the Shares.

     (o) For a period of two years after the date of this Agreement, so long as the Shares are outstanding, the Company will furnish to the Underwriter, as soon as they are available, copies of all reports or other communications (financial or other) furnished to holders of the Shares.

     (p) The Company will, pursuant to reasonable procedures developed in good faith, retain copies of each issuer free writing prospectus, if any, that is not filed with the Commission in accordance with Rule 433 under the Securities Act.

     (q) The Company will file with the Commission such reports as may be required by Rule 463 under the Securities Act.

     7. Covenants of the Underwriter. The Underwriter covenants with the Company not to take any action that would result in the Company being required to file with the Commission under Rule 433(d) a free writing prospectus prepared by or on behalf of the Underwriter that otherwise would not be required to be filed by the Company thereunder, but for the action of the Underwriter. The Underwriter also covenants with the Company to comply with the FINRA regulations with respect to the maximum commission or discount to be received by the Underwriter for the sale of the Shares.

     8. Indemnity and Contribution. (a) The Company agrees to indemnify and hold harmless the Underwriter, its directors, its officers, each person, if any, who controls the Underwriter within the meaning of either Section 15 of the Securities Act or Section 20 of the Exchange Act, and each affiliate of the Underwriter within the meaning of Rule 405 under the Securities Act from and against any and all losses, claims, damages and liabilities (including, without limitation, any legal or other expenses reasonably incurred in connection with defending or investigating any such action or claim) caused by any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement or any amendment thereof, any preliminary prospectus, the Time of Sale Prospectus, any issuer free writing prospectus, any Company information that the Company has filed, or is required to file, pursuant to Rule 433(d) of the Securities Act, or the Prospectus or any amendment or supplement thereto, or caused by any omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, except insofar as such losses, claims, damages or liabilities are caused by any such untrue statement or omission or alleged untrue statement or omission based upon information relating to the Underwriter furnished to the Company in writing by the Underwriter through you expressly for use therein.

     (b) [Intentionally omitted].

     (c) The Underwriter agrees to indemnify and hold harmless the Company, its directors, its officers who sign the Registration Statement and each person, if any, who controls the Company within the meaning of either Section 15 of the Securities Act or Section 20 of the Exchange Act to the same extent as the foregoing indemnity from the Company to the Underwriter, but only with reference to information relating to the Underwriter furnished to the Company in writing by the Underwriter expressly for use in the Registration Statement, any

preliminary prospectus, the Time of Sale Prospectus, any issuer free writing prospectus or the Prospectus or any amendment or supplement thereto.

     (d) In case any proceeding (including any governmental investigation) shall be instituted involving any person in respect of which indemnity may be sought pursuant to Section 8(a) or 8(c), such person (the “indemnified party”) shall promptly notify the person against whom such indemnity may be sought (the “indemnifying party”) in writing and the indemnifying party, upon request of the indemnified party, shall retain counsel reasonably satisfactory to the indemnified party to represent the indemnified party and any others the indemnifying party may designate in such proceeding and shall pay the reasonably incurred fees and disbursements of such counsel related to such proceeding. In any such proceeding, any indemnified party shall have the right to retain its own counsel, but the reasonably incurred fees and expenses of such counsel shall be at the expense of such indemnified party unless (i) the indemnifying party and the indemnified party shall have mutually agreed to the retention of such counsel or (ii) the named parties to any such proceeding (including any impleaded parties) include both the indemnifying party and the indemnified party and representation of both parties by the same counsel would be inappropriate due to actual or potential differing interests between them. It is understood that the indemnifying party shall not, in respect of the legal expenses of any indemnified party in connection with any proceeding or related proceedings in the same jurisdiction, be liable for the reasonably incurred fees and expenses of more than one separate firm (in addition to any local counsel) for all such indemnified parties and that all such fees and expenses shall be reimbursed as they are incurred. Such firm shall be designated in writing by the Underwriter, in the case of parties indemnified pursuant to Section 8(a) and by the Company, in the case of parties indemnified pursuant to Section 8(c). The indemnifying party shall not be liable for any settlement of any proceeding effected without its written consent, but if settled with such consent or if there be a final judgment for the plaintiff, the indemnifying party agrees to indemnify the indemnified party from and against any loss or liability by reason of such settlement or judgment. Notwithstanding the foregoing sentence, if at any time an indemnified party shall have requested an indemnifying party to reimburse the indemnified party for fees and expenses of counsel as contemplated by the second and third sentences of this paragraph, the indemnifying party agrees that it shall be liable for any settlement of any proceeding effected without its written consent if (i) such settlement is entered into more than 30 days after receipt by such indemnifying party of the aforesaid request and (ii) such indemnifying party shall not have reimbursed the indemnified party in accordance with such request prior to the date of such settlement. No indemnifying party shall, without the prior written consent of the indemnified party, effect any settlement of any pending or threatened proceeding in respect of which any indemnified party is or could have been a party and

indemnity could have been sought hereunder by such indemnified party, unless such settlement includes an unconditional release of such indemnified party from all liability on claims that are the subject matter of such proceeding.

     (e) To the extent the indemnification provided for in Section 8(a) or 8(c) is unavailable to an indemnified party or insufficient in respect of any losses, claims, damages or liabilities referred to therein, then each indemnifying party under such paragraph, in lieu of indemnifying such indemnified party thereunder, shall contribute to the amount paid or payable by such indemnified party as a result of such losses, claims, damages or liabilities (i) in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and the Underwriter on the other hand from the offering of the Shares or (ii) if the allocation provided by clause 8(e)(i) above is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause 8(e)(i) above but also the relative fault of the Company on the one hand and of the Underwriter on the other hand in connection with the statements or omissions that resulted in such losses, claims, damages or liabilities, as well as any other relevant equitable considerations. The relative benefits received by the Company shall be deemed to be equal to the total net proceeds from the offering (before deducting expenses) received by the Company, and the relative benefits received by the Underwriter shall be deemed to be equal to the total purchase discounts and commissions. The relative fault of the Company on the one hand and the Underwriter on the other hand shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company or by the Underwriter and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.

     (f) The Company and the Underwriter agree that it would not be just or equitable if contribution pursuant to this Section 8 were determined by pro rata allocation or by any other method of allocation that does not take account of the equitable considerations referred to in Section 8(e). The amount paid or payable by an indemnified party as a result of the losses, claims, damages and liabilities referred to in Section 8(e) shall be deemed to include, subject to the limitations set forth above, any legal or other expenses reasonably incurred by such indemnified party in connection with investigating or defending any such action or claim. Notwithstanding the provisions of this Section 8, the Underwriter shall not be required to contribute any amount in excess of the amount by which the total price at which the Shares underwritten by it and distributed to the public were offered to the public exceeds the amount of any damages that the Underwriter has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. No person guilty of fraudulent

misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The remedies provided for in this Section 8 are not exclusive and shall not limit any rights or remedies that may otherwise be available to any indemnified party at law or in equity.

     (g) The indemnity and contribution provisions contained in this Section 8 and the representations, warranties and other statements of the Company contained in this Agreement shall remain operative and in full force and effect regardless of (i) any termination of this Agreement, (ii) any investigation made by or on behalf of the Underwriter, its officers or directors, any person controlling the Underwriter or any affiliate of the Underwriter or by or on behalf of the Company, its officers or directors or any person controlling the Company and (iii) acceptance of and payment for any of the Shares.

     9. Termination. The Underwriter may terminate this Agreement by notice given by you to the Company, if after the execution and delivery of this Agreement and prior to the Closing Date (i) trading generally shall have been suspended or materially limited on, or by, as the case may be, any of the New York Stock Exchange, the American Stock Exchange or the Nasdaq Global Market, (ii) trading of any securities of the Company shall have been suspended on any exchange or in any over-the-counter market, (iii) a material disruption in securities settlement, payment or clearance services in the United States shall have occurred, (iv) any moratorium on commercial banking activities shall have been declared by Federal or New York State authorities or (v) there shall have occurred any outbreak or escalation of hostilities, or any change in financial markets or any calamity or crisis that, in your judgment, is material and adverse and that, singly or together with any other event specified in this clause (v), makes it, in your judgment, impracticable or inadvisable to proceed with the offer, sale or delivery of the Shares on the terms and in the manner contemplated in the Time of Sale Prospectus or the Prospectus.

     10. Effectiveness. This Agreement shall become effective upon the execution and delivery hereof by the parties hereto.

     If this Agreement shall be terminated by the Underwriter because of any failure or refusal on the part of the Company to comply with the terms or to fulfill any of the conditions of this Agreement, or if for any reason the Company shall be unable to perform its obligations under this Agreement, the Company will reimburse the Underwriter, severally, for all out-of-pocket expenses (including the fees and disbursements of its counsel) reasonably incurred by the Underwriter in connection with this Agreement or the offering contemplated hereunder.

     11. Entire Agreement. (a) This Agreement, together with any contemporaneous written agreements and any prior written agreements (to the extent not superseded by this Agreement) that relate to the offering of the Shares, represents the entire agreement between the Company and the Underwriter with respect to the preparation of any preliminary prospectus, the Time of Sale Prospectus, the Prospectus, the conduct of the offering, and the purchase and sale of the Shares.

     (b) The Company acknowledges that in connection with the offering of the Shares: (i) the Underwriter has acted at arms length, is not an agent of, and owes no fiduciary duties to, the Company or any other person, (ii) the Underwriter owes the Company only those duties and obligations set forth in this Agreement and prior written agreements (to the extent not superseded by this Agreement), if any, and (iii) the Underwriter may have interests that differ from those of the Company. The Company waives to the full extent permitted by applicable law any claims it may have against the Underwriter arising from an alleged breach of fiduciary duty in connection with the offering of the Shares.

     12. Counterparts. This Agreement may be signed in two or more counterparts, each of which shall be an original, with the same effect as if the signatures thereto and hereto were upon the same instrument.

     13. Applicable Law. This Agreement shall be governed by and construed in accordance with the internal laws of the State of New York.

     14. Headings. The headings of the sections of this Agreement have been inserted for convenience of reference only and shall not be deemed a part of this Agreement.

     15. Notices. All communications hereunder shall be in writing and effective only upon receipt and if to the Underwriter shall be delivered, mailed or sent to you in care of in care of Morgan Stanley & Co. Incorporated, 1585 Broadway, New York, New York 10036, Attention: Equity Syndicate Desk, with a copy to the Legal Department; and if to the Company shall be delivered, mailed or sent to 380 North Bernardo Avenue, Mountain View, California 94043, Attention: Gary C. Restani, with a copy to its General Counsel.

     If the foregoing is in accordance with your understanding, please indicate your acceptance of this Agreement by signing in the space provided below.

SCHEDULE I

Registration Statement File No.:		333-149561
Time of Sale Prospectus		Prospectus dated March 17, 2008 relating to the Shelf Shares Free Writing Prospectus, dated April 1, 2008 set forth in Exhibit E
Lock-up Restricted Period:		60 days
Title of Shares to be purchased:		Common Stock, par value $0.0001 per share
Number of Shares:		3,000,000
Purchase Price:		$13.34 per share
Closing Date and Time:		April 7, 2008 9:00 a.m.
Closing Location:		Latham & Watkins LLP
		650 Town Center Drive, 20th Floor
		Costa Mesa, CA 92626
Address for Notices to Underwriter:		Morgan Stanley & Co. Incorporated, 1585 Broadway, New York, New York 10036, Attention: Equity Syndicate Desk, with a copy to the Legal Department
Address for Notices to the Company:		380 North Bernardo Avenue, Mountain View, California 94043, Attention: Gary C. Restani, with a copy to its General Counsel

SCHEDULE II

Time of Sale Prospectus

1.		Prospectus dated March 17, 2008
2.		Free writing prospectus, dated April 1, 2008 and attached hereto as Exhibit E

SCHEDULE III

Lock Ups Received:

Christopher P. Lowe
David M. Shaw
De Novo Ventures II, L.P.
Frederic H. Moll, M.D.
Gary C. Restani
James M. Shapiro
John G. Fruend, M.D.
Joseph M. Mandato
Prospect Venture Partners II, L.P.
Prospect Associates II, L.P.
Robert G. Younge
Russell C. Hirsch, M.D., Ph.D.
Skyline Venture Partners Qualified Purchaser Fund III, L.P.
Skyline Expansion Fund L.P.
Skyline Venture Partners III, L.P.
Skyline Venture Management III, LLC
Steven M. Van Dick
Thomas C. McConnell
Thomas Weisel Healthcare Venture Partners, L.P.
Vanguard VII, L.P.
Vanguard VII-A, L.P.
Vanguard VII Accredited Affiliates Fund, L.P.
Vanguard VII Qualified Affiliates Fund, L.P.