SUBSCRIPTION AGREEMENT

Exhibit 10.1

SUBSCRIPTION AGREEMENT

Insmed Incorporated

8720 Stony Point Parkway

Suite 2000

Richmond, VA 23235

Ladies and Gentlemen:

The undersigned (the “Investor”) hereby confirms its agreement with you as follows:

1. This Subscription Agreement (this “Agreement”) is made as of the date set forth below between Insmed Incorporated, a Virginia corporation (the “Company”), and the Investor.

2. The Company has authorized the sale and issuance to certain investors of up to an aggregate of [                    ] units (the “Units”), each consisting of (i) one share (the “Share,” collectively the “Shares”) of its common stock, par value $0.01 per share (the “Common Stock”) and (ii) one warrant (the “Warrant,” collectively the “Warrants”) to purchase [                    ] shares of Common Stock (and the fractional amount being the “Warrant Ratio”), for a purchase price of $0.90 per Unit (the “Purchase Price”), reflecting a price of $[                    ] per Share and $[                    ] per Warrant. The Shares issuable upon the exercise of the Warrants are referred to herein as the “Warrant Shares.” The Warrant Shares, together with the Shares and the Warrants, are referred to herein as the “Securities.”

3. The offering and sale of the Units (the “Offering”) are being made pursuant to (1) an effective Registration Statement on Form S-3 (including the Prospectus contained therein (the “Base Prospectus”), the “Registration Statement”) filed by the Company with the Securities and Exchange Commission (the “Commission”), (2) if applicable, certain “free writing prospectuses” (as that term is defined in Rule 405 under the Securities Act of 1933, as amended), that have or will be filed with the Commission and delivered to the Investor on or prior to the date hereof and (3) a Prospectus Supplement (the “Prospectus Supplement” and together with the Base Prospectus, the “Prospectus”) containing certain supplemental information regarding the Securities and terms of the Offering that will be filed with the Commission and delivered to the Investor (or made available to the Investor by the filing by the Company of an electronic version thereof with the Commission) along with the Company’s counterpart to this Agreement.

4. The Company and the Investor agree that the Investor will purchase from the Company and the Company will issue and sell to the Investor the Units set forth below for the aggregate purchase price set forth below. The Units shall be purchased pursuant to the Terms and Conditions for Purchase of Units attached hereto as Annex I and incorporated herein by this reference as if fully set forth herein. The Investor acknowledges that the Offering is not being underwritten by the placement agent (the “Placement Agent”) named in the Prospectus Supplement and that there is no minimum offering amount.

5. The manner of settlement of the Shares included in the Units purchased by the Investor shall be determined by such Investor as follows (check one):

Signature Page to Subscription Agreement

Chase Manhattan Bank

ABA# 021 000 021

1 Chase Manhattan Plaza

NY NY 10005

FAO NFS (National Financial Services)

AC# 066-196-221

FC: C.E.U.T Private Banking Escrow Account #2

Acct# KRT-980102

– OR –

IT IS THE INVESTOR’S RESPONSIBILITY TO (A) MAKE THE NECESSARY WIRE TRANSFER OR CONFIRM THE PROPER ACCOUNT BALANCE IN A TIMELY MANNER AND (B) ARRANGE FOR SETTLEMENT BY WAY OF DWAC OR DVP IN A TIMELY MANNER. IF THE INVESTOR DOES NOT DELIVER THE AGGREGATE PURCHASE PRICE FOR THE UNITS OR DOES NOT MAKE PROPER ARRANGEMENTS FOR SETTLEMENT IN

Signature Page to Subscription Agreement

A TIMELY MANNER, THE SHARES AND WARRANTS MAY NOT BE DELIVERED AT CLOSING TO THE INVESTOR OR THE INVESTOR MAY BE EXCLUDED FROM THE CLOSING ALTOGETHER.

6. The executed Warrant shall be delivered in accordance with the terms thereof.

7. The Investor represents that, except as set forth below, (a) it has had no position, office or other material relationship within the past three years with the Company or persons known to it to be affiliates of the Company, (b) it is not a NASD member or an Associated Person (as such term is defined under the NASD Membership and Registration Rules Section 1011) as of the Closing, and (c) neither the Investor nor any group of Investors (as identified in a public filing made with the Commission) of which the Investor is a part in connection with the Offering of the Units, acquired, or obtained the right to acquire, 20% or more of the Common Stock (or securities convertible into or exercisable for Common Stock) or the voting power of the Company on a post-transaction basis. Exceptions:

(If no exceptions, write “none.” If left blank, response will be deemed to be “none.”)

8. The Investor represents that it has received (or otherwise had made available to it by the filing by the Company of an electronic version thereof with the Commission) the final Base Prospectus, dated February 3, 2006, which is a part of the Company’s Registration Statement, the documents incorporated by reference therein, and any free writing prospectus (collectively, the “Disclosure Package”), prior to or in connection with the receipt of this Agreement and the Prospectus Supplement (or the filing by the Company of an electronic version thereof with the Commission) along with the Company’s counterpart to this Agreement.

9. No offer by the Investor to buy Units will be accepted and no part of the Purchase Price will be delivered to the Company until the Company has accepted such offer by countersigning a copy of this Agreement, and any such offer may be withdrawn or revoked by the Investor, without obligation or commitment of any kind, at any time prior to the Company (or the Placement Agent on behalf of the Company) sending (orally, in writing, or by electronic mail) notice of its acceptance of such offer. An indication of interest will involve no obligation or commitment of any kind until this Agreement is accepted and countersigned by or on behalf of the Company.

Signature Page to Subscription Agreement

Purchased Shares:                                                 

Purchased Warrants:                                             

Aggregate Purchase Price: $                                

Please confirm that the foregoing correctly sets forth the agreement between us by signing in the space provided below for that purpose.

Dated as of: May     , 2007

Signature Page to Subscription Agreement

ANNEX I

TERMS AND CONDITIONS FOR PURCHASE OF UNITS

1. Authorization and Sale of the Units. Subject to the terms and conditions of this Agreement, the Company has authorized the sale of the Units, which consist of the Shares and the Warrants.

2. Agreement to Sell and Purchase the Units; Placement Agent.

2.1 At the Closing, the Company will sell to the Investor, and the Investor will purchase from the Company, upon the terms and conditions set forth herein, the number of Units set forth on the last page of the Subscription Agreement to which these Terms and Conditions for Purchase of Units are attached as Annex I (the “Signature Page”) for the aggregate purchase price therefor set forth on the Signature Page.

2.2 The Company proposes to enter into substantially this same form of Subscription Agreement with certain other investors (the “Other Investors”) and expects to complete sales of Units to them. The Investor and the Other Investors are hereinafter sometimes collectively referred to as the “Investors,” and this Agreement and the Subscription Agreements executed by the Other Investors are hereinafter sometimes collectively referred to as the “Agreements.”

2.3 Investor acknowledges that the Company has agreed to pay C.E. Unterberg, Towbin, LLC (the “Placement Agent”) a fee (the “Placement Fee”) in respect of the sale of Units to the Investor.

2.4 The Company has entered into a Placement Agent Agreement, dated May     , 2007 (the “Placement Agreement”), with the Placement Agent that contains certain representations, warranties, covenants and agreements of the Company that may be relied upon by the Investor, which shall be a third party beneficiary thereof.

3. Closings and Delivery of the Units and Funds.

3.1 Closing. The completion of the purchase and sale of the Units (the “Closing”) shall occur at a place and time (the “Closing Date”) to be specified by the Company and the Placement Agent, and of which the Investors will be notified in advance by the Placement Agent, in accordance with Rule 15c6-1 promulgated under the Securities Exchange Act of 1934, as amended (the “Exchange Act”). At the Closing, (a) the Company shall cause the Transfer Agent to deliver to the Investor the number of Shares (and Units) set forth on the Signature Page registered in the name of the Investor or, if so indicated on the Investor Questionnaire attached hereto as Exhibit A, in the name of a nominee designated by the Investor, (b) the Company shall cause to be delivered to the Investor a Warrant to purchase a number of whole Warrant Shares determined by multiplying the number of Shares (and Units) set forth on the signature page by the Warrant Ratio and rounding down to the nearest whole number and (c) the aggregate purchase price for the Units being purchased by the Investor will be delivered by or on behalf of the Investor to the Company.

3.2 Conditions to the Company’s Obligations. (a) The Company’s obligation to issue and sell the Units to the Investor shall be subject to: (i) the receipt by the Company of the purchase price for the Units being purchased hereunder as set forth on the Signature Page and (ii) the accuracy of the representations and warranties made by the Investor and the fulfillment of those undertakings of the Investor to be fulfilled prior to the Closing Date.

(b) Conditions to the Investor’s Obligations. The Investor’s obligation to purchase the Units will be subject to the accuracy of the representations and warranties made by the Company and the fulfillment of those undertakings of the Company to be fulfilled prior to the Closing Date, including without limitation, those contained in the Placement Agreement, and to the condition that the Placement Agent shall not have: (a) terminated the Placement Agreement pursuant to the terms thereof or (b) determined that the conditions to the closing in the Placement Agreement have not been satisfied. The Investor’s obligations are expressly not conditioned on the purchase by any or all of the Other Investors of the Units that they have agreed to purchase from the Company.

3.3 Delivery of Funds.

(a) Delivery by Electronic Book-Entry at The Depository Trust Company. If the Investor elects to settle the Shares purchased by such Investor through delivery by electronic book-entry at DTC, no later than one (1) business day after the execution of this Agreement by the Investor and the Company, the Investor shall remit by wire transfer the amount of funds equal to the aggregate purchase price for the Units being purchased by the Investor to the following account designated by the Placement Agent pursuant to the terms of that certain Placement Agreement:

Chase Manhattan Bank

ABA# 021 000 021

1 Chase Manhattan Plaza

NY NY 10005

FAO NFS (National Financial Services)

AC# 066-196-221

FC: C.E.U.T Private Banking Escrow Account #2

Acct# KRT-980102

Such funds shall be held in escrow until the Closing and delivered by the Placement Agent on behalf of the Investors to the Company upon the satisfaction, in the sole judgment of the Placement Agent, of the conditions set forth in Section 3.2(b) hereof. The Placement Agent shall have no rights in or to any of the escrowed funds except as set forth in the Placement Agreement. The Company and the Investor agree to indemnify and hold the Placement Agent harmless from and against any and all losses, costs, damages, expenses and claims (including, without limitation, court costs and reasonable attorneys fees) (“Losses”) arising under this Section 3.3 or otherwise with respect to the funds held in escrow pursuant hereto or arising under the Placement Agreement, unless it is finally determined that such Losses resulted directly from the willful misconduct or gross negligence of the Placement Agent. Anything in this Agreement to the contrary notwithstanding, in no event shall the Placement Agent be liable for any special, indirect or consequential loss or damage of any kind whatsoever (including but not limited to lost profits), even if the Placement Agent has been advised of the likelihood of such loss or damage and regardless of the form of action.

Investor shall also furnish to the Placement Agent a completed W-9 form (or, in the case of an Investor who is not a United States citizen or resident, a W-8 form).

(b) Delivery Versus Payment through The Depository Trust Company. If the Investor elects to settle the Shares purchased by such Investor by delivery versus payment through DTC, no later than one (1) business day after the execution of this Agreement by the Investor and the Company, the Investor shall confirm that the account or accounts at the Placement Agent to be credited with the Shares being purchased by the Investor have a minimum balance equal to the aggregate purchase price for the Units being purchased by the Investor.

3.4 Delivery of Shares.

(a) Delivery by Electronic Book-Entry at The Depository Trust Company. If the Investor elects to settle the Shares purchased by such Investor through delivery by electronic book-entry at DTC, no later than one (1) business day after the execution of this Agreement by the Investor and the Company, the Investor shall direct the broker-dealer at which the account or accounts to be credited with the Shares being purchased by such Investor are maintained, which broker/dealer shall be a DTC participant, to set up a Deposit/Withdrawal at Custodian (“DWAC”) instructing American Stock Transfer & Trust Company, the Company’s transfer agent, to credit such account or accounts with the Shares by means of an electronic book-entry delivery. Such DWAC shall indicate the settlement date for the deposit of the Shares, which date shall be provided to the Investor by the Placement Agent. Simultaneously with the delivery to the Company by the Placement Agent of the funds held in escrow pursuant to Section 3.3 above, the Company shall direct its transfer agent to credit the Investor’s account or accounts with the Shares pursuant to the information contained in the DWAC.

(b) Delivery Versus Payment through The Depository Trust Company. If the Investor elects to settle the Shares purchased by such Investor by delivery versus payment through DTC, no later than one (1) business day after the execution of this Agreement by the Investor and the Company, the Investor shall notify the Placement Agent of the account or accounts at the Placement Agent to be credited with the Shares being purchased by such Investor. On the Closing Date, the Company shall deliver the Shares to the Investor through DTC directly to the account or accounts at the Placement Agent identified by Investor and simultaneously therewith payment shall be made by the Placement Agent by wire transfer to the Company.

4. Representations, Warranties and Covenants of the Investor.

The Investor represents and warrants to, and agrees with, the Company and the Placement Agent that:

4.1 The Investor (a) is knowledgeable, sophisticated and experienced in making, and is qualified to make decisions with respect to, investments in shares presenting an investment decision like that involved in the purchase of the Units, including investments in securities issued by the Company and investments in comparable companies, (b) has answered all questions on the Signature Page and the Investor Questionnaire for use in preparation of the Prospectus Supplement and the answers thereto are true and correct as of the date hereof and will be true and correct as of the Closing Date and (c) in connection with its decision to purchase the number of Units set forth on the Signature Page, has received and is relying solely upon the Disclosure Package and the documents incorporated by reference therein.

4.2 The Investor acknowledges that (a) no action has been or will be taken in any jurisdiction outside the United States by the Company or the Placement Agent that would permit an offering of the Units, or possession or distribution of offering materials in connection with the issue of the Securities in any jurisdiction outside the United States where action for that purpose is required, (b) if the Investor is outside the United States, it will comply with all applicable laws and regulations in each foreign jurisdiction in which it purchases, offers, sells or delivers Securities or has in its possession or distributes any offering material, in all cases at its own expense and (c) the Placement Agent is not authorized to make and has not made any representation, disclosure or use of any information in connection with the issue, placement, purchase and sale of the Units, except as set forth or incorporated by reference in the Base Prospectus or the Prospectus Supplement.

4.3 The Investor acknowledges that (a) the Investor has full right, power, authority and capacity to enter into this Agreement and to consummate the transactions contemplated hereby and has taken all necessary action to authorize the execution, delivery and performance of this Agreement, and (b) this Agreement constitutes a valid and binding obligation of the Investor enforceable against the Investor in accordance with its terms, except as enforceability may be limited by applicable bankruptcy, insolvency, reorganization, moratorium or similar laws affecting creditors’ and contracting parties’ rights generally and except as enforceability may be subject to general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law) and except as to the enforceability of any rights to indemnification or contribution that may be violative of the public policy underlying any law, rule or regulation (including any federal or state securities law, rule or regulation).

4.4 The Investor understands that nothing in this Agreement, the Prospectus or any other materials presented to the Investor in connection with the purchase and sale of the Units constitutes legal, tax or investment advice. The Investor has consulted such legal, tax and investment advisors as it, in its sole discretion, has deemed necessary or appropriate in connection with its purchase of Units.

4.5 Since the date on which the Placement Agent first contacted such Investor about the Offering, it has not engaged in any transactions in the securities of the Company (including, without limitation, any Short Sales (as defined below) involving the Company’s securities). Each Investor covenants that it will not engage in any transactions in the securities of the Company (including Short Sales) prior to the time that the transactions contemplated by this Agreement are publicly disclosed. Each Investor agrees that it will not use any of the Units acquired pursuant to this Agreement to cover any short position in the Common Stock if doing so would be in violation of applicable securities laws. For purposes hereof, “Short Sales” include, without limitation, all “short sales” as defined in Rule 200 promulgated under Regulation SHO under the Exchange Act, whether or not against the box, and all types of direct and indirect stock pledges, forward sales contracts, options, puts, calls, short sales, swaps, “put equivalent positions” (as defined in Rule 16a-1(h) under the Exchange Act) and similar arrangements (including on a total return basis), and sales and other transactions through non-US broker dealers or foreign regulated brokers.

5. Representations, Warranties and Covenants of the Investor.

The Company represents and warrants to, and agrees with, the Investor and the Placement Agent that:

(a) The Company has full corporate power and authority to enter into this Agreement. This Agreement has been duly authorized, executed and delivered by the Company and constitutes a valid and binding agreement of the Company, enforceable against the Company in accordance with the terms hereof except to the extent enforceability may be limited by bankruptcy, insolvency, reorganization, moratorium or similar laws affecting creditors’ rights generally and by general principles of equity. The performance of this Agreement and the consummation of the transactions contemplated hereby will not result in the creation or imposition of any lien, charge or encumbrance upon any of the assets of the Company or any subsidiaries pursuant to the terms or provisions of, or result in a breach or violation of any of the terms or provisions of, or conflict with or constitute a default under, or give any party a right to terminate any of its obligations under, or result in the acceleration of any obligation under, the certificate or articles of incorporation or by-laws (or any analogous documents) of the Company or any subsidiary, any indenture, mortgage, deed of trust, voting trust agreement, loan agreement, bond, debenture, note agreement or other evidence of indebtedness, or any material lease, contract or other agreement or instrument to which the Company or any subsidiary is a party or by which the Company or any subsidiary, or any of their respective properties, is bound or affected, or violate or conflict with any judgment, ruling, decree, order, statute, rule or regulation of any court or other governmental agency or body applicable to the business or properties of the Company or any subsidiary.

(b) The Registration Statement was declared effective by the Commission on February 14, 2006. The Registration Statement is effective on the date hereof and the Company has not received notice that the Commission has issued or intends to issue a stop order with respect to the Registration Statement or that the Commission otherwise has suspended or withdrawn the effectiveness of the Registration Statement, either temporarily or permanently, or intends or has threatened in writing to do so. The “Plan of Distribution” section in the Prospectus describes the issuance and sale of the Shares and the Warrants. Each part of the Registration Statement, when it became effective, did not contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary in order to make the statements therein not misleading. As of the date the Base Prospectus, or any amendment or supplement to the Base Prospectus, was or is filed with the Commission and at the Closing Date, the Base Prospectus or any amendment or supplement thereto, did not and 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.

(c) The Company shall (i) before the opening of trading on the Nasdaq Global Market on the next trading day after the date hereof, issue a press release, disclosing all material aspects of the transactions contemplated hereby and (ii) make such other filings and notices in the manner and time required by the Commission with the respect to the transaction contemplated hereby. The Company shall not identify the Investor by name in any press release or public filing, or otherwise publicly disclose the Investor’s name, without the Investor’s prior, written consent, unless required by law or the rules and regulations of any self-regulatory organization which the Company or its securities are subject.

6. Survival of Representations, Warranties and Agreements; Third Party Beneficiary. Notwithstanding any investigation made by any party to this Agreement or by the Placement Agent, all covenants, agreements, representations and warranties made by the Company and the Investor herein will survive the execution of this Agreement, the delivery to the Investor of the Units being purchased and the payment therefor.

7. Notices. All notices, requests, consents and other communications hereunder will be in writing, will be mailed (a) if within the domestic United States by first-class registered or certified airmail, or nationally recognized overnight express courier, postage prepaid, or by facsimile or (b) if delivered from outside the United States, by International Federal Express or facsimile, and will be deemed given (i) if delivered by first-class registered or certified mail domestic, three (3) business days after so mailed, (ii) if delivered by nationally recognized overnight carrier, one (1) business day after so mailed, (iii) if delivered by International Federal Express, two business days after so mailed and (iv) if delivered by facsimile, upon electric confirmation of receipt and will be delivered and addressed as follows:

(a) if to the Company, to:

Insmed Incorporated

8720 Stony Point Parkway

Richmond, VA 23235

Attention: Kevin P. Tully, C.G.A.

Facsimile: 804 ###-###-####

with copies to:

Goodwin Procter, LLP

53 State Street

Boston, MA 02109

Attention: James R. Kasinger, Esq.

Facsimile: (617)  ###-###-####

(b) if to the Investor, at its address on the Signature Page hereto, or at such other address or addresses as may have been furnished to the Company in writing.

8. Changes. This Agreement may not be modified or amended except pursuant to an instrument in writing signed by the Company and the Investor.

9. Headings. The headings of the various sections of this Agreement have been inserted for convenience of reference only and will not be deemed to be part of this Agreement.

10. Severability. In case any provision contained in this Agreement should be invalid, illegal or unenforceable in any respect, the validity, legality and enforceability of the remaining provisions contained herein will not in any way be affected or impaired thereby.

11. Governing Law. This Agreement will be governed by, and construed in accordance with, the internal laws of the State of New York, without giving effect to the principles of conflicts of law that would require the application of the laws of any other jurisdiction.

12. Counterparts. This Agreement may be executed in two or more counterparts, each of which will constitute an original, but all of which, when taken together, will constitute but one instrument, and will become effective when one or more counterparts have been signed by each party hereto and delivered to the other parties. The Company and the Investor acknowledge and agree that the Company shall deliver its counterpart to the Investor along with the Prospectus Supplement (or the filing by the Company of an electronic version thereof with the Commission).

13. Confirmation of Sale. The Investor acknowledges and agrees that such Investor’s receipt of the Company’s counterpart to this Agreement, together with the Prospectus Supplement (or the filing by the Company of an electronic version thereof with the Commission), shall constitute written confirmation of the Company’s sale of Units to such Investor.

14. Press Release. The Company and the Investor agree that the Company shall issue a press release disclosing the material terms of the Offering prior to the opening of the financial markets in New York City on the business day immediately after the date hereof.

15. Termination. In the event that the Placement Agreement is terminated by the Placement Agent pursuant to the terms thereof, this Agreement shall terminate without any further action on the part of the parties hereto.

EXHIBIT A

INSMED INCORPORATED

INVESTOR QUESTIONNAIRE

Pursuant to Section 3 of Annex I to the Agreement, please provide us with the following information: