Form of Capped Call Transaction Confirmation

DATE:

TO:

Alnylam Pharmaceuticals, Inc.

675 West Kendall Street, Henri A. Termeer Square

Cambridge, Massachusetts 02142

FROM:

Include in the Base Call Option Confirmation.

Include in the Base Call Option Confirmation.

Include in the Additional Call Option Confirmation.

Include in the Base Call Option Confirmation.

Include in the Additional Call Option Confirmation.

Insert if Indenture is not completed at the time of the Confirmation.

All indenture cross-references and defined terms are subject to review of draft of Indenture.

Include in the Base Call Option Confirmation. Include in the Additional Call Option Confirmation if it is executed before closing of the base deal.

Include in the Additional Call Option Confirmation, but only if the Additional Call Option Confirmation is executed after closing of the base deal.

Include cross-reference to Indenture section permitting amendments without holder consent to conform the Indenture to the Description of Notes.

General Terms.

Trade Date:

Effective Date:

Option Style:

Option Type:

Buyer:

Seller:

Shares:

Number of Options:

Include cross-reference to Indenture section relating to Merger Events.

To be included for Dealers without a long-term debt rating (to be ultimate parent if applicable).

For the Base Call Option Confirmation, this is equal to the number of Convertible Notes in principal amount of $1,000 initially issued on the closing date for the Convertible Notes. For the Additional Call Option Confirmation, this is equal to the number of additional Convertible Notes in principal amount of $1,000.

Applicable Percentage:

Option Entitlement:

Strike Price:

Cap Price:

Premium:

Premium Payment Date:

Exchange:

Related Exchange(s):

Excluded Provisions:

Procedures for Exercise.

Conversion Date:

Free Convertibility Date:

Expiration Time:

Expiration Date:

Multiple Exercise:

Automatic Exercise:

To be the relevant percentage for each Dealer.

Insert the initial Conversion Rate for the Convertible Notes.

Include cross-reference to section(s) of the Indenture containing discretionary adjustments to the Conversion Rate by Counterparty.

Include cross-reference to Indenture section(s) dealing with make-whole adjustments to the Conversion Rate.

Include cross-reference to section(s) of the Indenture setting forth the requirements for conversion of the Convertible Notes.

Include cross-reference to section of the Indenture containing provisions for exchange in lieu of conversion.

Notice of Exercise:

Valuation Time:

Include for Additional Call Option Confirmation only.

Market Disruption Event:

Settlement Terms.

Settlement Method:

Relevant Settlement Method:

Include cross-reference to section of the Indenture containing provisions for full physical settlement of the Convertible Notes.

Include cross-reference to section of the Indenture containing provisions for combination settlement of the Convertible Notes.

Include cross-reference to section of the Indenture containing provisions for combination settlement of the Convertible Notes.

Include cross-reference to section of the Indenture containing provisions for combination settlement of the Convertible Notes.

Net Share Settlement:

Combination Settlement:

Include cross-reference to section of the Indenture containing provisions for cash settlement of the Convertible Notes.

Cash Settlement:

Daily Option Value:

Applicable Limit:

Applicable Limit Price:

Valid Day:

Scheduled Valid Day:

Business Day:

Relevant Price:

Settlement Averaging Period:

Settlement Date:

Settlement Currency:

Other Applicable Provisions:

Representation and Agreement:

3.  Additional Terms applicable to the Transaction.

Adjustments applicable to the Transaction:

Potential Adjustment Events:

To be the number of Valid Days that is equal to the number of trading days in the observation period for the Convertible Notes.

Method of Adjustment:

(i) if the Calculation Agent, acting in good faith and a commercially reasonable manner, disagrees with any adjustment to the Convertible Notes that involves an exercise of discretion by Counterparty or its board of directors (including, without limitation, pursuant to Section [___]²⁹ of the Indenture, Section [__]³⁰ of the Indenture or any supplemental indenture entered into thereunder or in connection with any proportional adjustment or the determination of the fair value of any securities, property, rights or other assets), then in each such case, the Calculation Agent will determine the adjustment to be made to any one or more of the Strike Price, Number of Options, Option Entitlement and any other variable relevant to the exercise, settlement or payment for the Transaction in a commercially reasonable manner; provided that, notwithstanding the foregoing, if any Potential Adjustment Event

Include cross reference to provision in the Indenture providing for pass-through of Distributed Property, at the same time as it is received by holders of the Shares, in lieu of a Conversion Rate adjustment.

Include cross reference to provision in the Indenture providing for pass-through of cash, at the same time as it is received by holders of the Shares, in lieu of a Conversion Rate adjustment.

Include cross-reference to specific paragraph of the section of the Indenture providing for adjustments where a Conversion Rate adjustment occurs during a period over which VWAP, conversion value, settlement amount or closing price is calculated.

Include cross-reference to Indenture section relating to Merger Events.

occurs during the Settlement Averaging Period but no adjustment was made to any Convertible Note under the Indenture because the relevant Holder (as such term is defined in the Indenture) was deemed to be a record owner of the underlying Shares on the related Conversion Date, then the Calculation Agent shall make an adjustment, as determined by it, to the terms hereof in order to account for such Potential Adjustment Event in a commercially reasonable manner;

(ii)  in connection with any Potential Adjustment Event as a result of an event or condition set forth in Section [__(_)]³¹ of the Indenture or Section [__(_)]³² of the Indenture where, in either case, the period for determining “Y” (as such term is used in Section [__(_)] of the Indenture) or “SP0” (as such term is used in Section [__(_)] of the Indenture), as the case may be, begins before Counterparty has publicly announced the event or condition giving rise to such Potential Adjustment Event, then the Calculation Agent shall have the right to adjust any variable relevant to the exercise, settlement or payment for the Transaction as appropriate to reflect the costs (including, but not limited to, hedging mismatches and market losses) and expenses incurred by Dealer in connection with its hedging activities as a result of such event or condition not having been publicly announced prior to the beginning of such period; and

(iii)  if any Potential Adjustment Event is declared and (a) the event or condition giving rise to such Potential Adjustment Event is subsequently amended, modified, cancelled or abandoned, (b) the “Conversion Rate” (as defined in the Indenture) is otherwise not adjusted at the time or in the manner contemplated by the relevant Dilution Adjustment Provision based on such declaration or (c) the “Conversion Rate” (as defined in the Indenture) is adjusted as a result of such Potential Adjustment Event and subsequently re-adjusted (each of clauses (a), (b) and (c), a “Potential Adjustment Event Change”) then, in each case, the Calculation Agent shall have the right to adjust any variable relevant to the exercise, settlement or payment for the Transaction as appropriate to reflect the costs (including, but not limited to, hedging mismatches and market losses) and expenses incurred by Dealer in connection with its hedging activities as a result of such Potential Adjustment Event Change.

Include cross-reference to section of the Indenture providing for an adjustment to the Conversion Rate in connection with a below-market rights, options or warrants offering.

Include cross-reference to section of the Indenture providing for an adjustment to the Conversion Rate in connection with distributions of Distributed Property.

Dilution Adjustment Provisions:

Extraordinary Events applicable to the Transaction:

Merger Events:

Tender Offers:

Consequences of Merger Events/

Tender Offers:

Consequences of Announcement Events:

Include cross-reference to specific paragraphs of the section of the Indenture containing anti-dilution adjustments to the Conversion Rate.

Include cross-reference to specific paragraph of the section of the Indenture providing for adjustments where a Conversion Rate adjustment occurs during a period over which VWAP, conversion value, settlement amount or closing price is calculated.

Include cross-reference to the section of the Indenture describing consequences of Merger Events.

Include cross-reference to the section of the Indenture describing consequences of tender offers.

Announcement Event:

Valid Third Party Entity:

Composition of Combined Consideration:

Nationalization, Insolvency or Delisting:

Additional Disruption Events:

Change in Law:

Failure to Deliver:

Hedging Disruption:

Increased Cost of Hedging:

Hedging Party:

Determining Party:

Hedge Positions:

Acknowledgments:

Non-Reliance:

Agreements and Acknowledgments

Regarding Hedging Activities:

Additional Acknowledgments:

4.  Calculation Agent.

Account Details.

Account for payments to Dealer:

Offices.

The Office of Counterparty for the Transaction is: Inapplicable, Counterparty is not a Multibranch Party.

The Office of Dealer for the Transaction is: [____]

Notices.

Address for notices or communications to Counterparty:

Address for notices or communications to Dealer:

Representations and Warranties of Counterparty.

(i) Counterparty has all necessary corporate power and authority to execute, deliver and perform its obligations in respect of the Transaction; (ii) such execution, delivery and performance have been duly authorized by all necessary corporate action on Counterparty’s part; this Confirmation has been duly and validly executed and delivered by Counterparty; and (iii) constitutes its valid and binding obligation, enforceable against Counterparty in accordance with its terms, subject to applicable bankruptcy, insolvency, fraudulent conveyance, reorganization, moratorium and similar laws affecting creditors’ rights and remedies generally, and subject, as to enforceability, to general principles of equity, including principles of commercial reasonableness, good faith and fair dealing (regardless of whether enforcement is sought in a proceeding at law or in equity) and except that rights to indemnification and contribution hereunder may be limited by federal or state securities laws or public policy relating thereto.

In lieu of the representation set forth in Section 3(a)(iii) of the Agreement, neither the execution and delivery of this Confirmation nor the incurrence or performance of obligations of Counterparty hereunder will conflict with or result in a breach of the certificate of incorporation or by-laws (or any equivalent documents) of Counterparty, or any applicable law or regulation, or any order, writ, injunction or decree of any court or governmental authority or agency, or any agreement or instrument filed as an exhibit to Counterparty’s Annual Report on Form 10-K for the year ended December 31, 2021, as updated by any subsequent filings, or constitute a default under, or result in the creation of any lien under, any such agreement or instrument.

No consent, approval, authorization, or order of, or filing with, any governmental agency or body or any court is required in connection with the execution, delivery or performance by Counterparty of this Confirmation, except such as have been obtained or made and such as may be required under the Securities Act of 1933, as amended (the “Securities Act”), or state securities laws.

Counterparty is not and, after consummation of the transactions contemplated hereby, will not be required to register as an “investment company” as such term is defined in the Investment Company Act of 1940, as amended.

Counterparty is an “eligible contract participant” (as such term is defined in Section 1a(18) of the Commodity Exchange Act, as amended (the “CEA”), other than a person that is an eligible contract participant under Section 1a(18)(C) of the CEA).

Counterparty is not, on the date hereof, in possession of any material non-public information with respect to Counterparty or the Shares.

Counterparty is not aware of any state or local (including any non-U.S. jurisdiction’s) law, rule, regulation or regulatory order applicable to the Shares that would give rise to any reporting, consent, registration or other requirement (including without limitation a requirement to obtain prior approval from any person or entity) as a result of Dealer or its affiliates owning or holding (however defined) Shares.

Counterparty (A) is capable of evaluating investment risks independently, both in general and with regard to all transactions and investment strategies involving a security or securities; (B) will exercise independent judgment in evaluating the recommendations of any broker-dealer or its associated persons, unless it has otherwise notified the broker-dealer in writing; and (C) has total assets of at least USD 50 million.

The assets used in the Transaction (1) are not assets of any “plan” (as such term is defined in Section 4975 of the U.S. Internal Revenue Code (the “Code”)) subject to Section 4975 of the Code or any “employee benefit plan” (as such term is defined in Section 3(3) of the U.S. Employee Retirement Income Security Act of 1974, as amended (“ERISA”)) subject to Title I of ERISA, and (2) do not constitute “plan assets” within the meaning of Department of Labor Regulation 2510.3-101, 29 CFR Section 2510-3-101.

On and immediately after each of the Trade Date and the Premium Payment Date, (A) the Counterparty will not be insolvent or rendered insolvent, left with unreasonably small capital or intend to incur debts beyond its ability to pay its debts as they mature, as these concepts are used in Section 548(a)(1)(B) of the U.S. Bankruptcy Code (Title 11 of the United States Code) (the “Bankruptcy Code”)) and (B) the Counterparty would be able to purchase the Number of Shares in compliance with Section 160 of the General Corporation Law of the State of Delaware.

Without limiting the generality of Section 13.1 of the Equity Definitions, Counterparty acknowledges that neither Dealer nor any of its affiliates is making any representations or warranties or taking any position or expressing any view with respect to the treatment of the Transaction under any accounting standards including ASC Topic 260, Earnings Per Share, ASC Topic 815, Derivatives and Hedging, or ASC Topic 480, Distinguishing Liabilities from Equity and ASC 815-40, Derivatives and Hedging—Contracts in Entity’s Own Equity (or any successor issue statements) or any other accounting guidance.

Counterparty acknowledges that the Transaction may constitute a purchase of its equity securities. Counterparty further acknowledges that, pursuant to the provisions of the Coronavirus Aid, Relief and Economic Security Act (the “Cares Act”), the Counterparty will be required to agree to certain time-bound restrictions on its ability to purchase its equity securities if it receives loans, loan guarantees or direct loans (as that term is defined in the Cares Act) under section 4003(b) of the Cares Act. Counterparty further acknowledges that it may be required to agree to certain time-bound restrictions on its ability to purchase its equity securities if it receives loans, loan guarantees or direct loans (as that term is defined in the Cares Act) under programs or facilities established by the Board of Governors of the Federal Reserve System for the purpose of providing liquidity to the financial system. Accordingly, Counterparty represents and warrants that it has not applied, and throughout the Term of this Transaction shall not apply, for a loan, loan guarantee, direct loan (as that term is defined in the Cares Act) or other investment, or to receive any financial assistance or relief (howsoever defined) under any program or facility that (a) is established under applicable law, including the Cares Act and the Federal Reserve Act, as amended, and (b) requires, as a condition of such loan, loan guarantee, direct loan (as that term is defined in the Cares Act), investment, financial assistance or relief, that the Counterparty agree, attest, certify or warrant that it has not, as of the date specified in such condition, repurchased, or will not repurchase, any equity security of Counterparty.

Other Provisions.

Opinions. Counterparty shall deliver to Dealer an opinion of counsel, dated as of the Premium Payment Date and reasonably acceptable to Dealer in form and substance, with respect to the matters set forth in Sections 8(a)(i) and (ii), (b) and (c) of this Confirmation, subject to customary assumptions, qualifications and exceptions. Delivery of such opinion to Dealer shall be a condition precedent for the purpose of Section 2(a)(iii) of the Agreement with respect to each obligation of Dealer under Section 2(a)(i) of the Agreement.

Repurchase Notices. Counterparty shall, on any day on which Counterparty effects any repurchase of Shares, promptly give Dealer a written notice of such repurchase (a “Repurchase Notice”) on such day if following such repurchase, the number of outstanding Shares as determined on such day is (i) less than [__]³⁷ million (in the case of the first such notice) or (ii) thereafter more than [__]³⁸ million less than the number of Shares included in the immediately preceding Repurchase Notice. Counterparty agrees to indemnify and hold harmless Dealer and its affiliates and their respective officers, directors, employees, affiliates, advisors, agents and controlling persons (each, an “Indemnified Person”) from and against any and all losses (including losses relating to Dealer’s hedging activities as a consequence of becoming, or of the risk of becoming, a Section 16 “insider”, including without limitation, any forbearance from hedging activities or cessation of hedging

To be the number of Shares outstanding that would cause Dealer’s current position in the shares underlying the Transaction (including the number of Shares underlying any additional transaction if the greenshoe is exercised in full, and any Shares under pre-existing call option transactions with Counterparty) to increase by 0.5%. To be determined with respect to Dealer with greatest number of underlying Shares.

To be the number of Shares that, if repurchased, would cause Dealer’s current position in the shares underlying the Transaction (including the number of Shares underlying any additional transaction if the greenshoe is exercised in full, and any Shares under pre-existing call option transactions with Counterparty) to increase by a further 0.5% from the threshold for the first Repurchase Notice. To be determined with respect to Dealer with greatest number of underlying Shares.

Regulation M. Counterparty is not on the Trade Date engaged in a distribution, as such term is used in Regulation M under the Exchange Act, of any securities of Counterparty, other than a distribution meeting the requirements of the exception set forth in Rules 101(b)(10) and 102(b)(7) of Regulation M. Counterparty shall not, until the second Scheduled Trading Day immediately following the Effective Date, engage in any such distribution.

No Manipulation. Counterparty is not entering into the Transaction to create actual or apparent trading activity in the Shares (or any security convertible into or exchangeable for the Shares) or to raise or depress or otherwise manipulate the price of the Shares (or any security convertible into or exchangeable for the Shares) or otherwise in violation of the Exchange Act.

Transfer or Assignment.

Counterparty shall have the right to transfer or assign its rights and obligations hereunder with respect to all, but not less than all, of the Options hereunder (such Options, the “Transfer Options”); provided that such transfer or assignment shall be subject to reasonable conditions that Dealer may impose, including but not limited, to the following conditions:

With respect to any Transfer Options, Counterparty shall not be released from its notice and indemnification obligations pursuant to Section 9(b) or any obligations under Section 9(n) or 9(s) of this Confirmation;

Any Transfer Options shall only be transferred or assigned to a third party that is a United States person (as defined in the Code);

Such transfer or assignment shall be effected on terms, including any reasonable undertakings by such third party (including, but not limited to, an undertaking with respect to compliance with applicable securities laws in a manner that, in the commercially reasonable judgment of Dealer, will not expose Dealer to material risks under applicable securities laws) and execution of any documentation and delivery of legal opinions with respect to securities laws and other matters by such third party and Counterparty, as are requested and reasonably satisfactory to Dealer;

Dealer will not, as a result of such transfer and assignment, be required to pay the transferee on any payment date an amount under Section 2(d)(i)(4) of the Agreement greater than an amount that Dealer would have been required to pay to Counterparty in the absence of such transfer and assignment;

An Event of Default, Potential Event of Default or Termination Event will not occur as a result of such transfer and assignment;

Without limiting the generality of clause (B), Counterparty shall cause the transferee to make such Payee Tax Representations and to provide such tax documentation as may be reasonably requested by Dealer to permit Dealer to determine that results described in clauses (D) and (E) will not occur upon or after such transfer and assignment; and

Counterparty shall be responsible for reasonable out-of-pocket costs and expenses, including reasonable counsel fees, incurred by Dealer in connection with such transfer or assignment.

Dealer may, without Counterparty’s consent, transfer or assign all or any part of its rights or obligations under the Transaction (A) to any affiliate of Dealer (1) that has a long-term issuer rating or a rating for its long term, unsecured and unsubordinated indebtedness that is equal to or better than the lesser of (a) Dealer’s long-term issuer rating or the rating for Dealer’s long-term, unsecured and unsubordinated indebtedness at the time of such transfer or assignment and (b) A- by Standard and Poor’s Rating Group, Inc. or its successor (“S&P”), or A3 by Moody’s Investor Service, Inc. (“Moody’s”) or, if either S&P or Moody’s ceases to rate such issuer or such indebtedness, as the case may be, at least an equivalent rating or better by a substitute rating agency mutually agreed by Counterparty and Dealer, or (2) whose obligations hereunder will be guaranteed, pursuant to the terms of a customary guarantee in a form used by Dealer generally for similar transactions, by Dealer (or its ultimate parent), or (B) to any other third party with a long-term issuer rating or a rating for its long term, unsecured and unsubordinated indebtedness equal to or better than the lesser of (1) Dealer’s long-term issuer rating or the rating for Dealer’s long-term, unsecured and unsubordinated indebtedness at the time of the transfer and (2) A- by S&P, or A3 by Moody’s or, if either S&P or Moody’s ceases to rate such issuer or such indebtedness, as the case may be, at least an equivalent rating or better by a substitute rating agency mutually agreed by Counterparty and Dealer; provided that Dealer and such affiliate or third party both qualify as “dealers in securities” within the meaning of Section 475(c)(1) of the Code or such transfer or assignment does not result in a deemed exchange by Counterparty within the meaning of Section 1001 of the Code. Dealer shall notify Counterparty of any transfer or assignment pursuant to the foregoing sentence promptly following such transfer or assignment. If at any time at which (A) the Section 16 Percentage exceeds 7.5%, (B) the Option Equity Percentage exceeds 14.5% or (C) the Share Amount exceeds the Applicable Share Limit (if any applies) (any such condition described in clauses (A), (B) or (C), an “Excess Ownership Position”), Dealer is unable after using its commercially reasonable efforts to effect a transfer or assignment of Options to a third party on pricing terms reasonably acceptable to Dealer and within a time period

Notwithstanding any other provision in this Confirmation to the contrary requiring or allowing Dealer to purchase, sell, receive or deliver any Shares or other securities, or make or receive any payment in cash, to or from Counterparty, Dealer may designate any of its affiliates to purchase, sell, receive or deliver such Shares or other securities, or make or receive such payment in cash, and otherwise to perform Dealer’s obligations in respect of the Transaction and any such designee may assume such obligations. Dealer shall be discharged of its obligations to Counterparty to the extent of any such performance.

Staggered Settlement. If upon advice of counsel with respect to applicable legal and regulatory requirements, including any requirements relating to Dealer’s hedging activities hereunder, Dealer reasonably determines that it would not be practicable or advisable to deliver, or to acquire Shares to deliver, any or all of the Shares to be delivered by Dealer on any Settlement Date for the Transaction, Dealer may, by notice to Counterparty on or prior to any Settlement Date (a “Nominal Settlement Date”), elect to deliver the Shares on two or more dates (each, a “Staggered Settlement Date”) as follows:

in such notice, Dealer will specify to Counterparty the related Staggered Settlement Dates (the first of which will be such Nominal Settlement Date and the last of which will be no later than the twentieth (20^th) Exchange Business Day following such Nominal Settlement Date) and the number of Shares that it will deliver on each Staggered Settlement Date;

the aggregate number of Shares that Dealer will deliver to Counterparty hereunder on all such Staggered Settlement Dates will equal the number of Shares that Dealer would otherwise be required to deliver on such Nominal Settlement Date; and

the Relevant Settlement Method terms will apply on each Staggered Settlement Date, except that the cash and/or Shares due upon settlement will be allocated among such Staggered Settlement Dates as specified by Dealer in the notice referred to in clause (i) above.

[Role of Agent. [Insert relevant Dealer agency or communications language, if any.]]

Additional Termination Events.

Notwithstanding anything to the contrary in this Confirmation, upon any Early Conversion in respect of which a “Notice of Conversion” (as such term is defined in the Indenture) that is effective as to Counterparty has been delivered by the relevant converting Holder:

Counterparty shall, within one Scheduled Trading Day of the Conversion Date for such Early Conversion, provide written notice (an “Early Conversion Notice”) to Dealer specifying the number of Convertible Notes surrendered for conversion on such Conversion Date (such Convertible Notes, the “Affected Convertible Notes”), and the giving of such Early Conversion Notice shall constitute an Additional Termination Event as provided in this clause (i);

upon receipt of any such Early Conversion Notice, Dealer shall designate an Exchange Business Day as an Early Termination Date (which Exchange Business Day shall be no earlier than one Scheduled Trading Day following the Conversion Date for such Early Conversion) with respect to the portion of the Transaction corresponding to a number of Options (the “Affected Number of Options”) equal to the lesser of (x) the number of Affected Convertible Notes [minus the “Affected Number of Options” (as defined in the Base Call Option Confirmation), if any, that relate to such Affected Convertible Notes]³⁹ and (y) the Number of Options as of the Conversion Date for such Early Conversion;

any payment hereunder with respect to such termination shall be calculated pursuant to Section 6 of the Agreement as if (x) an Early Termination Date had been designated in respect of a Transaction having terms identical to the Transaction and a Number of Options equal to the Affected Number of Options, (y) Counterparty were the sole Affected Party with respect to such Additional Termination Event and (z) the terminated portion of the Transaction were the sole Affected Transaction; provided that the amount payable with respect to such termination shall not be greater than (1) the Applicable Percentage, multiplied by (2) the Affected Number of Options, multiplied by (3) the excess of (x) the aggregate of (I) the number of Shares, if any, delivered to the Holder (as such term is defined in the Indenture) of an Affected Convertible Note upon conversion of such Affected Convertible Note, multiplied by the opening price as displayed under the heading “Op” on Bloomberg page ALNY <equity> (or any successor thereto) on the date on which such payment is made and (II) the amount of cash, if any, paid to the Holder of an Affected Convertible Note upon conversion of such Affected Convertible Note, over (y) USD 1,000;

for the avoidance of doubt, in determining the amount payable in respect of such Affected Transaction pursuant to Section 6 of the Agreement, the Calculation Agent shall assume that (x) the relevant Early Conversion and any conversions, adjustments, agreements, payments, deliveries or acquisitions by or on behalf of Counterparty leading thereto had not occurred, (y) no adjustments to the Conversion Rate have occurred pursuant to any Excluded Provision and (z) the corresponding Convertible Notes remain outstanding; and

Include in Additional Call Option Confirmation only.

the Transaction shall remain in full force and effect, except that, as of the Conversion Date for such Early Conversion, the Number of Options shall be reduced by the Affected Number of Options.

Insert for Additional Call Option Confirmation.

Insert for Additional Call Option Confirmation.

Insert for Additional Call Option Confirmation.

Notwithstanding anything to the contrary in this Confirmation, if an event of default with respect to Counterparty occurs under the terms of the Convertible Notes as set forth in Section [___]⁴³ of the Indenture and such event of default results in the Convertible Notes becoming or being declared due and payable pursuant to the terms of the Indenture, then such event of default shall constitute an Additional Termination Event applicable to the Transaction and, with respect to such Additional Termination Event, (A) Counterparty shall be deemed to be the sole Affected Party, (B) the Transaction shall be the sole Affected Transaction and (C) Dealer shall be the party entitled to designate an Early Termination Date pursuant to Section 6(b) of the Agreement.

Amendments to Equity Definitions.

Section 11.2(e)(v) of the Equity Definitions is hereby amended by adding the phrase “, provided that, notwithstanding this Section 11.2(e)(v), the parties hereto agree that, with respect to the Transaction, the following repurchases of Shares by the Issuer or any of its subsidiaries shall not be considered Potential Adjustment Events: any repurchases of Shares in open-market transactions at prevailing market prices or privately negotiated accelerated Share repurchase (or similar) transactions that are entered into at prevailing market prices and in accordance with customary market terms for transactions of such type to repurchase the Shares, in each case, to the extent that, after giving effect to such transactions, the aggregate number of Shares repurchased during the term of the Transaction pursuant to all transactions described in this proviso would not exceed 20% of the number of Shares outstanding as of the Trade Date, as determined by the Calculation Agent” at the end of such Section.

Section 11.2(e)(vii) of the Equity Definitions is hereby amended by deleting the words “that may have a diluting or concentrative effect on the theoretical value of the relevant Shares” and replacing them with the words “that is the result of a corporate event involving the Issuer or its securities that has, in the commercially reasonable judgment of the Calculation Agent, a material economic effect on the Shares or options on the Shares; provided that such event is not based on (a) an observable market, other than the market for the Counterparty’s own stock or (b) an observable index, other than an index calculated and measured solely by reference to Counterparty’s own operations.”

Section 12.1(d) of the Equity Definitions is hereby amended by replacing “10%” with “20%”.

Section 12.6(a)(ii) of the Equity Definitions is hereby amended by (1) deleting from the fourth line thereof the word “or” after the word “official” and inserting a comma therefor, and (2) deleting the semi-colon at the end of subsection (B) thereof and inserting the following words therefor “or (C) at Dealer’s option, the occurrence of any of the events specified in Section 5(a)(vii) (1) through (9) of the ISDA Master Agreement with respect to that Issuer.”

Section 12.9(b)(i) of the Equity Definitions is hereby amended by (1) replacing “either party may elect” with “Dealer may elect” and (2) replacing “notice to the other party” with “notice to Counterparty” in the first sentence of such section.

Include cross-reference to the Indenture section containing events of default.

Section 12.9(b)(vi) of the Equity Definitions is hereby amended by (1) replacing the comma immediately following clause (A) thereof with the word “or”, (2) deleting clause (C) thereof in its entirety and (3) replacing the words “either party” in the last sentence thereof with the words “the Hedging Party”.

No Collateral or Setoff. Notwithstanding any provision of the Agreement or any other agreement between the parties to the contrary, the obligations of Counterparty hereunder are not secured by any collateral. Obligations under the Transaction shall not be set off by either party against any other obligations of the parties, whether arising under the Agreement, this Confirmation, under any other agreement between the parties hereto, by operation of law or otherwise. For the avoidance of doubt and notwithstanding anything to the contrary provided in this Section 9(j), in the event of bankruptcy or liquidation of either party, neither party shall have the right to set off any obligation that it may have to the other party under the Transaction against any obligation such other party may have to it, whether arising under the Agreement, this Confirmation or any other agreement between the parties hereto, by operation of law or otherwise.

Alternative Calculations and Payment on Early Termination and on Certain Extraordinary Events. If (a) an Early Termination Date (whether as a result of an Event of Default or a Termination Event) occurs or is designated with respect to the Transaction or (b) the Transaction is cancelled or terminated upon the occurrence of an Extraordinary Event (except as a result of (i) a Nationalization, Insolvency or Merger Event in which the consideration to be paid to holders of Shares consists solely of cash, (ii) a Merger Event or Tender Offer that is within Counterparty’s control, or (iii) an Event of Default in which Counterparty is the Defaulting Party or a Termination Event in which Counterparty is the Affected Party other than an Event of Default of the type described in Section 5(a)(iii), (v), (vi), (vii) or (viii) of the Agreement or a Termination Event of the type described in Section 5(b) of the Agreement, in each case that resulted from an event or events outside Counterparty’s control), and if Dealer would owe any amount to Counterparty pursuant to Section 6(d)(ii) and Section 6(e) of the Agreement or any Cancellation Amount pursuant to Article 12 of the Equity Definitions (any such amount, a “Payment Obligation”), then Dealer shall satisfy the Payment Obligation by the Share Termination Alternative (as defined below), unless (a) Counterparty gives irrevocable telephonic notice to Dealer, confirmed in writing within one Scheduled Trading Day, no later than 12:00 p.m. (New York City time) on the Merger Date, Tender Offer Date, Announcement Date (in the case of a Nationalization, Insolvency or Delisting), Early Termination Date or date of cancellation, as applicable, of its election that the Share Termination Alternative shall not apply, (b) Counterparty remakes the representation set forth in Section 8(f) as of the date of such election and (c) Dealer agrees, in its sole discretion, to such election, in which case the provisions of Section 12.7 or Section 12.9 of the Equity Definitions, or the provisions of Section 6(d)(ii) and Section 6(e) of the Agreement, as the case may be, shall apply.

Registration. Counterparty hereby agrees that if, in the good faith, reasonable judgment of Dealer based on the advice of counsel, the Shares (“Hedge Shares”) acquired by Dealer for the purpose of hedging its obligations pursuant to the Transaction cannot be sold in the public market by Dealer without registration under the Securities Act, Counterparty shall, at its election, either (i) in order to allow Dealer to sell the Hedge Shares in a registered offering, make available to Dealer an effective registration statement under the Securities Act and (A) enter into an agreement, in form and substance reasonably satisfactory to Dealer, substantially in the form of an underwriting agreement for a registered secondary offering as is customary for registered secondary offerings of substantially similar size, (B) acting in good faith, use its commercially reasonable efforts to provide accountant’s “comfort” letters customary in form for registered offerings of equity securities, (C) provide disclosure opinions of nationally recognized outside counsel to Counterparty reasonably acceptable to Dealer, (D) provide other customary opinions, certificates and closing documents customary in form for registered offerings of equity securities and (E) afford Dealer a reasonable opportunity to conduct a due diligence investigation with respect to Counterparty customary in scope for underwritten offerings of equity securities; provided, however, that if Dealer, in its sole reasonable discretion, is not satisfied with access to due diligence materials, the results of its due diligence investigation, or the procedures and documentation for the registered offering referred to above, then clause (ii) or clause (iii) of this paragraph shall apply at the election of Counterparty, (ii) in order to allow Dealer to sell the Hedge Shares in a private placement, enter into and comply with a

Notice of Certain Other Events. Counterparty covenants and agrees that:

promptly following the public announcement of the results of any election by the holders of Shares with respect to the consideration due upon consummation of any Merger Event, Counterparty shall give Dealer written notice of the weighted average of the types and amounts of consideration actually received by holders upon consummation of such Merger Event (the date of such notification, the “Consideration Notification Date”); provided that in no event shall the Consideration Notification Date be later than the date on which such Merger Event is consummated; and

promptly following any adjustment to the Convertible Notes in connection with any Potential Adjustment Event, Merger Event or Tender Offer, Counterparty shall give Dealer written notice of the details of such adjustment.

Tax Disclosure. Effective from the date of commencement of discussions concerning the Transaction, Counterparty and each of its employees, representatives, or other agents may disclose to any and all persons, without limitation of any kind, the tax treatment and tax structure of the Transaction and all materials of any kind (including opinions or other tax analyses) that are provided to Counterparty relating to such tax treatment and tax structure.

Right to Extend. Dealer may postpone or add, in whole or in part, any Valid Day or Valid Days during the Settlement Averaging Period or any other date of valuation, payment or delivery by Dealer, with respect to some or all of the Options hereunder, if Dealer reasonably determines, based on advice of counsel, that such action is reasonably necessary or appropriate to preserve Dealer’s commercially reasonable hedging or hedge unwind activity hereunder in light of existing liquidity conditions or to enable Dealer to effect purchases of Shares in connection with its commercially reasonable hedging, hedge unwind or settlement activity hereunder in a manner that would, if Dealer were Counterparty or an affiliated purchaser of Counterparty, be in compliance with applicable legal, regulatory or self-regulatory organization requirements, or with related policies and procedures applicable to Dealer; provided that no such Valid Day or other date of valuation, payment or delivery may be postponed or added more than [_]⁴⁴ Valid Days after the original Valid Day or other date of valuation, payment or delivery, as the case may be.

Status of Claims in Bankruptcy. Dealer acknowledges and agrees that this Confirmation is not intended to convey to Dealer rights against Counterparty with respect to the Transaction that are senior to the claims of common stockholders of Counterparty in any United States bankruptcy proceedings of Counterparty; provided that nothing herein shall limit or shall be deemed to limit Dealer’s right to pursue remedies in the event of a breach by Counterparty of its obligations and agreements with respect to the Transaction; provided, further, that nothing herein shall limit or shall be deemed to limit Dealer’s rights in respect of any transactions other than the Transaction.

Securities Contract; Swap Agreement. The parties hereto agree and acknowledge that Dealer is a “financial institution,” “swap participant” and “financial participant” within the meaning of Sections 101(22), 101(53C) and 101(22A) of the Bankruptcy Code. The parties hereto further agree and acknowledge (A) that this Confirmation is (i) a “securities contract,” as such term is defined in Section 741(7) of the Bankruptcy Code, with respect to which each payment and delivery hereunder or in connection herewith is a “termination value,” “payment amount” or “other transfer obligation”

To be the number of Valid Days that is equal to the number of trading days in the observation period for the Convertible Notes.

Waiver of Jury Trial. Each party waives, to the fullest extent permitted by applicable law, any right it may have to a trial by jury in respect of any suit, action or proceeding relating to the Transaction. Each party (i) certifies that no representative, agent or attorney of either party has represented, expressly or otherwise, that such other party would not, in the event of such a suit, action or proceeding, seek to enforce the foregoing waiver and (ii) acknowledges that it and the other party have been induced to enter into the Transaction, as applicable, by, among other things, the mutual waivers and certifications provided herein.

Wall Street Transparency and Accountability Act. In connection with Section 739 of the Wall Street Transparency and Accountability Act of 2010 (“WSTAA”), the parties hereby agree that neither the enactment of WSTAA or any regulation under the WSTAA, nor any requirement under WSTAA or an amendment made by WSTAA, shall limit or otherwise impair either party’s otherwise applicable rights to terminate, renegotiate, modify, amend or supplement this Confirmation or the Agreement, as applicable, arising from a termination event, force majeure, illegality, increased costs, regulatory change or similar event under this Confirmation, the Equity Definitions incorporated herein, or the Agreement (including, but not limited to, rights arising from Change in Law, Hedging Disruption, Increased Cost of Hedging, an Excess Ownership Position, or Illegality (as defined in the Agreement)).

Agreements and Acknowledgements Regarding Hedging. Counterparty understands, acknowledges and agrees that: (A) at any time on and prior to the Expiration Date, Dealer and its affiliates may buy or sell Shares or other securities or buy or sell options or futures contracts or enter into swaps or other derivative securities in order to adjust its hedge position with respect to the Transaction; (B) Dealer and its affiliates also may be active in the market for Shares other than in connection with hedging activities in relation to the Transaction; (C) Dealer shall make its own determination as to whether, when or in what manner any hedging or market activities in securities of Counterparty shall be conducted and shall do so in a manner that it deems appropriate to hedge its price and market risk with respect to the Relevant Prices; and (D) any market activities of Dealer and its affiliates with respect to Shares may affect the market price and volatility of Shares, as well as the Relevant Prices, each in a manner that may be adverse to Counterparty.

Early Unwind. In the event the sale of the [“Underwritten Securities”]⁴⁵[“Option Securities”]⁴⁶ (as defined in the Purchase Agreement) is not consummated with the Initial Purchasers for any reason, or Counterparty fails to deliver to Dealer opinions of counsel as required pursuant to Section 9(a), in each case, by 5:00 p.m. (New York City time) on the Premium Payment Date, or such later date as agreed upon by the parties (the Premium Payment Date or such later date the “Early Unwind Date”), the Transaction shall automatically terminate (the “Early Unwind”), on the Early Unwind Date and (i) the Transaction and all of the respective rights and obligations of Dealer and Counterparty under the Transaction shall be cancelled and terminated and (ii) each party shall be released and discharged by the other parties from and agrees not to make any claim against any other party with respect to any obligations or liabilities of any other party arising out of and to be performed in connection with the Transaction either prior to or after the Early Unwind Date. Each of Dealer and Counterparty represents and acknowledges to the other parties that, upon an Early Unwind, all obligations with respect to the Transaction shall be deemed fully and finally discharged.

Include in Base Call Option Confirmation only (conformed to Purchase Agreement).

Include in Additional Call Option Confirmation only (conformed to Purchase Agreement).

Payment by Counterparty. In the event that, following payment of the Premium, (i) an Early Termination Date occurs or is designated with respect to the Transaction as a result of a Termination Event or an Event of Default (other than an Event of Default arising under Section 5(a)(ii) or 5(a)(iv) of the Agreement) and, as a result, Counterparty owes to Dealer an amount calculated under Section 6(e) of the Agreement, or (ii) Counterparty owes to Dealer, pursuant to Section 12.7 or Section 12.9 of the Equity Definitions, an amount calculated under Section 12.8 of the Equity Definitions, such amount shall be deemed to be zero.

Other Adjustments Pursuant to the Equity Definitions. Notwithstanding anything to the contrary in this Confirmation, solely purposes of this Section 9(w), the terms “Potential Adjustment Event,” “Merger Event,” and “Tender Offer” shall each have the meanings assigned to such term in the Equity Definitions (as amended by Section 9(j)(i), (ii) and (iii)), and upon the occurrence of a Merger Date, the occurrence of a Tender Offer Date, or declaration by Counterparty of the terms of any Potential Adjustment Event, respectively, as such terms are defined in the Equity Definitions, the Calculation Agent shall, acting in good faith and in a commercially reasonable manner, adjust the Cap Price as appropriate to account for the economic effect on the Transaction of such event, without duplication of any other adjustment hereunder or under the Agreement or the Equity Definitions in respect of such event; provided that in no event shall the Cap Price be less than the Strike Price.

Counterparts. This Confirmation may be executed in several counterparts, each of which shall be deemed an original but all of which together shall constitute one and the same instrument.

Tax Matters.

Tax Documentation. For the purpose of Sections 4(a)(i) and (ii) of the Agreement, Counterparty agrees to deliver to Dealer one duly executed and completed U.S. Internal Revenue Service Form W-9 (or successor thereto) and Dealer agrees to deliver to Counterparty [DEALER TAX FORM TO COME]. Such forms or documents shall be delivered (i) on or before the date of execution of this Confirmation, (ii) upon Counterparty or Dealer, as applicable, learning that any such tax form previously provided by it has become obsolete or incorrect and (iii) upon reasonable request of the other party.

Withholding Tax imposed on payments to non-US counterparties under the United States Foreign Account Tax Compliance Act. “Indemnifiable Tax”, as defined in Section 14 of the Agreement, shall not include any U.S. federal withholding tax imposed or collected pursuant to Sections 1471 through 1474 of the Revenue Code, any current or future regulations or official interpretations thereof, any agreement entered into pursuant to Section 1471(b) of the Revenue Code, or any fiscal or regulatory legislation, rules or practices adopted pursuant to any intergovernmental agreement entered into in connection with the implementation of such Sections of the Revenue Code (a “FATCA Withholding Tax”). For the avoidance of doubt, a FATCA Withholding Tax is a Tax the deduction or withholding of which is required by applicable law for the purposes of Section 2(d) of the Agreement.

HIRE Act. “Indemnifiable Tax”, as defined in Section 14 of the Agreement, shall not include any tax imposed on payments treated as dividends from sources within the United States under Section 871(m) of the Revenue Code or any regulations issued thereunder. For the avoidance of doubt, any such tax imposed under Section 871(m) of the Revenue Code is a Tax the deduction or withholding of which is required by applicable law for the purposes of Section 2(d) of the Agreement.

[DEALER BOILERPLATE, INCLUDING APPLICABLE RESOLUTION STAY PROTOCOL LANGUAGE, TO COME.]

Hedging Adjustment. For the avoidance of doubt, whenever Dealer, the Determining Party or the Calculation Agent makes an adjustment or calculation, or the Determining Party or the Calculation Agent makes a determination, in each case, permitted or required to be made pursuant to the terms of this Confirmation or the Equity Definitions to take into account the effect of any event (other than an adjustment, calculation or determination made by reference to the Indenture), the Calculation Agent, the Determining Party or Dealer, as the case may be, shall make such adjustment, calculation or determination in a commercially reasonable manner and by reference to the effect of such event on Dealer assuming that Dealer maintains a commercially reasonable hedge position.

ALNYLAM PHARMACEUTICALS, INC.

By:

Authorized Signatory

Name: