Form of Common Stock Warrant pursuant to the Securities Purchase Agreement



 Exhibit 10.2 

NEITHER THIS SECURITY NOR THE SECURITIES INTO WHICH THIS SECURITY IS EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE
COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN
EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN AVAILABLE EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE SECURITIES LAWS AS
EVIDENCED BY A LEGAL OPINION OF COUNSEL TO THE TRANSFEROR TO SUCH EFFECT, THE SUBSTANCE OF WHICH SHALL BE REASONABLY ACCEPTABLE TO THE COMPANY. 

Void after 5:00 p.m. (New York time) on the    th day
of             , 2017. 
  

			
	Number of Warrants:	  	Warrant Certificate No.


ACHILLION PHARMACEUTICALS, INC. 

(A corporation existing under the laws of the State of Delaware) 

THIS COMMON STOCK PURCHASE WARRANT (the “Warrant”) certifies that, for value
received,                     (the “Holder”), is entitled, upon the terms and subject to the limitations on exercise and the
conditions hereinafter set forth, including without limitation Section 3(c), at any time on or after the date hereof and on or prior to 5:00 p.m. (New York time) on            , 2017
(the “Expiry Time”) but not thereafter, to subscribe for and purchase from Achillion Pharmaceuticals, Inc., a Delaware corporation (the “Company”), up
to                    shares (the “Warrant Shares”) of Common Stock, par value $0.001 per share, of the Company (the “Common
Stock”), subject to adjustment as provided herein. The purchase price of one share of Common Stock under this Warrant shall be equal to the Exercise Price, as defined in Section 2(b). 

Section 1. Definitions. Capitalized terms used and not otherwise defined herein shall have the
meanings set forth in that certain Securities Purchase Agreement (the “Securities Purchase Agreement”), dated August 18, 2010, among the Company and the purchasers signatory thereto. 

Section 2. Exercise. 

a) Exercise of Warrant. Exercise of the purchase rights represented by this Warrant may be made, in whole or in
part, at any time or times on or after the date of issuance of this Warrant and on or before the Expiry Time by delivery to the principal office of the Company of a duly executed copy of the Notice of Exercise Form annexed hereto (or to such other
office or agency of the Company as it may designate by notice in writing to the registered Holder at the address of such Holder appearing on the books of the Company) and the Company shall have received payment of the aggregate Exercise Price of the
shares thereby purchased by wire transfer or cashier’s check drawn on a United States bank (the “Exercise Date”); provided, however, if this Warrant is exercised in full, the Holder shall have surrendered this Warrant to








 
the Company within three (3) business days of the date the Notice of Exercise is delivered to the Company. Notwithstanding anything herein to the contrary, the Holder shall not be required
to physically surrender this Warrant to the Company until the Holder has purchased all of the Warrant Shares available hereunder and the Warrant has been exercised in full. Partial exercises of this Warrant resulting in purchases of a portion of the
total number of Warrant Shares available hereunder shall have the effect of lowering the outstanding number of Warrant Shares purchasable hereunder in an amount equal to the applicable number of Warrant Shares purchased. The Holder and the Company
shall maintain records showing the number of Warrant Shares purchased and the date of such purchases. The Company shall deliver any objection to any Notice of Exercise Form within two (2) Business Days of receipt of such notice. The Holder and
any assignee, by acceptance of this Warrant, acknowledge and agree that, by reason of the provisions of this paragraph, following the purchase of a portion of the Warrant Shares hereunder, the number of Warrant Shares available for purchase
hereunder at any given time may be less than the amount stated on the face hereof. 
 Immediately prior to the
Expiry Time, the portion of this Warrant not exercised prior thereto shall automatically be deemed to be exercised in full in the manner set forth in Section 2(c), without any further action on behalf of the Holder; provided, however, that in
the event that the cashless exercise formula set forth in Section 2(c) yields a result that is less than or equal to zero, then the unexercised portion of this Warrant shall automatically terminate and become void. The Company may not call or
redeem any portion of this Warrant without the prior written consent of the affected Holder. 
 b) Exercise
Price. The exercise price of the Common Stock under this Warrant shall be $3.1125 per share, subject to adjustment hereunder. 

c) Cashless Exercise. This Warrant may also be exercised by means of a “cashless exercise” in which the
Holder shall be entitled to receive a certificate for the number of Warrant Shares equal to the quotient obtained by dividing [(A-B)*(X)] by (A), where: 
  

			
	(A) =	 	the VWAP on the trading day immediately preceding the date of such election;
		
	(B) =	 	the Exercise Price of this Warrant, as adjusted; and
		
	(X) =	 	the number of Warrant Shares issuable upon exercise of this Warrant in accordance with the terms of this Warrant by means of a cash exercise rather than a cashless
exercise.

 The “VWAP” means, for any date, the price determined by the first of
the following clauses that applies: (a) if the Common Stock is then listed or quoted on a Trading Market, the daily volume weighted average price of the Common Stock for such date (or the nearest preceding date) on the Trading Market on which
the Common Stock is then listed or quoted as reported by Bloomberg Financial L.P. (based on a Trading Day from 9:30 a.m. Eastern Time to 4:02 p.m. Eastern Time); (b) the volume weighted average price of the Common Stock for such date (or the
nearest preceding date) on the OTC Bulletin Board or (c) if the Common Stock is not then listed or quoted on the OTC Bulletin Board and if prices for the Common Stock are then 

 

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reported in the “Pink Sheets” published by the Pink Sheets, LLC (or a similar organization or agency succeeding to its functions of reporting prices), the most recent bid price per
share of the Common Stock so reported; or (d) in all other cases, the fair market value of a share of Common Stock as determined by a good faith determination of the Company’s Board of Directors. 

d) Percentage Limitation. Notwithstanding anything herein to the contrary, the Company shall not issue to any
Holder any shares of Common Stock, including pursuant to any rights herein, including, without limitation, any exercise rights, to the extent such shares, when added to the number of shares of Common Stock then beneficially owned by such Holder and
any Persons whose beneficial ownership of Common Stock would be aggregated with such Holder for purposes of Section 13(d) of the Securities Exchange Act, would cause the total number of shares of Common Stock beneficially owned by such Holder
and any such Persons to exceed 19.999% of the total number of outstanding shares of Common Stock of the Company at the time of such issuance (the “Maximum Aggregate Share Amount”), provided, however, that this Section 2(d)
shall not apply to the exercise of this Warrant in connection with any Fundamental Transaction (as defined below) in which the Company is acquired by a third party, whether by merger or stock purchase. For purposes of this Section 2(d),
beneficial ownership shall be determined in accordance with Section 13(d) of the Exchange Act and the rules and regulations promulgated thereunder. If on any attempted exercise of this Warrant other than in connection with a Fundamental
Transaction, the issuance of Warrant Shares would exceed the Maximum Aggregate Share Amount, then the Company shall issue to the Holder requesting a Warrant exercise such number of Warrant Shares as may be issued below the Maximum Aggregate Share
Amount and, with respect to the remainder of the aggregate number of Warrant Shares, this Warrant shall remain exercisable, subject to this Section 2(d). Notwithstanding anything to the contrary contained in this Section 2(d), the
limitations contained herein shall not apply unless (i) such limitations are required under Nasdaq Global Market Rule 5635 or (ii) the Holder has, by providing the Company with written notice, lowered the Maximum Aggregate Share Amount to
a percentage below 19.999% of the total number of outstanding shares of Common Stock (such amount being the “Adjusted Maximum Aggregate Share Amount”). Upon providing the Company with at least 61 days prior written notice, the
Holder may increase the Adjusted Maximum Aggregate Share Amount up to 19.999% of the shares of Common Stock outstanding immediately after giving effect to such exercise, provided, however, that in the event that Nasdaq Global Market Rule 5635 does
not require the limitations contained in this Section 2(c), the Holder may increase the Adjusted Maximum Aggregate Share Amount above 19.999% of the shares Common Stock outstanding immediately after giving effect to such exercise. 

e) Mechanics of Exercise. 

i. Authorization of Warrant Shares. The Company covenants that all Warrant Shares which may be issued upon the
exercise of the purchase rights represented by this Warrant will, upon exercise of the purchase rights represented by this Warrant and payment to the Company of the purchase price therefor, be duly authorized, validly issued, fully paid and
nonassessable and free from all taxes, liens and charges in respect of the issue thereof (other than taxes in respect of any transfer occurring contemporaneously with such issue). 

 

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 ii. Delivery of Certificates Upon Exercise. Certificates for shares
purchased hereunder shall be transmitted by the transfer agent of the Company to the Holder by crediting the account of the Holder’s prime broker with the Depository Trust Company through its Deposit Withdrawal Agent Commission
(“DWAC”) system if the Company is a participant in such system, and otherwise by physical delivery to the address specified by the Holder in the Notice of Exercise within three (3) Trading Days from the delivery to the Company
of the Notice of Exercise Form, surrender of this Warrant (if required) and payment of the aggregate Exercise Price (unless exercised by means of a cashless exercise pursuant to Section 2(c)) (“Warrant Share Delivery Date”).
This Warrant shall be deemed to have been exercised on the date the Exercise Price is received by the Company (or in the case of a cashless exercise pursuant to Section 2(c), the date this Warrant is surrendered). If all or any part of a
Warrant is exercised at a time when there is an effective registration statement to cover the issuance or resale of the Warrant Shares and if the legend is not required under applicable securities laws, such Warrant Shares shall be issued free of
all legends on or before the Warrant Share Delivery Date. The Warrant Shares shall be deemed to have been issued, and Holder or any other Person so designated to be named therein shall be deemed to have become a holder of record of such shares for
all purposes, as of the Exercise Date irrespective of the date such Warrant Shares are credited to the Holder’s DWAC account, or the date of delivery of certificates evidencing the Warrant Shares, as the case may be. 

iii. Delivery of New Warrants Upon Exercise. If this Warrant shall have been exercised in part, the Company
shall, at the request of a Holder and upon surrender of this Warrant certificate, at the time of delivery of the certificate or certificates representing Warrant Shares, deliver to Holder a new Warrant evidencing the rights of Holder to purchase the
unpurchased Warrant Shares called for by this Warrant, which new Warrant shall in all other respects be identical with this Warrant. 

iv. No Fractional Shares or Scrip. No fractional shares or scrip representing fractional shares shall be issued
upon the exercise of this Warrant. As to any fraction of a share that Holder would otherwise be entitled to purchase upon such exercise, the Company shall pay a cash adjustment in respect of such final fraction in an amount equal to such fraction
multiplied by the Exercise Price. 
 v. Charges, Taxes and Expenses. Issuance of certificates for
Warrant Shares shall be made without charge to the Holder for any issue or transfer tax or other incidental expense in respect of the issuance of such certificate, all of which taxes and expenses shall be paid by the Company, and such certificates
shall be issued in the name of the Holder or in such name or names as may be directed by the Holder; provided, however, that in the event certificates for Warrant Shares are to be issued in a name other than the name of the Holder, this Warrant when
surrendered for exercise shall be accompanied by the Assignment Form attached hereto duly executed by the Holder; and the Company may require, as a condition thereto, the payment of a sum sufficient to reimburse it for any transfer tax incidental
thereto. 
 f) The Company’s obligations to issue and deliver Warrant Shares in accordance with the terms
hereof are absolute and unconditional, irrespective of any action or inaction by the Holder to enforce the same, any waiver or consent with respect to any provision hereof, the recovery of any judgment against any Person or any action to enforce the
same, or any setoff, counterclaim, recoupment, limitation or termination, or any breach or alleged breach by the Holder or any other Person of any obligation to the Company or any violation or alleged

  

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violation of law by the Holder or any other Person, and irrespective of any other circumstance which might otherwise limit such obligation of the Company to the Holder in connection with the
issuance of Warrant Shares. Nothing herein shall limit a Holder’s right to pursue any other remedies available to it hereunder, at law or in equity including, without limitation, a decree of specific performance and/or injunctive relief with
respect to the Company’s failure to timely deliver the Warrant Shares upon exercise of the Warrant as required pursuant to the terms hereof. 

Section 3. Certain Adjustments. 

a) Stock Dividends and Splits. If the Company, at any time while this Warrant is outstanding: (A) pays a stock
dividend or otherwise makes a distribution or distributions on shares of its Common Stock or any other equity or equity equivalent securities payable in shares of Common Stock (which, for avoidance of doubt, shall not include any shares of Common
Stock issued by the Company pursuant to this Warrant), (B) subdivides outstanding shares of Common Stock into a larger number of shares, (C) combines (including by way of reverse stock split) outstanding shares of Common Stock into a
smaller number of shares, or (D) issues by reclassification of shares of the Common Stock any shares of capital stock of the Company, then in each case the Exercise Price shall be multiplied by a fraction, of which the numerator shall be the
number of shares of Common Stock (excluding treasury shares, if any) outstanding immediately before such event and of which the denominator shall be the number of shares of Common Stock outstanding immediately after such event and the number of
shares issuable upon exercise of this Warrant shall be proportionately adjusted in an inverse manner (e.g., an increase in the Exercise Price shall result in a decrease in the number of shares of Common Stock). Any adjustment made pursuant to
this Section 3(a) shall become effective immediately after the record date for the determination of stockholders entitled to receive such dividend or distribution and shall become effective immediately after the effective date in the case of a
subdivision, combination or re-classification. 
 b) Pro Rata Distributions. If the Company, at any time
prior to the Expiry Time, shall declare, or distribute any dividend or other distribution to all holders of Common Stock (and not to Holders of the Warrants) evidences of its indebtedness or assets (including cash and cash dividends) or rights or
warrants to subscribe for or purchase any security other than the Common Stock, then in each such case the Exercise Price shall be adjusted by multiplying the Exercise Price in effect immediately prior to the record date fixed for determination of
stockholders entitled to receive such distribution by a fraction, of which the denominator shall be the VWAP determined as of the record date mentioned above, and of which the numerator shall be such VWAP on such record date less the then per share
fair market value at such record date of the portion of such assets or evidence of indebtedness so distributed applicable to one outstanding share of the Common Stock as determined by the Board of Directors of the Company in good faith. The
adjustment shall be described in a statement provided to the Holder. Such adjustment shall be made whenever any such distribution is made and shall become effective immediately after the record date mentioned above. 

c) Fundamental Transaction; Automatic Exercise. If, at any time while this Warrant is outstanding, the Company
effects (A) any merger or consolidation of the Company with or into another Person (an “Acquisition”), (B) any sale of all or substantially all of its assets in one or a series of related transactions (an “Asset
Sale”), (C) any tender offer or exchange offer 
  

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(whether by the Company or another Person) pursuant to which holders of Common Stock are permitted to tender or exchange their shares for other securities, cash or property (a “Tender
Offer”), or (D) any reclassification of the Common Stock or any compulsory share exchange pursuant to which the Common Stock is effectively converted into or exchanged for other securities, cash or property (in any such case, a
“Fundamental Transaction”), then, this Warrant shall remain outstanding according to its terms except that, upon any subsequent exercise of this Warrant, the Holder shall have the right to receive, for each Warrant Share that would
have been issuable upon such exercise immediately prior to the occurrence of such Fundamental Transaction, the number of shares of Common Stock of the successor or acquiring corporation or of the Company, if it is the surviving corporation, and any
additional consideration (the “Alternate Consideration”) receivable upon or as a result of such reorganization, reclassification, merger, consolidation or disposition of assets by a Holder of the number of shares of Common Stock for
which this Warrant is exercisable immediately prior to such event. Notwithstanding the foregoing, in the event the Fundamental Transaction is in the form of an Acquisition, Asset Sale or Tender Offer, and the consideration payable with respect to
such transaction is cash (a “Cash Transaction”), then Holder shall exercise its conversion or purchase right under this Warrant and such exercise will be deemed effective immediately prior to the consummation of such Cash
Transaction, and, if Holder does not so exercise, this Warrant shall automatically be exercised pursuant to Section 2(c) hereof, without any action by Holder immediately prior to the consummation of such Cash Transaction. The Company shall
provide the Holder with written notice of its request relating to the foregoing (together with such reasonable information as the Holder may request in connection with such contemplated Acquisition giving rise to such notice), which is to be
delivered to Holder not less than ten (10) days prior to the closing of the proposed Cash Transaction. The provisions of Section 2(d) shall apply to any such exercise. To the extent necessary to effectuate the foregoing provisions, any
successor to the Company or surviving entity in such Fundamental Transaction shall issue to the Holder a new warrant consistent with the foregoing provisions and evidencing the Holder’s right to exercise such warrant for the Alternate
Consideration. The terms of any agreement pursuant to which a Fundamental Transaction is effected shall include terms requiring any such successor or surviving entity to comply with the provisions of this Section 3(c) and insuring that this
Warrant (or any such replacement security) will be similarly adjusted upon any subsequent transaction analogous to a Fundamental Transaction. 

d) Calculations. All calculations under this Section 3 shall be made to the nearest cent or the nearest
1/100th of a share, as the case may be. For purposes of this Section 3, the number of shares of Common Stock deemed to be issued and outstanding as of a given date shall be the sum of the number of shares of Common Stock (excluding treasury
shares, if any) issued and outstanding. 
 e) Notice to Holders. 

i. Adjustment to Exercise Price. Whenever the Exercise Price is adjusted pursuant to this Section 3, the
Company shall promptly mail to each Holder a notice setting forth the Exercise Price after such adjustment and setting forth a brief statement of the facts requiring such adjustment. 

 

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 ii. Notice to Allow Exercise by Holder. If (A) the Company
shall declare a dividend (or any other distribution) on the Common Stock; (B) the Company shall declare a special nonrecurring cash dividend on or a redemption of the Common Stock; (C) the Company shall authorize the granting to all
holders of the Common Stock rights or warrants to subscribe for or purchase any shares of capital stock of any class or of any rights; (D) the approval of any stockholders of the Company shall be required in connection with any Fundamental
Transaction; (E) the Company shall authorize the voluntary or involuntary dissolution, liquidation or winding up of the affairs of the Company; then, in each case, the Company shall cause to be mailed to the Holder at its last address as it
shall appear upon the Warrant Register of the Company, at least 10 calendar days prior to the applicable record or effective date hereinafter specified, a notice stating (x) the date on which a record is to be taken for the purpose of such
dividend, distribution, redemption, rights or warrants, or if a record is not to be taken, the date as of which the holders of the Common Stock of record to be entitled to such dividend, distributions, redemption, rights or warrants are to be
determined or (y) the date on which such reclassification, consolidation, merger, sale, transfer or share exchange is expected to become effective or close, and the date as of which it is expected that holders of the Common Stock of record
shall be entitled to exchange their shares of the Common Stock for securities, cash or other property deliverable upon such reclassification, consolidation, merger, sale, transfer or share exchange; provided, in each case that such information shall
be made known to the public through a press release, filing with the Commission, or other public announcement prior to or in conjunction with such notice being provided to the Holder, and provided further that the failure to mail such notice or any
defect therein or in the mailing thereof shall not affect the validity of the corporate action required to be specified in such notice. The Holder is entitled to exercise this Warrant during the 10-day period commencing on the date of such notice to
the effective date of the event triggering such notice. 
 Section 4. Transfer of Warrant.

 a) Transferability. This Warrant and all rights hereunder are transferable, in whole or in part, upon
surrender of this Warrant at the principal office of the Company, together with a written assignment of this Warrant substantially in the form attached hereto duly executed by the Holder or its agent or attorney and funds sufficient to pay any
transfer taxes payable upon the making of such transfer. Upon such surrender and, if required, such payment, the Company shall execute and deliver a new Warrant or Warrants in the name of the assignee or assignees and in the denomination or
denominations specified in such instrument of assignment, and shall issue to the assignor a new Warrant evidencing the portion of this Warrant not so assigned, and this Warrant shall promptly be cancelled. A Warrant, if properly assigned, may be
exercised by a new holder for the purchase of Warrant Shares without having a new Warrant issued. The Holder represents that by accepting this Warrant it understands that this Warrant and any securities obtainable upon exercise of this Warrant have
not been registered for sale under Federal or state securities laws and are being offered and sold to the Holder pursuant to one or more exemptions from the registration requirements of such securities laws. In the absence of an effective
registration of such securities or an exemption therefrom, any certificates for such securities shall bear the legend set forth on the first page hereof. The Holder understands that it must bear the economic risk of its investment in this Warrant
and any securities obtainable upon exercise of this Warrant for an indefinite period of time, as this Warrant and such securities have not been registered under Federal or state securities laws and therefore cannot be sold unless subsequently
registered under such laws, unless an exemption from such registration is available. 
  

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 b) New Warrants. This Warrant may be divided or combined with other
Warrants upon presentation hereof at the aforesaid office of the Company, together with a written notice specifying the names and denominations in which new Warrants are to be issued, signed by the Holder or its agent or attorney. Subject to
compliance with Section 4(a), as to any transfer which may be involved in such division or combination, the Company shall execute and deliver a new Warrant or Warrants in exchange for the Warrant or Warrants to be divided or combined in
accordance with such notice. 
 c) Warrant Register. The Company shall register this Warrant, upon
records to be maintained by the Company for that purpose (the “Warrant Register”), in the name of the record Holder hereof. The Company may deem and treat the registered Holder of this Warrant as the absolute owner hereof for the
purpose of any exercise hereof or any distribution to the Holder, and for all other purposes, absent actual notice to the contrary. 

Section 5. Miscellaneous. 

a) No Rights as Stockholder Until Exercise. This Warrant does not entitle the Holder to any voting rights or other
rights as a stockholder of the Company prior to the exercise hereof. Upon the surrender of this Warrant and the payment of the aggregate Exercise Price (or by means of a cashless exercise), the Warrant Shares so purchased shall be and be deemed to
be issued to such Holder as the record owner of such shares as of the close of business on the later of the date of such surrender or payment. 

b) Loss, Theft, Destruction or Mutilation of Warrant. The Company covenants that upon receipt by the Company of
evidence reasonably satisfactory to it of the loss, theft, destruction or mutilation of this Warrant or any stock certificate relating to the Warrant Shares, and in case of loss, theft or destruction, of indemnity or security reasonably satisfactory
to it (which, in the case of the Warrant, shall not include the posting of any bond), and upon surrender and cancellation of such Warrant or stock certificate, if mutilated, the Company will make and deliver a new Warrant or stock certificate of
like tenor and dated as of such cancellation, in lieu of such Warrant or stock certificate. 
 c) Saturdays,
Sundays, Holidays, etc. If the last or appointed day for the taking of any action or the expiration of any right required or granted herein shall be a Saturday, Sunday or a legal holiday, then such action may be taken or such right may be
exercised on the next succeeding day not a Saturday, Sunday or legal holiday. 
 d) Authorized Shares.
The Company covenants that during the period the Warrant is outstanding, it will maintain a reserve, free from preemption rights, from its duly authorized shares of Common Stock for issuance pursuant to the Transaction Documents in such amount as
may be required to fulfill its obligations in full under the Transaction Documents. The Company further covenants that its issuance of this Warrant shall constitute full authority to its officers who are charged with the duty of executing stock
certificates to execute and issue the necessary certificates for the Warrant Shares upon the exercise of the purchase rights under this 

 

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Warrant. The Company will take all such reasonable action as may be necessary to assure that such Warrant Shares may be issued as provided herein without violation of any applicable law or
regulation, or of any requirements of the Trading Market upon which the Common Stock may be listed. If at any time prior to the Expiry Time the number of authorized but unissued shares of Common Stock shall not be sufficient to permit exercise of
this Warrant, the Company will take such corporate action as may, in the opinion of its counsel, be necessary to increase its authorized but unissued shares of Common Stock (or other securities as provided herein) to such number of shares as shall
be sufficient for such purposes. 
 Except and to the extent as waived or consented to by the Holder, the
Company hereby covenants to not by any action, including, without limitation, amending its certificate of incorporation, bylaws or through any reorganization, transfer of assets, consolidation, merger, dissolution, issue or sale of securities or any
other voluntary action, avoid or seek to avoid the observance or performance of any of the terms of this Warrant, and will at all times in good faith assist in the carrying out of all such terms and in the taking of all such actions as may be
necessary or appropriate to protect the rights of Holder as set forth in this Warrant against impairment. Without limiting the generality of the foregoing, the Company will (a) not increase the par value of any Warrant Shares above the Exercise
Price then in effect and (b) take all such action as may be necessary or appropriate in order that the Company may validly and legally issue fully paid and nonassessable Warrant Shares upon the exercise of this Warrant. 

e) Jurisdiction. All questions concerning the construction, validity, enforcement and interpretation of this
Warrant shall be determined in accordance with the provisions of the Securities Purchase Agreement. 
 f)
Restrictions. The Holder acknowledges that the Warrant Shares acquired upon the exercise of this Warrant, if not registered, will contain a legend to that effect. 

g) Nonwaiver and Expenses. No course of dealing or any delay or failure to exercise any right hereunder on the
part of Holder shall operate as a waiver of such right or otherwise prejudice Holder’s rights, powers or remedies, notwithstanding the fact that all rights hereunder terminate on the Expiry Time. If the Company willfully and knowingly fails to
comply with any provision of this Warrant, which results in any material damages to the Holder, the Company shall pay to Holder such amounts as shall be sufficient to cover any costs and expenses incurred by Holder in collecting any amounts due
pursuant hereto or in otherwise enforcing any of its rights, powers or remedies hereunder. 
 h) Notices.
Any notice, request or other document required or permitted to be given or delivered to the Holder by the Company shall be delivered in accordance with the notice provisions of the Securities Purchase Agreement. 

i) Limitation of Liability. No provision hereof, in the absence of any affirmative action by Holder to exercise
this Warrant or purchase Warrant Shares, and no enumeration herein of the rights or privileges of Holder, shall give rise to any liability of Holder for the purchase price of any Common Stock or as a stockholder of the Company, whether such
liability is asserted by the Company or by creditors of the Company. 
  

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 j) Remedies. The remedies provided in this Warrant shall be
cumulative and in addition to all other remedies available or granted by law, including recovery of damages. Each of the parties hereto will be entitled to specific performance of its rights under this Warrant. The Company acknowledges that a breach
by it of its obligations hereunder will cause irreparable harm to the Holder and agrees that monetary damages would not be adequate compensation for any loss incurred by reason of a breach or threatened breach by it of the provisions of this Warrant
and hereby agrees to waive the defense in any action for specific performance that a remedy at law would be adequate including making a showing of economic loss and the posting of a bond or other security. 

k) Successors and Assigns. Subject to applicable securities laws, this Warrant and the rights and obligations
evidenced hereby shall inure to the benefit of and be binding upon the successors of the Company and the successors and permitted assigns of Holder. The provisions of this Warrant are intended to be for the benefit of all Holders from time to time
of this Warrant and shall be enforceable by any such Holder or holder of Warrant Shares. 
 l) Amendment.
This Warrant may be modified or amended or the provisions hereof waived only with the written consent of the Company and the Holder. 

m) Severability. Wherever possible, each provision of this Warrant shall be interpreted in such manner as to be
effective and valid under applicable law, but if any provision of this Warrant shall be prohibited by or invalid under applicable law, such provision shall be ineffective to the extent of such prohibition or invalidity, without invalidating the
remainder of such provisions or the remaining provisions of this Warrant. 
 n) Headings. The headings
used in this Warrant are for the convenience of reference only and shall not, for any purpose, be deemed a part of this Warrant. 
  

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 IN WITNESS WHEREOF, the Company has caused this Warrant to be executed by
its officer thereunto duly authorized. 
 Dated:             , 2010

  

			
	ACHILLION PHARMACEUTICALS, INC.
		
	By:	 	  

		 	Name:
		 	Title:









 NOTICE OF EXERCISE 

TO: ACHILLION PHARMACEUTICALS, INC. 

(1) The undersigned hereby elects to purchase             
Warrant Shares of the Company pursuant to the terms of the attached Warrant (only if exercised in full), and tenders herewith payment of the Exercise Price in full, together with all applicable transfer taxes, if any. 

(2) Payment shall take the form of (check applicable box): 

 

	 	 ̈	 in lawful money of the United States; or (if available) 



 

	 	 ̈	 the cancellation of such number of Warrant Shares as is necessary, in accordance with the formula set forth in subsection 2(c), to exercise this
Warrant with respect to the maximum number of Warrant Shares purchasable pursuant to the cashless exercise procedure set forth in subsection 2(c). 



(3) Please issue a certificate or certificates representing said Warrant Shares in the name of the undersigned or in such
other name as is specified below: 
  

					
		  	  
	  	

 The Warrant Shares shall be delivered to the following: 

 

					
		  	  
	  	
		  	  
	  	
		  	  
	  	

 (4) Accredited Investor. The undersigned is an “accredited investor”
as defined in Regulation D promulgated under the Securities Act of 1933, as amended. 
 Name of Investing Entity:
                                         
                                         
                                         
                                      

Signature of Authorized Signatory of Investing Entity:
                                         
                                         
                                  

Name of Authorized Signatory:
                                         
                                         
                                         
                             

Title of Authorized Signatory:
                                         
                                         
                                         
                               

Date:
                                         
                                         
                                         
                                         
                              







 ASSIGNMENT FORM 

(To assign the foregoing warrant, execute 

this form and supply required information. 

Do not use this form to exercise the warrant.) 

FOR VALUE RECEIVED, the foregoing Warrant and all rights evidenced thereby are hereby assigned to: 

                      
                                         
                                  

whose address is: 

                      
                                         
                                  

                      
                                         
                                  

Dated:             ,
         
 Holder’s Signature:
                                         
                                      

Holder’s Address:
                                         
                                        

                   
                                         
                     

Signature Guaranteed:
                                         
                                         
   
 NOTE: The signature to this Assignment Form must correspond with the name as it appears on the face of the
Warrant, without alteration or enlargement or any change whatsoever, and must be guaranteed by a bank or trust company. Officers of corporations and those acting in a fiduciary or other representative capacity should file proper evidence of
authority to assign the foregoing Warrant.