EXHIBIT 10.14

NEITHER THIS WARRANT NOR THE SECURITIES ISSUABLE UPON EXERCISE OF THIS WARRANT
HAVE BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED. NO SALE OR
DISPOSITION MAY BE EFFECTED EXCEPT IN COMPLIANCE WITH RULE 144 UNDER SAID ACT OR
WITHOUT AN EFFECTIVE REGISTRATION STATEMENT RELATED THERETO OR AN OPINION OF
COUNSEL FOR HOLDER, SATISFACTORY TO COMPANY, THAT SUCH REGISTRATION IS NOT
REQUIRED UNDER THE ACT OR RECEIPT OF A NO-ACTION LETTER FROM THE SECURITIES AND
EXCHANGE COMMISSION.

WARRANT TO PURCHASE 21,368 SHARES OF COMMON STOCK

February 26, 2008

THIS CERTIFIES THAT, for value received, Oxford Finance Corporation (“Holder”)
is entitled to subscribe for and purchase Twenty-One Thousand Three Hundred
Sixty-Eight (21,368) shares of fully paid and nonassessable Common Stock of
Achillion Pharmaceuticals, Inc., a Delaware corporation (the “Company”), at the
Warrant Price (as hereinafter defined), subject to the provisions and upon the
terms and conditions hereinafter set forth. As used herein, the term “Common
Stock” shall mean Company’s presently authorized common stock and any stock into
which such common stock may hereafter be converted or exchanged and the term
“Warrant Shares” shall mean the shares of Common Stock which Holder may acquire
pursuant to this Warrant and any other shares of stock into which such shares of
Common Stock may hereafter be converted or exchanged.

1. Warrant Price. The “Warrant Price” shall initially be Four and 68/100 dollars
($4.68) per share, subject to adjustment as provided in Section 7 below.

2. Conditions to Exercise. The purchase right represented by this Warrant may be
exercised at any time, or from time to time, in whole or in part during the term
commencing on the date hereof and ending at 5:00 P.M. Pacific time on the tenth
anniversary of the date of this Warrant (the “Expiration Date”).

3. Method of Exercise or Conversion; Payment; Issuance of Shares; Issuance of
New Warrant.

(a) Cash Exercise. Subject to Section 2 hereof, the purchase right represented
by this Warrant may be exercised by Holder hereof, in whole or in part, by the
surrender of this Warrant (with a duly executed Notice of Exercise in the form
attached hereto) at the principal office of Company (as set forth in Section 19
below) and by payment to Company, by check, of an amount equal to the then
applicable Warrant Price per share multiplied by the number of shares then being
purchased. In the event of any exercise of the rights represented by this
Warrant, certificates for the shares of stock so purchased shall be in the name
of, and delivered to, Holder hereof, or as such Holder may direct (subject to
the terms of transfer contained herein and upon payment by such Holder hereof of
any applicable transfer taxes). Such delivery shall be made within 30 days after
exercise of this Warrant and at Company’s expense and, unless this Warrant has
been fully exercised or expired, a new Warrant having terms and conditions
substantially identical to this Warrant and representing the portion of the
Shares, if any, with respect to which this Warrant shall not have been
exercised, shall also be issued to Holder hereof within 30 days after exercise
of this Warrant.

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(b) Conversion. In lieu of exercising this Warrant as specified in Section 3(a),
Holder may from time to time convert this Warrant, in whole or in part, into
Warrant Shares by surrender of this Warrant (with a duly executed Notice of
Exercise in the form attached hereto) at the principal office of Company, in
which event Company shall issue to Holder the number of Warrant Shares computed
using the following formula:

 

X   =   Y (A-B)        A    Where: X   =   the number of Warrant Shares to be
issued to Holder. Y   =   the number of Warrant Shares purchasable under this
Warrant (at the date of such calculation). A   =   the Fair Market Value of one
share of Company’s Common Stock (at the date of such calculation). B   =  
Warrant Price (as adjusted to the date of such calculation).

(c) Fair Market Value. For purposes of this Section 3, Fair Market Value of one
share of Company’s Common Stock shall mean:

(i) If Company’s common stock is listed on the Nasdaq Global Market or another
national securities exchange, the average of the high and low sale prices of
Common Stock quoted on the Nasdaq Global Market or on any other national
securities exchange on which the Common Stock is listed for the three (3)
trading days prior to the date of exercise; or

(ii) In the event of an exercise in connection with a merger, acquisition or
other consolidation in which Company is not the surviving entity, the per share
Fair Market Value for the Common Stock shall be the value to be received per
share of Common Stock by all holders of the Common Stock in such transaction as
determined by the Board of Directors; or

(iii) In any other instance, the per share Fair Market Value for the Common
Stock shall be as determined in the reasonable good faith judgment of Company’s
Board of Directors.

In the event of 3(c)(ii) or 3(c)(iii), above, Company’s Board of Directors shall
prepare a certificate, to be signed by an authorized officer of Company, setting
forth in reasonable detail the basis for and method of determination of the per
share Fair Market Value of the Common Stock. The Board of Directors will also
certify to Holder that this per share Fair Market Value will be applicable to
all holders of Company’s Common Stock. Such certification must be made to Holder
at least thirty (30) business days prior to the proposed effective date of the
merger, consolidation, sale, or other triggering event as defined in 3(c)(ii) or
3(c)(iii).

(d) Automatic Exercise. To the extent this Warrant is not previously exercised,
it shall be automatically exercised in accordance with Sections 3(b) and 3(c)
hereof (even if not surrendered) immediately before its expiration, involuntary
termination or cancellation unless Holder notifies Company in writing to the
contrary prior to such automatic exercise.

 

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(e) Treatment of Warrant Upon Acquisition of Company.

(i) Certain Definitions. For the purpose of this Warrant, “Acquisition” means
any sale, license, or other disposition of all or substantially all of the
assets of Company, or any reorganization, consolidation, or merger of Company,
or sale of Company securities, where the holders of Company’s securities before
the transaction beneficially own less than 50% of the outstanding voting
securities of the surviving entity after the transaction, and “Affiliate” shall
mean any person or entity that owns or controls directly or indirectly ten
(10) percent or more of the stock of Company, any person or entity that controls
or is controlled by or is under common control with such persons or entities,
and each of such person’s or entity’s officers, directors, joint venturers or
partners, as applicable.

(ii) Cash Acquisition. In the event of an Acquisition in which the sole
consideration is cash, Holder may either (a) exercise its conversion or purchase
right under this Warrant and such exercise will be deemed effective immediately
prior to the consummation of such Acquisition or (b) permit the Warrant to
expire upon the consummation of such Acquisition. Company shall provide Holder
with written notice of any proposed Acquisition together with such reasonable
information as 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) business days prior to the closing of the proposed
Acquisition.

(iii) Asset Sale. In the event of an Acquisition that is an arms length sale of
all or substantially all of Company’s assets (and only its assets) to a third
party that is not an Affiliate of Company (a “True Asset Sale”), Holder may
either (a) exercise its conversion or purchase right under this Warrant and such
exercise will be deemed effective immediately prior to the consummation of such
Acquisition or (b) permit the Warrant to continue until the Expiration Date if
Company continues as a going concern following the closing of any such True
Asset Sale. Company shall provide Holder with written notice of any proposed
asset sale together with such reasonable information as Holder may request in
connection with such asset sale giving rise to such notice, which is to be
delivered to Holder not less than ten (10) business days prior to the closing of
the proposed asset sale.

(iv) Assumption of Warrant. Upon the closing of any Acquisition other than those
particularly described in subsections (ii) and (iii) above, the successor entity
shall assume the obligations of this Warrant, and this Warrant shall be
exercisable for the same securities, cash, and property as would be payable for
the Warrant Shares issuable upon exercise of the unexercised portion of this
Warrant as if such Warrant Shares were outstanding on the record date for the
Acquisition and subsequent closing. The Warrant Price and/or number of Warrant
Shares shall be adjusted accordingly.

4. Representations and Warranties of Holder and Company.

(a) Representations and Warranties by Holder. Holder represents and warrants to
Company with respect to this purchase as follows:

(i) Evaluation. Holder has substantial experience in evaluating and investing in
private placement transactions of securities of companies similar to Company so
that Holder is capable of evaluating the merits and risks of its investment in
Company and has the capacity to protect its interests.

(ii) Resale. Except for transfers to an affiliate of Holder, Holder is acquiring
this Warrant

 

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and the Warrant Shares issuable upon exercise of this Warrant (collectively the
“Securities”) for investment for its own account and not with a view to, or for
resale in connection with, any distribution thereof. Holder understands that the
Securities have not been registered under the Securities Act of 1933, as amended
(the “Act”) by reason of a specific exemption from the registration provisions
of the Act which depends upon, among other things, the bona fide nature of the
investment intent as expressed herein.

(iii) Rule 144. Holder acknowledges that the Securities must be held
indefinitely unless subsequently registered under the Act or an exemption from
such registration is available. Holder is aware of the provisions of Rule 144
promulgated under the Act.

(iv) Accredited Investor. Holder is an “accredited investor” within the meaning
of Regulation D promulgated under the Act.

(v) Opportunity To Discuss. Holder has had an opportunity to discuss Company’s
business, management and financial affairs with its management and an
opportunity to review Company’s facilities. Holder understands that such
discussions, as well as the written information issued by Company, were intended
to describe the aspects of Company’s business and prospects which Company
believes to be material but were not necessarily a thorough or exhaustive
description.

(b) Representations and Warranties by Company. Company hereby represents and
warrants to Holder that the statements in the following paragraphs of this
Section 4(b) are true and correct (a) as of the date hereof and (b) except where
any such representation and warranty relates specifically to an earlier date, as
of the date of any exercise of this Warrant.

(i) Corporate Organization and Authority. Company (a) is a corporation duly
organized, validly existing, and in good standing in its jurisdiction of
incorporation, (b) has the corporate power and authority to own and operate its
properties and to carry on its business as now conducted and as proposed to be
conducted; and (c) is qualified as a foreign corporation in all jurisdictions
where such qualification is required.

(ii) Corporate Power. Company has all requisite legal and corporate power and
authority to execute, issue and deliver this Warrant, to issue the Warrant
Shares issuable upon exercise or conversion of this Warrant, and to carry out
and perform its obligations under this Warrant and any related agreements.

(iii) Authorization; Enforceability. All corporate action on the part of
Company, its officers, directors and shareholders necessary for the
authorization, execution, delivery and performance of its obligations under this
Warrant and for the authorization, issuance and delivery of this Warrant and the
Warrant Shares issuable upon exercise of this Warrant has been taken and this
Warrant constitutes the legally binding and valid obligation of Company
enforceable in accordance with its terms.

(iv) Valid Issuance of Warrant and Warrant Shares. This Warrant has been validly
issued and is free of restrictions on transfer other than restrictions on
transfer set forth herein and under applicable state and federal securities
laws. The Warrant Shares issuable upon conversion of this Warrant, when issued,
sold and delivered in accordance with the terms of this Warrant for the
consideration expressed herein, will be duly and validly issued, fully paid and
nonassessable, and will be free of restrictions on transfer other than
restrictions on transfer under this Warrant and under applicable state and
federal securities laws. Subject to

 

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applicable restrictions on transfer, the issuance and delivery of this Warrant
and the Warrant Shares issuable upon exercise or conversion of this Warrant are
not subject to any preemptive or other similar rights or any liens or
encumbrances except as specifically set forth in Company’s Certificate of
Incorporation or this Warrant. The offer, sale and issuance of the Warrant
Shares, as contemplated by this Warrant, are exempt from the prospectus and
registration requirements of applicable United States federal and state security
laws, and neither Company nor any authorized agent acting on its behalf has or
will take any action hereafter that would cause the loss of such exemption.

(v) No Conflict. The execution, delivery, and performance of this Warrant will
not result in (a) any violation of, be in conflict with, or constitute a default
under, with or without the passage of time or the giving of notice (1) any
provision of Company’s Certificate of Incorporation or by-laws; (2) any
provision of any judgment, decree, or order to which Company is a party, by
which it is bound, or to which any of its material assets are subject; (3) any
contract, obligation, or commitment to which Company is a party or by which it
is bound; or (4) any statute, rule, or governmental regulation applicable to
Company, or (b) the creation of any lien, charge or encumbrance upon any assets
of Company.

(vi) Reports. Company has previously furnished or made available to Holder
complete and accurate copies, as amended or supplemented, of its (a) Annual
Report on Form 10-K for the fiscal year ended December 31, 2006, as filed with
the Securities and Exchange Commission (the “SEC”), and (b) all other reports
filed by Company under Section 13 or subsections (a) or (c) of Section 14 of the
Securities Exchange Act of 1934 (as amended, the “Exchange Act”) with the SEC
since December 31, 2006 (such reports are collectively referred to herein as the
“Company Reports”). The Company Reports constitute all of the documents required
to be filed by Company under Section 13 or subsections (a) or (c) of Section 14
of the Exchange Act with the SEC from December 31, 2006 through the date of this
Warrant.

5. Legends.

(a) Legend. Each certificate representing the Warrant Shares shall be endorsed
with the following legend:

THESE SECURITIES HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 AND
MAY NOT BE TRANSFERRED UNLESS COVERED BY AN EFFECTIVE REGISTRATION STATEMENT
UNDER SAID ACT, A “NO ACTION” LETTER FROM THE SECURITIES AND EXCHANGE COMMISSION
WITH RESPECT TO SUCH TRANSFER, A TRANSFER MEETING THE REQUIREMENTS OF RULE 144
OF THE SECURITIES AND EXCHANGE COMMISSION, OR (IF REASONABLY REQUIRED BY
COMPANY) AN OPINION OF COUNSEL SATISFACTORY TO COMPANY TO THE EFFECT THAT ANY
SUCH TRANSFER IS EXEMPT FROM SUCH REGISTRATION.

Company need not enter into its stock records a transfer of Warrant Shares
unless the conditions specified in the foregoing legend are satisfied. Company
may also instruct its transfer agent not to allow the transfer of any of the
Warrant Shares unless the conditions specified in the foregoing legend are
satisfied.

(b) Removal of Legend and Transfer Restrictions. The legend relating to the Act
endorsed on a certificate pursuant to paragraph 5(a) of this Warrant shall be
removed and Company shall issue a certificate without such legend to Holder if
(i) the Securities are registered under the Act and a prospectus meeting the
requirements of Section 10 of the Act is available or (ii) Holder provides to

 

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Company an opinion of counsel for Holder reasonably satisfactory to Company, a
no-action letter or interpretive opinion of the staff of the SEC reasonably
satisfactory to Company, or other evidence reasonably satisfactory to Company,
to the effect that public sale, transfer or assignment of the Securities may be
made without registration and without compliance with any restriction such as
Rule 144.

6. Condition of Transfer or Exercise of Warrant. It shall be a condition to any
transfer or exercise of this Warrant that at the time of such transfer or
exercise, Holder shall provide Company with a representation in writing that
Holder or transferee is acquiring this Warrant and the shares of Common Stock to
be issued upon exercise for investment purposes only and not with a view to any
sale or distribution, or will provide Company with a statement of pertinent
facts covering any proposed distribution. As a further condition to any transfer
of this Warrant or any or all of the shares of Common Stock issuable upon
exercise of this Warrant, other than a transfer registered under the Act,
Company may request a legal opinion, in form and substance satisfactory to
Company and its counsel, reciting the pertinent circumstances surrounding the
proposed transfer and stating that such transfer is exempt from the registration
and prospectus delivery requirements of the Act. Company shall not require
Holder to provide an opinion of counsel if the transfer is to an affiliate of
Holder. Each certificate evidencing the Warrant Shares issued upon exercise of
this Warrant or upon any transfer of the Warrant Shares (other than a transfer
registered under the Act or any subsequent transfer of shares so registered)
shall, at Company’s option, if the Warrant Shares are not freely saleable under
Rule 144(b)(1)(ii) under the Act, contain a legend in form and substance
satisfactory to Company and its counsel, restricting the transfer of the Warrant
Shares to sales or other dispositions exempt from the requirements of the Act.
As further condition to each transfer, at the request of Company, Holder shall
surrender this Warrant to Company and the transferee shall receive and accept a
Warrant, of like tenor and date, executed by Company.

7. Adjustment for Certain Events. The number and kind of securities purchasable
upon the exercise of this Warrant and the Warrant Price shall be subject to
adjustment from time to time upon the occurrence of certain events, as follows:

(a) Reclassification or Merger. In case of (i) any reclassification or change of
securities of the class issuable upon exercise of this Warrant (other than a
change in par value, or from par value to no par value, or from no par value to
par value, or as a result of a subdivision or combination), (ii) any merger of
Company with or into another corporation (other than a merger with another
corporation in which Company is the acquiring and the surviving corporation and
which does not result in any reclassification or change of outstanding
securities issuable upon exercise of this Warrant), or (iii) any sale of all or
substantially all of the assets of Company, Company, or such successor or
purchasing corporation, as the case may be, shall duly execute and deliver to
Holder a new Warrant (in form and substance satisfactory to Holder of this
Warrant), or Company shall make appropriate provision without the issuance of a
new Warrant, so that Holder shall have the right to receive, at a total purchase
price not to exceed that payable upon the exercise of the unexercised portion of
this Warrant, and in lieu of the Warrant Shares theretofore issuable upon
exercise or conversion of this Warrant, the kind and amount of shares of stock,
other securities, money and property receivable upon such reclassification,
change, merger or sale by a holder of the number of shares of Common Stock then
purchasable under this Warrant, or in the case of such a merger or sale in which
the consideration paid consists all or in part of assets other than securities
of the successor or purchasing corporation, at the option of Holder, the
securities of the successor or purchasing corporation having a value at the time
of the transaction equivalent to the value of the Warrant Shares purchasable
upon exercise of this Warrant at the time of the transaction. Any new Warrant
shall provide for adjustments that shall be as nearly equivalent as may be
practicable to the adjustments provided for in this Section 7. The provisions of
this subparagraph (a) shall similarly apply to successive reclassifications,
changes, mergers and transfers.

 

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(b) Stock Splits and Combinations of Common Stock. If outstanding shares of
Company’s Common Stock shall be subdivided into a greater number of shares or a
dividend in Common Stock shall be paid in respect of Common Stock, the Warrant
Price in effect immediately prior to such subdivision or at the record date of
such dividend shall simultaneously with the effectiveness of such subdivision or
immediately after the record date of such dividend be proportionately reduced
and if outstanding shares of Common Stock shall be combined into a smaller
number of shares, the Warrant Price with respect to such shares of Common Stock
in effect immediately prior to such combination shall, simultaneously with the
effectiveness of such combination, be proportionately increased. When any
adjustment is required to be made in the Warrant Price pursuant to this
Section 7(b), the number of Shares purchasable upon the exercise of this Warrant
shall be changed to the number determined by dividing (i) an amount equal to the
number of shares issuable upon the exercise of this Warrant immediately prior to
such adjustment, by (ii) the Warrant Price in effect immediately after such
adjustment.

8. Notice of Adjustments. Whenever any Warrant Price or the kind or number of
securities issuable under this Warrant shall be adjusted pursuant to Section 7
hereof, Company shall prepare a certificate signed by an officer of Company
setting forth, in reasonable detail, the event requiring the adjustment, the
amount of the adjustment, the method by which such adjustment was calculated,
and the Warrant Price and number or kind of shares issuable upon exercise of
this Warrant after giving effect to such adjustment, and shall cause copies of
such certificate to be mailed (by certified or registered mail, return receipt
required, postage prepaid) within thirty (30) days of such adjustment to Holder
as set forth in Section 19 hereof.

9. Financial and Other Reports. From time to time up to the earlier of the
Expiration Date or the complete exercise of this Warrant, Company shall furnish
to Holder (i) within 90 days after the close of each fiscal year of Company an
audited balance sheet and statement of changes in financial position at and as
of the end of such fiscal year, together with an audited statement of income for
such fiscal year; and (ii) within 45 days after the close of each fiscal quarter
of Company, an unaudited balance sheet and statement of cash flows at and as of
the end of such quarter, together with an unaudited statement of income for such
quarter; provided, however, that so long as Company remains subject to and in
compliance with the Exchange Act, Company will be deemed to have complied with
such requirements upon the timely filing of annual and quarterly reports as
required by the Exchange Act.

10. Transferability of Warrant. This Warrant is transferable on the books of
Company at its principal office by the registered Holder hereof upon surrender
of this Warrant properly endorsed, subject to compliance with Section 6 and
applicable federal and state securities laws. Company shall issue and deliver to
the transferee a new Warrant representing the Warrant so transferred. Upon any
partial transfer, Company will issue and deliver to Holder a new Warrant with
respect to the Warrant not so transferred. Holder shall not have any right to
transfer any portion of this Warrant to any direct competitor of Company.

11. No Fractional Shares. No fractional share of Common Stock will be issued in
connection with any exercise or conversion hereunder, but in lieu of such
fractional share Company shall make a cash payment therefor upon the basis of
the Warrant Price then in effect.

12. Charges, Taxes and Expenses. Issuance of certificates for shares of Common
Stock upon the exercise or conversion of this Warrant shall be made without
charge to Holder for any United States or state of the United States documentary
stamp tax or other incidental expense with respect to the issuance of such
certificate, all of which taxes and expenses shall be paid by Company, and such
certificates shall be issued in the name of Holder.

 

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13. No Shareholder Rights Until Exercise. Except as expressly provided herein,
this Warrant does not entitle Holder to any voting rights or other rights as a
shareholder of Company prior to the exercise hereof.

14. Registry of Warrant. Company shall maintain a registry showing the name and
address of the registered Holder of this Warrant. This Warrant may be
surrendered for exchange or exercise, in accordance with its terms, at such
office or agency of Company.

16. Loss, Theft, Destruction or Mutilation of Warrant. Upon receipt by Company
of evidence reasonably satisfactory to it of the loss, theft, destruction or
mutilation of this Warrant, and, in the case of loss, theft, or destruction, of
indemnity reasonably satisfactory to it, and, if mutilated, upon surrender and
cancellation of this Warrant, Company will execute and deliver a new Warrant,
having terms and conditions substantially identical to this Warrant, in lieu
hereof.

17. Miscellaneous.

(a) Issue Date. The provisions of this Warrant shall be construed and shall be
given effect in all respect as if it had been issued and delivered by Company on
the date hereof.

(b) Successors. This Warrant shall be binding upon any successors or assigns of
Company.

(c) Headings. The headings used in this Warrant are used for convenience only
and are not to be considered in construing or interpreting this Warrant.

(d) Saturdays, Sundays, Holidays. 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 or a Sunday or shall be a legal holiday in the State of Connecticut,
then such action may be taken or such right may be exercised on the next
succeeding day not a legal holiday.

(e) Attorney’s Fees. In the event of any dispute between the parties concerning
the terms and provisions of this Warrant, the party prevailing in such dispute
shall be entitled to collect from the other party all costs incurred in such
dispute, including reasonable attorney’s fees.

18. No Impairment. Company will not, by amendment of its Certificate of
Incorporation or any other voluntary action, avoid or seek to avoid the
observance or performance of any of the terms of this Warrant, but will at all
times in good faith assist in the carrying out of all such terms and in the
taking of all such action as may be necessary or appropriate in order to protect
the rights of Holder hereof against impairment.

19. Addresses. Any notice required or permitted hereunder shall be in writing
and shall be mailed by overnight courier, registered or certified mail, return
receipt requested, and postage prepaid, or otherwise delivered by hand or by
messenger, addressed as set forth below, or at such other address as Company or
Holder hereof shall have furnished to the other party in accordance with the
delivery instructions set forth in this Section 19.

 

If to Company:   Achillion Pharmaceuticals, Inc.   300 George Street   New
Haven, CT 06511   Attn: Mary Kay Fenton, Chief Financial Officer

 

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With a copy to:   Wilmer Cutler Pickering Hale and Dorr, LLP   WilmerHale
Venture Group   Bay Colony Corporate Center  

1100 Winter Street

Waltham, MA 02451

  Attn: Susan Mazur, Esq. If to Holder:   Oxford Finance Corporation  

133 North Fairfax Street

Alexandria, VA 22314

  Attention:   Timothy A. Lex     Executive Vice President & Chief Operating
Officer

If mailed by registered or certified mail, return receipt requested, and postage
prepaid, notice shall be deemed to be given five (5) days after being sent, and
if sent by overnight courier, by hand or by messenger, notice shall be deemed to
be given when delivered (if on a business day, and if not, on the next business
day).

20. WAIVER OF JURY TRIAL. EACH OF THE PARTIES HERETO HEREBY WAIVES TO THE
FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY RIGHT IT MAY HAVE TO A TRIAL BY
JURY IN RESPECT OF ANY LITIGATION DIRECTLY OR INDIRECTLY ARISING OUT OF, UNDER
OR IN CONNECTION WITH THIS WARRANT OR THE WARRANT SHARES.

21. GOVERNING LAW. THIS WARRANT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE
WITH THE LAWS OF THE STATE OF DELAWARE.

 

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

 

ACHILLION PHARMACEUTICALS, INC. By:  

 

Name:   Mary Kay Fenton Title:   Chief Financial Officer Dated as of February
26, 2008.

SIGNATURE PAGE

OXFORD WARRANT

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NOTICE OF EXERCISE

 

To:   Achillion Pharmaceuticals, Inc.

300 George Street

New Haven, CT 06511

Attn:   Mary Kay Fenton, Chief Financial Officer

 

1. The undersigned Warrantholder (“Holder”) elects to acquire shares of the
Common Stock (the “Common Stock”) of Achillion Pharmaceuticals, Inc. (the
“Company”), pursuant to the terms of the Stock Purchase Warrant dated
February 26, 2008 (the “Warrant”).

 

2. Holder exercises its rights under the Warrant as set forth below:

 

  (            ) Holder elects to purchase                      shares of Common
Stock as provided in Section 3(a) and tenders herewith a check in the amount of
$                     as payment of the purchase price.

 

  (            ) Holder elects to convert the purchase rights into shares of
Common Stock as provided in Section 3(b) of the Warrant.

 

3. Holder surrenders the Warrant with this Notice of Exercise.

Holder represents that it is acquiring the aforesaid shares of Common Stock for
investment and not with a view to or for resale in connection with distribution
and that Holder has no present intention of distributing or reselling the
shares.

Please issue a certificate representing the shares of the Common Stock in the
name of Holder or in such other name as is specified below:

 

Name:  

 

  Address:  

 

  Taxpayer I.D.:  

 

 

 

OXFORD FINANCE CORPORATION By:  

 

Name:  

 

Title:  

 

Date:                    ,200