Exhibit 10.1

CONSULTING AGREEMENT

This CONSULTING AGREEMENT (this “Agreement”) is effective as of this 6th day of
January, 2010 (the “Effective Date”), by and between PHARMASSET, INC., with
offices at 303-A College Road East, Princeton, NJ 08540 (“PHARMASSET”) and
FREDRIC D. PRICE, of 64 Quarry Lane, Bedford, NY 10506 (“CONSULTANT”).
PHARMASSET and CONSULTANT are each referred to herein as a “Party” and
collectively as the “Parties.”

RECITALS:

WHEREAS, PHARMASSET would like CONSULTANT to provide certain consulting services
and CONSULTANT would like to provide such services upon the terms and conditions
of this Agreement.

NOW, THEREFORE, in consideration of the premises and the mutual promises
contained herein, the Parties hereto agree as follows:

1. SERVICES.

During the Term (as defined in Section 4 below), CONSULTANT agrees to provide
the consulting services as further described on Exhibit A attached hereto (the
“Services”).

2. COMPENSATION.

As consideration for CONSULTANT’s performance of the Services, PHARMASSET shall
pay CONSULTANT the amount set forth in Exhibit A (the “Consultant Fee”).
PHARMASSET shall also pay CONSULTANT for reasonable and necessary travel and
other expenses approved in advance by PHARMASSET that are incurred by CONSULTANT
in the performance of the Services. No other form of compensation shall be paid
by PHARMASSET to CONSULTANT except as otherwise approved in writing by
PHARMASSET. PHARMASSET is required to file IRS Form 1099 with the United States
Internal Revenue Service for all payees. Therefore, at PHARMASSET’s request,
CONSULTANT shall provide PHARMASSET with CONSULTANT’s Social Security or Federal
Identification Number, as applicable, upon execution of this Agreement.

3. REPRESENTATIONS AND WARRANTIES. CONSULTANT represents, warrants and covenants
to PHARMASSET that CONSULTANT:

(a) is not now a party to any agreement which would prevent CONSULTANT from
fulfilling CONSULTANT’s obligations under this Agreement and CONSULTANT will not
knowingly enter into any agreement with any other party that would in any way
prevent CONSULTANT from performing the Services;

(b) is not and has never been (i) under investigation for debarment or debarred
pursuant to the Generic Drug Enforcement Act of 1992, 21 U.S.C. § 335(a), as
amended, or any similar state law or regulation, (ii) excluded by the Office of
Inspector General pursuant to 42 U.S.C. § 1320a-7, et seq. or any state agency
from participation in any federal or state health care program; or
(iii) otherwise disqualified or restricted by the FDA pursuant to 21 C.F.R.
312.70 or any other regulatory authority;

(c) will notify PHARMASSET immediately in the event any investigation or
proceeding for debarment, exclusion or disqualification is initiated against
CONSULTANT;

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(d) is qualified and has sufficient technical expertise to perform the Services;
and

(e) will perform the Services in compliance in all material respects with all
applicable foreign, federal, state and local laws, rules and regulations.

4. TERM AND TERMINATION.

(a) Term. This Agreement shall begin as of the Effective Date and shall expire
on March 31, 2010 (the “Term”). Notwithstanding the foregoing, the Parties may
mutually agree in writing to extend the Term.

(b) Termination. This Agreement may be terminated as follows: (i) immediately by
either Party in the event of a material breach by the other Party, if such
breach is not cured within fifteen (15) days after the breaching Party’s receipt
of written notice of such breach from the non-breaching Party; and (ii) by
CONSULTANT by giving PHARMASSET fifteen (15) days prior written notice of
termination.

(c) Effect of Termination. In the event of early termination, CONSULTANT shall
immediately discontinue performing the Services.

5. CONFIDENTIALITY.

(a) Confidential Information Defined. CONSULTANT acknowledges and agrees that
any data, documents, materials or information of any type whatsoever, in
whatever form or medium, whether or not marked as “confidential” or
“proprietary,” and which could reasonably be expected to be valuable or
sensitive to PHARMASSET, including but not limited to, any information
concerning or relating to the property, products, research, development,
technology, business and affairs of PHARMASSET, that is learned, created by,
disclosed to or becomes known by CONSULTANT pursuant to this Agreement
constitutes the confidential information of PHARMASSET (collectively,
“Confidential Information”). Consultant shall treat all Confidential Information
as confidential and shall only use such Confidential Information to perform the
Services under this Agreement. Consultant shall not use any Confidential
Information for personal gain or in connection with a purchase or sale of
PHARMASSET common stock. These restrictions upon disclosure and use of
Confidential Information shall continue during the Term and shall extend beyond
the Term for a period of ten (10) years. Upon expiration or termination of this
Agreement, CONSULTANT will, at the request of PHARMASSET, return or destroy all
written and electronic copies of any Confidential Information in CONSULTANT’s
possession.

(b) Exceptions to Confidential Information. Notwithstanding the foregoing,
Confidential Information shall not include information which: (i) is or
hereafter becomes generally available to the trade or public other than by
reason of any breach hereof; (ii) was already known to CONSULTANT, prior to the
date of disclosure; (iii) is disclosed to CONSULTANT by a third party who has
the right to disclose such information without any obligations of
confidentiality; or (iv) is otherwise required to be disclosed by CONSULTANT in
order to comply with applicable legal requirements of a public authority, law,
rule of court or regulation, provided that (a) CONSULTANT promptly notifies
PHARMASSET of the obligation to disclose in order to allow PHARMASSET to object
or seek a protective order; (b) CONSULTANT only discloses the minimum amount of
Confidential Information that is necessary to comply with the required
disclosure; and (c) such information remains Confidential Information for all
other purposes.

 

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6. WORK PRODUCT.

(a) Inventions. CONSULTANT agrees that any inventions, works of authorship,
other intellectual property and/or scientific information or documentation that
is conceived, developed, originated, fixed or reduced to practice by CONSULTANT
resulting from CONSULTANT’s engagement by PHARMASSET (collectively,
“Inventions”), shall be the sole and complete property of PHARMASSET or any of
its Affiliates, and shall be treated as Confidential Information. CONSULTANT
shall fully and promptly disclose to PHARMASSET all Inventions conceived or
reduced to practice by CONSULTANT. CONSULTANT hereby assigns and conveys to
PHARMASSET or any of its Affiliates CONSULTANT’s entire right, title and
interest to any and all Inventions. CONSULTANT agrees to execute all
assignments, declarations, powers of attorney, applications or registrations for
patents and copyrights, and any other instruments deemed necessary or helpful
for PHARMASSET or its Affiliates to secure and enforce its rights hereunder.

(b) Use of PHARMASSET Materials. CONSULTANT will only use the materials provided
by or on behalf of PHARMASSET under this Agreement consistent with and as
contemplated by this Agreement and will not undertake any actions which would
jeopardize the copyright, trademark, tradename and other intellectual property
rights of PHARMASSET or its Affiliates in any such materials.

7. INDEMNIFICATION.

Each Party shall indemnify, defend and hold harmless (the “Indemnitor”) the
other Party and its respective affiliates, employees, officers, directors,
attorneys, agents, representatives, successors and assigns (collectively, the
“Indemnitee”) from and against all causes of action, liabilities, damages,
penalties, costs, expenses, fines, claims, losses, suits, demands, liens, and
all expenses of any kind or nature whatsoever (including, without limitation,
reasonable attorneys’ fees) (collectively, “Losses”) that may be incurred by,
made, charged, or instituted against an Indemnitee, and which arise out of,
result from or are based on (a) the material breach of this Agreement by the
Indemnitor; or (b) the negligence or willful misconduct of the Indemnitor,
except to the extent that such Losses are attributable to the negligence,
wrongful act or omission, willful malfeasance or misconduct by the Indemnitee.

8. MISCELLANEOUS.

(a) Entire Agreement; Modification. This Agreement together with any exhibits
attached hereto constitutes the entire understanding and agreement between the
Parties with respect to the subject matter covered herein and supercedes any and
all prior agreements, understandings, covenants, promises, warranties and
representations, oral or written, express or implied, between the Parties that
relates to the subject matter hereof. This Agreement may not be amended or
supplemented in any way except in writing, dated and signed by authorized
representatives of both Parties.

(b) Publicity. CONSULTANT shall not disclose the fact of, terms of, or subject
matter of this Agreement to any third party without the prior written consent of
PHARMASSET. CONSULTANT will not disclose any material of any kind that uses the
name, logo, trademark or tradename of PHARMASSET or any Affiliate without
PHARMASSET’s prior written consent.

(c) Independent Contractors. The Services set forth herein shall be performed by
CONSULTANT as an independent contractor and shall not create an
employer/employee relationship between CONSULTANT and PHARMASSET. Consequently,
CONSULTANT shall not be entitled to receive any employee benefits which are made
available to employees of PHARMASSET. CONSULTANT shall not have actual,
apparent, or implied authority to bind PHARMASSET to any obligation whatsoever.

 

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(d) Assignment. The Services provided herein are personal in nature and,
therefore, CONSULTANT may not assign or transfer this Agreement or any part
hereof without the express written consent of PHARMASSET. PHARMASSET may assign
its rights and obligations under this Agreement without CONSULTANT’s consent.

(e) Notice. Any notices, consents or other communications required or permitted
under this Agreement must be in writing and shall be deemed to have been duly
given as of the date (a) actually delivered by hand; (b) three (3) days after
being sent by registered or certified mail, postage prepaid, return receipt
requested; or (c) actually delivered by overnight courier, to the other Party at
the address as set forth below, or to such other address or addresses as may be
designated in writing by notice given to the other Party pursuant to this
paragraph:

 

If to CONSULTANT:    Fredric D. Price    64 Quarry Lane    Bedford, NY 10506 If
to PHARMASSET:    Pharmasset, Inc.    Attention: General Counsel    303-A
College Road East    Princeton, NJ 08540

(f) Severability; Waiver. The invalidity or unenforceability of any term or
provision of this Agreement shall not affect the validity or enforceability of
any other term or provision of this Agreement. Waiver by either Party or the
failure by either Party to claim a breach of any provision of this Agreement
shall not be deemed to constitute a waiver or estoppel with respect to any
subsequent breach of any provision hereof.

(g) Governing Law. This Agreement will be governed by and construed in
accordance with the laws of the State of New Jersey, without regard to its
conflict of laws rules or principles.

(h) Survival. All provisions of this Agreement which may reasonably be
interpreted or construed as surviving termination shall survive, including
without limitation Sections 5, 6, 7 and 8.

[Signature page follows.]

 

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IN WITNESS WHEREOF, the Parties have each caused this Agreement to be executed
by their duly authorized representatives as of the Effective Date.

 

PHARMASSET:     CONSULTANT: PHARMASSET, INC.     FREDRIC D. PRICE By:  
/S/    PAUL LUBETKIN            

/S/    FREDRIC D. PRICE        

Name:   PAUL LUBETKIN       Title:  
Executive Vice President, General Counsel, and Secretary      

 

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EXHIBIT A

SERVICES AND COMPENSATION

 

1. Services. In accordance with the terms and conditions of the Agreement to
which this Exhibit is attached and incorporated therein by reference, the
CONSULTANT shall perform the following Services:

 

  a) At the request of the PHARMASSET board or management, provide counsel and
advice about PHARMASSET’s opportunities, business development strategies and
programs, or financial or other strategies and opportunities; and

 

  b) Other services as may be requested by PHARMASSET from time to time.

 

2. Compensation.

In consideration of the performance of Services as described above, PHARMASSET
shall (a) allow CONSULTANT to retain the March 23, 2009 restricted stock grant
awarded to him as a member of its board of directors until such grant is fully
vested and shall thereafter use reasonable efforts consistent with the federal
securities laws to assist CONSULTANT in obtaining unlegended certificates, and
(b) extend until December 31, 2010 CONSULTANT’s right to exercise PHARMASSET
stock options held by him which are fully vested and exercisable as of March 17,
2010.