Exhibit 10.73

November 10, 2008

Dear Nancy:

As discussed, your employment position is being eliminated as part of a
reduction-in-force, and your employment will terminate as a result. This letter
sets forth the substance of the separation agreement (the “Agreement”) that
Anesiva Inc. (the “Company”) is offering to you to aid in your employment
transition.

1. Separation. Your last day of work with the Company and your employment
termination date will be November 21, 2008 (the “Separation Date”).

2. Accrued Salary And Paid Time Off. On the Separation Date, the Company will
pay you all accrued salary, and all accrued and unused vacation earned through
the Separation Date, subject to standard payroll deductions and withholdings.
You are entitled to these payments by law.

3. Severance Benefits. Although the Company otherwise has no obligation to do
so, if you enter this Agreement, the Company will provide you the following
severance benefits (the “Severance Benefits”), pursuant to the Company’s
Severance Benefit Plan (the “Severance Plan”, a copy of which is attached as
Exhibit A):

(a) Severance Payments. The Company will make severance payments to you in the
form of continuation of your base salary in effect on the Separation Date
through January 9, 2009. These payments will be made on the Company’s regular
pay schedule, and will be subject to standard payroll deductions and
withholdings.

(b) Health Insurance. To the extent provided by federal COBRA law or, if
applicable, state insurance laws, and by the Company’s current group health
insurance policies, you will be eligible to continue your group health insurance
benefits at your own expense following the Separation Date. Later, you may be
able to convert to an individual policy through the provider of the Company’s
health insurance, if you wish. You will be provided with a separate notice
describing your rights and obligations under COBRA. If you timely elect
continued coverage under COBRA, the Company, as an additional severance benefit
under this Agreement, will pay your COBRA premiums to continue your group health
insurance coverage at the level in effect as of the Separation Date through
January 31, 2009. The Company’s obligation to pay COBRA Premiums shall commence
when you execute this Agreement.

4. Equity. Under the terms of your stock option and/or restricted stock unit
agreement(s) and the applicable plan documents, vesting of your stock options
and restricted stock units will cease as of the Separation Date. Your right to
exercise any vested shares/units,

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and all other rights and obligations with respect to your stock options and/or
restricted stock units, will be as set forth in your stock option and/or
restricted stock unit agreements, grant notices and applicable plan documents.

5. Other Compensation Or Benefits. You acknowledge that, except as expressly
provided in this Agreement, you have not earned and will not receive any
additional compensation, severance, stock option vesting, or benefits after the
Separation Date, with the sole exception of any benefit, the right to which has
vested as of the Separation Date under the express terms of a Company benefit
plan (e.g. 401(k) plan).

6. Expense Reimbursements. You agree that, within ten (10) days of the
Separation Date, you will submit your final documented expense reimbursement
statement reflecting all business expenses you incurred through the Separation
Date, if any, for which you seek reimbursement. The Company will reimburse you
for these expenses pursuant to its regular business practice.

7. Return Of Company Property. You agree that, on the Separation Date, you will
return to the Company all Company documents (and all copies thereof) and other
Company property in your possession or control, including, but not limited to,
any Company equipment, files, correspondence, memoranda, reports, lists,
proposals, agreements, drafts, notes, minutes, drawings, records, plans,
forecasts, purchase orders, research and development information, customer
information and contact lists, sales and marketing information, personnel
information, vendor information, promotional literature and instructions,
financial and operational information, technical information, specifications,
computer-recorded information, electronic information (including email and
correspondence), other tangible property (including, but not limited to,
computers), credit cards, entry cards, identification badges and keys; and, any
materials of any kind that contain or embody any proprietary or confidential
information of the Company (and all reproductions thereof in whole or in part).
You agree to make a diligent search to locate any such documents, property and
information on the Separation Date. In addition, if you have used any personal
computer, server, or e-mail system to receive, store, review, prepare or
transmit any Company confidential or proprietary data, materials or information,
you agree to provide the Company with a computer-useable copy of such
information and then permanently delete and expunge such Company confidential or
proprietary information from those systems; and you agree to provide the Company
access to your system as requested to verify that the necessary copying and/or
deletion is done. Your timely compliance with this paragraph is a precondition
of your receipt of the Severance Benefits.

8. Proprietary Information Obligations. You acknowledge your continuing
obligations under your Employee Proprietary Information and Inventions
Agreement, a copy of which is attached hereto as Exhibit B.

9. Confidentiality. The provisions of this Agreement will be held in strictest
confidence by you and the Company and will not be publicized or disclosed in any
manner whatsoever; provided, however, that: (a) you may disclose this Agreement
in confidence to your immediate family; (b) the parties may disclose this
Agreement in confidence to their respective attorneys, accountants, auditors,
tax preparers, and financial advisors; (c) the Company may disclose this
Agreement as necessary to fulfill standard or legally required corporate
reporting or

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disclosure requirements; and (d) the parties may disclose this Agreement insofar
as such disclosure may be necessary to enforce its terms or as otherwise
required by law. In particular, and without limitation, you agree not to
disclose the terms of this Agreement to any current or former Company employee
or independent contractor.

10. Nondisparagement. You agree not to disparage the Company, its officers,
directors, employees, shareholders, subsidiaries, affiliates, and agents, in any
manner likely to be harmful to its or their business, business reputation, or
personal reputation; provided that you will respond accurately and fully to any
question, inquiry or request for information when required by legal process.

11. No Admissions. You understand and agree that the promises and payments in
consideration of this Agreement shall not be construed to be an admission of any
liability or obligation by the Company to you or to any other person, and that
the Company makes no such admission.

12. No Voluntary Adverse Action. You agree that you will not voluntarily assist
any person in bringing or pursuing any claim or action of any kind against the
Company, its parents, subsidiaries, affiliates, distributors, officers,
directors, employees or agents, unless pursuant to subpoena or other compulsion
of law.

13. Nonsolicitation of Employees. You agree that for twelve (12) months after
the Separation Date, you will not, either directly or through others, solicit,
induce, or attempt to solicit or induce any employee, consultant or independent
contractor of the Company to terminate his or her relationship with the Company.

14. Release of Claims. In exchange for the payments and other consideration
under this Agreement to which you would not otherwise be entitled (including but
not limited to the Severance Benefits) and as required by the Severance Plan,
and except as otherwise set forth in this Agreement, you hereby generally and
completely release the Company and its current and former directors, officers,
employees, shareholders, partners, agents, attorneys, predecessors, successors,
parent and subsidiary entities, insurers, affiliates, and assigns from any and
all claims, liabilities and obligations, both known and unknown, that arise out
of or are in any way related to events, acts, conduct, or omissions occurring at
any time prior to and including the date you sign this Agreement. This general
release includes, but is not limited to: (a) all claims arising out of or in any
way related to your employment with the Company or the termination of that
employment; (b) all claims related to your compensation or benefits from the
Company, including salary, bonuses, commissions, vacation pay, expense
reimbursements, severance pay, fringe benefits, stock, stock options, or any
other ownership interests in the Company; (c) all claims for breach of contract,
wrongful termination, and breach of the implied covenant of good faith and fair
dealing; (d) all tort claims, including claims for fraud, defamation, emotional
distress, and discharge in violation of public policy; and (e) all federal,
state, and local statutory claims, including claims for discrimination,
harassment, retaliation, attorneys’ fees, or other claims arising under the
federal Civil Rights Act of 1964 (as amended), the federal Americans with
Disabilities Act of 1990, the federal Age Discrimination in Employment Act of
1967 (as amended) (“ADEA”), the Pennsylvania Human Relations Act (as amended),
and the California Fair Employment and Housing Act (as amended).

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15. Exception. You are not releasing any claim that cannot be waived under
applicable state or federal law, and you are not releasing any rights that you
have to be indemnified (including any right to reimbursement of expenses)
arising under applicable law, the certificate of incorporation or by-laws (or
similar constituent documents of the Company), any indemnification agreement
between you and the Company, or any directors’ and officers’ liability insurance
policy of the Company. The foregoing notwithstanding, nothing in this Agreement
shall prevent you from filing, cooperating with, or participating in any
proceeding before the Equal Employment Opportunity Commission, the Department of
Labor, the Pennsylvania Human Relations Commission, or the California Department
of Fair Employment and Housing, except that you acknowledge and agree that you
shall not recover any monetary benefits in connection with any such claim,
charge or proceeding with regard to any claim released herein. Nothing in this
Agreement shall prevent you from challenging the validity of the release in a
legal or administrative proceeding.

16. ADEA Waiver. You acknowledge that you are knowingly and voluntarily waiving
and releasing any rights you may have under the ADEA (“ADEA Waiver”), and that
the consideration given for the ADEA Waiver and release in the preceding
paragraph hereof is in addition to anything of value to which you are already
entitled. You further acknowledge that you have been advised, as required by the
ADEA, that: (a) your ADEA Waiver and release do not apply to any rights or
claims that may arise after the date that you sign this Agreement; (b) you have
the right to consult with an attorney prior to signing this Agreement (although
you may choose voluntarily not to do so); (c) you have forty-five (45) days from
the date you receive this Agreement to consider this Agreement (although you may
choose voluntarily to sign it earlier); (d) you have seven (7) days following
the date you sign this Agreement to revoke the Agreement by providing written
notice of your revocation to the Company’s Senior Director of Human Resources;
and (e) the ADEA Waiver will not be effective until the date upon which the
revocation period has expired, which will be the eighth day after the date that
this Agreement is signed by you (the “Effective Date”). Nevertheless, your
general release of claims, except for the ADEA Waiver, is effective immediately,
and not revocable. You hereby acknowledge that the Company has provided you with
the ADEA Disclosure information (under Title 29 U.S. Code Section 626(f)(1)(H)),
enclosed with this Agreement.

17. Section 1542 Waiver. YOU UNDERSTAND THAT THIS AGREEMENT INCLUDES A RELEASE
OF ALL KNOWN AND UNKNOWN CLAIMS. In granting the release herein, which includes
claims which may be unknown to you at present, you acknowledge that you have
read and understand Section 1542 of the California Civil Code: “A general
release does not extend to claims which the creditor does not know or suspect to
exist in his or her favor at the time of executing the release, which if known
by him or her must have materially affected his or her settlement with the
debtor.” You hereby expressly waive and relinquish all rights and benefits under
that section and any law or legal principle of similar effect in any
jurisdiction with respect to the releases granted herein, including but not
limited to the release of unknown and unsuspected claims granted in this
Agreement.

18. Representations. You hereby represent that you have been paid all
compensation owed and for all hours worked, have received all the leave and
leave benefits and protections for which you are eligible, pursuant to the
Family and Medical Leave Act or otherwise, and have not suffered any on-the-job
injury for which you have not already filed a claim.

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19. Miscellaneous. This Agreement, including Exhibits A and B, constitutes the
complete, final and exclusive embodiment of the entire agreement between you and
the Company with regard to its subject matter. It is entered into without
reliance on any promise or representation, written or oral, other than those
expressly contained herein, and it supersedes any other such promises,
warranties or representations. This Agreement may not be modified or amended
except in a writing signed by both you and a duly authorized officer of the
Company. This Agreement will bind the heirs, personal representatives,
successors and assigns of both you and the Company, and inure to the benefit of
both you and the Company, their heirs, successors and assigns. If any provision
of this Agreement is determined to be invalid or unenforceable, in whole or in
part, this determination will not affect any other provision of this Agreement
and the provision in question will be modified so as to be rendered enforceable
to the fullest extent permitted by law, consistent with the intent of the
parties. This Agreement will be deemed to have been entered into and will be
construed and enforced in accordance with the laws of the State of California
without regard to conflict of laws principles. Any ambiguity in this Agreement
shall not be construed against either party as the drafter. Any waiver of a
breach of this Agreement shall be in writing and shall not be deemed to be a
waiver of any successive breach. This Agreement may be executed in counterparts
and facsimile signatures will suffice as original signatures.

If this Agreement is acceptable to you, please sign below no earlier than the
Separation Date and return the original to me. You have forty-five (45) calendar
days to decide whether you would like to accept this Agreement. The Company’s
offer contained herein will automatically expire if you do not accept it by the
date that is the later of: (a) forty-five (45) days after you receive this
letter; or (b) your Separation Date.

We wish you the best in your future endeavors.

Sincerely,

Anesiva Inc.

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By:   /s/ Jean-Frederic Viret  

Jean-Frederic Viret

Vice President and Chief Financial Officer

Exhibit A – Anesiva Inc. Severance Benefit Plan

Exhibit B – Employee Proprietary Information and Inventions Agreement

Enclosure: Disclosure under 29 U.S.C. § 626(f)(1)(H)

I HAVE READ, UNDERSTAND AND AGREE FULLY TO THE FOREGOING AGREEMENT:

 

/s/ Nancy E. Donahue NANCY DONAHUE
Date:            11/11/08