Exhibit 10.63

DIADEXUS, INC.

CHANGE IN CONTROL AND SEVERANCE AGREEMENT

This Change in Control and Severance Agreement (the “Agreement”) is made and
entered into by and between Jean-Frédéric Viret (“Executive”) and diaDexus, Inc.
(the “Company”), effective as of the latest date set forth by the signatures of
the parties hereto below (the “Effective Date”).

R E C I T A L S

A. It is expected that the Company from time to time will consider the
possibility of an acquisition by another company or other change in control. The
Compensation Committee (the “Compensation Committee”) of the Board of Directors
of the Company (the “Board”) recognizes that such consideration as well as the
possibility of an involuntary termination can be a distraction to Executive and
can cause Executive to consider alternative employment opportunities. The
Compensation Committee has determined that it is in the best interests of the
Company and its stockholders to assure that the Company will have the continued
dedication and objectivity of Executive, notwithstanding the possibility, threat
or occurrence of such an event.

B. The Compensation Committee believes that it is in the best interests of the
Company and its stockholders to provide Executive with an incentive to continue
Executive’s employment and to motivate Executive to maximize the value of the
Company upon a Change in Control (as defined below) for the benefit of its
stockholders.

C. The Board believes that it is imperative to provide Executive with severance
benefits upon certain terminations of Executive’s service to the Company that
enhance Executive’s financial security and provide incentive and encouragement
to Executive to remain with the Company notwithstanding the possibility of such
an event.

D. Certain capitalized terms used in this Agreement are defined in Section 7
below.

The parties hereto agree as follows:

1. Term of Agreement. This Agreement shall become effective as of the Effective
Date and terminate upon the date that all obligations of the parties hereto with
respect to this Agreement have been satisfied.

2. At-Will Employment. The Company and Executive acknowledge that Executive’s
employment is and shall continue to be “at-will,” as defined under applicable
law. If Executive’s employment terminates for any reason, Executive shall not be
entitled to any payments, benefits, damages, awards or compensation other than
as provided by this Agreement.

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3. Termination without Cause Outside of a Change in Control Period. If, on or
after the first anniversary of Executive’s commencement of employment with the
Company, Executive’s employment with the Company is terminated by the Company
other than for Cause and such termination occurs outside of a Change in Control
Period, then, subject to Executive executing a general release of all claims
against the Company and its affiliates in a form acceptable to the Company (a
“Release of Claims”) and such Release of Claims becoming effective and
irrevocable within sixty (60) days following such termination of employment,
then in addition to any accrued but unpaid salary, bonus, vacation and expense
reimbursement payable in accordance with applicable law (“Accrued Obligations”),
the Company shall provide Executive with the following:

(a) Severance. Executive shall be entitled to receive an amount equal to six
(6) months of Executive’s base salary at the rate in effect immediately prior to
Executive’s termination of employment payable in substantially equal
installments in accordance with the Company’s standard payroll policies, less
applicable withholdings, with such payments to commence on the payroll date that
immediately follows the date the Release of Claims is effective and irrevocable.

(b) Continued Healthcare. If Executive elects to receive continued healthcare
coverage pursuant to the provisions of the Consolidated Omnibus Budget
Reconciliation Act of 1985, as amended (“COBRA”), the Company shall directly
pay, or reimburse Executive for, the COBRA premium for Executive and Executive’
s covered dependents through the earlier of (i) the six (6) month anniversary of
the date of Executive’s termination of employment and (ii) the date Executive
and Executive’s covered dependents, if any, become eligible for healthcare
coverage under another employer’s plan(s). After the Company ceases to pay or
reimburse premiums pursuant to the preceding sentence, Executive may, if
eligible, elect to continue healthcare coverage at Executive’s expense in
accordance with the provisions of COBRA.

4. Certain Terminations During a Change in Control Period. If, on or after the
first anniversary of Executive’s commencement of employment with the Company,
Executive’s employment with the Company is terminated by the Company for other
than Cause or by Executive for Good Reason and such termination occurs during a
Change in Control Period, then, subject to Executive executing a Release of
Claims and such Release of Claims becoming effective and irrevocable within
sixty (60) days following such termination of employment, in addition to the
Accrued Obligations, the Company shall provide Executive with the following:

(a) Severance. Executive shall be entitled to receive an amount equal to six
(6) months of Executive’s base salary at the rate in effect immediately prior to
Executive’s termination of employment payable in substantially equal
installments in accordance with the Company’s standard payroll policies, less
applicable withholdings, with such payments to commence on the payroll date that
immediately follows the date the Release of Claims is effective and irrevocable.

(b) Continued Healthcare. If Executive elects to receive continued healthcare
coverage pursuant to the provisions of COBRA, the Company shall directly pay, or
reimburse Executive for, the COBRA premium for Executive and Executive’ s
covered dependents through the earlier of (i) the six (6) month anniversary of
the date of Executive’s termination of employment and (ii) the date Executive
and Executive’s covered dependents, if any, become eligible for healthcare

 

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coverage under another employer’s plan(s). After the Company ceases to pay
premiums pursuant to the preceding sentence, Executive may, if eligible, elect
to continue healthcare coverage at Executive’s expense in accordance with the
provisions of COBRA.

(c) Equity Awards. Effective as of immediately prior to such Covered
Termination, Executive’s options to purchase shares of the common stock of the
Company shall become vested and exercisable and/or the restrictions applicable
to unvested or restricted shares of the common stock of the Company held by
Executive shall lapse, in each case, with respect to that number of shares which
would have become vested had Executive remained in continuous service with the
Company for an additional six (6) months following the date of Executive’s
Covered Termination.

5. Other Termination. If Executive’s employment with the Company is terminated
by the Company for Cause or by Executive for any or no reason other than Good
Reason within a Change in Control Period or if Executive fails to execute a
Release of Claims or such Release of Claims fails to become effective and
irrevocable within sixty (60) days following Executive’s termination of
employment, then Executive shall not be entitled to any benefits hereunder other
than to receive Executive’s Accrued Obligations and to elect any continued
healthcare coverage as may be required under COBRA or similar state law.

6. Limitation on Payments.

(a) Parachute Payments. Any provision of this Agreement to the contrary
notwithstanding, if any payment or benefit Executive would receive from the
Company pursuant to this Agreement or otherwise (“Payment”) would (i) constitute
a “parachute payment” within the meaning of Section 280G of the Code, and
(ii) but for this sentence, be subject to the excise tax imposed by Section 4999
of the Code (the “Excise Tax”), then such Payment will be equal to the Reduced
Amount (as defined below). The “Reduced Amount” will be either (l) the largest
portion of the Payment that would result in no portion of the Payment (after
reduction) being subject to the Excise Tax or (2) the entire Payment, whichever
amount after taking into account all applicable federal, state and local
employment taxes, income taxes, and the Excise Tax (all computed at the highest
applicable marginal rate, net of the maximum reduction in federal income taxes
which could be obtained from a deduction of such state and local taxes), results
in Executive’ s receipt, on an after-tax basis, of the greatest amount of the
Payment. If a reduction in the Payment is to be made so that the Payment equals
the Reduced Amount, (x) the Payment will be paid only to the extent permitted
under the Reduced Amount alternative, and Executive will have no rights to any
additional payments and/or benefits constituting the Payment, and (y) reduction
in payments and/or benefits will occur in the following order: (1) reduction of
cash payments; (2) cancellation of accelerated vesting of equity awards other
than stock options; (3) cancellation of accelerated vesting of stock options;
and (4) reduction of other benefits paid to Executive. In the event that
acceleration of vesting of equity award compensation is to be reduced, such
acceleration of vesting will be cancelled in the reverse order of the date of
grant of Executive’s equity awards.

(b) Accounting Firm. The accounting firm engaged by the Company for general tax
purposes as of the day prior to the Change in Control will perform the
calculations set forth in

 

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Section 6(a). If the firm so engaged by the Company is serving as accountant or
auditor for the acquiring company, the Company will appoint a nationally
recognized accounting firm to make the determinations required hereunder. The
Company will bear all expenses with respect to the determinations by such firm
required to be made hereunder. The accounting firm engaged to make the
determinations hereunder will provide its calculations, together with detailed
supporting documentation, to the Company within fifteen (15) days before the
consummation of a Change in Control (if requested at that time by the Company)
or such other time as requested by the Company. If the accounting firm
determines that no Excise Tax is payable with respect to a Payment, either
before or after the application of the Reduced Amount, it will furnish the
Company with documentation reasonably acceptable to the Company that no Excise
Tax will be imposed with respect to such Payment. Any good faith determinations
of the accounting firm made hereunder will be final, binding and conclusive upon
the Company and Executive.

7. Definition of Terms. The following terms referred to in this Agreement shall
have the following meanings:

(a) Cause. “Cause” means (i) Executive’s willful failure to substantially
perform Executive’s duties for the Company (other than any such failure
resulting from Executive’s total and permanent disability); (ii) Executive’s
willful failure to carry out, or comply with, in any material respect any lawful
directive of the Board; (iii) Executive’s commission at any time of any act or
omission that results in, or may reasonably be expected to result in, a
conviction, plea of no contest, plea of nolo contendere, or imposition of
unadjudicated probation for any felony or crime involving moral turpitude;
(iv) Executive’s unlawful use (including being under the influence) or
possession of illegal drugs on the Company’s premises or while performing
Executive’s duties and responsibilities for the Company; (v) Executive’s
commission at any time of any act of fraud, embezzlement, misappropriation,
misconduct, conversion of assets of the Company, or breach of fiduciary duty
against the Company (or any predecessor thereto or successor thereof); or
(vi) Executive’s material breach of any agreement with the Company (including,
without limitation, any breach of the restrictive covenants of any such
agreement); and which, in the case of clauses (i), (ii) and (vi), continues
beyond thirty (30) days after the Company has provided Executive written notice
of such failure or breach (to the extent that, in the reasonable judgment of the
Board, such failure or breach can be cured by Executive). Whether or not an
event giving rise to “Cause” occurs will be determined by the Board in its sole
discretion.

(b) Change in Control. “Change in Control” means (i) the acquisition of the
Company by another entity, or entities acting as a group, by means of any
transaction or series of related transactions (including, without limitation,
any reorganization, merger or consolidation) that results in such entity or
entities holding more than fifty percent (50%) of the outstanding voting power
of the Company (other than a bona fide equity financing transaction or transfers
between affiliated funds) or (ii) a sale or other disposition by the Company of
all or substantially all of the assets of the Company.

 

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(c) Change in Control Period. “Change in Control Period” means that period of
time commencing on the consummation of a Change in Control and ending on the
first anniversary of such Change in Control.

(d) Good Reason. “Good Reason” means Executive’s resignation from employment
with the Company after the occurrence, without Executive’s written consent, of
any of the following on or after a Change in Control: one or more of the
following conditions occurs on or following a Change in Control without
Executive’s written consent: (i) a material diminution in Executive’s authority,
duties, or responsibilities as in effect as of immediately prior to a Change in
Control; (ii) a material reduction in Executive’s Annual Base Salary as in
effect as of immediately prior to a Change in Control (other than a reduction
that affects all senior executives of the Company to a similar degree); or(iii)
a material change in the geographic location of the principal offices at which
Executive must perform Executive’s services as of immediately prior to a Change
in Control (which shall in no event include a relocation of Executive’s
principal office of less than sixty (60) miles from South San Francisco, CA).
Notwithstanding the foregoing, in no event shall Executive have Good Reason to
terminate Executive’s employment unless Executive provides to the Company
written notice of the condition giving rise to Good Reason within sixty
(60) days after the initial occurrence of such condition, such condition
continues beyond thirty (30) days after the Company receives such notice (the
“Cure Period”) and Executive’s resignation for Good Reason is effective within
thirty (30) days after the end of the Cure Period.

8. Successors.

(a) Company’s Successors. Any successor to the Company (whether direct or
indirect and whether by purchase, merger, consolidation, liquidation or
otherwise) to all or substantially all of the Company’s business and/or assets
shall assume the obligations under this Agreement and agree expressly to perform
the obligations under this Agreement in the same manner and to the same extent
as the Company would be required to perform such obligations in the absence of a
succession. For all purposes under this Agreement, the term “Company” shall
include any successor to the Company’s business and/or assets.

(b) Executive’s Successors. The terms of this Agreement and all rights of
Executive hereunder shall inure to the benefit of, and be enforceable by,
Executive’s personal or legal representatives, executors, administrators,
successors, heirs, distributees, devisees and legatees.

9. Notices. Notices and all other communications contemplated by this Agreement
shall be in writing and shall be deemed to have been duly given when personally
delivered or one day following mailing via Federal Express or similar overnight
courier service. In the case of Executive, mailed notices shall be addressed to
Executive at Executive’s home address that the Company has on file for
Executive. In the case of the Company, mailed notices shall be addressed to its
corporate headquarters, and all notices shall be directed to the attention of
its Chief Executive Officer.

 

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10. Restrictive Covenants.

(a) Proprietary Information Agreement. Executive shall remain bound by
Executive’s obligations under the Company’s standard Proprietary Information and
Inventions Assignment Agreement (the “Proprietary Information Agreement”).

(b) Proprietary Information. Without limiting the Proprietary Information
Agreement, except as Executive reasonably and in good faith determines to be
required in the faithful performance of Executive’s duties to the Company,
Executive shall at all times before and after Executive’s termination of
employment maintain in confidence and shall not directly or indirectly, use,
disseminate, disclose or publish, for Executive’s benefit or the benefit of any
other person or entity, any confidential or proprietary information or trade
secrets of or relating to the Company, including, without limitation,
information with respect to the Company’s operations, processes, protocols,
products, inventions, business practices, finances, principals, vendors,
suppliers, customers, potential customers, marketing methods, costs, prices,
contractual relationships, regulatory status, compensation paid to employees or
other terms of employment (“Proprietary Information”), or deliver to any person
or entity, any document, record, notebook, computer program or similar
repository of or containing any such Proprietary Information. Executive’s
obligation to maintain and not use, disseminate, disclose or publish, or use for
Executive’s benefit or the benefit of any other person or entity, any
Proprietary Information after the date Executive terminates employment will
continue so long as such Proprietary Information is not, or has not by
legitimate means become, generally known and in the public domain (other than by
means of Executive’s direct or indirect disclosure of such Proprietary
Information) and continues to be maintained as Proprietary Information by the
Company. The parties hereby stipulate and agree that as between them, the
Proprietary Information identified herein is important, material and affects the
successful conduct of the businesses of the Company (and any successor or
assignee of the Company).

(c) Nonsolicitation. Without limiting the Proprietary Information Agreement,
Executive hereby agrees that Executive shall not while employed or otherwise
providing services to the Company and with respect to subsection (ii) below,
within the one year period immediately following the termination of Executive’s
employment or other service to the Company, directly or indirectly, either for
Executive or on behalf of any other person or entity, (i) recruit or otherwise
solicit or induce any employee, customer or supplier of the Company to terminate
its employment or arrangement with the Company, or otherwise change its
relationship with the Company, or (ii) hire, or cause to be hired, any person
who was employed by the Company at any time during the twelve (12)-month period
immediately prior to the date Executive terminates employment with the Company
or who thereafter becomes employed by the Company.

(d) Return of Materials. Upon termination of Executive’s employment with the
Company for any reason, Executive will promptly deliver to the Company (i) all
correspondence, drawings, manuals, letters, notes, notebooks, reports, programs,
plans, proposals, financial documents, or any other documents that are
Proprietary Information, including all physical and digital copies thereof, and
(ii) all other Company property (including, without limitation, any personal
computer or wireless device and related accessories, keys, credit cards and
other similar items) which is in Executive’s possession, custody or control.

 

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(e) Execption to Restrictive Covenants. Notwithstanding anything in this
Section 10 to the contrary, Executive may respond to a lawful and valid subpoena
or other legal process but shall give the Company the earliest possible notice
thereof, and shall, as much in advance of the return date as possible, make
available to the Company and its counsel the documents and other information
sought, and shall assist such counsel in resisting or otherwise responding to
such process.

(f) Nondisparagement. Executive agrees not to disparage the Company, any of its
products or practices, or any of its directors, officers, agents,
representatives, partners, members, equity holders or affiliates, either orally
or in writing, at any time, provided, that Executive may confer in confidence
with Executive’s legal representatives and make truthful statements as required
by law.

(g) Subsequent Employment. Prior to accepting other employment or any other
service relationship prior to the first anniversary of Executive’s termination
of employment, Executive shall provide a copy of this Section 10 to any
recruiter who assists Executive in obtaining other employment or any other
service relationship and to any employer or other person or entity with which
Executive discusses potential employment or any other service relationship.

(h) Enforceability. In the event the terms of this Section 10 shall be
determined by any court of competent jurisdiction to be unenforceable by reason
of its extending for too great a period of time or over too great a geographical
area or by reason of its being too extensive in any other respect, it will be
interpreted to extend only over the maximum period of time for which it may be
enforceable, over the maximum geographical area as to which it may be
enforceable, or to the maximum extent in all other respects as to which it may
be enforceable, all as determined by such court in such action. Any breach or
violation by Executive of the provisions of this Section 10 shall toll the
running of any time periods set forth in this Section 10 for the duration of any
such breach or violation.

(i) Affiliates. As used in this Section 6, the term “Company” shall include the
Company and any parent, affiliated, related and/or direct or indirect subsidiary
entity thereof.

11. Dispute Resolution. To ensure the timely and economical resolution of
disputes that arise in connection with this Agreement, Executive and the Company
agree that any and all controversies, claims and disputes arising out of or
relating to this Agreement, including without limitation any alleged violation
of its terms, shall be resolved by final and binding arbitration before a single
neutral arbitrator in San Mateo County, California, in accordance with the
Employment Dispute Resolution Rules of the American Arbitration Association
(“AAA”). The arbitration shall be commenced by filing a demand for arbitration
with the AAA within fourteen (14) days after the filing party has given notice
of such breach to the other party. The arbitrator shall award the prevailing
party attorneys’ fees and expert fees, if any. Notwithstanding the foregoing, it
is acknowledged that it will be impossible to measure in money the damages that
would be suffered if

 

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the parties fail to comply with any of the obligations imposed on them under
Section 10 hereof, and that in the event of any such failure, an aggrieved
person will be irreparably damaged and will not have an adequate remedy at law.
Any such person shall, therefore, be entitled to injunctive relief, including
specific performance, to enforce such obligations, and if any action shall be
brought in equity to enforce any of the provisions of Section 10 of this
Agreement, none of the parties hereto shall raise the defense that there is an
adequate remedy at law.

12. Miscellaneous Provisions.

(a) Section 409A.

(i) Separation from Service. Notwithstanding any provision to the contrary in
this Agreement, no amount deemed deferred compensation subject to Section 409A
of the Code shall be payable pursuant to Sections 3 or 4 unless Executive’s
termination of employment constitutes a “separation from service” with the
Company within the meaning of Section 409A of the Code and the Department of
Treasury regulations and other guidance promulgated thereunder (a “Separation
from Service”) and, except as provided under Section 12(a)(ii) of this
Agreement, any such amount shall be paid, or in the case of installments
commencement payment, on the sixtieth (60th) day following Executive’s
Separation from Service.

(ii) Specified Employee. Notwithstanding any provision to the contrary in this
Agreement, if Executive is deemed at the time of Executive’s Separation from
Service to be a “specified employee” for purposes of Section 409A(a)(2)(B)(i) of
the Code, to the extent delayed commencement of any portion of the benefits to
which Executive is entitled under this Agreement is required in order to avoid a
prohibited distribution under Section 409A(a)(2)(B)(i) of the Code, such portion
of Executive’s benefits shall not be provided to Executive until the earlier of
(a) the expiration of the six (6)-month period measured from the date of
Executive’s Separation from Service or (b) the date of Executive’s death. Upon
the first business day following the expiration of the applicable Code
Section 409A(a)(2)(B)(i) period, all payments deferred pursuant to this
Section 12(a)(ii) shall be paid in a lump sum to Executive, and any remaining
payments due under this Agreement shall be paid as otherwise provided herein.

(iii) Expense Reimbursements. To the extent that any reimbursements payable
pursuant to this Agreement are subject to the provisions of Section 409A of the
Code, any such reimbursements payable to Executive pursuant to this Agreement
shall be paid to Executive no later than December 31 of the year following the
year in which the expense was incurred, the amount of expenses reimbursed in one
year shall not affect the amount eligible for reimbursement in any subsequent
year, and Executive’s right to reimbursement under this Agreement will not be
subject to liquidation or exchange for another benefit.

(iv) Installments. For purposes of Section 409A of the Code, Executive’s right
to receive installment payments pursuant to Sections 3 and 4 shall be treated as
a right to receive a series of separate and distinct payments.

 

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(b) Waiver. No provision of this Agreement shall be modified, waived or
discharged unless the modification, waiver or discharge is agreed to in writing
and signed by Executive and by an authorized officer of the Company (other than
Executive). No waiver by either party of any breach of, or of compliance with,
any condition or provision of this Agreement by the other party shall be
considered a waiver of any other condition or provision or of the same condition
or provision at another time.

(c) Whole Agreement. This Agreement and the Proprietary Information Agreement
represent the entire understanding of the parties hereto with respect to the
subject matter hereof and supersede all prior arrangements and understandings
regarding same including, without limitation, any severance provisions of any
offer letter agreement or employment agreement between Executive and the
Company.

(d) Choice of Law. The validity, interpretation, construction and performance of
this Agreement shall be governed by the laws of the State of California.

(e) Severability. The invalidity or unenforceability of any provision or
provisions of this Agreement shall not affect the validity or enforceability of
any other provision hereof, which shall remain in full force and effect.

(f) Counterparts. This Agreement may be executed in counterparts, each of which
shall be deemed an original, but all of which together will constitute one and
the same instrument.

(Signature page follows)

 

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IN WITNESS WHEREOF, each of the parties has executed this Agreement, in the case
of the Company by its duly authorized officer, as of the day and year set forth
below.

 

DIADEXUS, INC. By:   /s/ Brian E. Ward Title:   CEO Date:   Feb 2, 2012

 

EXECUTIVE /s/ Jean-Frédéric Viret Jean-Frédéric Viret Date:   1/8/2012 (Jan 8,
2012)

Signature Page to Change in Control and Severance Agreement