Pinnacle Holdco Parent, Inc. c/o Kohlberg Kravis Roberts & Co. L.P. 9 West 57th St., Suite 4200 New York, New York 10019 Re: Transaction Fee Letter Ladies and Gentlemen:

Exhibit 10.20

December 2, 2013

Pinnacle Holdco Parent, Inc.
x/x Xxxxxxxx Xxxxxx Xxxxxxx & Co. L.P.
0 Xxxx 00xx Xx., Xxxxx 0000
Xxx Xxxx, Xxx Xxxx 00000

Re:  Transaction Fee Letter

Ladies and Gentlemen:

Reference is made to the Monitoring Agreement, dated as of September 23, 2013 (the “Monitoring Agreement”), by and between Pinnacle Holdco Parent, Inc. (the “Company”) and Kohlberg Kravis Xxxxxxx & Co. L.P. (the “Manager”).

1. In consideration for our services rendered in connection with the transactions contemplated in the Stock Purchase Agreement (the “Purchase Agreement”), dated as of November 12, 2013, by and among Pharmaceutical Research Associates, Inc., a Virginia corporation and wholly owned subsidiary of the Company, and CRI Holding Company, LLC, a Delaware company (the “Transaction”) and pursuant to paragraph 2 of the Monitoring Agreement, the Company agrees to pay the Manager (or a designee of the Manager) a transaction fee payable in cash, in an amount equal to $850,000 payable concurrently with the completion of the Transaction.  All amounts paid pursuant to this Section 1 shall be paid in the respective proportions and to the respective bank accounts designated by the Manager (or its designee) and shall not be refundable under any circumstances.

2. Any advice or opinions provided by us may not be disclosed or referred to publicly or to any third party (other than the Company’s or any of its affiliate’s legal, tax, financial or other advisors), except in accordance with our prior written consent.

3. We shall act as an independent contractor, with duties solely to the Company.  The provisions hereof shall inure to the benefit of and shall be binding upon the parties hereto and their respective successors and assigns.  Nothing in this agreement, expressed or implied, is intended to confer on any person other than the parties hereto or their respective successors and assigns any rights or remedies under or by reason of this agreement.  Without limiting the generality of the foregoing, the parties acknowledge that nothing in this agreement, expressed or implied, is intended to confer on any present or future holders of any securities of the Company or its subsidiaries or affiliates, or any present or future creditor of the Company or its subsidiaries or affiliates, any rights or remedies under or by reason of this agreement or any performance hereunder.

4. This agreement shall be governed by and construed in accordance with the laws of the State of New York.

5. This agreement shall continue in effect unless amended or terminated by mutual consent of the Company and the Manager.

6. Each party hereto represents and warrants that the execution and delivery of this agreement by such party has been duly authorized by all necessary action of such party.

7. If any term or provision of this agreement or the application thereof shall, in any jurisdiction and to any extent, be invalid and unenforceable, such term or provision shall be ineffective, as to such jurisdiction, solely to the extent of such invalidity or unenforceability without rendering invalid or unenforceable any remaining terms or provisions hereof or affecting the validity or enforceability of such term or provision in any other jurisdiction.  To the extent permitted by applicable law, the parties hereto waive any provision of law that renders any term or provision of this agreement invalid or unenforceable in any respect.

8. Each party hereto waives all right to trial by jury in any action, proceeding or counterclaim (whether based upon contract, tort or otherwise) related to or arising out of our retention pursuant to, or our performance of the services contemplated by this agreement.

9. The Company hereby acknowledges and agrees that the services provided by the Manager hereunder are being provided subject to the terms of the Indemnification Agreement, dated as of the date hereof, between the Company, PRA Holdings, Inc., the Manager and the other parties thereto (as the same may be amended from time to time, the “Indemnification Agreement”).

10. Any notices or other communications required or permitted by this agreement will be sufficiently given if delivered personally or sent by facsimile with confirmed receipt, or by overnight courier, addressed as follows or to such other address of which the parties may have given written notice:

if to the Manager:

Kohlberg Kravis Xxxxxxx & Co. L.P.

0 Xxxx 00xx Xx., Xxxxx 0000

Xxx Xxxx, Xxx Xxxx 00000

Attention: Xxxxx Xxxxxx, Esq.

Facsimile: (000) 000-0000

with a copy (which will not constitute notice) to:

Xxxxxxx Xxxxxxx & Xxxxxxxx LLP

000 Xxxxxxxxx Xxxxxx

Xxx Xxxx, Xxx Xxxx 00000

Attention:  Xxxx Xxxxxxxx, Esq.

Facsimile:  (000) 000-0000

if to the Company:

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Pinnacle Holdco Parent, Inc.
x/x Xxxxxxxx Xxxxxx Xxxxxxx & Xx. X.X.
0 Xxxx 00xx Xxxxxx, Xxxxx 0000

Xxx Xxxx, Xxx Xxxx 00000

Attention:  Xxxxx Xxxxxx, Esq.
Facsimile:  (000) 000-0000

with a copy (which will not constitute notice) to:

Xxxxxxx Xxxxxxx & Xxxxxxxx LLP

000 Xxxxxxxxx Xxxxxx

Xxx Xxxx, Xxx Xxxx 00000

Attention:  Xxxx Xxxxxxxx, Esq.

Facsimile:  (000) 000-0000

11. It is expressly understood that the foregoing Sections 2 through 5 and 7 through 12 in their entirety, survive any termination of this agreement.

12. This agreement may be executed in counterparts (including by facsimile), each of which shall be deemed an original agreement, but all of which together shall constitute one and the same instrument.

[remainder of page intentionally left blank]

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If the foregoing sets forth the understanding between us, please so indicate on the enclosed signed copy of this letter in the space provided therefor and return it to us, whereupon this letter shall constitute a binding agreement among us.

	Very truly yours,
	KOHLBERG KRAVIS XXXXXXX & CO. L.P.
	By:	/s/ Xxxxxxx Xxxxxxxxxx
		Name: Xxxxxxx Xxxxxxxxxx
		Title: Chief Financial Officer

[Signature Page to Transaction Fee Letter]

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AGREED TO AND ACCEPTED BY:
	PINNACLE HOLDCO PARENT, INC.
	By:	/s/ Xxx X. Xxxxxx
		Name: Xxx X. Xxxxxx
		Title: Treasurer and Assistant Secretary

[Signature Page to Transaction Fee Letter]

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