January 4, 2012

January 4, 2012

Xxxxxx Xxxxxxx & Co. LLC

X.X. Xxxxxx Securities LLC

c/o Morgan Xxxxxxx & Co. LLC

0000 Xxxxxxxx

Xxx Xxxx, XX 00000

Ladies and Gentlemen:

The undersigned understands that Xxxxxx Xxxxxxx & Co. LLC (“Xxxxxx Xxxxxxx”) and X.X. Xxxxxx Securities LLC (“X.X. Xxxxxx”) propose to enter into an Underwriting Agreement (the “Underwriting Agreement”) with Synageva BioPharma Corp., a Delaware corporation (the “Company”), providing for the public offering (the “Public Offering”) by the several Underwriters, including Xxxxxx Xxxxxxx and X.X. Xxxxxx (the “Underwriters”), of  shares (the “Shares”) of the Company’s common stock, $0.001 par value per share (the “Common Stock”).

To induce the Underwriters that may participate in the Public Offering to continue their efforts in connection with the Public Offering, the undersigned hereby agrees that, without the prior written consent of Xxxxxx Xxxxxxx and X.X. Xxxxxx on behalf of the Underwriters, it will not, during the period commencing on the date hereof and ending 90 days after the date of the final prospectus supplement relating to the Public Offering (the “Prospectus”), (1) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock owned by the undersigned or any other securities so owned convertible into or exercisable or exchangeable for Common Stock or (2) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of the Common Stock, whether any such transaction described in clause (1) or (2) above is to be settled by delivery of Common Stock or such other securities, in cash or otherwise. The foregoing sentence shall not apply to, (a) transfers of shares of Common Stock or any security convertible into Common Stock as a bona fide gift, (b) distributions of shares of Common Stock or any security convertible into Common Stock to limited partners or stockholders of the undersigned, (c) transfers of shares of Common Stock or any security convertible into Common Stock to any trust for the direct or indirect benefit of the undersigned or the immediate family of the undersigned, provided that any such transfer shall not involve a disposition for value or (d) transfers of Common Stock pursuant to a trading plan established pursuant to Rule 10b5-l under the Exchange Act prior to the date hereof; provided that in the case of any transfer or distribution pursuant to clauses (a), (b) or (c), (i) each donee, distributee or trustee shall sign and deliver a lock-up letter substantially in the form of this letter and (ii) no filing under Section 16(a) of the Exchange Act, reporting a reduction in beneficial ownership of shares of Common Stock, shall be required or shall be voluntarily made during the restricted period referred to in the foregoing sentence. For purposes of this Lock-Up Agreement, “immediate family” shall mean any relationship by blood, marriage or adoption, not more remote than first cousin, and “owned” shall mean Common Stock in which the undersigned has a direct pecuniary interest, expressly excluding Common Stock owned by 14159, L.P., 667, L.P., Xxxxx Biotech Fund II(A), L.P., Xxxxx Bros. Investments, L.P., Xxxxx Brothers Investments II, L.P., Xxxxx Brothers Life Sciences, L.P. and Xxxxx/Xxxxx Investments, L.P. In addition, the undersigned agrees that, without the prior written consent of Xxxxxx Xxxxxxx and X.X. Xxxxxx on behalf of the Underwriters, it will not, during the period commencing on the date hereof and ending 90 days after the date of the Prospectus, make any demand for or exercise any right with respect to, the registration of any shares of Common Stock or any security convertible into or exercisable or exchangeable for Common Stock. The undersigned also agrees and consents to the entry of stop transfer instructions with the Company’s transfer agent and registrar against the transfer of the undersigned’s shares of Common Stock except in compliance with the foregoing restrictions.

If:

(1)       during the last 17 days of the restricted period the Company issues an earnings release or material news or a material event relating to the Company occurs; or

(2)       prior to the expiration of the restricted period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the restricted period;

the restrictions imposed by this agreement shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event.

The undersigned shall not engage in any transaction that may be restricted by this agreement during the 34-day period beginning on the last day of the initial restricted period unless the undersigned requests and receives prior written confirmation from the Company or Xxxxxx Xxxxxxx and X.X. Xxxxxx that the restrictions imposed by this agreement have expired.

The undersigned understands that the Company and the Underwriters are relying upon this agreement in proceeding toward consummation of the Public Offering. The undersigned further understands that this agreement is irrevocable and shall be binding upon the undersigned’s heirs, legal representatives, successors and assigns.

Whether or not the Public Offering actually occurs depends on a number of factors, including market conditions. Any Public Offering will only be made pursuant to an Underwriting Agreement, the terms of which are subject to negotiation between the Company and the Underwriters.

This agreement shall automatically terminate upon the earliest to occur, if any, of: (1) either Xxxxxx Xxxxxxx or X.X. Xxxxxx advising the Company in writing that the Underwriters have determined not to proceed with the Public Offering, or the Company advising Xxxxxx Xxxxxxx and X. X. Xxxxxx in writing that it has determined not to proceed with the Public Offering, (2) termination of the Underwriting Agreement before the sale of any shares of Common Stock to the Underwriters and (3) January 22, 2012, in the event that the Public Offering has not been consummated by that date.

Very truly yours,

/s/ Xxxxx Xxxxx, Ph.D.

Xxxxx Xxxxx, Ph.D.

000 Xxxxxxx Xxx

(Xxxxxxx)

Xxx Xxxx, XX 00000

[Lock-up Agreement]