EXHIBIT 10.33 AMENDMENT AGREEMENT between SmithKline Beecham Corporation and NPS Pharmaceuticals, Inc. dated October 27, 1997. 27 October 97 NPS Pharmaceuticals, Inc. 420 Chipeta Way Salt Lake City, Utah 84108 RE: Amendment Agreement Dear Sirs: This Amendment Agreement (hereinafter "Amendment Agreement") will confirm that the Letter Agreement dated October 28, 1996 between NPS Pharmaceuticals, Inc., a corporation of the state of Delaware, having a place of business at 420 Chipeta Way, Salt Lake City, Utah 84108, U.S.A. (herein referred to as "NPS") and SmithKline Beecham Corporation, a corporation of the Commonwealth of Pennsylvania, having a place of business at One Franklin Plaza, Philadelphia, Pennsylvania 19101, U.S.A. (hereinafter referred to as "SB") shall be amended, effective as of the date of NPS' signature below, as follows: . In Paragraph 2.01, delete the words "four (4) years" and replace them with the words "forty nine (49) months"; . All other terms and conditions of the Letter Agreement shall remain in full force and effect. Please indicate your acceptance of this Amendment Agreement by signing and dating the duplicate copies of this letter below and returning on such fully executed copy to SB. Very truly yours, SMITHKLINE BEECHAM CORPORATION By: /k/ Tamar Howson ------------------------------------- Title: Senior VP, Business Development ---------------------------------- Date: 10/31/97 ----------------------------------- AGREED TO AND ACCEPTED: NPS PHARMACEUTICALS, INC. By: /k/ Hunter Jackson ----------------------- Title: CEO --------------------