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                                                                EXHIBIT 10.63


                                AMENDMENT NO. ONE
                                       TO
                                LICENSE AGREEMENT


         THIS AMENDMENT NUMBER ONE TO LICENSE AGREEMENT FOR INTERFERON GAMMA
("AMENDMENT") is entered into effective December 28, 1998, between Genentech,
Inc. ("GENENTECH") and Connetics Corporation ("CONNETICS"). Terms not otherwise
defined in this Amendment shall have the meanings as defined in the License
Agreement.

                                 R E C I T A L S

A.       The parties have previously entered into a License Agreement effective
         May 5, 1998, relating to interferon gamma (the "LICENSE AGREEMENT"),
         together with a Stock Purchase Agreement of even date (the "STOCK
         AGREEMENT").

B.       Pursuant to Section 2.3(c) of the License Agreement, Connetics had the
         right to sublicense the Agreement to InterMune, and has in fact entered
         into a sublicense to that effect dated August 21, 1998.

C.       Pursuant to Section 8.1 of the License Agreement, and the terms of the
         Stock Agreement, Connetics agreed to issue additional stock to
         Genentech if certain conditions were not met by December 28, 1998, and
         the parties anticipate that those conditions will not be met by that
         date.

D.       The parties desire to amend the License Agreement effective as of the
         date first written above, on the terms [set] forth in this Amendment,
         and simultaneously with a corresponding Amendment Number One to the 
         Stock Purchase Agreement ("STOCK AGREEMENT AMENDMENT").

NOW THEREFORE, the parties agree as follows:

                                    AGREEMENT

1.       Section 8.1 of the License Agreement is hereby amended to read in its
         entirety as follows:

         8.1 Up-front Payment. Connetics shall issue to Genentech upon the
         Original Closing Date (as defined in the Stock Agreement) shares of
         Connetics Common Stock ("Original Issuance Shares" as defined in the
         Stock Agreement) with a fair market value equal to two million dollars
         ($2,000,000), on the terms and conditions set forth in the Stock
         Agreement. If on the Notification Date or, if later, the Second Closing
         Date (each as defined in the Stock Agreement Amendment), the aggregate
         market value of the Original Issuance Shares (based on the Second
         Issuance Price, as defined in the Stock Agreement Amendment) is less
         than $4,000,000, then Connetics shall issue to Genentech on the Second
         Closing Date that number of additional shares of its Common Stock (the
         "SECOND ISSUANCE SHARES") equal to the lesser of: (i) the number of
         shares necessary to increase the aggregate market value of the Original
         Issuance Shares (based on the Second Issuance Price) and the Second
         Issuance Shares (based on the Second Issuance Price) to $4,000,000; or
         (ii) the number of shares 



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         (rounded to the nearest whole number) necessary to increase the
         aggregate number of shares of Connetics Common Stock held by Genentech
         (exclusive of any shares that Genentech has purchased from parties
         other than Connetics) to 9.9% of Connetics' total outstanding shares of
         Common Stock as of the close of business on the Notification Date or
         the Second Closing Date, if later. In lieu of all or any portion of the
         Second Issuance Shares that Connetics is obligated to issue to
         Genentech on the Second Closing Date, Connetics may elect to pay
         Genentech the cash value of such Second Issuance Shares (based on the
         Second Issuance Price). The Original Closing of the stock issuances
         shall take place as described in the Stock Agreement and the Second
         Closing of the stock issuances shall take place as described in the
         Stock Agreement Amendment. In the event that Connetics does not issue
         to Genentech all of the Second Issuance Shares or the cash value of the
         Second Issuance Shares, Genentech may, in addition to other remedies
         available to it by law or in equity, immediately terminate this
         Agreement and the licenses granted to Connetics under this Agreement.
         Such termination by Genentech of the Agreement and the licenses
         hereunder does not discharge Connetics' obligation to issue all of the
         Second Issuance Shares or to pay to Genentech the cash value of the
         Second Issuance Shares. The up-front payment shall not be creditable
         against any royalty payments owed by Connetics under Sections 8.3 and
         8.4 of this Agreement.

2.       To the extent necessary, the remaining provisions of the License
         Agreement are amended to reflect the revised definitions of Second
         Closing Date and Second Issuance Shares, as modified by the Stock
         Agreement Amendment.

3.       The remainder of the License Agreement, including the exhibits to that
         Agreement (except the Stock Agreement, to the extent modified by the
         Stock Agreement Amendment), will continue in full force and effect as
         though fully set forth in this Amendment.

IN WITNESS WHEREOF, the parties have executed this Amendment Number One to
License Agreement as of the date first written above.

Genentech, Inc.                                   Connetics Corporation


By:  /s/ W. D. Young KM                           By:  /s/ T. Wiggans
     _____________________________                     _________________________
     William D. Young                                  Thomas G. Wiggans
     Chief Operating Officer                           President and Chief 
                                                       Executive Officer



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