RooM 5 6 00

3 0 RoCKEFELLER PLAZA

NEw YoRK, N .Y. 10112

(212) 649 -5600

october 28, 1991

Dear Michael:

Many thanks for your letter and I, too, enjoyed our conversation at the Venrock dinner in Pocantico. Your work is tremendously exciting and I can understand the enthusiasm which fuels your energy in this work. I enjoyed reading the article you enclosed and am impressed by the people you have attracted to your Board of Directors. This says a great deal in itself.

Your invitation to visit is tempting, indeed. I don't get to San Francisco as often as I'd like, but will keep your suggestion very much in mind for future trips. Thank you for the suggestion.

With kind regards,

!Jr. Michael L. Riordan President Gilead Sciences 346 Lakeside Drive, Foster City, California 94404

Sincerely,

David Rockefeller

R o oM 5 6 00

Dear Michael:

3 0 RoCKEFELLER PLAZA

NEW Y ORK, N.Y. 10112

January 14, 1992

(212) 649-56 0 0

Thank you for your most recent letter and the newly printed prospectus. You must be very pleased with your initial public offering, and I hope the response is all that you hope for. Although I am sure your friends in Venrock have already received a copy, I am forwarding this one to my colleagues in Rockefeller & Company. I am sure they will find it of interest.

With best wishes for the New Year,

Dr. Michael L. Riordan President

-lilleaa~·scierices - - -346 Lakeside Drive Foster City, California 94404

Sincerely,

David Rockefeller