Instruction for Conditional Exercise for Tender of Option Shares and Warrant Shares
Penwest Pharmaceuticals Co.
Pursuant to the Offer to Purchase Dated August 20, 2010
West Acquisition Corp.
an indirect wholly-owned subsidiary of
Endo Pharmaceuticals Holdings Inc.
(Note: Before completing the Conditional Election Form attached hereto, you should read these instructions carefully, as well as
the Offer to Purchase)
YOU ARE NOT REQUIRED TO EXERCISE YOUR OPTIONS OR WARRANTS IN CONNECTION WITH THE OFFER. IF
YOU WISH TO CONDITIONALLY EXERCISE YOUR OPTIONS AND/OR WARRANTS AND TENDER ALL OF THE
UNDERLYING SHARES, THE CONDITIONAL ELECTION FORM MUST BE RECEIVED BY AMERICAN STOCK
TRANSFER & TRUST COMPANY (THE “DEPOSITARY”) BEFORE 12:00 MIDNIGHT, NEW YORK CITY TIME, AT THE
END OF FRIDAY, SEPTEMBER 17, 2010, UNLESS THE OFFER IS EXTENDED (SUCH DATE AND TIME, AS IT MAY BE
EXTENDED, THE “EXPIRATION DATE”). YOU MUST SIGN AND COMPLETE THIS FORM FOR YOUR DIRECTION TO
Send the Conditional Election Form to:
Note: Delivery of the Conditional Election Form to an address or a facsimile number other than as set forth above will not
constitute a valid delivery.
By signing this Conditional Election Form, you acknowledge receipt of the materials relating to the offer of West
Acquisition Corp. (“Purchaser”), a Delaware corporation and an indirect wholly-owned subsidiary of Endo Pharmaceuticals
Holdings Inc. (“Endo”), a Delaware corporation, to purchase all outstanding shares of common stock, par value $0.001 per share
(“Shares”), of Penwest Pharmaceuticals Co., a Washington corporation (“Penwest”), at a price of $5.00 per Share, net to the
seller in cash (less any required withholding taxes and without interest, the “Offer Price”) as described in the Offer to Purchase,
dated August 20, 2010 (as it may be amended or supplemented from time to time, the “Offer to Purchase” and, together with the
associated Letter of Transmittal, the “Offer”), as well as receipt of t