Table of Contents
Offer to Purchase
All Outstanding Shares of Common Stock
Penwest Pharmaceuticals Co.
$5.00 Net Per Share in Cash
West Acquisition Corp.
an indirect wholly-owned subsidiary of
Endo Pharmaceuticals Holdings Inc.
THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 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 ”).
West Acquisition Corp., a Delaware corporation (“ Purchaser ”), is offering to purchase all outstanding shares of common
stock, par value $0.001 per share (including shares of common stock issuable upon the conditional exercise of options to
purchase shares of common stock and warrants to acquire shares of common stock, each option and warrant having an exercise
price of less than $5.00 per share, collectively, the “ Shares ”), of Penwest Pharmaceuticals Co., a Washington corporation (“
Penwest ”), at a price of $5.00 per Share, net to the seller in cash, without interest (such consideration or any other
consideration paid pursuant to the Offer, the “ Offer Price ”) and less any required withholding taxes, upon the terms and
subject to the conditions set forth in this Offer to Purchase (together with any amendments or supplements hereto, this “ Offer
to Purchase ”) and in the related Letter of Transmittal (together with any amendments or supplements thereto, the “ Letter of
Transmittal ” and, together with this Offer to Purchase, the “ Offer ”). The Offer is being made in connection with the
Agreement and Plan of Merger, dated as of August 9, 2010 (together with any amendments or supplements thereto, the “
Merger Agreement ”), by and among Penwest, Endo Pharmaceuticals Holdings Inc., a Delaware corporation and our indirect
parent (“ Endo ”), and Purchaser, pursuant to which, after the completion of the Offer and the satisfaction or waiver of certain
conditions, we will be merged with and into Penwest,