USE OF PROCEEDS

The net proceeds we will receive from the sale of the              shares of common stock offered by us in this offering at the initial public offering price are estimated to be $             or $             million if the underwriters’ over-allotment option is exercised in full. This is based on an assumed initial public offering price of $             per share, which is the midpoint of our expected public offering range, and after deducting the underwriting discounts and commissions and the estimated offering expenses payable by us.

We intend to use the net proceeds of this offering for general corporate purposes, including acquisitions of products and product candidates and working capital, and the retirement of long-term debt. Our debt was incurred in March 2003 to assist in the retirement of our product acquisition notes payable with Elan, has a current contractual interest rate of 11% and matures in March 2008. We have not yet determined the expected expenditures and thus cannot estimate the amounts to be used for each specified purpose. The actual amounts and timing of these expenditures will vary significantly depending on a number of factors, including the amount of cash used in or generated by our operations. We continually evaluate opportunities to acquire products or product candidates, although currently we have no specific agreements with respect to any acquisitions of products or product candidates. Accordingly, our management will retain broad discretion as to the allocation of the net proceeds of this offering. We intend to invest the net proceeds of this offering in short-term, interest-bearing investment grade securities until they are used.