News Releases

Pfenex Announces Closing of Public Offering of 7,820,000 Shares of Common Stock Including Full Exercise of Option to Purchase Additional Shares

SAN DIEGO, May 25, 2018 — Pfenex Inc. (NYSE American: PFNX), a clinical-stage development and licensing biotechnology company focused on leveraging its Pfenex Expression Technology® to improve protein therapies for unmet patient needs, today announced the closing of its previously announced underwritten public offering of 7,820,000 shares of its common stock at a price of $5.50 per share, which includes the full exercise by the underwriters of their option to purchase an additional 1,020,000 shares of Pfenex's common stock, pursuant to Pfenex's existing shelf registration statement. Net proceeds to Pfenex from the offering were approximately $39.4 million. Pfenex intends to use the net proceeds from the offering to fund expenses in connection with obtaining regulatory approval and commercialization and launch of PF708, to conduct ongoing research and development, and for general corporate purposes and working capital.

Barclays Capital Inc. and William Blair & Company, L.L.C. acted as joint book-running managers of this offering.

A shelf registration statement on Form S-3 relating to the common stock offered in the public offering described above was filed with the Securities and Exchange Commission (SEC) on August 27, 2015 (File No. 333-206625) and declared effective by the SEC on September 2, 2015. The offering was made only by means of a written prospectus and prospectus supplement that form a part of the registration statement. A final prospectus supplement and accompanying prospectus relating to the offering have been filed with the SEC and are available on the SEC's website at www.sec.gov. Copies of the final prospectus supplement and the accompanying prospectus may also be obtained by contacting Barclays Capital Inc., c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, NY 11717, by telephone at (888) 603-5847 or by email at barclaysprospectus@broadridge.com, or William Blair & Company, L.L.C., Attention: Prospectus Department, 150 North Riverside Plaza, Chicago, IL 60606, by telephone at (800) 621-0687 or by email at prospectus@williamblair.com.

This press release shall not constitute an offer to sell or the solicitation of an offer to buy the securities being offered, nor shall there be any sale of the securities being offered in any state or other jurisdiction in which such offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of any such state or other jurisdiction.

About Pfenex Inc.
We are a clinical-stage development and licensing biotechnology company focused on leveraging our Pfenex Expression Technology® to improve protein therapies for unmet patient needs. Using the patented Pfenex Expression Technology platform, we have created an advanced pipeline of therapeutic equivalents, vaccines, biologics and biosimilars. Our lead product candidates are PF708, a therapeutic equivalent candidate to Forteo® (teriparatide) for the treatment of osteoporosis, and our novel anthrax vaccine candidates, Px563L and RPA563, funded through an advanced development contract with the U.S. government. In addition, we are developing hematology/oncology products in collaboration with Jazz Pharmaceuticals. Furthermore, our pipeline includes biosimilar candidates to Lucentis® and Neulasta®.

For further information: Susan A. Knudson Chief Financial Officer (858) 352-4324 sknudson@pfenex.com