Prothena Announces Pricing of Public Offering of 4,750,000 Ordinary Shares

DUBLIN, Ireland, June 25, 2014 (GLOBE NEWSWIRE) -- Prothena Corporation plc (Nasdaq:PRTA), a clinical stage biotechnology company focused on the discovery, development and commercialization of novel antibodies for the potential treatment of diseases that involve protein misfolding or cell adhesion, announced today that it has priced an underwritten public offering of 4,750,000 of its ordinary shares at a price to the public of $22.50 per ordinary share, before underwriting discounts and commissions. All of the ordinary shares in the offering are to be sold by Prothena. In addition, Prothena has granted the underwriters a 30-day option to purchase up to an additional 712,500 ordinary shares.

Net proceeds to Prothena from the ordinary shares to be sold by Prothena in the offering are expected to be $102.5 million, after deducting the underwriting discount and estimated offering expenses, but excluding any exercise of the underwriters' option to purchase additional ordinary shares. The offering is expected to close on June 30, 2014, subject to customary closing conditions.

Entities managed by Woodford Investment Management LLP have agreed to purchase 2,222,222 of Prothena's ordinary shares in this offering at the public offering price. Such ordinary shares will be purchased by the underwriters at the public offering price without the underwriting discount.

BofA Merrill Lynch, Credit Suisse and RBC Capital Markets are acting as joint book-running managers, and Wedbush PacGrow Life Sciences and Ladenburg Thalmann are acting as co-managers for the offering.

The ordinary shares of Prothena described above were offered only by means of a prospectus supplement and base prospectus forming part of an effective shelf registration statement previously filed with the Securities and Exchange Commission. Copies of the prospectus for this offering may be obtained, when available, by contacting BofA Merrill Lynch, 222 Broadway, New York, NY 10038, Attn: Prospectus Department, email:; Credit Suisse Securities (USA) LLC, One Madison Avenue, New York, NY 10010; Tel: 1-800-221-1037; Attn: Credit Suisse Prospectus Department, email:; or RBC Capital Markets, LLC, 3 World Financial Center, 200 Vesey Street, 8th Floor, New York, NY 10281-8098; Attention: Equity Syndicate; Tel: 877-822-4089; Fax: 212-428-6260.

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

CONTACT: Investors: Tran Nguyen, CFO 650-837-8535, Media: Anita Kawatra 646-256-5116, anita.kawatra@prothena.comSource:Prothena Corporation plc