Keytruda ® is a registered trademark of Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, N.J., USA. Additional Information about the Proposed Merger involving Galena Biopharma, Inc. (NASDAQ: GALE ) and SELLAS Life Sciences Group Ltd. and Where to Find It In connection with the previously disclosed proposed merger involving Galena Biopharma, Inc. (Galena) and SELLAS Life Sciences Group Ltd., Galena and SELLAS intend to file relevant materials with the Securities and Exchange Commission, or the SEC. On September 22, 2017, Galena filed a registration statement on Form S-4 with the SEC that contains a preliminary proxy statement/prospectus/consent solicitation statement. Galena and SELLAS will mail the final proxy statement/prospectus/consent solicitation statement to their respective stockholders when it becomes available.