SELLAS Life Sciences (SLS) 10-Q 2016 Q1 Quarterly report

Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the accompanying Quarterly Report of Galena Biopharma, Inc., (the “Company”) on Form 10-Q for the quarter ended March 31, 2016 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), the undersigned officers of the Company certify, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that to their knowledge:

1. The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

2. The information contained in the Report fairly presents, in all material respects, the Company’s financial condition and result of operations.

/s/ Mark W. Schwartz	/s/ John T. Burns
Mark W. Schwartz	John T. Burns
President and Chief Executive Officer	Controller and Principal Accounting Officer
May 10, 2016	May 10, 2016