BOSTON, Dec. 02, 2015 (GLOBE NEWSWIRE) — Zafgen, Inc. (Nasdaq:ZFGN), a biopharmaceutical company dedicated to significantly improving the health and well-being of patients affected by obesity and complex metabolic disorders, today provided an update on the open label extension (OLE) portion of the pivotal Phase 3 ZAF-311 bestPWS clinical trial …