MBX Biosciences Obesity Portfolio Update: MBX 4291 Phase 1 Once-Monthly Profile, MBX 5765 Amycretin Prodrug Nominated, Imapextide Phase 2a STEADI Hits Proof of Concept in Post-Bariatric Hypoglycemia
MBX Biosciences (Nasdaq: MBX) released a May 11 obesity portfolio update covering three programs. MBX 4291, a GLP-1/GIP co-agonist prodrug, posted preliminary blinded Phase 1 MAD Part B data showing a T1/2Cmax1 of ~26 days, consistent with true once-monthly dosing; 12-week MAD Part C data expected Q4 2026. MBX 5765, a new amycretin prodrug combining GLP-1, GIP, glucagon, and DACRA (dual amylin and calcitonin receptor agonist) activity in a single construct, is in IND-enabling studies starting Q2 2026. Once-weekly imapextide hit proof of concept in the Phase 2a STEADI trial in post-bariatric hypoglycemia, with glucose nadir increased 17-34% across doses and insulin peak decreased 11-45% — directly competing with Amylyx's avexitide (Phase 3 LUCIDITY topline Q3 2026) for the same indication.