Clinical TrialMay 11, 2026, 07:03 AM
MBX Biosciences MBX 4291 Phase 1 shows 7% weight loss at 8 weeks
AI Summary
MBX Biosciences announced positive preliminary blinded data from its ongoing Phase 1 trial for MBX 4291, a GLP-1/GIP co-agonist prodrug for obesity, demonstrating a mean weight loss of 7% at 8 weeks and good tolerability. The company also nominated MBX 5765 as its lead amycretin prodrug candidate, a novel GLP-1/GIP/glucagon/DACRA agonist designed for once-monthly dosing, with IND-enabling studies expected in Q2 2026. Additionally, imapextide achieved positive proof of concept in its Phase 2a STEADI™ trial for post-bariatric hypoglycemia, though the company will not pursue further Phase 2b investment, opting to prioritize its expanding obesity pipeline.
Key Highlights
- MBX 4291 Phase 1 MAD Part B cohort showed mean weight loss of 7% (range 0-16%) at 8 weeks (n=8, 2 placebo).
- MBX 4291 was generally well tolerated with only one GI event through 8 weeks in the first MAD Part B cohort.
- MBX 4291 12-week Phase 1 MAD Part C data remain on track for Q4 2026.
- MBX 5765 was nominated as a novel GLP-1/GIP/glucagon/DACRA agonist for once-monthly dosing.
- IND-enabling studies for MBX 5765 are expected to begin in Q2 2026.
- Imapextide Phase 2a STEADI™ trial showed positive proof of concept in post-bariatric hypoglycemia (PBH).
- Imapextide increased glucose nadir by 17% (45 mg), 28% (100 mg), and 34% (200 mg).
- MBX Biosciences will not commit further investment to a Phase 2b trial of imapextide in PBH, prioritizing other candidates.