MBX Biosciences, a clinical-stage biopharmaceutical company, has dosed its first participant in a Phase 1 trial for MBX 4291, its GLP-1/GIP co-agonist prodrug candidate intended to treat obesity, the company said that the randomized, double-blind, placebo-controlled study will evaluate safety, tolerability, pharmacokinetics and pharmacodynamics of single and multiple ascending doses in adults with obesity.
In Part A (single ascending dose), five cohorts of eight participants each will receive MBX 4291 or placebo in a 3:1 ratio, with follow-up extending up to 63 days. In Part B (multiple ascending dose over four weeks), three cohorts of eight participants each will receive weekly doses, again randomized 3:1, with follow-up through 71 days. The company claims that after completion of these parts, it plans a longer 12-week multiple ascending dose phase in up to two cohorts of 30 participants each, randomized 2:1, receiving up to 12 doses with follow-up of around 120 days.
According to the company, MBX 4291 was designed via its proprietary PEP™ platform as a long-acting dual agonist, aimed at improved tolerability, enhanced adherence, and potentially greater long-term weight loss compared to existing therapies. Preclinical studies showed activity similar to the weekly co-agonist tirzepatide, with extended duration supporting once-monthly administration.
The company said that topline results from the Phase 1 trial are anticipated in 2027.
