MBX Biosciences (MBX) Status update summary

Strategic Focus and Portfolio Progress

• Advancing a portfolio of obesity therapeutics using proprietary PEP technology, targeting once-monthly dosing and improved tolerability.

• Lead candidate MBX 4291, a GLP-1 GIP co-agonist prodrug, demonstrated promising preliminary phase I data with a self-titrating PK profile and competitive weight loss.

• MBX 5765, a multi-mechanism amycretin/GLP-1/GIP/glucagon/DACRA agonist, and a triple agonist candidate are in preclinical or candidate selection stages, aiming for differentiated efficacy and monthly dosing.

• Resource allocation is prioritized for canvuparatide and obesity programs, with no further investment in Phase 2b for imapextide in PBH after proof of concept.

• $440 million in cash provides operational runway into 2029, supporting ongoing and future clinical programs.

Clinical Data and Study Design

• MBX 4291 phase I SAD and MAD cohorts showed dose-proportional, gradual, and sustained drug exposure, supporting monthly dosing.

• In the MAD cohort, a 7% mean weight loss (range 0–16%) was observed over 8 weeks, with only one GI-related adverse event (diarrhea) and no serious adverse events.

• The PK profile features a delayed Tmax (~2 weeks) and t half Cmax of 26 days, exceeding comparator MET-097i and supporting improved tolerability.

• The ongoing phase I study will expand to a larger 12-week MAD cohort, with top-line results expected in Q4 2026.

• No notable injection site reactions or serious adverse events have been observed to date.

Market Landscape and Unmet Needs

• Obesity prevalence is rising globally, with projections of 25% of the world population affected by 2035 and a market size expected to exceed $90 billion by 2031.

• U.S. adult obesity rates are expected to reach 40% by 2030, with the highest growth in those with BMI >35.

• Key unmet needs include greater efficacy (weight loss >20%), prevention of weight regain, improved tolerability, convenience, and preservation of lean body mass.

• High discontinuation rates for current therapies highlight the need for better adherence and persistence, which monthly dosing and improved tolerability may address.

• Flexibility in dosing frequency and individualized titration are seen as important for addressing patient heterogeneity.