Weight Loss & Safety Data Validates Self-Titrating Prodrug Platform For Obesity

Research evidence excerpt

Weight Loss & Safety Data Validates Self-Titrating Prodrug Platform For Obesity

TD Cowen MBX Biosciences

Global Research May 11, 2026

MBX Announces Quad Amycretin Candidate

MBX announced its amycretin candidate, MBX 5765, a triple G agonist combined with a dual

amylin and calcitonin receptor agonist (DACRA) in a single construct. The mechanism should

support a once-monthly dosing profile, superior efficacy, and improved tolerability, per the

company. MBX will begin IND enabling-studies this quarter for MBX 5765.

MBX also remains on track to announce its triple G candidate in Q3. We believe MBX's

platform could be well suited to improve the triple G mechanism, since the data from Eli Lilly's

retatrutide to-date demonstrates the highest achieved weight loss (~30%), but at the expense

of more substantial tolerability challenges.

Imapextide Phase IIa Data Is Competitive In PBH, But MBX Will Deprioritize Development

MBX also reported the topline Phase IIa STEADI data from imapextide, its once-weekly GLP-1

antagonist for post-bariatric hypoglycemia (PBH) that has been shown to be more potent

in vitro compared to the lead competitor, avexitide, with a much longer half-life (90 vs. 2.5

hours), supporting its once-weekly dosing profile.

Across the three doses tested (45mg, 100mg, and 200mg), imapextide led to a 17%, 28%,

and 34% increase from baseline in glucose nadir, which is competitive with avexitide's ~25%.

Similarly, the average decrease in insulin peak was also competitive with avexitide's ~20-25%

range, as impatextide led to 11%, 33%, and 45% decrease across the three doses, respectively.

The initial data provide proof-of-concept that imapextide could be an effective GLP-1

antagonist with a once-weekly profile for PBH. Nonetheless, the company is deprioritizing