Obesity Day: MBX Hits Target GLP/GIP PK Profile And Derisks Obesity Pipeline

Research evidence excerpt

Obesity Day: MBX Hits Target GLP/GIP PK Profile And Derisks Obesity Pipeline

TD Cowen MBX Biosciences

Global Research May 12, 2026

together provide a compelling validation to us that MBX has achieved its target product

profile.

As we discussed previously here, the 7% mean average weight loss at eight weeks is in

line with tirzepatide. Most impressively, there was only one diarrhea even that occurred

through eight weeks, and no vomiting or nausea. Given this, we wonder if MBX achieved

the "Goldilocks" regimen with the first MAD cohort. The diarrhea event occurred following

the first 30mg administration. The lack of events from then on demonstrates the combined

self-titration of MBX 4291 and the steady accumulation of drug through the weekly titration

tolerates the patient very well to the 4x larger monthly dose. In contrast to competitors,

this should allow MBX to conduct a relatively fast and simple titration scheme in its clinical

development for MBX 4291. Because there were no GI events observed at 120mg following

the titration, we imagine MBX could explore an even higher dose (e.g., 150, 180mg) with the

expectation that there would be much lower GI rates than what was observed in the SAD

Beyond GI side effects, management noted that were no other unexpected AEs and that the

rate of injection-site reactions was not worrisome.

MBX Will Report Part C Obesity Data In Q4:2026, Which Are Now Heavily Derisked

MBX reiterated its expectation to report the first cohort of the 12-week obesity Part C data in

Q4:2026. Compared to the Part B MAD, the primary difference is that the individual cohorts

are much larger (30 vs. 8) and that there will be two monthly doses (instead of just one)

following the four weekly doses for a total of twelve weeks of follow-up.