MBX - Quick Take - MBX-4291 shows favorable GI tolerability profile and 8 week efficacy; Hosting Obesity Day today at 10:30 AM ET

Research evidence excerpt

MBX - Quick Take - MBX-4291 shows favorable GI tolerability profile and 8 week efficacy; Hosting Obesity Day today at 10:30 AM ET

Truist Securities

Equity Research Report May 11, 2026

HEALTHCARE: Biotech MBX Biosciences, Inc. (MBX)

MBX - Quick Take - MBX-4291 shows favorable GI tolerability Srikripa Devarakonda, Ph.D.

212-303-4173 profile and 8 week efficacy; Hosting Obesity Day today at 10:30 AM

Srikripa.Devarakonda@truist.com ET

Alexander Xenakis

212-590-0954 This morning, MBX (MBX, Buy) reported positive Ph1 SAD and Cohort 1 MAD data from

Alexander.Xenakis@truist.com monthly MBX 4291, a GLP-1/GIP co-agonist prodrug for obesity. In the first MAD cohort

(n=8; n=6 active) with 30mg weekly x4 + 120mg once for monthly dosing showed mean

Anna Li weight loss of 7% (range 0-16%) at 8 weeks in first MAD Part B cohort and importantly,

212-326-6090 only one event of diarrhea, nausea or vomiting through 8 weeks in first MAD Part B

Anna.Li@truist.com cohort (13%). This compares favorably to other monthly agents that are being explored

(see our initiation here). We remain on the lookout for 1) more color on MBX-4291 and

perspective from KOL; 2) new amycretin candidate MBX-5765; and 3) additional detail

Current Price (May 8, $40.97 on imapextide's POC in PBH at its Obesity Day today at 10:30 AM ET. 2026)

What was the PK profile like and how does this translate to safety? MBX-4291

Stock Rating BUY demonstrated a PK profile supporting the potential for once-monthly dosing with a 26-day

Unchanged first half-life interval after Cmax. Furthermore, a slow accumulation and gradually increasing

concentrations of active peptide were demonstrated, with a Tmax of ~13-14 days and

Price Target $70.00 sustained exposure which is supportive of once-monthly dosing potential. Dose dependency