MBX Biosciences (Nasdaq: MBX) is a precision-peptide company built around its Precision Endocrine Peptide (PEP) platform, designed to extend peptide half-lives into once-weekly or once-monthly dosing without compromising pharmacology. The pipeline now covers endocrinology, post-bariatric hypoglycemia, and obesity.
The lead asset is canvuparatide, a once-weekly PTH replacement therapy for chronic hypoparathyroidism. The Phase 2 Avail trial reported on June 12, 2026 hit its primary endpoint with a 63% responder rate at 12 weeks versus 31% on placebo, and the one-year open-label extension sustained the effect with a 57% responder rate, normalized serum calcium, restored bone metabolism, and a 90% patient retention rate. A registrational Phase 3 starts Q3 2026. The obesity portfolio adds MBX 4291, a GLP-1/GIP co-agonist prodrug with a ~26-day half-life supporting true once-monthly dosing, and MBX 5765, an amycretin prodrug combining GLP-1, GIP, glucagon, and DACRA activity. Once-weekly imapextide hit Phase 2a proof of concept in post-bariatric hypoglycemia, directly competing with Amylyx's avexitide.
Stories here cover MBX clinical readouts, the PEP platform, and the once-monthly obesity race. See [[canvuparatide]], [[hypoparathyroidism]], and [[once-monthly]] for adjacent threads.
MBX Biosciences (Nasdaq: MBX) on June 12 reported full 12-week Phase 2 Avail data and one-year open-label extension results for once-weekly canvuparatide, a precision PTH peptide for chronic hypoparathyroidism. The trial hit its primary endpoint with a 63% responder rate versus 31% on placebo at 12 weeks; the OLE delivered a 79% responder rate at six months and 57% at one year. Patients showed normalized serum calcium, reduced urine calcium excretion, restored bone metabolism, and improved eGFR; 90% of OLE patients remained on study at one year with no new safety signals. A registrational Phase 3 in chronic hypoparathyroidism starts Q3 2026.
MBX Biosciences (Nasdaq: MBX) released a May 11 obesity portfolio update covering three programs. MBX 4291, a GLP-1/GIP co-agonist prodrug, posted preliminary blinded Phase 1 MAD Part B data showing a T1/2Cmax1 of ~26 days, consistent with true once-monthly dosing; 12-week MAD Part C data expected Q4 2026. MBX 5765, a new amycretin prodrug combining GLP-1, GIP, glucagon, and DACRA (dual amylin and calcitonin receptor agonist) activity in a single construct, is in IND-enabling studies starting Q2 2026. Once-weekly imapextide hit proof of concept in the Phase 2a STEADI trial in post-bariatric hypoglycemia, with glucose nadir increased 17-34% across doses and insulin peak decreased 11-45% — directly competing with Amylyx's avexitide (Phase 3 LUCIDITY topline Q3 2026) for the same indication.
MBX Biosciences announced an April 23 press release confirming its May 11 virtual Obesity Day event, at which the company will formally update investors on its Precision Endocrine Peptide (PEP) platform. The portfolio includes MBX 4291 (Phase 1 GLP-1/GIP co-agonist prodrug designed for once-monthly dosing), an amycretin prodrug with Q2 2026 nomination expected, and a GLP-1/GIP/GCGR triple agonist prodrug with Q3 2026 nomination — all targeting once-monthly administration. Richard DiMarchi and Katherine Saunders will headline the event.