MBX Biosciences rises after mid-stage trial win for hormone disorder drug

** Shares of drug developer MBX Biosciences MBX.O surge 84% to $18.5 in premarket trading

** MBX says its once-weekly experimental drug, canvuparatide, met main goal in mid-stage trial for adults with chronic hypoparathyroidism, a hormone disorder that causes low calcium levels

** In 12-week study, 63% of patients on canvuparatide kept calcium in normal range without needing active vitamin D or more than 600 mg of daily calcium supplements, compared with 31% on placebo, difference of which was statically significant

** The drug was well tolerated with no serious adverse events, company says

** MBX plans to start late-stage trial in 2026

** As of last close, MBX stock was down 45.7% YTD