Clementia Pharmaceuticals Inc. (NASDAQ:CMTA) lost $4.05 (21%) to $14.85 on Wednesday after reporting data from a Phase II trial of palovarotene to treat fibrodysplasia ossificans progressiva (FOP). FOP is a rare, genetic bone disease characterized by heterotopic ossification (HO), or bone formation outside of the normal skeleton in muscles, tendons or soft tissue.
Part B of the trial has enrolled 41 evaluable adults and skeletally mature children ages 13 and older to receive a chronic/flare-up dosing regimen of oral palovarotene. Among 33 evaluable patients with 12-month whole body CT scans, palovarotene led to a 28% reduction in whole body volume of new HO compared with 55 untreated control patients. The company powered its Phase III MOVE trial of palovarotene in the indication to detect about a 65% reduction in new HO volume, CEO Clarissa Desjardins said on a conference call Wednesday.
Clementia said one patient in the 33-patient analysis had multiple flare-ups that were not treated with the flare-up dosing regimen of palovarotene because they did not meet the Part B treatment protocol requirements. Excluding the one patient from the analysis, the company said palovarotene led to a 65% reduction in whole body volume of new HO compared with untreated controls. Clementia added that the excluded patient would have qualified for treatment in MOVE, which removed flare-up treatment restrictions that were used in the Phase II trial to now require only one flare-up symptom.
Among all 41 adults and children enrolled, oral palovarotene significantly reduced mean volume of new HO by 91% at week 12 for the 29 flare-ups treated compared with 60 untreated control flare-ups (p=0.01). In nine evaluable patients with no new HO at 12 weeks at the flare-up location, there was also no new HO anywhere in the body at 12 months.
Patients received once-daily 5 mg palovarotene for up to 24 months. In the event of an eligible flare-up, patients received once-daily 20 mg palovarotene for four weeks followed by 10 mg for eight weeks.
The control group comprises pooled data in 10 flare-ups from placebo-treated patients in a previous Phase II trial and 50 untreated flare-ups from Clementia’s natural history study.
The trial has enrolled 53 patients, including a cohort of 12 pediatric patients who only received palovarotene when a flare-up was reported.
Clementia said it is on track to complete enrollment of 80 patients ages four and older in MOVE by year end, with interim data expected in mid-2019.
Palovarotene is a selective small molecule retinoic acid receptor gamma (RARG) agonist. The product has Fast Track, breakthrough therapy and Orphan Drug designations in the U.S. and Orphan Drug designation in the EU to treat FOP.
Clementia has exclusive, worldwide rights to palovarotene from Roche (SIX:ROG; OTCQX:RHHBY).