An Efficacy and Safety Study of Palovarotene for the Treatment of MO

Multiple osteochondromas is a rare condition where children develop multiple benign cartilage-capped bony tumors called osteochondromas on bones throughout the body, resulting in pain, deformity, limb length discrepancy, disability, and eventually arthritis and possible malignancy. The primary objective is to compare the efficacy of two dosage regimens of palovarotene with placebo to prevent the formation of new osteochondromas in pediatric MO subjects with exostosin 1 or exostosin 2 gene mutations. Osteochondroma formation was assessed by whole body magnetic resonance imaging (MRI). Secondary efficacy objectives were to compare the effects of palovarotene with placebo on the volume of osteochondromas as assessed by MRI; the proportion of subjects with no new osteochondromas as assessed by whole-body MRI; the annualized rate of new or worsening deformities; the annualized rate of MO-related surgeries; and palatability. The overall safety and pharmacokinetics of palovarotene and the effects of palovarotene on linear growth, bone growth plates, bone mineral density, quality of life, and pain due to osteochondromas was also studied.