for people ages 2-14 (full criteria)
at San Francisco, California and other locations
study started
estimated completion
Principal Investigator
by Jessica Tenney



This is a randomized, double-blind, placebo-controlled study comparing the safety and efficacy of 2 dosage regimens of palovarotene versus placebo in preventing disease progression in pediatric subjects with multiple osteochondromas (MO).

Official Title

A Phase 2, Randomized, Double-Blind, Placebo-Controlled Efficacy and Safety Study of Palovarotene in Subjects With Multiple Osteochondromas


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 will be assessed by whole body magnetic resonance imaging (MRI). Secondary efficacy objectives are to compare the effect of palovarotene on the volume of osteochondromas as assessed by MRI; and on the annualized rate of new or worsening deformities and MO-related surgeries. The overall safety of palovarotene and the effects of palovarotene on linear growth, bone growth plates, bone mineral density, quality of life, and pain due to osteochondromas will also be studied.


Exostoses, Multiple Hereditary Multiple osteochondromas Osteochondroma Palovarotene Hereditary multiple exostoses HME MO Retinoic acid receptor gamma agonist Retinoic acid receptor agonist Osteochondromatosis Exostoses Osteophyte Palovarotene 2.5 mg Palovarotene 5.0 mg


You can join if…

Open to people ages 2-14

  • Written, signed, and dated informed subject/parent consent and age-appropriate assent (performed according to local regulations).
  • A clinical diagnosis of MO with disease-causing exostosin 1 or 2 gene mutations.
  • Male or female from 2 to 14 years of age.
  • Female subjects must be premenarchal at screening.
  • A bone age at screening of 14 years or less.
  • Symptomatic MO, defined as five or more clinically-evident osteochondromas and a new or enlarged osteochondroma that occurred in the preceding 12 months, five or more clinically-evident osteochondromas and the presence of a painful osteochondroma, a skeletal deformity, a joint limitation, or prior surgery for a MO-related complication.
  • The ability to undergo whole body MRI with or without sedation/general anesthesia.
  • Use of two effective methods of birth control during treatment, and for 1 month after treatment discontinuation, unless committed to true abstinence from heterosexual sex. Sexually active females of child-bearing potential must also agree to start effective methods of birth control at screening.

You CAN'T join if...

  • Weight under 10 kg.
  • Other syndromic conditions such as Langer-Giedion or Potocki-Shaffer.
  • Any subject with neurologic signs suggestive of spinal cord impingement.
  • Concomitant medications that are strong inhibitors or inducers of cytochrome P450 3A4 activity.
  • Amylase or lipase >2 times the above the upper limit of normal (>2×ULN) or with a history of chronic pancreatitis.
  • Elevated aspartate aminotransferase or alanine aminotransferase above 2.5×ULN.
  • Any surgical implant that is contraindicated for MRI.


  • University of California-San Francisco
    San Francisco California 94158 United States
  • Shriners Hospital for Children - Sacramento
    Sacramento California 95817 United States

Lead Scientist at UCSF


in progress, not accepting new patients
Start Date
Completion Date
Clementia Pharmaceuticals Inc.
MHE Coalition MHE Research Foundation
Phase 2
Study Type
Last Updated