NOW ENROLLING: Multiple Osteochondromas (MO-Ped) Trial

The MO-Ped Trial is a Phase 2 study to assess the efficacy and safety of palovarotene in children with MO

About MO (Multiple Osteochondromas)

MO is a rare genetic bone disease resulting in the development and growth of osteochondromas (OCs) in most patients. OCs are cartilage-capped benign bone tumors.

The course and severity of MO varies widely:

  • Some patients have a few small OCs while others can have multiple large OCs1
  • The patients’ abilities to perform activities of daily living vary and may change over their lifetime, ranging from small reductions in range of motion to bone deformities resulting in severe disabilities1,2
    • Many patients with MO have bone deformities with short stature and shortened forearms1,3,4
  • A majority of patients with MO experience both chronic and acute pain in daily life, beginning in childhood and continuing, often increasing with age5,6
  • Many MO patients undergo multiple surgeries to remove painful OCs and to correct limb deformities beginning in childhood and continuing in adulthood5
  • Malignant transformation occurs in approximately 1-5% of patients, generally during adulthood, with 29 years as the mean age of transformation.7 Malignant transformation is very rare in adolescence.7,8

MO is also referred to as hereditary multiple exostoses (HME) or multiple hereditary exostoses (MHE).


The diagnosis of MO is based on clinical and/or radiographic findings of multiple exostoses in one or more members of a family. The two genes in which pathogenic variants are known to cause MO are EXT1 and EXT2. A combination of sequence analysis and deletion analysis of the entire coding regions of both EXT1 and EXT2 detects pathogenic variants in 70%-95% of affected individuals.1
MO Disease Progression

Current Treatment

Currently, there is no approved treatment for patients with MO. The only available options include physical therapy, pain management, and surgery. While these may provide some relief, none will slow or stop the disease from progressing. Additionally, treating physicians are encouraged to monitor adult patients with MO for the development of chondrosarcoma as part of the standard of care.1,7

At least 20 out of every million people have MO; 70-90% have inherited disease, while others have spontaneous disease2,5,9

About the MO-Ped Study

Phase 2 MO-Ped Trial Eligibility Criteria

To enroll, subjects must:

  • Be between 2 and 14 years old
  • Have symptomatic MO
  • Have confirmed EXT1 or EXT2 mutations
  • Reside in a country where a clinical site is located, due to regulatory requirements
  • Additional information is available at
MO Treatment Timeline

What is the Level of Commitment Required by Individuals Participating in the Study?

While participating in the study, in addition to receiving the experimental treatment, subjects will be expected to:

  1. Participate in: study-related assessments during the applicable screening period, 24 months of treatment, and 6 months of follow-up after discontinuation of treatment
  2. Attend regular visits with their medical team both at their physician’s clinic and remotely

About Palovarotene

Palovarotene is an oral agent that is being investigated for the treatment of multiple osteochondromas (MO). For more information, please refer to the Frequently Asked Questions (FAQ) section.

MO Marketing Authorization

Frequently Asked Questions

To access the FAQ in your preferred language, please select from one of the options below:

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  1. Wuyts W et al. 2013, Gene Reviews
  2. Pedrini E et al. 2011, J Bone Joint Surg Am
  3. Wicklund C et al. 1995, AJMG
  4. Fogel G et al. 1984, J Bone Joint Surg Am
  5. Goud AL et al. 2012, J Bone Joint Surg Am
  6. Darilek S et al. 2005, J Pediatr Orthop
  7. Czajka C et al. 2015, Clin Orthop Relat Res
  8. Bovée J 2008, Orphanet J of Rare Diseases
  9. Beltrami G et al. 2016, Clin Cases in Mineral & Bone Metabolism
  10. Ryckx A et al. 2013, Acta Orthop Belg
  11. Schmale G et al. 1994, J Bone Joint Surg Am
  12. Pacifici M 2017, Curr Osteoporos Rep


Study Sponsor

Clementia Pharmaceuticals Inc.
1000, de la Gauchetière, suite 1200
Montreal, QC H3B 4W5 Canada

This website is designed to assist patients and other people seeking general information about clinical trials, as well as those interested in learning about the MO-Ped Trial. It is not intended to substitute for the medical advice of your doctor. Please consult with your doctor to determine the best treatment plan for you.

The following organizations provide educational resources related to MO and support research to help families living with these and other rare diseases.