FOP is caused by a mutation in the ACVR1 gene that encodes for the ACVR1/ALK2 receptor.  In healthy individuals, a protein called Activin A usually turns off this receptor.  However, scientists have shown that in FOP, Activin A instead turns the mutant receptor on, resulting in the formation of abnormal bone growth that is characteristic of FOP.   REGN2477 is an antibody that has been engineered to bind (ie. hold onto) to Activin A, and remove this protein from the body.  Hence by binding and blocking Activin A, REN2477 may slow or prevent the formation of new HO.

About the Clinical Trial

The REGN2477 Phase 2 trial is a global, multi-center, placebo controlled trial. Up to 40 adults 18 years of age or older with the classic FOP mutation (R206H mutation) will be needed to complete the Phase 2 clinical trial. The trial is designed to evaluate the safety of REGN2477, and whether monthly dosing of drug will reduce the formation of new HO.

Eligibility Criteria Icon
Eligibility Criteria*
  • AGE: ≥ 18
  • DISEASE ACTIVITY: Participants need to have had FOP disease activity within one year of the screening visit.
Study Design Icon
Study Design*
  • STUDY TYPE:  Interventional
  • PLACEBO CONTROLLED:  Yes (At the end of the first 6 months, all participants will have the opportunity to receive REGN2477)
Status Icon

Phase 2, Enrolling

Therapy Approach Icon
Therapy Approach

Blocking Antibody

Study Sponsor Icon
Study Sponsor

Regeneron Pharmaceuticals

Q and A icon
Q & A

Q: Who can participate in the RENG trial?
A: Answer here

Q: In what countries will the study be conducted?
A: Answer here

Q: If I’m currently enrolled in Clementia’s Natural History Study, can I participate in the REGN 24 trial?
A: Answer here

Participating Clinical Sites

Mayo Clinic
Rochester, Minnesota, 55905
Contact: Robert Pignolo
Principal Investigator: Robert Pignolo, MD, PhD

Istituto Giannina, Department of Pediatrics
Genova, Liguria, Italy, 16148
Contact: Maja Di Rocco, MD
Principal Investigator: Maja Di Rocco, MD

VU University Medical Center
Amsterdam, The Netherlands, 1081 HV
Contact: Marelise Eekhoff, MD, PhD
Principal Investigator: Marelise Eekhoff, MD, PhD

Royal National Orthopaedic Hospital, Brockely Hill
Stanmore, United Kingdom, HA7 4LP
Contact: Richard Keen, MD <
Contact: Jackie Vinton
Principal Investigator: Richard Keen, MD

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