Phase 2 Study R2477-FOP-1940 has been withdrawn and the next phase of the development program is being planned

The primary safety objective of the study is to assess the safety and tolerability of garetosmab in Japanese male and female adult patients with FOP.

The primary efficacy objective of the study is to assess the effect of garetosmab on Heterotopic ossification (HO) in Japanese adult patients with FOP, as determined by the number of new heterotopic bone lesions identified by computed tomography (CT).

Key Inclusion Criteria:

• Clinical diagnosis of FOP (based on findings of congenital malformation of the great toes, episodic soft tissue swelling, and/or progressive HO)
• Confirmation of FOP diagnosis with documentation of any Type I activin A receptor (ACVR1) mutation
• FOP disease activity, as defined in the protocol, within 1 year of screening visit
• Willing and able to undergo PET and CT imaging procedures and other procedures as defined in this study
• Able to understand and complete study-related questionnaires and diaries (assistance from caregivers is allowed)

Key Exclusion Criteria:

• Patient has significant concomitant illness or history of significant illness such as but not limited to cardiac, renal, rheumatologic, neurologic, psychiatric, endocrine, metabolic, or lymphatic disease, that in the opinion of the study investigator might confound the results of the study or pose additional risk to the patient by their participation in the study
• Previous history or diagnosis of cancer
• Severely impaired renal function defined as estimated glomerular filtration rate <30 mL/min/1.73 m2 calculated by the Modification of Diet in Renal Disease equation (1 retest is allowed)
• Uncontrolled diabetes defined as hemoglobin A1C (HbA1c) >9% at screening (1 retest allowed)
• History of severe respiratory compromise, as defined in protocol
• Concurrent participation in another interventional clinical study or a non-interventional study with radiographic measures or invasive procedures
• Pregnant or breastfeeding women

NOTE: Other protocol defined inclusion/exclusion criteria apply.

All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing

When Regeneron has received marketing authorization from major health authorities (e.g., FDA, European Medicines Agency (EMA), Pharmaceuticals and Medical Devices Agency (PMDA), etc.) for the product and indication, has made the study results publicly available (e.g., scientific publication, scientific conference, clinical trial registry), has the legal authority to share the data, and has ensured the ability to protect participant privacy.

Qualified researchers can submit a proposal for access to individual patient or aggregate level data from a Regeneron-sponsored clinical trial through Vivli. Regeneron's Independent Research Request Evaluation Criteria can be found at: https://www.regeneron.com/sites/default/files/Regeneron-External-Data-Sharing-Policy-and-Independent-Research-Request-Evaluation-Criteria.pdf