An Open-Label Extension Study of Palovarotene Treatment in Fibrodysplasia Ossificans Progressiva (FOP)

Inclusion Criteria: * Completion of Study PVO-1A-202/Part B. * Written, signed, and dated informed consent and, for participants who are minors, age-appropriate participant assent (performed according to local regulations). * Accessible for treatment with palovarotene and follow-up (able and willing to travel to a site for the initial and all follow-up clinic visits). * Able to undergo low-dose, WBCT scan, excluding head. * Females of child-bearing potential must have a negative blood or urine pregnancy test (with sensitivity of at least 50 mIU/mL) prior to administration of palovarotene. * Male and FOCBP participants must agree to remain abstinent from heterosexual sex during treatment and for 1 month after treatment or, if sexually active, to use two effective methods of birth control during and for 1 month after treatment. Additionally, sexually active females of childbearing potential (FOCBP) participants must already be using two effective methods of birth control 1 month before treatment is to start. Specific risk of the use of retinoids during pregnancy, and the agreement to remain abstinent or use two effective methods of birth control will be clearly defined in the informed consent and the participant or legally authorized representatives. Exclusion Criteria: * Any reason that, in the opinion of the Investigator, would lead to the inability of the participant and/or family to comply with the protocol. * Amylase or lipase \>2x above the upper limit of normal or wit…