Fibrodysplasia Ossificans Progressiva (FOP) is a rare, severely disabling disease characterized by painful, recurrent episodes of soft tissue swelling (flare-ups) that result in abnormal bone formation (heterotopic ossification or HO) in muscles, tendons, and ligaments. Flare-ups begin early in life and may occur spontaneously or after soft tissue trauma, vaccinations, or influenza infections. Recurrent flare-ups progressively restrict movement by locking joints leading to cumulative loss of function and disability. Mouse models of FOP have demonstrated the ability of retinoic acid receptor gamma (RARγ) agonists such as palovarotene to prevent HO following injury. This 36-month study will evaluate the long-term safety and efficacy of episodic treatment with palovarotene for flare-ups in FOP subjects who successfully complete two flare-up treatment periods (6 weeks duration) and two follow-up periods (6 weeks duration) in Study PVO-1A-202.
The primary objective of this Phase 2, open-label, multicenter, single-arm, extension study is to investigate the safety and efficacy of episodic treatment with palovarotene in FOP subjects with flare-ups. Secondary objectives are: The effect of episodic treatment of flare-ups with palovarotene on range of motion (ROM) as assessed by the subject global assessment of movement. * The effect of episodic treatment of flare-ups with palovarotene on ROM as assessed by the Cumulative Analogue Joint Involvement Scale for FOP (CAJIS) for subjects with video-conferencing capability. * The effect of episodic treatment of flare-ups with palovarotene on the total burden of heterotopic ossification (HO) as assessed by low-dose whole body computerized tomography (WBCT), excluding the head; and whole body dual energy x-ray absorptiometry (DEXA). * The effect of episodic treatment of flare-ups with palovarotene on physical function using age-appropriate forms of the FOP-Physical Function Questionnaire (FOP-PFQ). * The effect of episodic treatment of flare-ups with palovarotene on physical and mental health using age appropriate forms of the Patient Reported Outcomes Measurement Information System (PROMIS) Global Health Scale. * The effects of episodic treatment of flare-ups with palovarotene on pain and swelling associated with the flare-up using numeric rating scales (NRS) or the Faces Pain Scale-Revised (FPS-R) in subjects under 8 years of age. * The use of assistive devices and adaptations for daily living by FOP subjects. The follow-up portion of the study will consist of a Screening visit that will correspond to the last day (Study Day 84) of Study PVO-1A-202 and bi-annual assessments at Months 6, 12, 18, 24, 30, and 36. Subjects experiencing a new, distinct flare-up during the 36-month follow-up will be evaluated and if eligible, receive palovarotene at the weight-adjusted equivalent of 10 mg for 14 days followed by 5 mg for at least 28 days. Any subject who received a lower dosing regimen due to tolerability issues during Study PVO-1A-202 will receive that tolerated dose. For each flare-up there will be two periods: 1. A Screening period to occur within 7 days of the start of a new, distinct flare-up. The first dose of palovarotene will be taken within 10 days of the flare-up onset to allow for shipment of study medication to the subject's home. 2. A treatment period of at least 6 weeks duration. Subjects experiencing a new, distinct flare-up will be evaluated
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
6
Palovarotene will be taken orally once daily at approximately the same time each day. Powder filled hard gelatin capsules may be opened and the contents added onto specific food.
University of California San Francisco, Division of Endocrinology and Metabolism
San Francisco, California, United States
University of Pennsylvania, Center for Research in FOP & Related Disorders
Philadelphia, Pennsylvania, United States
Number of Subjects With Treatment-emergent Adverse Events (TEAEs)
The primary endpoint was the safety of palovarotene as assessed by the incidence of TEAEs (including those known to be associated with retinoids) and serious adverse event (SAEs) monitored throughout the treatment period. TEAEs were adverse events reported during treatment with palovarotene or within 6 weeks after the end of treatment. Day 1 was the first day that study drug was administered for a flare-up. The number of subjects experiencing at least one TEAE or treatment-emergent SAE are presented.
Time frame: Day 1 until 6 weeks after the end of treatment (an expected average treatment of 6 weeks). Assessed until data cut-off for study termination (maximum of 35 days).
Subject Global Assessment of Movement as Determined by a Subject Completed Questionnaire, or Proxy Completed Questionnaire in Subjects Under 8 Years of Age
Time frame: Every 6 weeks while on study drug, at the end of treatment (should treatment be extended beyond 6 weeks), and 6 weeks after the end of treatment.
Change From Baseline in Cumulative Analogue Joint Involvement Scale for FOP as Assessed by the Investigator Using Remote Video-conferencing
Time frame: Baseline (flare-up screening), every 6 weeks while on study drug, at the end of treatment (should treatment be extended beyond 6 weeks), and 6 weeks after the end of treatment.
Change From Baseline in Extent of Heterotopic Ossification (HO) by Whole Body Low-dose Computerized Tomography (CT) Scan, Excluding the Head
Time frame: Baseline (final visit for Study PVO-1A-202/Part A) and at end of study (36 months).
Change From Baseline in Extent of HO by Whole Body Dual Energy X-ray Absorptiometry (DEXA) Scan
Time frame: Baseline (screening/enrollment visit) and at end of study (36 months).
Change From Baseline in Pain and Swelling at the Flare-up Site Using Numeric Rating Scales, or Faces Pain Scale-Revised in Subjects Under 8 Years of Age
Time frame: Baseline (flare-up screening), every 2 weeks while on study drug, at the end of treatment (should treatment be extended beyond 6 weeks), and 6 weeks after the end of treatment.
Change From Baseline in Physical Function Using Age-appropriate Forms of the FOP-Physical Function Questionnaire
Time frame: Baseline (flare-up screening), every 6 weeks while on study drug, at the end of treatment (should treatment be extended beyond 6 weeks), and 6 weeks after the end of treatment, and 6-month intervals for duration of study.
Change From Baseline in Physical and Mental Health Using Age-appropriate Forms of the Patient-Reported Outcomes Measurement Information System (PROMIS) Global Health Scale
Time frame: Baseline (flare-up screening), every 6 weeks while on study drug, at the end of treatment (should treatment be extended beyond 6 weeks), 6 weeks after the end of treatment, and 6-month intervals for duration of study.
Duration of Active, Symptomatic Flare-up as Assessed by the Subject and the Investigator
Time frame: Baseline (flare-up screening), after 6 weeks on study drug, and every 2 weeks after Week 6 until flare-up resolution.
Change From Baseline in the Use of Assistive Devices and Adaptations for Daily Living by FOP Subjects
Time frame: Baseline (flare-up screening), 6 weeks after the end of treatment, and 6-month intervals for duration of study.
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