Conditions: Fibrodysplasia Ossificans Progressiva
Keywords: Open-label study Clinical trial Phase 2 Efficacy and safety Heterotopic ossification Fibrodysplasia Ossificans Progressiva Flare-up Palovarotene Retinoic acid receptor agonist Retinoic acid receptor gamma agonist Clementia Myositis Ossificans Progressiva Munchmeyer's Disease FOP
Allocation: NA | Intervention model: SINGLE_GROUP
Enrollment: 6
Healthy volunteers: no

Brief summary:
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.

Detailed description:
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

Arms:
arm 1: The protocol is open only to the subjects who completed Clementia Study PVO-1A-202. Eligible subjects will receive a weight-based equivalent dose of palovarotene 10 mg once daily for 14 days, followed by 5 mg once daily for 28 days. Should treatment be extended beyond 6 weeks, a weight-based equivalent dose of 5 mg will be administered in 2-week increments.

Interventions: intervention 1: Palovarotene
Intervention descriptions: intervention 1: 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.

Protocol document: