An Observational Study of IL1 Inhibition for Blocking ACVR1-Induced Flare Activity and Heterotopic Ossification in Fibrodysplasia Ossificans Progressiva (FOP)
This is an observational pre-post study to observe if the off label use of anti-IL1 therapies, such as anakinra or canakinumab, can block ACVR1-induced flare activity and heterotopic ossification in FOP. It will also generate key tools and preliminary data that are needed to design a future Phase II study. This study specifically focuses on patients with severe FOP who are being considered by their medical team for rescue therapy with anti-IL1 therapy. Preliminary data suggests patients experience significant decreases in flare frequency when taking anti-IL1 therapy, but other measures of efficacy remain unassessed, such as changes in heterotopic ossification formation, changes in pain medication use, and changes in functionality.
• Patients with a clinical presentation consistent with FOP and a genetic diagnosis of classical FOP (ACVR1R206H variant) (2), male or female aged 6-17 years old.
• Patients with unusually severe FOP disease activity. This will be determined by FOP flare frequency of \>6 flares per year, which is 3 times higher than the reported average in prior FOP studies ; or by a persistent flare that has failed to resolve after 3 months of standard-of-care therapy.
• Patients whose primary medical team has decided that rescue therapy with an anti-IL1 medication should be initiated. Once the primary medical team has decided that anti-IL1 therapy should be pursued, the subject will be told about this clinical-observational study and enrolled in the pre-treatment phase while access to the anti-IL1 therapy is being obtained by the clinical management team.
• Ability to participate in all assessments, including blood draws, radiology assessments, and travel. Age 6 is chosen as the lower limit to avoid the need for anesthesia for whole body CT in younger subjects.
• No history of unexplained infections, known autoimmune disease, or contraindication to anti-IL1 therapy.
• Written informed consent (and assent when applicable) obtained from subject or subject's legal representative and ability for subject to comply with the requirements of the study.