Successful experience of tofacitinib treatment in patients with Fibrodysplasia Ossificans Progressiva

Fibrodysplasia ossificans progressiva complicated with post traumatic and infectious myositis ossificans in masseter: A case report

RATIONALE

Myositis ossificans (MO) is characterized by benign heterotopic ossificans in soft tissues like muscles, which can be classified into nonhereditary MO and fibrodysplasia ossificans progressiva (FOP). Nonhereditary MO is characterized by ossification of the soft tissues after acute or repetitive trauma, burns, or surgical intervention. FOP is a rare and crippling disease characterized by congenital malformation of the big toe and heterotopic ossification in muscle. The majority of FOP's musculoskeletal traits are associated with dysregulated chondrogenesis. The diagnosis is mainly based on clinical manifestation, imaging examination, and genetic analysis. There is still no effective treatment to cure or slow its progression. The best approach remains early diagnosis, conservative drug treatment, and injury prevention to avoid local ossification.

PATIENT CONCERNS

A 34-year-old male presented at our hospital because of trismus caused by ossification of the masseter muscle. In addition, he had serious stiffness and multiple bony masses throughout the body, which led to limited movement.

DIAGNOSES

Based on the clinical manifestation of movement restriction, characteristic radiographic images of ossification of soft tissues, the genetic test showing a heterozygous molecule (c.974G > C, p.G325A) of the activin A receptor type I, the patient was diagnosed as FOP complicated with localized MO in masseter after trauma and infection.

INTERVENTIONS

The patient underwent the surgical resection of ossification in the masseter muscle, he was instructed to insist on mouth-opening exercises and take glucocorticoids and nonsteroidal anti-inflammatory medications after surgery.

OUTCOMES

The symptoms of trismus are relieved, and eating can be basically achieved after surgery, while the symptoms of trismus recurred 2 years later.

LESSONS

Although FOP has unique clinical manifestations, its diagnosis may be difficult because of its rarity. Gene analysis is the main standard for diagnosis, while patients with different genotypic variations may show different clinical symptoms. Therapeutic interventions are still supportive and preventive, and surgery is not recommended except under certain circumstances.

Long-term use of interleukin-1 inhibitors reduce flare activity in patients with fibrodysplasia ossificans progressiva

OBJECTIVES

Fibrodysplasia ossificans progressiva (FOP) is one of the most catastrophic forms of genetic heterotopic ossification (HO). FOP is characterized by severe, progressive inflammatory flare-ups, that often lead to HO. The flare-ups are associated with increased inflammatory cytokine production, suggesting auto-inflammatory features driven by IL-1β. This study describes the short- and long-term responses of FOP patients to anti-IL-1 therapy.

METHODS

Previously, we reported that a patient with FOP treated with anti-IL-1 agents showed dramatically lower rates of flare-ups, improved flare-up symptoms, decreased use of glucocorticoids and apparently decreased size of residual lesions. Plasma analyses also showed marked elevation in IL-1β levels during a FOP flare, further supporting a role of IL-1β in the pathogenesis of FOP flares. Here, we report results from long-term therapy with IL-1 inhibitors in that patient and describe 3 additional patients, from two medical centres.

RESULTS

All 4 patients showed persistent improvement in flare activity during treatment with IL-1 inhibitors, with minimal formation of new HO sites. Two patients who stopped therapy experienced a resurgence of flare activity that was re-suppressed upon re-initiation. These patients had IL-1β levels comparable to those in IL-1β-driven diseases. Child Health Assessment Questionnaires confirmed extensive subjective improvements in the pain and general health visual analogue scales.

CONCLUSION

This case series demonstrates significant benefits from IL-1 inhibitors for reducing flare activity and improving the general health of patients with FOP. These data provide strong support for additional studies to better understand the function of IL-1 inhibition, primarily in reducing the formation of new HO.

FUNDING

RH received support from the International FOP Association ACT grant; ECH received support from NIH/NIAMS R01AR073015 and the UCSF Robert Kroc Chair in Connective Tissue and Rheumatic Diseases III.

Navigating the Complex Landscape of Fibrodysplasia Ossificans Progressiva: From Current Paradigms to Therapeutic Frontiers

Fibrodysplasia ossificans progressiva (FOP) is an enigmatic, ultra-rare genetic disorder characterized by progressive heterotopic ossification, wherein soft connective tissues undergo pathological transformation into bone structures. This incapacitating process severely limits patient mobility and poses formidable challenges for therapeutic intervention. Predominantly caused by missense mutations in the ACVR1 gene, this disorder has hitherto defied comprehensive mechanistic understanding and effective treatment paradigms. This write-up offers a comprehensive overview of the contemporary understanding of FOP's complex pathobiology, underscored by advances in molecular genetics and proteomic studies. We delve into targeted therapy, spanning genetic therapeutics, enzymatic and transcriptional modulation, stem cell therapies, and innovative immunotherapies. We also highlight the intricate complexities surrounding clinical trial design for ultra-rare disorders like FOP, addressing fundamental statistical limitations, ethical conundrums, and methodological advancements essential for the success of interventional studies. We advocate for the adoption of a multi-disciplinary approach that converges bench-to-bedside research, clinical expertise, and ethical considerations to tackle the challenges of ultra-rare diseases like FOP and comparable ultra-rare diseases. In essence, this manuscript serves a dual purpose: as a definitive scientific resource for ongoing and future FOP research and a call to action for innovative solutions to address methodological and ethical challenges that impede progress in the broader field of medical research into ultra-rare conditions.