Study methodology and insights from the palovarotene clinical development program in fibrodysplasia ossificans progressiva

BACKGROUND

The design of clinical trials in rare diseases is often complicated by a lack of real-world translational knowledge. Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare genetic disorder characterized by skeletal malformations and progressive heterotopic ossification (HO). Palovarotene is a selective retinoic acid receptor gamma agonist. Here, we describe the methodology of three studies in the palovarotene clinical development program in FOP and discuss insights that could inform future research, including endpoint suitability and the impact of trial design.

METHODS

PVO-1A-001 (NCT02322255) was a prospective, protocol-specified, longitudinal FOP natural history study (NHS). PVO-1A-201 (NCT02190747) was a randomized, double-blind, placebo-controlled phase II trial; PVO-1A-202 (NCT02279095) was its open-label extension. Trial designs, including treatment regimens and imaging assessments, were refined between PVO-1A-201 and PVO-‍1A-202, and within PVO-1A-202, based on emerging data as the studies progressed. Palovarotene doses were administered using a flare-up treatment regimen (higher dose for 2/4 weeks, followed by lower dose for 4/≥8 weeks; from flare-up onset), with or without accompanying chronic (daily) treatment. Flare-up and disease progression outcomes were assessed, including incidence and volume of new HO during flare-ups and/or annually, as well as other clinical, patient-reported, and exploratory outcomes. Safety was monitored throughout all studies.

RESULTS

Overall, 114 and 58 individuals with FOP were enrolled in the NHS and phase II trials, respectively. Results of the NHS and PVO-1A-201 were published in 2022; complete results of PVO-1A-202 will be publicly available in due course. Together the studies yielded important information on endpoint suitability, including that low-dose whole-body computed tomography was the optimum imaging modality for assessing HO progression annually and that long study durations are needed to detect substantial changes in functional and patient-reported outcomes.

CONCLUSIONS

A flexible clinical development program is necessary for underexplored rare diseases to overcome the many challenges faced. Here, the NHS provided a longitudinal evaluation of FOP progression and interventional trials were based on emerging data. The studies described informed the design and endpoints implemented in the phase III MOVE trial (NCT03312634) and provide a foundation for future clinical trial development.

TRIAL REGISTRATION

NCT02322255 (registered 23/12/2014); NCT02190747 (registered 15/07/2014); NCT02279095 (registered 30/10/2014).

Garetosmab in fibrodysplasia ossificans progressiva: a randomized, double-blind, placebo-controlled phase 2 trial

Fibrodysplasia ossificans progressiva (FOP) is a rare disease characterized by heterotopic ossification (HO) in connective tissues and painful flare-ups. In the phase 2 LUMINA-1 trial, adult patients with FOP were randomized to garetosmab, an activin A-blocking antibody (n = 20) or placebo (n = 24) in period 1 (28 weeks), followed by an open-label period 2 (28 weeks; n = 43). The primary end points were safety and for period 1, the activity and size of HO lesions. All patients experienced at least one treatment-emergent adverse event during period 1, notably epistaxis, madarosis and skin abscesses. Five deaths (5 of 44; 11.4%) occurred in the open-label period and, while considered unlikely to be related, causality cannot be ruled out. The primary efficacy end point in period 1 (total lesion activity by PET-CT) was not met (P = 0.0741). As the development of new HO lesions was suppressed in period 1, the primary efficacy end point in period 2 was prospectively changed to the number of new HO lesions versus period 1. No placebo patients crossing over to garetosmab developed new HO lesions (0% in period 2 versus 40.9% in period 1; P = 0.0027). Further investigation of garetosmab in FOP is ongoing. ClinicalTrials.gov identifier NCT03188666 .

The International X-Linked Hypophosphatemia (XLH) Registry: first interim analysis of baseline demographic, genetic and clinical data

BACKGROUND

X-linked hypophosphatemia (XLH) is a rare, hereditary, progressive, renal phosphate-wasting disorder characterized by a pathological increase in FGF23 concentration and activity. Due to its rarity, diagnosis may be delayed, which can adversely affect outcomes. As a chronic disease resulting in progressive accumulation of musculoskeletal manifestations, it is important to understand the natural history of XLH over the patient's lifetime and the impact of drug treatments and other interventions. This multicentre, international patient registry (International XLH Registry) was established to address the paucity of these data. Here we present the findings of the first interim analysis of the registry.

RESULTS

The International XLH Registry was initiated in August 2017 and includes participants of all ages diagnosed with XLH, regardless of their treatment and management. At the database lock for this first interim analysis (29 March 2021), 579 participants had entered the registry before 30 November 2020 and are included in the analysis (360 children [62.2%], 217 adults [37.5%] and 2 whose ages were not recorded [0.3%]; 64.2% were female). Family history data were available for 319/345 (92.5%) children and 145/187 (77.5%) adults; 62.1% had biological parents affected by XLH. Genetic testing data were available for 341 (94.7%) children and 203 (93.5%) adults; 370/546 (67.8%) had genetic test results; 331/370 (89.5%) had a confirmed PHEX mutation. A notably longer time to diagnosis was observed in adults ≥ 50 years of age (mean [median] duration 9.4 [2.0] years) versus all adults (3.7 [0.1] years) and children (1.0 [0.2] years). Participants presented with normal weight, shorter length or height and elevated body mass index (approximately - 2 and + 2 Z-scores, respectively) versus the general population. Clinical histories were collected for 349 participants (239 children and 110 adults). General data trends for prevalence of bone, dental, renal and joint conditions in all participants were aligned with expectations for a typical population of people with XLH.

CONCLUSION

The data collected within the International XLH Registry, the largest XLH registry to date, provide substantial information to address the paucity of natural history data, starting with demographic, family history, genetic testing, diagnosis, auxology and baseline data on clinical presentation.

Reduction of New Heterotopic Ossification (HO) in the Open-Label, Phase 3 MOVE Trial of Palovarotene for Fibrodysplasia Ossificans Progressiva (FOP)

Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare, severely disabling genetic disorder of progressive heterotopic ossification (HO). The single-arm, open-label, phase 3 MOVE trial (NCT03312634) assessed efficacy and safety of palovarotene, a selective retinoic acid receptor gamma agonist, in patients with FOP. Findings were compared with FOP natural history study (NHS; NCT02322255) participants untreated beyond standard of care. Patients aged ≥4 years received palovarotene once daily (chronic: 5 mg; flare-up: 20 mg for 4 weeks, then 10 mg for ≥8 weeks; weight-adjusted if skeletally immature). The primary endpoint was annualized change in new HO volume versus NHS participants (by low-dose whole-body computed tomography [WBCT]), analyzed using a Bayesian compound Poisson model (BcPM) with square-root transformation. Twelve-month interim analyses met futility criteria; dosing was paused. An independent Data Monitoring Committee recommended trial continuation. Post hoc 18-month interim analyses utilized BcPM with square-root transformation and HO data collapsed to equalize MOVE and NHS visit schedules, BcPM without transformation, and weighted linear mixed-effects (wLME) models, alongside prespecified analysis. Safety was assessed throughout. Eighteen-month interim analyses included 97 MOVE and 101 NHS individuals with post-baseline WBCT. BcPM analyses without transformation showed 99.4% probability of any reduction in new HO with palovarotene versus NHS participants (with transformation: 65.4%). Mean annualized new HO volume was 60% lower in MOVE versus the NHS. wLME results were similar (54% reduction fitted; nominal p = 0.039). All palovarotene-treated patients reported ≥1 adverse event (AE); 97.0% reported ≥1 retinoid-associated AE; 29.3% reported ≥1 serious AE, including premature physeal closure (PPC)/epiphyseal disorder in 21/57 (36.8%) patients aged <14 years. Post hoc computational analyses using WBCT showed decreased vertebral bone mineral density, content, and strength, and increased vertebral fracture risk in palovarotene-treated patients. Thus, post hoc analyses showed evidence for efficacy of palovarotene in reducing new HO in FOP, but high risk of PPC in skeletally immature patients. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Benefit of burosumab in adults with X-linked hypophosphataemia (XLH) is maintained with long-term treatment

OBJECTIVES

To report the impact of continued burosumab treatment on clinical laboratory tests of efficacy, patient-reported outcomes (PROs) and ambulatory function in adults with X-linked hypophosphataemia who continued from a 96-week phase 3 study into a 48-week open-label extension.

METHODS

Eligible participants from the phase 3 study continued on the burosumab regimen received at the end of the phase 3 study for a further 48 weeks (n=31). Some (not all) received compassionate burosumab treatment between the two studies (a period of 6-18 months). The primary efficacy outcome was fasting serum phosphate concentration; secondary outcomes were serum 1,25 dihydroxyvitamin D concentration, renal phosphate reabsorption, PROs and ambulatory function.

RESULTS

Improvements in fasting serum phosphate, serum 1,25 dihydroxyvitamin D and renal phosphate reabsorption at 96 weeks were maintained through the 48-week extension. Improvements were also maintained in stiffness and physical function measured using the Western Ontario and McMaster Universities Osteoarthritis Index, pain and fatigue endpoints measuring using the Brief Pain Inventory short-form and Brief Pain Inventory, respectively, and in ambulatory function (6-Minute Walk Test).A post-hoc exploratory analysis exploring outcomes in participants who discontinued burosumab treatment between the studies (n=7) and those who received at least one dose (n=23) indicated that the benefits of burosumab on clinical laboratory tests of efficacy, PROs and ambulatory function may be lost when treatment is interrupted but recover over time when treatment is reinstated.

CONCLUSION

Continued treatment with burosumab appears necessary for sustained clinical benefit.

TRIAL REGISTRATION NUMBERS

Phase 3: NCT02526160; open-label extension: NCT03920072.

The natural history of fibrodysplasia ossificans progressiva: A prospective, global 36-month study

PURPOSE

We report the first prospective, international, natural history study of the ultra-rare genetic disorder fibrodysplasia ossificans progressiva (FOP). FOP is characterized by painful, recurrent flare-ups, and disabling, cumulative heterotopic ossification (HO) in soft tissues.

METHODS

Individuals aged ≤65 years with classical FOP (ACVR1^R206H variant) were assessed at baseline and over 36 months.

RESULTS

In total, 114 individuals participated; 33 completed the study (mean follow up: 26.8 months). Median age was 15.0 (range: 4-56) years; 54.4% were male. During the study, 82 (71.9%) individuals reported 229 flare-ups (upper back: 17.9%, hip: 14.8%, shoulder: 10.9%). After 84 days, 14 of 52 (26.9%) imaged flare-ups had new HO at the flare-up site (mean new HO volume: 28.8 × 10³ mm³). Mean baseline low-dose whole-body computed tomography (excluding head) HO volume was 314.4 × 10³ mm³; lowest at 2 to <8 years (68.8 × 10³ mm³) and increasing by age (25-65 years: 575.2 × 10³ mm³). The mean annualized volume of new HO was 23.6 × 10³ mm³/year; highest at 8 to <15 and 15 to <25 years (21.9 × 10³ and 41.5 × 10³ mm³/year, respectively) and lowest at 25 to 65 years (4.6 × 10³ mm³/year).

CONCLUSION

Results from individuals receiving standard care for up to 3 years in this natural history study show the debilitating effect and progressive nature of FOP cross-sectionally and longitudinally, with greatest progression during childhood and early adulthood.

Efficacy of Burosumab in Adults with X-linked Hypophosphatemia (XLH): A Post Hoc Subgroup Analysis of a Randomized Double-Blind Placebo-Controlled Phase 3 Study

The anti-fibroblast growth factor 23 monoclonal antibody burosumab corrects hypophosphatemia in adults with X-linked hypophosphatemia (XLH) and improves pain, stiffness, physical function, and fatigue. This post hoc subgroup analysis used data from the 24-week placebo-controlled period of a phase 3 study in 134 adults with XLH (ClinicalTrials.gov NCT02526160), to assess whether the benefits of burosumab are evident in 14 clinically relevant subgroups defined by baseline demographic and functional criteria, including sex, Brief Pain Inventory-short form (BPI-SF) Average And Worst Pain, region, race, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC®) Stiffness, Physical Function and Pain domains and total score, use of opioid/other pain medication, active fractures/pseudo-fractures, and 6-min walk test distance. There were no statistically significant interactions between any of the subgroups and treatment arm for any endpoint. Higher proportions of subjects achieved mean serum phosphate concentration above the lower limit of normal (the primary endpoint) with burosumab than with placebo in all subgroups. For the key secondary endpoints (WOMAC Stiffness and Physical Function; BPI-SF Worst Pain) individual subgroup categories showed improvements with burosumab relative to placebo. For additional efficacy endpoints, burosumab was favored in some subgroups but differences were not significant and confidence intervals were wide. For some endpoints the treatment effect is small at 24 weeks in all subjects. This subgroup analysis shows that burosumab was largely superior to placebo across endpoints in the 14 clinically relevant subgroup variables at 24 weeks and is likely to benefit all symptomatic adults with active XLH.

Palovarotene for Fibrodysplasia Ossificans Progressiva (FOP): Results of a Randomized, Placebo-Controlled, Double-Blind Phase 2 Trial

Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare genetic disorder characterized by progressive heterotopic ossification (HO), often heralded by flare-ups, leading to reduced movement and life expectancy. This placebo-controlled, double-blind trial (NCT02190747) evaluated palovarotene, an orally bioavailable selective retinoic acid receptor gamma agonist, for prevention of HO in patients with FOP. Patients experiencing a flare-up were enrolled in two cohorts: (1) patients ≥15 years were randomized 3:1 to palovarotene 10/5 mg (weeks 1-2/3-6) or placebo; (2) patients ≥6 years were randomized 3:3:2 to palovarotene 10/5 mg, palovarotene 5/2.5 mg (weeks 1-2/3-6), or placebo. Cohort data were pooled. The primary endpoint was the proportion of responders (no/minimal new HO at flare-up body region by plain radiograph) at week 6. Change from baseline in HO volume and new HO incidence were assessed by computed tomography (CT) at week 12. Tissue edema was assessed by magnetic resonance imaging (MRI) or ultrasound. Forty patients (aged 7-53 years) were enrolled (placebo: n = 10; palovarotene 5/2.5 mg: n = 9; palovarotene 10/5 mg: n = 21). Disease history was similar between groups. In the per-protocol population, the proportion of responders at week 6 by plain radiograph was 100% with palovarotene 10/5 mg; 88.9% with palovarotene 5/2.5 mg; 88.9% with placebo (Cochran-Armitage trend test: p = 0.17). At week 12, the proportions were 95.0% with palovarotene 10/5 mg; 88.9% with palovarotene 5/2.5 mg; 77.8% with placebo (Cochran-Armitage trend test: p = 0.15). Week 12 least-squares mean (LSmean) new HO volume, assessed by CT, was 3.8 × 10³  mm³ with palovarotene 10/5 mg; 1.3 × 10³  mm³ with palovarotene 5/2.5 mg; 18.0 × 10³  mm³ with placebo (pairwise tests versus placebo: p ≤ 0.12). Palovarotene was well-tolerated. No patients discontinued treatment or required dose reduction; one patient had dose interruption due to elevated lipase. Although these findings were not statistically significant, they support further evaluation of palovarotene for prevention of HO in FOP in larger studies. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Post-authorisation safety study of burosumab use in paediatric, adolescent and adult patients with X-linked hypophosphataemia: rationale and description

Background:

X-linked hypophosphataemia (XLH) is a rare, inherited, phosphate-wasting disorder that elevates fibroblast growth factor 23 (FGF23), causing renal phosphate-wasting and impaired active vitamin D (1,25(OH)₂D) synthesis. Disease characteristics include rickets, osteomalacia, odontomalacia, and short stature. Historically, treatment has been oral phosphate and 1,25(OH)₂D supplements. However, these treatments do not correct the primary pathogenic mechanism or treat all symptoms and can be associated with adverse effects. Burosumab is a recombinant human immunoglobulin G1 monoclonal antibody against FGF23, approved for treating XLH in several geographical regions, including Europe and Israel. Burosumab restores normal serum phosphate levels, minimising the clinical consequences of XLH. Safety data on long-term treatment with burosumab are lacking owing to the rarity of XLH. This post-authorisation safety study (PASS) aims to evaluate the safety outcomes in patients aged >1 year.

Methods:

The PASS is a 10-year retrospective and prospective cohort study utilising data from the International XLH Registry (NCT03193476), which includes standard diagnostic and monitoring practice data at participating centres. The PASS aims to evaluate frequency and severity of safety outcomes, frequency and outcomes of pregnancies in female patients, and safety outcomes in patients with mild to moderate kidney disease at baseline, in children, adolescents and adults treated with burosumab for XLH. It is expected that there will be at least 400 patients who will be administered burosumab.

Results:

Data collection started on 24 April 2019. The expected date of the final study report is 31 December 2028, with two interim reports.

Conclusion:

This PASS will provide data on the long-term safety of burosumab treatment for XLH patients and describe safety outcomes for patients receiving burosumab contrasted with those patients receiving other XLH treatments, to help inform the future management of XLH patients. The PASS will be the largest real-world safety study of burosumab.

Registry identification:

The International XLH Registry is registered with clinicaltrials.gov as NCT03193476 (https://clinicaltrials.gov/ct2/show/NCT03193476), and the PASS is registered with the European Union electronic Register of Post-Authorisation Studies as EUPAS32190 (http://www.encepp.eu/encepp/viewResource.htm?id=32191).

Physical function and physical activity in adults with X-linked hypophosphatemia

We described physical function and activity in UK adults with X-linked hypophosphatemia (XLH). Our data indicate that low physical activity and impaired mobility are common in adults with XLH. Deficits in lower limbs muscle power and functional capacity contribute to the loss of physical function in adults with XLH.

INTRODUCTION

There is a dearth of literature on physical function and physical activity in adults with X-linked hypophosphatemia (XLH). We described muscle strength and power, functional capacity, mobility and physical activity level and explored the relationships among these variables in adults with XLH.

METHODS

Participants were recruited as part of a UK-based prospective cohort study, the RUDY Study. They underwent a clinical visit and physical examination, including assessment of handgrip strength, jump power (mechanography), six-minute walk test (6MWT) and short physical performance battery (SPPB), and completed the International Physical Activity Questionnaire (IPAQ). Performance data were analysed using parametric and non-parametric tests, whereas correlations were assessed by univariate analysis.

RESULTS

Twenty-six adults with XLH (50% males) with a mean age of 44 ± 16.1 years were recruited. Jump power and 6MWT distances (p < 0.0001) were 54.4% and 38.6% lower respectively in individuals with XLH compared with normative values. These deficits were not associated with age or sex. Handgrip strength values were similar to expected values. Deficits in muscle power were more pronounced than those reported at 6MWT (p < 0.0001). Univariate analysis revealed only a correlation between total physical activity and muscle power (r = 0.545, p = 0.019).

CONCLUSIONS

Adults with XLH have a marked deficit in lower limb muscle power and a reduced functional capacity, with a high incidence of impaired mobility and inactivity. In addition to metabolic effects of XLH, low physical activity may contribute to deficits in lower limb power. Further studies are required to develop novel treatment approaches to improve physical function and mobility.

Protocol paper: a multi-center, double-blinded, randomized, 6-month, placebo-controlled study followed by 12-month open label extension to evaluate the safety and efficacy of Saracatinib in Fibrodysplasia Ossificans Progressiva (STOPFOP)

Background

Fibrodysplasia Ossificans Progressiva (FOP) is a genetic, progressive and devastating disease characterized by severe heterotopic ossification (HO), loss of mobility and early death. There are no FDA approved medications. The STOPFOP team identified AZD0530 (saracatinib) as a potent inhibitor of the ALK2/ACVR1-kinase which is the causative gene for this rare bone disease. AZD0530 was proven to prevent HO formation in FOP mouse models. The STOPFOP trial investigates the repositioning of AZD0530, originally developed for ovarian cancer treatment, to treat patients with FOP.

Methods

The STOPFOP trial is a phase 2a study. It is designed as a European, multicentre, 6-month double blind randomized controlled trial of AZD0530 versus placebo, followed by a 12-month trial comparing open-label extended AZD0530 treatment with natural history data as a control. Enrollment will include 20 FOP patients, aged 18–65 years, with the classic FOP mutation (ALK2 R206H). The primary endpoint is objective change in heterotopic bone volume measured by low-dose whole-body computer tomography (CT) in the RCT phase. Secondary endpoints include ¹⁸F NaF PET activity and patient reported outcome measures.

Discussion

Clinical trials in rare diseases with limited study populations pose unique challenges. An ideal solution for limiting risks in early clinical studies is drug repositioning – using existing clinical molecules for new disease indications. Using existing assets may also allow a more fluid transition into clinical practice.

With positive study outcome, AZD0530 may provide a therapy for FOP that can be rapidly progressed due to the availability of existing safety data from 28 registered clinical trials with AZD0530 involving over 600 patients.

Trial registration

EudraCT, 2019–003324-20. Registered 16 October 2019, https://www.clinicaltrialsregister.eu/ctr-search/trial/2019-003324-20/NL. Clinicaltrials.gov, NCT04307953. Registered 13 March 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05471-x.

The prevalence of musculoskeletal pain and therapy needs in adults with Osteogenesis Imperfecta (OI) a cross-sectional analysis

BACKGROUND

Osteogenesis Imperfecta affects approximately 1 in every 10,000 people. Musculoskeletal disorders and pain are common in adults with Osteogenesis Imperfecta, but specific knowledge of the problems people have is lacking. Access to therapy services for adults with Osteogenesis Imperfecta is variable. We designed this analysis to better understand the musculoskeletal disorders and consequent therapy needs for adults with Osteogenesis Imperfecta.  METHODS: This study was a cross-sectional analysis of outpatients with Osteogenesis Imperfecta. Adults attending a newly established multidisciplinary clinic at a tertiary centre in 2019 were included. A highly specialist physiotherapist worked within the clinic to offer therapy input if required and to refer patients to appropriate therapy as needed. People over the age of 18 were included if they had a diagnosis of Osteogenesis Imperfecta. Data were collected over a five month period using routinely collected clinical information and patient reported outcomes.

RESULTS

Over five months 50 patients attended the clinic. Musculoskeletal pain was a significant feature reported by 84% of patients. Over 50% of patients reported persistent pain for longer than one year duration and the most common site of pain was in the spine (46%). No difference in pain between types of OI and age. Forty five per cent (n = 19) of patients reported moderate to severe problems with mobility on the EQ-5D with over half reporting problems with self-care and ability to carry out usual activities. Over 50% of patients in clinic also reported anxiety (EQ-5D). During the consultation 70% of patients received therapy input which was either advice in clinic or an onward referral to the appropriate service. The referral rate to specialist out-patient rehabilitation services at a tertiary centre was 30%.

CONCLUSIONS

This analysis highlights the high prevalence of MSK pain in adults with OI and the effect on physical function and emotional wellbeing. This study demonstrates the diverse needs of the adult Osteogenesis Imperfecta population and the need for suitable multidisciplinary therapy services.

P025 Do referrals to rheumatology meet the new British Society of Rheumatology (BSR) guidelines for adult patients with osteoporosis? A retrospective audit of a tertiary osteoporosis service

Background/Aims

British Society of Rheumatology (BSR) released national guidance in September 2021 outlining appropriate referrals to adult rheumatology departments from primary care. Our tertiary metabolic bone service accepts referrals from primary care, secondary care and internal referrals.

Methods

We retrospectively audited the new patient referrals for 50 patients with osteoporosis seen in our clinic over the 6 months prior to the guidance publication. 86% were referred from primary care, 6% from secondary care and 8% from our orthopaedic colleagues. 92% patients were female and 8% patients were male. Mean age was 61.7 years (range 17- 85 years).

Results:

We found that the majority of patients with osteoporosis referred to our specialist service were within the new BSR guidance (45/50 patients or 90% of patients). Reasons for referring patients outside of the BSR guidance included deterioration in bone mineral density without fracture and a family history of osteoporosis. Of these patients, four were referred from primary care and one from secondary care (another rheumatology department). Of the 50 patients seen in our clinic, 48% were advised to commence parenteral bone protection medication. 2% were advised to start hormone replacement therapy (HRT) only. 6% were advised to either start or continue oral bisphosphonates. 38% of patients were advised to remain without bone protection treatment and monitor. 2% were given an alternate diagnosis other than osteoporosis.

Conclusion

We plan to undertake a further audit for a period of 6 months after the release of the guidance.

No funding to declare

Disclosure

F. Baldeweg: None. J. Bubbear: None. R. Keen: None.

Burosumab treatment in adults with X-linked hypophosphataemia: 96-week patient-reported outcomes and ambulatory function from a randomised phase 3 trial and open-label extension

Objectives

To report the impact of burosumab on patient-reported outcomes (PROs) and ambulatory function in adults with X-linked hypophosphataemia (XLH) through 96 weeks.

Methods

Adults diagnosed with XLH were randomised 1:1 in a double-blinded trial to receive subcutaneous burosumab 1 mg/kg or placebo every 4 weeks for 24 weeks (NCT02526160). Thereafter, all subjects received burosumab every 4 weeks until week 96. PROs were measured using the Western Ontario and the McMaster Universities Osteoarthritis Index (WOMAC), Brief Pain Inventory-Short Form (BPI-SF) and Brief Fatigue Inventory (BFI), and ambulatory function was measured with the 6 min walk test (6MWT).

Results

Subjects (N=134) were randomised to burosumab (n=68) or placebo (n=66) for 24 weeks. At baseline, subjects experienced pain, stiffness, and impaired physical and ambulatory function. At week 24, subjects receiving burosumab achieved statistically significant improvement in some BPI-SF scores, BFI worst fatigue (average and greatest) and WOMAC stiffness. At week 48, all WOMAC and BPI-SF scores achieved statistically significant improvement, with some WOMAC and BFI scores achieving meaningful and significant change from baseline. At week 96, all WOMAC, BPI-SF and BFI achieved statistically significant improvement, with selected scores in all measures also achieving meaningful change. Improvement in 6MWT distance and percent predicted were statistically significant at all time points from 24 weeks.

Conclusions

Adults with XLH have substantial burden of disease as assessed by PROs and 6MWT. Burosumab treatment improved phosphate homoeostasis and was associated with a steady and consistent improvement in PROs and ambulatory function.

Trial registration number

NCT02526160.

Dual neutralisation of IL-17F and IL-17A with bimekizumab blocks inflammation-driven osteogenic differentiation of human periosteal cells

OBJECTIVES

Interleukin (IL)-17 signalling has been shown to be a key regulator of disease in ankylosing spondylitis (AS) with several IL-17 blockers currently clinically approved. Despite this, the role of IL-17 in bone pathology is poorly understood. This study aimed to investigate IL-17 signalling in the context of pathological bone formation.

METHODS

A biomimetic human periosteum-derived cell (hPDC) model of osteogenic differentiation was used in combination with recombinant IL-17 cytokines, T-cell supernatants or serum from patients with AS. IL-17A, IL-17F and bimekizumab monoclonal antibodies were used to block IL-17 cytokine action.

RESULTS

Recombinant IL-17A and IL-17F are pro-osteogenic with respect to hPDC differentiation. T helper 17 or γδ-T cell supernatants also potently stimulated in vitro bone formation, which was blocked deeper by dual inhibition of IL-17A and IL-17F than by neutralisation of IL-17A or IL-17F individually. Osteogenic blockade may be due to an increase in expression of the Wnt antagonist DKK1. Interestingly, osteocommitment was also induced by serum obtained from patients with AS, which was also abrogated by dual neutralisation of IL-17A and IL-17F.

CONCLUSIONS

These data show for the first time that IL-17A and IL-17F enhance in vitro osteogenic differentiation and bone formation from hPDCs, inhibition of which may offer an attractive therapeutic strategy to prevent pathological bone formation.

Garetosmab Reduces Flare-ups in Patients With Fibrodysplasia Ossificans Progressiva

Background: Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare, autosomal dominant disorder driven by mutations in ACVR1 that render it responsive to Activin A. FOP is characterized by progressive heterotopic ossification (HO) and distressing inflammatory events called “flare-ups.” Flare-ups can precede new HO; however, limited prospective data exists on this phenomenon. Garetosmab (GAR), an investigational human monoclonal antibody against Activin A, blocks formation of new HO in FOP. Methods: This is a post-hoc analysis of LUMINA-1 (NCT03188666) a phase 2, randomized, double-blind, placebo-controlled study, which evaluated the safety and efficacy of GAR (10 mg/kg/week IV) versus placebo (PBO) in adult patients with FOP over 28 weeks. Patient-reported flare-ups were collected via a patient diary and severity level was reported as mild, moderate or severe. Clinician-reported flare-ups were collected as adverse events in the trial. HO lesions were imaged by 18F-NaF positron emission tomography (PET) and whole-body low-dose X-ray computed tomography (CT). Results: There was a two-fold higher proportion of patients who reported one or more flare-ups on PBO 17/24 (71%) compared with GAR 7/20 (35%). Clinicians reported a four-fold higher proportion of patients experiencing one or more flare-ups on PBO 10/24 (42%) compared with GAR 2/20 (10%). Overall rates of flare-up events were two-fold higher on PBO vs. GAR (1.4 vs. 0.65 events/patient/28 weeks) for patient-reported events and eight-fold higher on PBO vs. GAR by clinician report (0.83 vs. 0.10 events/patient/28 weeks). Most flare-ups occurred on the extremities and back; pain was the most commonly reported symptom. Patient-reported flare-ups on PBO were more frequently reported as severe (29.4%) compared with GAR (7.7%). Among subjects with at least 12 weeks of follow-up from start of patient-reported flare-up, development of new HO near the site was 5/27 (18.5%) on PBO and (0%) on GAR. Of all new HO lesions, 41% on PBO and 0% on GAR occurred with spatial and temporal relation to flare-up. Conclusions: Approximately two-thirds of patients on PBO reported flare-ups over 28 weeks. GAR was associated with reductions in frequency and severity of flare-ups. Fewer than 20% of patient-reported flare-ups were associated with new HO, indicating frequent discordance of these phenomena, and compatible with previous reports. GAR’s ability to reduce patient- and clinician-reported flare-ups, as well as new HO lesions may provide an important therapeutic option.

Adult North Star Network (ANSN): Consensus Guideline For The Standard Of Care Of Adults With Duchenne Muscular Dystrophy

There are growing numbers of adults with Duchenne Muscular Dystrophy living well into their fourth decade. These patients have complex medical needs that to date have not been addressed in the International standards of care. We sought to create a consensus based standard of care through a series of multi-disciplinary workshops with specialists from a wide range of clinical areas: Neurology, Cardiology, Respiratory Medicine, Gastroenterology, Endocrinology, Palliative Care Medicine, Rehabilitation, Renal, Anaesthetics and Clinical Psychology. Detailed reports of evidence reviewed and the consensus building process were produced following each workshop and condensed into this final document which was approved by all members of the Adult North Star Network including service users. The aim of this document is to provide a framework to improve clinical services and multi-disciplinary care for adults living with Duchenne Muscular Dystrophy.

Burden of disease associated with X-linked hypophosphataemia in adults: a systematic literature review

This systematic review collated evidence on the burden of XLH in adults. Data captured highlight the substantial ongoing burden of XLH in adulthood and identified unmet needs. Greater awareness and understanding of the impact of XLH in adulthood are needed to improve care and outcomes in adults with XLH.

INTRODUCTION

X-linked hypophosphataemia (XLH) is a rare metabolic bone disease characterized by renal phosphate wasting and musculoskeletal manifestations. Whilst the disease's impact in children is well documented, information on the effects of this progressive, debilitating condition on adults is lacking. This systematic review aimed to collate existing evidence on the burden of XLH in adulthood to identify unmet needs.

METHODS

MEDLINE, Embase and Cochrane Library databases and recent congress reports were searched on 19 February 2019 for English-language publications describing the medical, humanistic and socio-economic impact of XLH in adults (≥ 18 years old). In addition, a structured Internet search was conducted.

RESULTS

Of the 2351 articles identified, 91 met the selection criteria along with 44 congress abstracts. Data show that adults with XLH experience a range of clinical manifestations, particularly skeletal deformities and (pseudo)fractures, along with pain, dental abnormalities and impaired physical function and mobility. XLH in adulthood impacts on quality of life and places limitations on daily activities. The level of healthcare resource utilization among adults with XLH is indicative of substantial socio-economic burden; further research is needed to quantitate the economic impact on the healthcare system, society and patients. Adults with XLH may not receive appropriate care and treatment; a possible explanation for this is a lack of awareness among healthcare professionals.

CONCLUSION

XLH in adults is associated with considerable disease burden and unmet needs. Forthcoming studies and increased awareness of the impact of XLH in adulthood should help to improve management of XLH in adulthood and patient outcomes.

Fibrodysplasia Ossificans Progressiva: What Have We Achieved and Where Are We Now? Follow-up to the 2015 Lorentz Workshop

Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare progressive genetic disease effecting one in a million individuals. During their life, patients with FOP progressively develop bone in the soft tissues resulting in increasing immobility and early death. A mutation in the ACVR1 gene was identified as the causative mutation of FOP in 2006. After this, the pathophysiology of FOP has been further elucidated through the efforts of research groups worldwide. In 2015, a workshop was held to gather these groups and discuss the new challenges in FOP research. Here we present an overview and update on these topics.

Economic evaluation of suture versus clip anastomosis in arteriovenous fistula creation

OBJECTIVE

Techniques such as the use of nonpenetrating vascular clips for arteriovenous fistula (AVF) anastomotic creation have been developed in an effort to reduce fistula-related complications. However, the outcomes data for the use of clips have remained equivocal, and the cost evaluations to support their use have been largely theoretical. Therefore, the present study aimed to determine both the clinical and the cost outcomes of AVFs created with nonpenetrating vascular clips compared with the continuous suture technique during a 10-year period at a single institution.

METHODS

All patients undergoing AVF creation in the upper extremity from 2009 through 2018 were retrospectively analyzed. The patient demographics and AVF outcomes were collected and compared stratified by the surgical technique used. A cost analysis was performed of a subgroup of patients from 2013 to 2018.

RESULTS

During the 10-year study period, 916 AVFs were created (79% using the continuous suture technique and 21% using nonpenetrating vascular clips). Patient demographics and comorbid conditions did not differ between the two groups, and no differences were present in maturation, primary patency, assisted primary patency, or complication rates between the two groups at 1 year. The suture group had a shorter time to maturation (4.3 months vs 5.5 months; P < .01) and improved secondary patency compared with the clip group (77.13% vs 69.59%; P = .03) The cost analysis of the procedures revealed a significant difference in direct costs (suture, $1389.26 vs clip, $1716.51; P < .01) and contribution margin (suture, $1770.19 vs clip, $1128.36; P < .01) for the two groups.

CONCLUSIONS

Both suture and clip techniques in AVF creation demonstrated equivalent rates of maturation, primary patency, assisted primary patency, and complications at 1 year with higher expense associated with the use of clips. Thus, in an effort to reduce the economic burden of healthcare in the United States, the findings from the present study support the preferential use of the standard polypropylene suture technique when creating upper extremity AVFs.

Patients with ACVR1R206H mutations have an increased prevalence of cardiac conduction abnormalities on electrocardiogram in a natural history study of Fibrodysplasia Ossificans Progressiva

Background

Genetic contributors to cardiac arrhythmias are often found in cardiovascular conduction pathways and ion channel proteins. Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare disease of massive heterotopic ossification caused by a highly recurrent R206H mutation in ACVR1/ALK2. This mutation causes abnormal activation of the bone morphogenetic protein (BMP) pathway in response to Activin A. Prior studies suggested increased risks of cardiopulmonary complications in FOP. We examined participants in a Natural History Study (NHS) of FOP (ClinicalTrials.gov #NCT02322255) to better understand their cardiovascular status.

Methods

The NHS is an ongoing 3 year international multi-center longitudinal study of 114 patients (ages 4–56 years) with genetically confirmed ACVR1/ALK2^R206H FOP. Patients were clinically assessed at baseline and 12 months. Electrocardiograms (ECGs) were reviewed in a central ECG laboratory. Conduction abnormalities were compared against clinical data collected in the NHS, and echocardiograms collected from NHS and non-NHS patients.

Results

Conduction abnormalities were present in 45.3% of baseline ECGs, with the majority of abnormalities classified as nonspecific intraventricular conduction delay (37.7%). More specifically, 22.2% of patients > 18 years old had conduction abnormalities, which was significantly higher than a prior published study of a healthy population (5.9%; n = 3978) (p < 0.00001). Patients with FOP < 18 years old also had a high prevalence of conduction abnormalities (62.3%). The 12-month follow up data was similar to baseline results. Conduction abnormalities did not correlate with chest wall deformities, scoliosis, pulmonary function test results, or increased Cumulative Analog Joint Involvement Scale scores. Echocardiograms from 22 patients with FOP revealed 8 with structural cardiac abnormalities, only 1 of which correlated with a conduction abnormality.

Conclusions

We found that patients with FOP may have subclinical conduction abnormalities manifesting on ECG, independent of heterotopic ossification. Although clinically significant heart disease is not typically associated with FOP, and the clinical implications for cardiovascular risk remain unclear, knowledge about ECG and echocardiogram changes is important for clinical care and research trials in patients with FOP. Further studies on how ACVR1/ALK2^R206H affects cardiac health will help elucidate the underlying mechanism.

Rare musculoskeletal diseases in adults: a research priority setting partnership with the James Lind Alliance

BACKGROUND

Osteogenesis imperfecta, fibrous dysplasia/McCune-Albright syndrome and X-linked hypophosphatemia are three rare musculoskeletal diseases characterised by bone deformities, frequent fractures and pain. Little high-quality research exists on appropriate treatment and long-term management of these conditions in adults. This is further worsened by limited research funding in rare diseases and a general mismatch between the existing research priorities and those of the patients. This partnership adopted the James Lind Alliance approach to identify the top 10 research priorities for rare musculoskeletal diseases in adults through joint patient, carer and healthcare professional collaboration.

RESULTS

The initial survey for question collection recruited 198 respondents, submitting a total of 988 questions. 77% of the respondents were patients with a rare musculoskeletal disease. Following out-of-scope question exclusion, repeating query grouping and scientific literature check for answers, 39 questions on treatment and long-term management remained. In the second public survey, 220 respondents, of whom 85% were patients with a rare musculoskeletal disease, their carers, relatives or friends, prioritised these uncertainties, which allowed selection of the top 25. In the last stage, patients, carers and healthcare professionals gathered for a priority setting workshop to reach a consensus on the final top 10 research priorities. These focus on the uncertainties surrounding appropriate treatment and holistic long-term disease management, highlighting several aspects indirect to abnormal bone metabolism, such as extra-skeletal symptoms, psychological care of both patients and their families and disease course through ageing.

CONCLUSIONS

This James Lind Alliance priority setting partnership is the first to investigate rare bone diseases. The priorities identified here were developed jointly by patients, carers and healthcare professionals. We encourage researchers, funding bodies and other stakeholders to use these priorities in guiding future research for those affected by rare musculoskeletal disorders.

SUN-344 Patients with Fibrodysplasia Ossificans Progressiva Have an Increased Prevalence of Cardiac Conduction Abnormalities

Background

Genetic contributors to cardiac arrhythmias often found in cardiovascular conduction pathway and channel proteins. However, genes outside of these categories can contribute to cardiovascular conduction abnormalities. Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disease characterized by large volumes heterotopic ossification caused by a highly recurrent R206H mutation in the ACVR1/Alk2 gene. This mutation produces an abnormal activation of the bone morphogenetic pathway (BMP) pathway in response to Activin A. Prior studies suggested an increased risk of cardiopulmonary complications in FOP¹. We examined patients in a Natural History Study (NHS) of FOP (NCT02322255) to better understand their cardiovascular risk.

Methods

The NHS is an ongoing 3 year international multi-center cross-sectional study of 114 patients with FOP (ages 4–56 years) genetically verified to have the AVCR1 R206H mutation. Patients at baseline and 12 months were assessed by electrocardiogram (ECG). Abnormal lead placements were excluded. ECG readings were assessed in a central ECG laboratory.

Results

At baseline, 45.3% (48/106) of ECGs showed conduction abnormalities. The majority of these abnormalities were classified as nonspecific intraventricular conduction delay (37.7% of all ECGs). For patients > 18 years old, 22.7% (10/44) had conduction abnormalities, which was significantly higher than previously reported in the healthy population (5.9%; n=3978)² (proportional t-test; p<0.00001). FOP patients < 18 years of age also had an extremely high prevalence of conduction abnormalities (60.3%, 38/61). The NHS 12-month follow up data showed similar prevalence. The high frequency of conduction abnormalities did not correlate with the presence of chest wall deformities or scoliosis, abnormal pulmonary function test results, increased cumulative analog joint involvement scale (CAJIS) scores, or abnormal echocardiograms.

Conclusions

Our results show that some patients with FOP may have subclinical conduction abnormalities. These ECG changes appear to be independent of chest wall deformities or scoliosis, although ectopic bone may make ECG measurement in FOP patients challenging. Though there is no reported association of FOP with clinically significant heart block to date and clinical implications for cardiovascular risk remain unclear, knowledge about these ECG changes may be important for planning clinical care and clinical trials of investigational agents in patients with FOP. Further studies of how the AVCR1 R206H activating mutation and BMP signaling changes cardiac conduction are needed to better understand the mechanistic link.

References

(1)Hingorani et al. Indian J Med Res. 2012; 135:322–330

(2)Kussmaul et al. Clinical Orthopaedic Related Research. 1998; 346:104–109

Self-reported baseline phenotypes from the International Fibrodysplasia Ossificans Progressiva (FOP) Association Global Registry

A global, patient-reported registry has been established to characterize the course of disease and track clinical outcomes in patients with fibrodysplasia ossificans progressiva (FOP), an ultra-rare genetic condition of progressive heterotopic ossification (HO) that results in ankylosis of joints and renders most affected individuals immobile by the second decade of life. Here, we present baseline phenotypes on 299 patients (median age 21 years; range 0.1 to 78 years) from 54 countries based on aggregate data from the International FOP Association (IFOPA) Global Registry (the "FOP Registry"). The mean current age of the patients is 23.7 years (range, 0.1 to 78 years). Baseline characteristics are presented for FOP diagnosis, HO, flare-ups and precedent events, system-based prevalent symptomatology, encounters with medical and dental care providers, Patient Reported Outcomes Measurement Information System (PROMIS) Global Health Scale scores, physical function, as well as the use of aids, assistive devices, and adaptations. Correlations of PROMIS Global Health scores with HO burden and physical function are calculated. Associations of joint mobility with PROMIS Global Health scores, physical function, and use of aids, assistive devices, and adaptations are summarized. Overall, the FOP Registry database contains a broad sample of the global FOP patient population, providing a useful tool for expanding knowledge of FOP, designing clinical trials and facilitating evidence-based decisions about the optimal monitoring and management of affected individuals.

P194 Non-bacterial osteitis syndromes: characterising an adult population

Background

Inflammatory bone syndromes, such as SAPHO (synovitis, acne, pustulosis, hyperostosis and osteitis) and CRMO (chronic recurrent multifical osteomyelitis) are rare and have not been extensively described in the existing literature. Although there have been proposed classification and diagnostic criteria, there is still limited consensus and uniformity of approach in identifying and treating these patients. This may be due to a lack of data and understanding about the nature and prognosis of these conditions. Attempts to characterise, especially in adult populations, has been limited thus far. As a tertiary metabolic bone service with an allied regional sarcoma service, we present further data on these conditions in an adult population.

Methods

Retrospective analysis of notes of patients, with a diagnosis of SAPHO and CRMO, that were registered on a departmental database was performed. Data on demographics, symptom onset and character, serum and radiological tests and treatment were analysed.

Results

77 adults were identified with a diagnosis of SAPHO and CRMO, with a 60:40 % split respectively. Female preponderance was noted with 74% of this cohort represented. SAPHO patients tended to present slightly later with a mean age of symptom onset of 37 years as compared to 24 years in the CRMO group. Diagnostic delay was evident with mean time to diagnosis averaging 34 months. Pain and bony swelling were the most common symptoms (99% and 39% respectively), with the clavicle, sternum and spine being the most common sites involved. Osteitis was a universal feature in both groups, whereas skin and inflammatory joint involvement was more of a feature of SAPHO patients (59% vs 39%). There is limited consensus on appropriate diagnostic tests. This was reflected in this cohort with variable testing of inflammatory markers, serological testing of HLA B27 and extent and modality of imaging. Non-steroidal anti-inflammatories (NSAIDS), intravenous bisphosphonates, steroids and anti-microbials were all employed as treatment options, although efficacy was difficult to establish in this retrospective analysis, a significant source of referrals were from the local Sarcoma Unit; this may have introduced a degree of bias in our results.

Conclusion

As rare conditions, promoting awareness, having an index of suspicion and early referral to specialist centres would help address current issues faced by this patient population. Several national and international disease registries are in development and will undoubtly help to standardise data collection in order to guide further work in this area. Future studies examining treatment efficacy in current as well as emerging biological therapies, such as anti-tumour necrosis factor, anti- interleukin 1 and 17 agents, would be of significant value.

Disclosures

T. Gill None. J. Bubbear None. R. Keen None.

Continued Beneficial Effects of Burosumab in Adults with X-Linked Hypophosphatemia: Results from a 24-Week Treatment Continuation Period After a 24-Week Double-Blind Placebo-Controlled Period

Burosumab, a fully human monoclonal antibody to FGF23, is the only approved treatment for X-linked hypophosphatemia (XLH), a rare genetic disorder characterized by renal phosphate wasting and substantial cumulative musculoskeletal morbidity. During an initial 24-week randomized, controlled trial, 134 adults with XLH received burosumab 1 mg/kg (n = 68) or placebo (n = 66) every 4 weeks. After 24 weeks, all subjects received open-label burosumab until week 48. This report describes the efficacy and safety of burosumab during the open-label treatment period. From weeks 24-48, serum phosphorus concentrations remained normal in 83.8% of participants who received burosumab throughout and were normalized in 89.4% who received burosumab after placebo. By week 48, 63.1% of baseline fractures/pseudofractures healed fully with burosumab, compared with 35.2% with burosumab after placebo. In both groups, burosumab was associated with clinically significant and sustained improvement from baseline to week 48 in scores for patient-reported outcomes of stiffness, pain, physical function, and total distance walked in 6 min. Rates of adverse events were similar for burosumab and placebo. There were no fatal adverse events or treatment-related serious adverse events. Nephrocalcinosis scores did not change from baseline by more than one grade at either week 24 or 48. These data demonstrate that in participants with XLH, continued treatment with burosumab is well tolerated and leads to sustained correction of serum phosphorus levels, continued healing of fractures and pseudofractures, and sustained improvement in key musculoskeletal impairments.

Four patients with a clinically significant radial artery anomaly

The superficial radial artery is an anatomic variant in which the radial artery passes superficial to the tendons of the anatomic snuffbox. Cadaver studies have shown its incidence to be 0.5% to 1%. Four patients with this anatomic variation were encountered in our practice, and their clinical courses and anatomy are described. One patient presented with digital ischemia after catheter placement in the anomalous radial artery. Three patients with end-stage renal disease were found to have a superficial radial artery incidentally, and this was used for inflow in the creation of hemodialysis fistulas.

Natural history of fibrodysplasia ossificans progressiva: cross-sectional analysis of annotated baseline phenotypes

BACKGROUND

Fibrodysplasia Ossificans Progressiva (FOP; OMIM#135100) is an ultra-rare, severely disabling genetic disease characterized by congenital malformation of the great toes and progressive heterotopic ossification (HO) in muscles, tendons, ligaments, fascia, and aponeuroses often preceded by painful, recurrent soft tissue swelling (flare-ups). The formation of HO leads to progressive disability, severe functional limitations in joint mobility, and to a shortened life-span. In this prospective natural history study, we describe the baseline, cross-sectional disease phenotype of 114 individuals with FOP.

METHODS

All subjects underwent protocol-specified baseline assessments to determine their disease status. Cross-sectional analyses were performed using linear regression in which functional evaluations (Cumulative Analogue Joint Involvement Scale [CAJIS] and the FOP-Physical Function Questionnaire [FOP-PFQ]) and the burden of HO as measured by low-dose whole body CT (volume of HO and number of body regions with HO) were assessed.

RESULTS

Findings from 114 subjects (age range 4 to 56 years) were evaluated. While subject age was significantly (p < 0.0001) correlated with increased CAJIS (r = 0.66) and FOP-PFQ scores (r = 0.41), the estimated mean increases per year (based on cross-sectional average changes over time) were small (0.47 units and 1.2%, respectively). There was also a significant (p < 0.0001) correlation between baseline age and HO volume (r = 0.56), with an estimated mean increase of 25,574 mm³/year. There were significant (p < 0.0001) correlations between the objective assessment of HO volume and clinical assessments of CAJIS (r = 0.57) and FOP-PFQ (r = 0.52).

CONCLUSIONS

Based on the cross-sectional analysis of the baseline data, functional and physical disability as assessed by CAJIS and the FOP-PFQ increased over time. Although longitudinal data are not yet available, the cross-sectional analyses suggest that CAJIS and FOP-PFQ are not sensitive to detect substantial progression over a 1- to 2-year period. Future evaluation of longitudinal data will test this hypothesis. The statistically significant correlations between HO volume and the functional endpoints, and the estimated average annual increase in total HO volume, suggest that the formation of new HO will be measurable over the relative short-term course of a clinical trial, and represents an endpoint that is clinically meaningful to patients.

TRIAL REGISTRATION

This study ( NCT02322255 ) was first posted on 23 December, 2014.

Special considerations for clinical trials in fibrodysplasia ossificans progressiva (FOP)

Clinical trials for orphan diseases are critical for developing effective therapies. One such condition, fibrodysplasia ossificans progressiva (FOP; MIM#135100), is characterized by progressive heterotopic ossification (HO) that leads to severe disability. Individuals with FOP are extremely sensitive to even minor traumatic events. There has been substantial recent interest in clinical trials for novel and urgently‐needed treatments for FOP. The International Clinical Council on FOP (ICC) was established in 2016 to provide consolidated and coordinated advice on the best practices for clinical care and clinical research for individuals who suffer from FOP. The Clinical Trials Committee of the ICC developed a focused list of key considerations that encompass the specific and unique needs of the FOP community – considerations that are endorsed by the entire ICC. These considerations complement established protocols for developing and executing robust clinical trials by providing a foundation for helping to ensure the safety of subjects with FOP in clinical research trials.

Early clinical observations on the use of imatinib mesylate in FOP: A report of seven cases

BACKGROUND

Fibrodysplasia ossificans progressiva (FOP) is an ultrarare genetic disorder of progressive, disabling heterotopic ossification (HO) for which there is presently no definitive treatment. Research studies have identified multiple potential targets for therapy in FOP, and novel drug candidates are being developed for testing in clinical trials. A complementary approach seeks to identify approved drugs that could be re-purposed for off-label use against defined targets in FOP. One such drug is imatinib mesylate, a tyrosine kinase inhibitor originally developed for use in patients with chronic myeloid leukemia (CML). Imatinib has the desirable effect of attacking multiple targets involved in the early hypoxic and inflammatory stages of FOP flare-ups, including HIF1-α, PDGFRα, c-KIT, and multiple MAP kinases.

RESULTS

Based on compelling biologic rationale, strong preclinical data, and a favorable safety profile, imatinib has been prescribed on an off-label basis in a non-trial setting in seven children with continuous FOP flare-ups, predominantly in the axial regions, and which were not responsive to standard-of-care regimens. Anecdotal reports in these seven isolated cases document that the medication was well-tolerated with a ubiquitous reported decrease in the intensity of flare-ups in the six children who took the medication.

CONCLUSIONS

These early clinical observations support the implementation of clinical trials in children with uncontrolled FOP flare-ups to determine if imatinib may ameliorate symptoms or alter the natural history of this debilitating and life-threatening disease.

The FOP Connection Registry: Design of an international patient-sponsored registry for Fibrodysplasia Ossificans Progressiva

The Fibrodysplasia Ossificans Progressiva (FOP) Connection Registry is an international, voluntary, observational study that directly captures demographic and disease information initially from patients with FOP (the patient portal) and in the near future from treating physicians (the physician portal) via a secure web-based tool. It was launched by the International FOP Association (IFOPA) with a guiding vision to develop and manage one unified, global, and coordinated Registry allowing the assembly of the most comprehensive data on FOP. This will ultimately facilitate greater access and sharing of patient data and enable better and faster development of therapies and tracking their long-term treatment effectiveness and safety. This report outlines the FOP Connection Registry's design and procedures for data collection and reporting, as well as the long-term sustainability of Registry. Patient-reported, aggregate data are summarized for the first 196 enrolled patients, representing participation from 42 countries and approximately 25% of the world's known FOP population. Fifty-seven percent of the current Registry participants are female with a mean age of 23.8years (median=21years, range=1, 76years). Among the Registry participants who provided their FOP type, 51% reported FOP Classic (R206H), 41% reported FOP Type Unknown, and 8% reported FOP Variant. Patients reported 5.4years (median=3.0years, range=0, 45.8years) as the mean age at which they noticed their first FOP symptoms and a mean age at final FOP diagnosis of 7.5years (median=5.0years, range=0.1, 48.4years). Information on the patients' diagnostic journeys in arriving at a correct diagnosis of FOP is also presented. These early patient-reported data suggest that the IFOPA's vision of one, unified, global, and coordinated approach to the FOP Connection Registry is well underway to being realized. In addition, the positive response from the FOP patient community to the initial launch of the Registry's patient portal has created a solid foundation upon which to build the largest international registry for monitoring the clinical progression of FOP among patients.

Associations Between Clinical Evidence of Inflammation and Synovitis in Symptomatic Knee Osteoarthritis: A Cross-Sectional Substudy

OBJECTIVE

Painful knee osteoarthritis (KOA) has been associated with joint inflammation. There is, however, little literature correlating signs of localized inflammation with contrast-enhanced (CE) magnetic resonance imaging (MRI) of synovium. This study examined the relationship between clinical and functional markers of localized knee inflammation and CE MRI-based synovial scores.

METHODS

Patients with symptomatic KOA were enrolled into the randomized, double-blind, Vitamin D Evaluation in Osteoarthritis (VIDEO) trial. In this cross-sectional substudy, associations between validated MRI-based semiquantitative synovial scores of the knee and the following markers of inflammation were investigated: self-reported pain and stiffness, effusion, warmth, joint line tenderness, erythrocyte sedimentation rate, radiographic severity, and functional ability tests.

RESULTS

A total of 107 patients satisfied the inclusion criteria of complete data and were included in the analysis. Significant associations were found between the number of regions affected by synovitis and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, effusion, and joint line tenderness. Each additional region affected by synovitis was associated with an increase in WOMAC pain (1.82 [95% confidence interval (95% CI) 0.05, 3.58], P = 0.04), and the association with extent of medial synovitis was particularly strong (3.21 [95% CI 0.43, 5.99], P = 0.02). Extent of synovitis was positively associated with effusion (odds ratio 1.69 [95% CI 1.37, 2.08], P < 0.01) and negatively associated with joint line tenderness (relative risk 0.87 [95% CI 0.84, 0.90], P < 0.01).

CONCLUSION

There is a strong positive association between synovitis and self-reported patient pain and clinically detectable effusion. Nonoperative treatments directed at management of inflammation and future trials targeting the synovial tissue for treating KOA should consider these 2 factors as potential inclusion criteria.

International physician survey on management of FOP: a modified Delphi study

Fibrodysplasia ossificans progressiva (FOP), a disabling disorder of progressive heterotopic ossification (HEO), is caused by heterozygous gain-of- function mutations in Activin receptor A, type I (ACVR1, also known as ALK2), a bone morphogenetic protein (BMP) type I receptor. Presently, symptomatic management is possible, but no definitive treatments are available. Although extensive guidelines for symptomatic management are widely used, regional preferences exist. In order to understand if there was worldwide consensus among clinicians treating FOP patients, an expert panel of physicians directly involved in FOP patient care was convened. Using a modified Delphi method, broad international consensus was reached on four main topics: diagnosis, prevention of flare-ups, patient and family-centered care and general clinical management issues. This study of physician preferences provides a basis for standardization of clinical management for FOP.

The effect of vitamin D supplementation on knee osteoarthritis, the VIDEO study: a randomised controlled trial

OBJECTIVE

Epidemiological data suggest low serum 25-hydroxyvitamin D₃ (25-OH-D₃) levels are associated with radiological progression of knee osteoarthritis (OA). This study aimed to assess whether vitamin D supplementation can slow the rate of progression.

METHOD

A 3-year, double-blind, randomised, placebo-controlled trial of 474 patients aged over 50 with radiographically evident knee OA comparing 800 IU cholecalciferol daily with placebo. Primary outcome was difference in rate of medial joint space narrowing (JSN). Secondary outcomes included lateral JSN, Kellgren & Lawrence grade, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, function, stiffness and the Get up and Go test.

RESULTS

Vitamin D supplementation increased 25-OH-D₃ from an average of 20.7 (standard deviation (SD) 8.9) μg/L to 30.4 (SD 7.7) μg/L, compared to 20.7 (SD 8.1) μg/L and 20.3 (SD 8.1) μg/L in the placebo group. There was no significant difference in the rate of JSN over 3 years in the medial compartment of the index knee between the treatment group (average -0.01 mm/year) and placebo group (-0.08 mm/year), average difference 0.08 mm/year (95% confidence interval (CI) [-0.14-0.29], P = 0.49). No significant interaction was found between baseline vitamin D levels and treatment effect. There were no significant differences for any of the secondary outcome measures.

CONCLUSION

Vitamin D supplementation did not slow the rate of JSN or lead to reduced pain, stiffness or functional loss over a 3-year period. On the basis of these findings we consider that vitamin D supplementation has no role in the management of knee OA.