JEWELFISH: 24-month results from an open-label study in non-treatment-naïve patients with SMA receiving treatment with risdiplam

Risdiplam is a once-daily oral, survival of motor neuron 2 (SMN2) splicing modifier approved for the treatment of spinal muscular atrophy (SMA). JEWELFISH (NCT03032172) investigated the safety, tolerability, pharmacokinetics (PK), and PK/pharmacodynamic (PD) relationship of risdiplam in non-treatment-naïve patients with SMA. JEWELFISH enrolled adult and pediatric patients (N = 174) with confirmed diagnosis of 5q-autosomal recessive SMA who had previously received treatment with nusinersen (n = 76), onasemnogene abeparvovec (n = 14), olesoxime (n = 71), or were enrolled in the MOONFISH study (NCT02240355) of the splicing modifier RG7800 (n = 13). JEWELFISH was an open-label study with all participants scheduled to receive risdiplam. The most common adverse event (AE) was pyrexia (42 patients, 24%) and the most common serious AE (SAE) was pneumonia (5 patients, 3%). The rate of AEs and SAEs decreased by > 50% from the first to the second year of treatment, and there were no treatment-related AEs that led to withdrawal from treatment. An increase in SMN protein in blood was observed following risdiplam treatment and sustained over 24 months of treatment irrespective of previous treatment. Exploratory efficacy assessments of motor function showed an overall stabilization in mean total scores as assessed by the 32-item Motor Function Measure, Hammersmith Functional Motor Scale-Expanded, and Revised Upper Limb Module. The safety profile of risdiplam in JEWELFISH was consistent with previous clinical trials of risdiplam in treatment-naïve patients. Exploratory efficacy outcomes are reported but it should be noted that the main aim of JEWELFISH was to assess safety and PK/PD, and the study was not designed for efficacy analysis. TRIAL REGISTRATION: The study was registered (NCT03032172) on ClinicalTrials.gov on January 24, 2017; First patient enrolled: March 3, 2017.

Global Risdiplam Compassionate Use Program for Patients With Type 1 or 2 Spinal Muscular Atrophy

PURPOSE

Spinal muscular atrophy (SMA) is a genetic neuromuscular disease causing progressive muscle weakness and reducing life expectancy. Risdiplam (Evrysdi; Genentech/F. Hoffmann-La Roche Ltd, Basel, Switzerland) is a drug approved for use in the treatment of patients with SMA. The ongoing global risdiplam Compassionate Use Program (CUP), initiated in November 2019, is the largest CUP in SMA, currently providing access to risdiplam for >2000 patients with type 1 or 2 SMA in 59 countries. Here, the challenges and learnings from the risdiplam CUP are presented.

METHODS

Enrolled patients (aged ≥2 months) had type 1 or 2 SMA and no alternative treatment options (ie, they were not medically eligible for approved SMA treatments, were unable to continue their SMA treatment due to medical reasons, were at risk for lack/loss of SMA treatment efficacy, or did not qualify for/had no access to SMA treatment within a clinical trial). Requests were made by the treating physicians via an end-to-end system.

FINDINGS

The risdiplam CUP highlighted the importance of collaborating with patient advocacy groups early to learn about patients' perspectives on unmet medical needs, understanding the sometimes-unique nature of local regulations and requirements, and adapting physician- and patient-eligibility criteria. Key learnings were obtained from enrolling patients from low- to middle-income countries and from countries without dedicated Compassionate Use regulations, and from operating the CUP during the coronavirus disease 2019 pandemic.

IMPLICATIONS

The risdiplam CUP experience was successful in many ways and may help to design and implement future CUPs in rare diseases, as well as patients living in countries or in circumstances in which access to innovative treatments is a challenge.

Findings from the Longitudinal CINRG Becker Natural History Study

BACKGROUND

Becker muscular dystrophy is an X-linked, genetic disorder causing progressive degeneration of skeletal and cardiac muscle, with a widely variable phenotype.

OBJECTIVE

A 3-year, longitudinal, prospective dataset contributed by patients with confirmed Becker muscular dystrophy was analyzed to characterize the natural history of this disorder. A better understanding of the natural history is crucial to rigorous therapeutic trials.

METHODS

A cohort of 83 patients with Becker muscular dystrophy (5-75 years at baseline) were followed for up to 3 years with annual assessments. Muscle and pulmonary function outcomes were analyzed herein. Age-stratified statistical analysis and modeling were conducted to analyze cross-sectional data, time-to-event data, and longitudinal data to characterize these clinical outcomes.

RESULTS

Deletion mutations of dystrophin exons 45-47 or 45-48 were most common. Subgroup analysis showed greater pairwise association between motor outcomes at baseline than association between these outcomes and age. Stronger correlations between outcomes for adults than for those under 18 years were also observed. Using cross-sectional binning analysis, a ceiling effect was seen for North Star Ambulatory Assessment but not for other functional outcomes. Longitudinal analysis showed a decline in percentage predicted forced vital capacity over the life span. There was relative stability or improved median function for motor functional outcomes through childhood and adolescence and decreasing function with age thereafter.

CONCLUSIONS

There is variable progression of outcomes resulting in significant heterogeneity of the clinical phenotype of Becker muscular dystrophy. Disease progression is largely manifest in adulthood. There are implications for clinical trial design revealed by this longitudinal analysis of a Becker natural history dataset.

Systematic Literature Review of the Natural History of Spinal Muscular Atrophy: Motor Function, Scoliosis, and Contractures

BACKGROUND AND OBJECTIVES

Spinal muscular atrophy (SMA) is a progressive neuromuscular disorder associated with continuous motor function loss and complications, such as scoliosis and contractures. Understanding the natural history of SMA is key to demonstrating the long-term outcomes of SMA treatments. This study reviews the natural history of motor function, scoliosis, and contractures in patients with SMA.

METHODS

Electronic databases were searched from inception to June 27, 2022 (Embase, MEDLINE, and Evidence-Based Medicine Reviews). Observational studies, case-control studies, cross-sectional studies, and case series reporting on motor function (i.e., sitting, standing, and walking ability), scoliosis, and contracture outcomes in patients with types 1-3 SMA were included. Data on study design, baseline characteristics, and treatment outcomes were extracted. Data sets were generated from studies that reported Kaplan-Meier (KM) curves and pooled to generate overall KM curves.

RESULTS

Ninety-three publications were included, of which 68 reported on motor function. Of these, 10 reported KM curves (3 on the probability of sitting in patients with types 2 and 3 SMA and 8 on the probability of walking/ambulation in patients with type 3 SMA). The median time to loss of sitting (95% CI) was 14.5 years (14.1-31.5) for the type 2 SMA sitter population (their maximum ability was independent sitting). The median time to loss of ambulation (95% CI) was 13.4 years (12.5-14.5) for type 3a SMA (disease onset at age younger than 3 years) and 44.2 years (43.0-49.4) for type 3b SMA (disease onset at age 3 years or older). Studies including scoliosis and contracture outcomes mostly reported non-time-to-event data.

DISCUSSION

The results demonstrate that a high degree of motor function loss is inevitable, affecting patients of all ages. In addition, data suggest that untreated patients with types 2 and 3 SMA remain at risk of losing motor milestones during late adulthood, and patients with types 3a and 3b SMA are at risk of loss of ambulation over time. These findings support the importance of stabilization of motor function development even at older ages. Natural history data are key for the evaluation of SMA treatments as they contextualize the assessment of long-term outcomes.

Risdiplam in Patients Previously Treated with Other Therapies for Spinal Muscular Atrophy: An Interim Analysis from the JEWELFISH Study

INTRODUCTION

Risdiplam is a survival of motor neuron 2 (SMN2) splicing modifier for the treatment of patients with spinal muscular atrophy (SMA). The JEWELFISH study (NCT03032172) was designed to assess the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of risdiplam in previously treated pediatric and adult patients with types 1-3 SMA. Here, an analysis was performed after all patients had received at least 1 year of treatment with risdiplam.

METHODS

Patients with a confirmed diagnosis of 5q-autosomal recessive SMA between the ages of 6 months and 60 years were eligible for enrollment. Patients were previously enrolled in the MOONFISH study (NCT02240355) with splicing modifier RG7800 or treated with olesoxime, nusinersen, or onasemnogene abeparvovec. The primary objectives of the JEWELFISH study were to evaluate the safety and tolerability of risdiplam and investigate the PK after 2 years of treatment.

RESULTS

A total of 174 patients enrolled: MOONFISH study (n = 13), olesoxime (n = 71 patients), nusinersen (n = 76), onasemnogene abeparvovec (n = 14). Most patients (78%) had three SMN2 copies. The median age and weight of patients at enrollment was 14.0 years (1-60 years) and 39.1 kg (9.2-108.9 kg), respectively. About 63% of patients aged 2-60 years had a baseline total score of less than 10 on the Hammersmith Functional Motor Scale-Expanded and 83% had scoliosis. The most common adverse event (AE) was upper respiratory tract infection and pyrexia (30 patients each; 17%). Pneumonia (four patients; 2%) was the most frequently reported serious AE (SAE). The rates of AEs and SAEs per 100 patient-years were lower in the second 6-month period compared with the first. An increase in SMN protein was observed in blood after risdiplam treatment and was comparable across all ages and body weight quartiles.

CONCLUSIONS

The safety and PD of risdiplam in patients who were previously treated were consistent with those of treatment-naïve patients.

Two-year efficacy and safety of risdiplam in patients with type 2 or non-ambulant type 3 spinal muscular atrophy (SMA)

Risdiplam is an oral, survival of motor neuron 2 (SMN2) pre-mRNA splicing modifier approved for the treatment of spinal muscular atrophy (SMA). SUNFISH (NCT02908685) Part 2, a Phase 3, randomized, double-blind, placebo-controlled study, investigated the efficacy and safety of risdiplam in type 2 and non‑ambulant type 3 SMA. The primary endpoint was met: a significantly greater change from baseline in 32-item Motor Function Measure (MFM32) total score was observed with risdiplam compared with placebo at month 12. After 12 months, all participants received risdiplam while preserving initial treatment blinding. We report 24-month efficacy and safety results in this population. Month 24 exploratory endpoints included change from baseline in MFM32 and safety. MFM‑derived results were compared with an external comparator. At month 24 of risdiplam treatment, 32% of patients demonstrated improvement (a change of ≥ 3) from baseline in MFM32 total score; 58% showed stabilization (a change of ≥ 0). Compared with an external comparator, a treatment difference of 3.12 (95% confidence interval [CI] 1.67-4.57) in favor of risdiplam was observed in MFM-derived scores. Overall, gains in motor function at month 12 were maintained or improved upon at month 24. In patients initially receiving placebo, MFM32 remained stable compared with baseline (0.31 [95% CI - 0.65 to 1.28]) after 12 months of risdiplam; 16% of patients improved their score and 59% exhibited stabilization. The safety profile after 24 months was consistent with that observed after 12 months. Risdiplam over 24 months resulted in further improvement or stabilization in motor function, confirming the benefit of longer-term treatment.

Natural history of Type 1 spinal muscular atrophy: a retrospective, global, multicenter study

BACKGROUND

ANCHOVY was a global, multicenter, chart-review study that aimed to describe the natural history of Type 1 spinal muscular atrophy (SMA) from a broad geographical area and provide further contextualization of results from the FIREFISH (NCT02913482) interventional study of risdiplam treatment in Type 1 SMA.

METHODS

Data were extracted from medical records of patients with first symptoms attributable to Type 1 SMA between 28 days and 3 months of age, genetic confirmation of SMA, and confirmed survival of motor neuron 2 copy number of two or unknown. The study period started on 1 January 2008 for all sites; study end dates were site-specific due to local treatment availabilities. Primary endpoints were time to death and/or permanent ventilation and proportion of patients achieving motor milestones. Secondary endpoints included time to initiation of respiratory and feeding support.

RESULTS

Data for 60 patients from nine countries across Asia, Europe and North and South America were analyzed. The median age (interquartile range [IQR]) for reaching death or permanent ventilation was ~ 7.3 (5.9-10.5) months. The median age (IQR) at permanent ventilation was ~ 12.7 (6.9-16.4) months and at death was ~ 41.2 (7.3-not applicable) months. No patients were able to sit without support or achieved any level of crawling, standing or walking.

INTERPRETATION

Findings from ANCHOVY were consistent with published natural history data on Type 1 SMA demonstrating the disease's devastating course, which markedly differed from risdiplam-treated infants (FIREFISH Part 2). The results provide meaningful additions to the literature, including a broader geographical representation.

Risdiplam in Types 2 and 3 spinal muscular atrophy: a randomised, placebo-controlled, dose-finding trial followed by 24 months of treatment

BACKGROUND

Spinal muscular atrophy (SMA) is caused by reduced levels of survival of motor neuron (SMN) protein due to deletions and/or mutations in the SMN1 gene. Risdiplam is an orally administered molecule that modifies SMN2 pre-mRNA splicing to increase functional SMN protein.

METHODS

SUNFISH Part 1 was a dose-finding study conducted in 51 individuals with Types 2 and 3 SMA aged 2-25 years. A dose-escalation method was used to identify the appropriate dose for the subsequent pivotal Part 2. Individuals were randomised (2:1) to risdiplam or placebo at escalating dose levels for a minimum 12-week, double-blind, placebo-controlled period, followed by treatment for 24 months. The dose selection for Part 2 was based on safety, tolerability, pharmacokinetic and pharmacodynamic data. Exploratory efficacy was also measured.

RESULTS

There was no difference in safety findings for all assessed dose levels. A dose-dependent increase in blood SMN protein was observed; a median two-fold increase was obtained within 4 weeks of treatment initiation at the highest dose level. The increase in SMN protein was sustained over 24 months of treatment. Exploratory efficacy showed improvement or stabilisation in motor function. The pivotal dose selected for Part 2 was 5 mg for patients with a body weight ≥20 kg or 0.25 mg/kg for patients <20 kg.

CONCLUSIONS

SUNFISH Part 1 demonstrated a two-fold increase in SMN protein after treatment with risdiplam. The observed safety profile supported the initiation of the pivotal Part 2 study. The long-term efficacy and safety of risdiplam is being assessed with ongoing treatment.

Distribution of weight, stature, and growth status in children and adolescents with spinal muscular atrophy: An observational retrospective study in the United States

Introduction/Aims

Data regarding weight, height/length, and growth status of patients with spinal muscular atrophy (SMA) who have received only supportive care are limited. This cross‐sectional study describes these measurements in patients with Type 1 and Types 2/3 SMA and compares them with reference values from typically developing children.

Methods

Retrospective baseline data from three sites in the Pediatric Neuromuscular Clinical Research Network (Boston, New York, Philadelphia) were used. Descriptive statistics for weight, height/length, body mass index‐for‐age, as well as weight‐for‐length and absolute and relative deviations from reference values (ie, 50th percentile from World Health Organization/Centers for Disease Control growth charts) were calculated. Furthermore, growth status was reported.

Results

A total of 91 genetically confirmed patients with SMA receiving optimal supportive care and without any disease‐modifying treatment were stratified into Types 1 (n = 28) and 2/3 SMA (n = 63). Patients with Type 1 SMA weighed significantly less (median = −7.5%) compared with reference values and patients with Types 2/3 SMA were significantly shorter (mean = −3.0%) compared with reference values. The median weight was considerably below the 50th percentile in both groups of patients, even if they received a high standard of care and proactive feeding support.

Discussion

More research is needed to understand which factors influence growth longitudinally, and how to accurately capture growth in patients with SMA. Further research should investigate the best time to provide feeding support to avoid underweight, especially in patients with Type 1, and how to avoid the risk of overfeeding, especially in patients with Types 2/3 SMA.

Preferences and Utilities for Treatment Attributes in Type 2 and Non-ambulatory Type 3 Spinal Muscular Atrophy in the United Kingdom

BACKGROUND

Spinal muscular atrophy (SMA) is a rare neuromuscular disease that affects motor neurons, resulting in progressive skeletal muscle weakness and atrophy.

OBJECTIVE

The aim was to understand the value patients with SMA and caregivers place on treatment attributes and to estimate health utilities for SMA treatment outcomes from a general public sample.

METHODS

Two discrete choice experiments were designed to elicit treatment preferences and health utilities, respectively. Patients with Type 2 and non-ambulatory Type 3 SMA, caregivers of patients with SMA and a general public sample in the UK completed the surveys. Patients and caregiver participants were recruited through patient associations. General public participants were recruited via a survey recruitment panel. Attributes included motor function, breathing function, treatment administration, treatment reactions, eyesight monitoring, contraception (patients only) and overall survival (general public only). Clustered conditional logit models were used to estimate treatment preferences, and marginal rates of substitution were used to estimate disutilities.

RESULTS

Adult patients (n = 84) were twice as likely to choose a treatment with improved (vs. stable) motor and breathing function and four to five times less likely to choose a treatment with deteriorated (vs. stable) motor and breathing function as a treatment outcome. Caregivers (n = 83) were three to nine times more likely to choose improved and two to four times less likely to choose deteriorated (vs. stable) motor and breathing function. Both patients and caregivers preferred oral over intrathecal treatment. Treatment reactions, eyesight monitoring or contraception had no significant effect on patient choices. Conversely, caregivers preferred avoidance of treatment reactions. General public data (n = 506) yielded disutilities for unable to sit (- 0.408), need for > 16 h daily mechanical breathing support (- 0.304) and intrathecal therapy (- 0.071).

CONCLUSIONS

Study results show the importance of motor and breathing function to patients and caregivers, and an oral treatment preference. Disutilities (decrements to utility) were substantial for SMA disease outcomes and care aspects.

How does risdiplam compare with other treatments for Types 1-3 spinal muscular atrophy: a systematic literature review and indirect treatment comparison

Aim: To conduct indirect treatment comparisons between risdiplam and other approved treatments for spinal muscular atrophy (SMA). Patients & methods: Individual patient data from risdiplam trials were compared with aggregated data from published studies of nusinersen and onasemnogene abeparvovec, accounting for heterogeneity across studies. Results: In Type 1 SMA, studies of risdiplam and nusinersen included similar populations. Indirect comparison results found improved survival and motor function with risdiplam versus nusinersen. Comparison with onasemnogene abeparvovec in Type 1 SMA and with nusinersen in Types 2/3 SMA was challenging due to substantial differences in study populations; no concrete conclusions could be drawn from the indirect comparison analyses. Conclusion: Indirect comparisons support risdiplam as a superior alternative to nusinersen in Type 1 SMA.

A Patient-Centered Evaluation of Meaningful Change on the 32-Item Motor Function Measure in Spinal Muscular Atrophy Using Qualitative and Quantitative Data

The 32-item Motor Function Measure (MFM32) is an assessment of motor function used to evaluate fine and gross motor ability in patients with neuromuscular disorders, including spinal muscular atrophy (SMA). Reliability and validity of the MFM32 have been documented in individuals with SMA. Through semi-structured qualitative interviews (N = 40) and an online survey in eight countries (N = 217) with individuals with Types 2 and 3 SMA aged 2–59 years old and caregivers, the meaning of changes on a patient-friendly version of the MFM32 was explored. In an independent analysis of clinical trial data, anchor- and distribution-based analyses were conducted in a sample of individuals with Type 2 and non-ambulant Type 3 SMA to estimate patient-centered quantitative MFM32 meaningful change thresholds. The results from this study demonstrate that, based on patient and caregiver insights, maintaining functional ability as assessed by a patient-friendly version of the MFM32 is an important outcome. Quantitative analyses using multiple anchors (median age range of 5–8 years old across anchor groups) indicated that an ~3-point improvement in MFM32 total score represents meaningful change at the individual patient level. Overall, the qualitative and quantitative findings from this study support the importance of examining a range of meaningful change thresholds on the MFM32 including ≥0 points change reflecting stabilization or improvement and ≥3 points change reflecting a higher threshold of improvement. Future research is needed to explore quantitative differences in meaningful change on the MFM32 based on age and functional subgroups.

Development of the SMA independence scale-upper limb module (SMAIS-ULM): A novel scale for individuals with Type 2 and non-ambulant Type 3 SMA

BACKGROUND

The amount of assistance required to perform daily activities for individuals with Type 2 and non-ambulant Type 3 spinal muscular atrophy (SMA) is often cited as meaningful for quality of life, and important to routinely assess.

METHODS

The SMA Independence Scale (SMAIS), a patient-reported outcome measure for individuals with SMA aged ≥12 years, and an observer-reported outcome measure for caregivers of individuals aged ≥2 years, was developed and evaluated in two phases. In Phase 1, 30 draft items were developed following review of the literature. Semi-structured interviews were then conducted with individuals with SMA and caregivers to establish content validity, resulting in a 29-item measure. In Phase 2, classical test theory and Rasch measurement theory methods were used to examine the cross-sectional and longitudinal measurement performance of the SMAIS in two independent datasets.

RESULTS

Phase 1 qualitative findings supported the relevance, acceptability, and comprehensibility of 29 items. In Phase 2, psychometric analyses indicated that the five response options were poorly discriminated and were thus collapsed to three options for subsequent analyses. Items showed statistical misfit, implying that the SMAIS was not assessing a single underlying construct. Based on conceptual evaluation of the items, and assessment of item performance, a more targeted 22-item upper limb score was derived. Reliability and validity analyses confirmed acceptable measurement properties of this score.

CONCLUSIONS

Qualitative and quantitative analyses support the use of the 22-item SMAIS-Upper Limb Module in individuals with Type 2 and non-ambulant Type 3 SMA, aged ≥2 years.

Safety and efficacy of once-daily risdiplam in type 2 and non-ambulant type 3 spinal muscular atrophy (SUNFISH part 2): a phase 3, double-blind, randomised, placebo-controlled trial

BACKGROUND

Risdiplam is an oral small molecule approved for the treatment of patients with spinal muscular atrophy, with approval for use in patients with type 2 and type 3 spinal muscular atrophy granted on the basis of unpublished data. The drug modifies pre-mRNA splicing of the SMN2 gene to increase production of functional SMN. We aimed to investigate the safety and efficacy of risdiplam in patients with type 2 or non-ambulant type 3 spinal muscular atrophy.

METHODS

In this phase 3, randomised, double-blind, placebo-controlled study, patients aged 2-25 years with confirmed 5q autosomal recessive type 2 or type 3 spinal muscular atrophy were recruited from 42 hospitals in 14 countries across Europe, North America, South America, and Asia. Participants were eligible if they were non-ambulant, could sit independently, and had a score of at least 2 in entry item A of the Revised Upper Limb Module. Patients were stratified by age and randomly assigned (2:1) to receive either daily oral risdiplam, at a dose of 5·00 mg (for individuals weighing ≥20 kg) or 0·25 mg/kg (for individuals weighing <20 kg), or daily oral placebo (matched to risdiplam in colour and taste). Randomisation was conducted by permutated block randomisation with a computerised system run by an external party. Patients, investigators, and all individuals in direct contact with patients were masked to treatment assignment. The primary endpoint was the change from baseline in the 32-item Motor Function Measure total score at month 12. All individuals who were randomly assigned to risdiplam or placebo, and who did not meet the prespecified missing item criteria for exclusion, were included in the primary efficacy analysis. Individuals who received at least one dose of risdiplam or placebo were included in the safety analysis. SUNFISH is registered with ClinicalTrials.gov, NCT02908685. Recruitment is closed; the study is ongoing.

FINDINGS

Between Oct 9, 2017, and Sept 4, 2018, 180 patients were randomly assigned to receive risdiplam (n=120) or placebo (n=60). For analysis of the primary endpoint, 115 patients from the risdiplam group and 59 patients from the placebo group were included. At month 12, the least squares mean change from baseline in 32-item Motor Function Measure was 1·36 (95% CI 0·61 to 2·11) in the risdiplam group and -0·19 (-1·22 to 0·84) in the placebo group, with a treatment difference of 1·55 (0·30 to 2·81, p=0·016) in favour of risdiplam. 120 patients who received risdiplam and 60 who received placebo were included in safety analyses. Adverse events that were reported in at least 5% more patients who received risdiplam than those who received placebo were pyrexia (25 [21%] of 120 patients who received risdiplam vs ten [17%] of 60 patients who received placebo), diarrhoea (20 [17%] vs five [8%]), rash (20 [17%] vs one [2%]), mouth and aphthous ulcers (eight [7%] vs 0), urinary tract infection (eight [7%] vs 0), and arthralgias (six [5%] vs 0). The incidence of serious adverse events was similar between treatment groups (24 [20%] of 120 patients in the risdiplam group; 11 [18%] of 60 patients in the placebo group), with the exception of pneumonia (nine [8%] in the risdiplam group; one [2%] in the placebo group).

INTERPRETATION

Risdiplam resulted in a significant improvement in motor function compared with placebo in patients aged 2-25 years with type 2 or non-ambulant type 3 spinal muscular atrophy. Our exploratory subgroup analyses showed that motor function was generally improved in younger individuals and stabilised in older individuals, which requires confirmation in further studies. SUNFISH part 2 is ongoing and will provide additional evidence regarding the long-term safety and efficacy of risdiplam.

FUNDING

F Hoffmann-La Roche.

Risdiplam-Treated Infants with Type 1 Spinal Muscular Atrophy versus Historical Controls

BACKGROUND

Type 1 spinal muscular atrophy (SMA) is a progressive neuromuscular disease characterized by an onset at 6 months of age or younger, an inability to sit without support, and deficient levels of survival of motor neuron (SMN) protein. Risdiplam is an orally administered small molecule that modifies SMN2 pre-messenger RNA splicing and increases levels of functional SMN protein in blood.

METHODS

We conducted an open-label study of risdiplam in infants with type 1 SMA who were 1 to 7 months of age at enrollment. Part 1 of the study (published previously) determined the dose to be used in part 2 (reported here), which assessed the efficacy and safety of daily risdiplam as compared with no treatment in historical controls. The primary end point was the ability to sit without support for at least 5 seconds after 12 months of treatment. Key secondary end points were a score of 40 or higher on the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND; range, 0 to 64, with higher scores indicating better motor function), an increase of at least 4 points from baseline in the CHOP-INTEND score, a motor-milestone response as measured by Section 2 of the Hammersmith Infant Neurological Examination (HINE-2), and survival without permanent ventilation. For the secondary end points, comparisons were made with the upper boundary of 90% confidence intervals for natural-history data from 40 infants with type 1 SMA.

RESULTS

A total of 41 infants were enrolled. After 12 months of treatment, 12 infants (29%) were able to sit without support for at least 5 seconds, a milestone not attained in this disorder. The percentages of infants in whom the key secondary end points were met as compared with the upper boundary of confidence intervals from historical controls were 56% as compared with 17% for a CHOP-INTEND score of 40 or higher, 90% as compared with 17% for an increase of at least 4 points from baseline in the CHOP-INTEND score, 78% as compared with 12% for a HINE-2 motor-milestone response, and 85% as compared with 42% for survival without permanent ventilation (P<0.001 for all comparisons). The most common serious adverse events were pneumonia, bronchiolitis, hypotonia, and respiratory failure.

CONCLUSIONS

In this study involving infants with type 1 SMA, risdiplam resulted in higher percentages of infants who met motor milestones and who showed improvements in motor function than the percentages observed in historical cohorts. Longer and larger trials are required to determine the long-term safety and efficacy of risdiplam in infants with type 1 SMA. (Funded by F. Hoffmann-La Roche; FIREFISH ClinicalTrials.gov number, NCT02913482.).

Prognostic Factors and Treatment-Effect Modifiers in Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is a rare, progressive neuromuscular disease characterized by loss of motor neurons and muscle atrophy. Untreated infants with type 1 SMA do not achieve major motor milestones, and death from respiratory failure typically occurs before 2 years of age. Individuals with types 2 and 3 SMA exhibit milder phenotypes and have better functional and survival outcomes. Herein, a systematic literature review was conducted to identify factors that influence the prognosis of types 1, 2, and 3 SMA. In untreated infants with type 1 SMA, absence of symptoms at birth, a later symptom onset, and a higher survival of motor neuron 2 (SMN2) copy number are all associated with increased survival. Disease duration, age at treatment initiation, and, to a lesser extent, baseline function were identified as potential treatment‐modifying factors for survival, emphasizing that early treatment with disease‐modifying therapies (DMT) is essential in type 1 SMA. In patients with types 2 and 3 SMA, factors considered prognostic of changes in motor function were SMN2 copy number, age, and ambulatory status. Individuals aged 6–15 years were particularly vulnerable to developing complications (scoliosis and progressive joint contractures) which negatively influence functional outcomes and may also affect the therapeutic response in patients. Age at the time of treatment initiation emerged as a treatment‐effect modifier on the outcome of DMTs. Factors identified in this review should be considered prior to designing or analyzing studies in an SMA population, conducting population matching, or summarizing results from different studies on the treatments for SMA.

Risdiplam in Type 1 Spinal Muscular Atrophy

BACKGROUND

Type 1 spinal muscular atrophy is a rare, progressive neuromuscular disease that is caused by low levels of functional survival of motor neuron (SMN) protein. Risdiplam is an orally administered, small molecule that modifies SMN2 pre-messenger RNA splicing and increases levels of functional SMN protein.

METHODS

We report the results of part 1 of a two-part, phase 2-3, open-label study of risdiplam in infants 1 to 7 months of age who had type 1 spinal muscular atrophy, which is characterized by the infant not attaining the ability to sit without support. Primary outcomes were safety, pharmacokinetics, pharmacodynamics (including the blood SMN protein concentration), and the selection of the risdiplam dose for part 2 of the study. Exploratory outcomes included the ability to sit without support for at least 5 seconds.

RESULTS

A total of 21 infants were enrolled. Four infants were in a low-dose cohort and were treated with a final dose at month 12 of 0.08 mg of risdiplam per kilogram of body weight per day, and 17 were in a high-dose cohort and were treated with a final dose at month 12 of 0.2 mg per kilogram per day. The baseline median SMN protein concentrations in blood were 1.31 ng per milliliter in the low-dose cohort and 2.54 ng per milliliter in the high-dose cohort; at 12 months, the median values increased to 3.05 ng per milliliter and 5.66 ng per milliliter, respectively, which represented a median of 3.0 times and 1.9 times the baseline values in the low-dose and high-dose cohorts, respectively. Serious adverse events included pneumonia, respiratory tract infection, and acute respiratory failure. At the time of this publication, 4 infants had died of respiratory complications. Seven infants in the high-dose cohort and no infants in the low-dose cohort were able to sit without support for at least 5 seconds. The higher dose of risdiplam (0.2 mg per kilogram per day) was selected for part 2 of the study.

CONCLUSIONS

In infants with type 1 spinal muscular atrophy, treatment with oral risdiplam led to an increased expression of functional SMN protein in the blood. (Funded by F. Hoffmann-La Roche; ClinicalTrials.gov number, NCT02913482.).

Natural history of Type 2 and 3 spinal muscular atrophy: 2-year NatHis-SMA study

Objective

To characterize the natural history of spinal muscular atrophy (SMA) over 24 months using innovative measures such as wearable devices, and to provide evidence for the sensitivity of these measures to determine their suitability as endpoints in clinical trials.

Methods

Patients with Type 2 and 3 SMA (N = 81) with varied functional abilities (sitters, nonsitters, nonambulant, and ambulant) who were not receiving disease‐modifying treatment were assessed over 24 months: motor function (Motor Function Measure [MFM]), upper limb strength (MyoGrip, MyoPinch), upper limb activity (ActiMyo^®), quantitative magnetic resonance imaging (fat fraction [FF_T2] mapping and contractile cross‐sectional area [C‐CSA]), pulmonary function (forced vital capacity [FVC], peak cough flow, maximum expiratory pressure, maximum inspiratory pressure, and sniff nasal inspiratory pressure), and survival of motor neuron (SMN) protein levels.

Results

MFM32 scores declined significantly over 24 months, but not 12 months. Changes in upper limb activity could be detected over 6 months and continued to decrease significantly over 12 months, but not 24 months. Upper limb strength decreased significantly over 12 and 24 months. FVC declined significantly over 12 months, but not 24 months. FF_T2 increased over 12 and 24 months, although not with statistical significance. A significant increase in C‐CSA was observed at 12 but not 24 months. Blood SMN protein levels were stable over 12 and 24 months.

Interpretation

These data demonstrate that the MFM32, MyoGrip, MyoPinch, and ActiMyo^® enable the detection of a significant decline in patients with Type 2 and 3 SMA over 12 or 24 months.

Validity and Reliability of the 32-Item Motor Function Measure in 2- to 5-Year-Olds with Neuromuscular Disorders and 2- to 25-Year-Olds with Spinal Muscular Atrophy

INTRODUCTION

To investigate the validity and reliability of the 32-item Motor Function Measure (MFM32) in individuals with neuromuscular disorders (NMD), including spinal muscular atrophy (SMA), aged 2-5 years, and in non-ambulant individuals with Types 2 or 3 SMA, aged 2-25 years.

METHODS

Test-retest reliability (intraclass correlation coefficient [ICC]), internal consistency (Cronbach's alpha [α]), convergent validity (Spearman rank-order correlations), and known-groups validity (analysis of covariance comparing groups defined by the Clinical Global Impression of Severity [CGI-S] scale and Vignos grade) were calculated. The analysis was performed on a dataset provided by Hospices Civils De Lyon, extracted from the multinational MFM32 database. A total of 165 individuals were included in the analyses, of whom 84 were in the NMD group (aged 2-5 years) and 81 were in the SMA group (aged 2-25 years).

RESULTS

Strong evidence of test-retest reliability (ICC: 2- to 5-years' population = 0.94-0.95; 2- to 25-years' population = 0.97), internal consistency (Cronbach's α: 2- to 5-years' population = 0.96; 2- to 25-years' population = 0.95), convergent validity (2- to 5-years' population: CGI-S rho = - 0.84, Vignos grade rho = - 0.79; 2- to 25-years' population: CGI-S rho = - 0.49), and known-groups validity (all P < 0.001) were demonstrated.

CONCLUSIONS

These analyses provide supportive evidence of the validity and reliability of the MFM32 in younger individuals with NMDs, aged 2-5 years, and in non-ambulant individuals with Types 2 or 3 SMA, aged 2-25 years, supporting the use of the MFM32 across a wide age range.

Risdiplam treatment has not led to retinal toxicity in patients with spinal muscular atrophy

OBJECTIVE

Evaluation of ophthalmologic safety with focus on retinal safety in patients with spinal muscular atrophy (SMA) treated with risdiplam (EVRYSDI®), a survival of motor neuron 2 splicing modifier associated with retinal toxicity in monkeys. Risdiplam was approved recently for the treatment of patients with SMA, aged ≥ 2 months in the United States, and is currently under Health Authority review in the EU.

METHODS

Subjects included patients with SMA aged 2 months-60 years enrolled in the FIREFISH, SUNFISH, and JEWELFISH clinical trials for risdiplam. Ophthalmologic assessments, including functional assessments (age-appropriate visual acuity and visual field) and imaging (spectral domain optical coherence tomography [SD-OCT], fundus photography, and fundus autofluorescence [FAF]), were conducted at baseline and every 2-6 months depending on study and assessment. SD-OCT, FAF, fundus photography, and threshold perimetry were evaluated by an independent, masked reading center. Adverse events (AEs) were reported throughout the study.

RESULTS

A total of 245 patients receiving risdiplam were assessed. Comprehensive, high-quality, ophthalmologic monitoring assessing retinal structure and visual function showed no retinal structural or functional changes. In the youngest patients, SD-OCT findings of normal retinal maturation were observed. AEs involving eye disorders were not suggestive of risdiplam-induced toxicity and resolved with ongoing treatment.

INTERPRETATION

Extensive ophthalmologic monitoring conducted in studies in patients with SMA confirmed that risdiplam does not induce ophthalmologic toxicity in pediatric or adult patients with SMA at the therapeutic dose. These results suggest that safety ophthalmologic monitoring is not needed in patients receiving risdiplam, as also reflected in the United States Prescribing Information for risdiplam.

Long-term follow-up of patients with type 2 and non-ambulant type 3 spinal muscular atrophy (SMA) treated with olesoxime in the OLEOS trial

In a previous Phase 2 study, olesoxime had a favorable safety profile. Although the primary endpoint was not met, analyses suggested that olesoxime might help in the maintenance of motor function in patients with Types 2/3 SMA. This open-label extension study (OLEOS) further characterizes the safety, tolerability and efficacy of olesoxime over longer therapy durations. In OLEOS, no new safety risks were identified. Compared to matched natural history data, patients treated with olesoxime demonstrated small, non-significant changes in motor function over 52 weeks. Motor function scores were stable for 52 weeks but declined over the remainder of the study. The greatest decline in motor function was seen in patients ≤15 years old, and those with Type 2 SMA had faster motor function decline versus those with Type 3 SMA. Previous treatment with olesoxime in the Phase 2 study was not protective of motor function in OLEOS. Respiratory outcomes were stable in patients with Type 3 SMA >15 years old but declined in patients with Type 2 SMA and in patients with Type 3 SMA ≤15 years old. Overall, with no stabilization of functional measures observed over 130 weeks, OLEOS did not support significant benefit of olesoxime in patients with SMA.

Assessment of the validity and reliability of the 32-item Motor Function Measure in individuals with Type 2 or non-ambulant Type 3 spinal muscular atrophy

The 32-item Motor Function Measure (MFM32) is an assessment of motor function, and its measurement properties were established in a broad neuromuscular disease population. This study sought to investigate the reliability, validity, and ability to detect change of MFM32 in individuals with Type 2 and non-ambulant Type 3 spinal muscular atrophy (SMA). Data were used from the Phase 2 study assessing the efficacy and safety of olesoxime. A total of 110 individuals with Type 2 or 3 SMA were included in the analyses. Test-retest reliability (intraclass-correlation coefficient in global impression-defined stable individuals), internal consistency (Cronbach’s alpha), convergent validity (Spearman rank order correlations with other measures), known-groups validity (analysis of covariance comparing Hammersmith Functional Motor Scale -defined groups), and ability to detect change (analysis of covariance comparing global impression-defined groups) were calculated. Strong evidence of test-retest reliability (intraclass-correlation coefficient = 0.93–0.95), internal consistency (Cronbach’s alpha = 0.89), convergent validity (Hammersmith Functional Motor Scale: rho = 0.87; forced vital capacity: rho = 0.61), known-groups validity (all p<0.0001), and ability to detect change (all p<0.001) were demonstrated. These results provide evidence of the MFM32’s measurement properties, supporting its use in longitudinal research in individuals with Type 2 and non-ambulant Type 3 SMA.

The CINRG Becker Natural History Study: Baseline characteristics

We performed an observational, natural history study of males with in-frame dystrophin gene deletions causing Becker muscular dystrophy (BMD). A prospective natural history study collected longitudinal medical, strength, and timed function assessments. Eighty-three participants with genetically confirmed BMD were enrolled (age range 5.6-75.4 years). Lower extremity function and the percentage of participants who retained ambulation declined across the age span. The largest single group of participants had in-frame deletions that corresponded to an out-of-frame deletion treated with an exon 45 skip to restore the reading frame. This group of 54 participants showed similarities in baseline motor functional assessments when compared to the group of all others in the study. A prospective natural history cohort with in-frame dystrophin gene deletions offers the potential to contribute to clinical trial readiness for BMD and to analyze therapeutic benefit of exon skipping for Duchenne muscular dystrophy.