Recent advances in the genetics of familial and sporadic ALS.

ALS shows complex genetic inheritance patterns. In about 5% to 10% of cases, there is a family history of ALS or a related condition such as frontotemporal dementia in a first or second degree relative, and for about 80% of such people a pathogenic gene variant can be identified. Such variants are also seen in people with no family history because of factor influencing the expression of genes, such as age. Genetic susceptibility factors also contribute to risk, and the heritability of ALS is between 40% and 60%. The genetic variants influencing ALS risk include single base changes, repeat expansions, copy number variants, and others. Here we review what is known of the genetic landscape and architecture of ALS.

The ALSFRS-R Summit: a global call to action on the use of the ALSFRS-R in ALS clinical trials.

The Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS) was developed more than 25 years ago as an instrument to monitor functional change over time in patients with ALS. It has since been revised and extended to meet the needs of high data quality in ALS trials (ALSFRS-R), however a full re-validation of the scale was not completed. Despite this, the scale has remained a primary outcome measure in clinical trials. We convened a group of clinical trialists to discuss and explore opportunities to improve the scale and propose alternative measures. In this meeting report, we present a call to action on the use of the ALSFRS-Revised scale in clinical trials, focusing on the need for (1) harmonization of the ALSFRS-R administration globally, (2) alignment on a set of recommendations for clinical trial design and statistical analysis plans (SAPs), and (3) use of additional outcome measures.

Randomized double-blind personalized N-of-1 clinical trial to test the safety and potential efficacy of TJ-68 for treating muscle cramps in amyotrophic lateral sclerosis (ALS): study protocol for a TJ-68 trial.

INTRODUCTION/AIMS: Muscle cramps are a common and often disabling symptom in amyotrophic lateral sclerosis (ALS), a devastating and incurable neurodegenerative disorder. To date, there are no medications specifically approved for the treatment of muscle cramps. Ameliorating muscle cramps in ALS may improve and sustain quality of life. A widely prescribed traditional Japanese (Kampo) medicine against muscle cramps, shakuyakukanzoto (TJ-68), has been studied in advanced liver disease, spinal stenosis, kidney failure, and diabetic neuropathy. The Japanese ALS Management Guideline mentions TJ-68 for difficult muscle cramps in ALS. Therefore, the rationale of our trial is to investigate the safety and effectiveness of TJ-68 in treating painful and disabling muscle cramps in people with ALS outside of Japan. Accordingly, we are conducting a randomized clinical trial to test the safety and efficacy of TJ-68 in participants with ALS reporting frequent muscle cramps using an innovative, personalized N-of-1 design. If successful, TJ-68 may be used for muscle cramps in a broader population of people with ALS. METHODS: This is a two-site, double-blind, randomized personalized N-of-1 early clinical trial with TJ-68. At least 22 participants with ALS and daily muscle cramps will receive drug or placebo for 2 weeks (one treatment period) followed by a 1-week washout in a four-period cross-over design. While the primary objective is to evaluate the safety of TJ-68, the study has 85% power to detect a one-point shift on the Visual Analog Scale for Muscle Cramps Affecting Overall Daily Activity of the Columbia Muscle Cramp Scale (MCS). Secondary outcomes include the full MCS score, a Cramp Diary, Clinical Global Impression of Changes, Goal Attainment Scale, quality of life scale and ALS functional rating scale-revised (ALSFRS-R). DISCUSSION: The study is underway. A personalized N-of-1 trial design is an efficient approach to testing medications that alleviate muscle cramps in rare disorders. If TJ-68 proves safe and efficacious then it may be used to treat cramps in ALS, and help to improve and sustain quality of life. TRIAL REGISTRATION: This clinical trial has been registered with ClinicalTrials.gov (NCT04998305), 8/9/2021.

Design and Statistical Innovations in a Platform Trial for Amyotrophic Lateral Sclerosis.

Platform trials allow efficient evaluation of multiple interventions for a specific disease. The HEALEY ALS Platform Trial is testing multiple investigational products in parallel and sequentially in persons with amyotrophic lateral sclerosis (ALS) with the goal of rapidly identifying novel treatments to slow disease progression. Platform trials have considerable operational and statistical efficiencies compared with typical randomized controlled trials due to their use of shared infrastructure and shared control data. We describe the statistical approaches required to achieve the objectives of a platform trial in the context of ALS. This includes following regulatory guidance for the disease area of interest and accounting for potential differences in outcomes of participants within the shared control (potentially due to differences in time of randomization, mode of administration, and eligibility criteria). Within the HEALEY ALS Platform Trial, the complex statistical objectives are met using a Bayesian shared parameter analysis of function and survival. This analysis serves to provide a common integrated estimate of treatment benefit, overall slowing in disease progression, as measured by function and survival while accounting for potential differences in the shared control group using Bayesian hierarchical modeling. Clinical trial simulation is used to provide a better understanding of this novel analysis method and complex design. ANN NEUROL 2023;94:547-560.

COURAGE-ALS: a randomized, double-blind phase 3 study designed to improve participant experience and increase the probability of success.

Objective: To determine the target population and optimize the study design of the phase 3 clinical trial evaluating reldesemtiv in participants with amyotrophic lateral sclerosis (ALS).Methods: We evaluated the phase 2 study of reldesemtiv, FORTITUDE-ALS, to inform eligibility criteria and design features that would increase trial efficiency and reduce participant burden of the phase 3 trial.Results: In FORTITUDE-ALS, the effect of reldesemtiv was particularly evident among participants in the intermediate- and fast-progressing tertiles for pre-study disease progression. These participants most often had symptom onset ≤24 months and an ALS Functional Rating Scale-Revised (ALSFRS-R) total score ≤44 at baseline. Compared with the overall FORTITUDE-ALS population, the subgroup meeting these criteria declined by fewer ALSFRS-R points at 12 weeks (difference of least-squares mean [SE] versus placebo 1.84 [0.49] and 0.87 [0.35] for the overall population). These inclusion criteria will be used for the phase 3 clinical trial, COURAGE-ALS, in which the primary outcome is the change in ALSFRS-R total score at week 24. We also measure durable medical equipment use and evaluate strength in muscles expected to change rapidly. To reduce participant burden, study visits are often remote, and strength evaluation is simplified to reduce time and effort.Conclusions: In COURAGE-ALS, the phase 3 clinical trial to evaluate reldesemtiv, the sensitivity of detecting a potential treatment effect may be increased by defining eligibility criteria that limit the proportion of participants who have slower disease progression. Implementing remote visits and simplifying strength measurements will reduce both site and participant burden.ClinicalTrials.gov identifiers: NCT03160898 (FORTITUDE-ALS) and NCT04944784 (COURAGE-ALS).

Health utilities and quality-adjusted life years for patients with amyotrophic lateral sclerosis receiving reldesemtiv or placebo in FORTITUDE-ALS.

AIMS: To estimate the health utilities and quality-adjusted life years (QALYs) in patients with amyotrophic lateral sclerosis (ALS) receiving reldesemtiv versus placebo in FORTITUDE-ALS. MATERIALS AND METHODS: We performed a post hoc analysis of clinical trial data from FORTITUDE-ALS (NCT03160898). This Phase IIb, double-blind, randomized, dose-ranging, placebo-controlled, parallel-group, 12-week trial evaluated reldesemtiv in patients with ALS. Health utilities from the five-level version of the EuroQol five-dimensional questionnaire (EQ-5D-5L) were estimated using ALS Functional Rating Scale-Revised (ALSFRS-R) scores collected during the trial. QALYs were estimated using the area under the curve method. RESULTS: The full analysis set consisted of 456 patients (reldesemtiv n = 342, placebo n = 114), who received at least one dose of the double-blind study drug, and had ALSFRS-R assessed at baseline and at least one post-baseline assessment. The difference in EQ-5D-5L utility least-squares (LS) mean change from baseline to week 12 for reldesemtiv versus placebo, adjusted for baseline values, was statistically significant (0.03, 95% confidence interval [CI]: 0.01, 0.05; p = .0008). The incremental QALY of reldesemtiv versus placebo adjusted for baseline utility values showed a modest, but statistically significant, difference (0.004, 95% CI: 0.001, 0.007; p = .0058). CONCLUSIONS: This post hoc analysis of FORTITUDE-ALS suggests that reldesemtiv showed a modest but significant benefit in health utilities and QALYs compared with placebo. Future long-term studies that include direct collection of EQ-5D-5L data will be needed to confirm our findings. CLINICALTRIALS.GOV IDENTIFIER: NCT03160898.

Primary lateral sclerosis natural history study - planning, designing, and early enrollment.

Introduction/Aims. Primary lateral sclerosis (PLS) is exceedingly rare and has been an enigmatic disease. Recent progress has drastically changed this perception, with early biomarkers being investigated and potential medications for PLS emerging at the preclinical stage. The aim of this paper is to describe a study of PLS natural history and discuss the limitations and proposed solutions to the study of a rare and slowly progressive disease. Methods. The PLS Natural History Study is a 30-site, 24-month, prospective study that is supported by multiple funding sources. The study aims to enroll 50 early PLS (disease duration ≤4 years) and 50 definite PLS (disease duration 4 to 15 years) participants using modified PLS Diagnostic Criteria. Smartphone-based assessments including semi-quantitative and quantitative measures and patient-reported outcomes are utilized. In-person quantitative measures are also completed during site visits. The change in the PLS Functional Rating Scale score is the primary outcome. The study utilizes the NeuroBANK® patient-centric data capture and management platform. The biostatistical analysis plan has been developed. Results. In one year, 28 participants have been recruited. Enrollment has been much slower than anticipated due to the COVID-19 pandemic, the rarity of PLS, and potential study competition for internal resources from ALS clinical trials. Discussion. We discuss the need for more innovative methods to enroll and study individuals with such rare diseases and propose a number of mechanisms by which more efficient enrollment could be facilitated.

MiToS and King's staging as clinical outcome measures in ALS: a retrospective analysis of the FORTITUDE-ALS trial.

OBJECTIVE: To evaluate the Milano-Torino staging (MiToS) and King's staging systems as potential outcome measures for clinical trials in amyotrophic lateral sclerosis (ALS) by assessing these outcomes in FORTITUDE-ALS. METHODS: This was a post hoc analysis of the phase 2b FORTITUDE-ALS trial (NCT03160898), a double-blind, randomized, dose-ranging, placebo-controlled, parallel-group study of reldesemtiv in patients with ALS. The treatment period was 12 weeks, with a follow-up assessment at week 16. Patients were retrospectively classified into MiToS and King's stages. Outcomes were the mean time maintaining baseline stage and risk of progression from the baseline stage to a later stage. RESULTS: The full analysis set consisted of 456 patients randomized 3:1 (reldesemtiv n = 342, placebo n = 114) who received at least one dose of double-blind study drug and had at least one post-baseline assessment. At baseline, MiToS and King's stages were balanced between the reldesemtiv and placebo groups: >99% of patients were in MiToS stage 0 or 1 and King's stage 1, 2 or 3. Time of maintaining the baseline stage was similar in both groups, for each staging system. The two staging systems exhibited considerably disparate results for risk of progression from baseline to a later stage: hazard ratio (HR) = 0.62 (95% confidence interval [CI] 0.38, 0.99) for MiToS and HR = 0.96 (95% CI 0.63, 1.44) for King's. CONCLUSION: This exploratory analysis showed the feasibility of MiToS and King's staging as potential outcome measures in ALS. Additional studies of these staging systems are needed to further explore their utility in ALS clinical trials.

Amyotrophic Lateral Sclerosis Clinical Trials and Interpretation of Functional End Points and Fluid Biomarkers: A Review.

Importance: Clinical trial activity in amyotrophic lateral sclerosis (ALS) is dramatically increasing; as a result, trial modifications have been introduced to improve efficiency, outcome measures have been reassessed, and considerable discussion about the level of data necessary to advance a drug to approval has occurred. This review discusses what recent pivotal studies can teach the community about these topics. Observations: By restricting inclusion and exclusion criteria, recent trials have enrolled populations distinct from previous studies. This has led to efficacy signals being observed in studies that are smaller and shorter than was thought feasible previously. However, such trials raise questions about generalizability of results. Small trials with equivocal clinical results also raise questions about the data necessary to lead to regulatory approval. The ALS Functional Rating Scale-Revised remains the most commonly used primary outcome measure; this review discusses innovations in its use. Blood neurofilament levels can predict prognosis in ALS and may be a sensitive indicator of biologic effect; current knowledge does not yet support its use as a primary outcome. Conclusions and Relevance: It is now possible to use specific inclusion criteria to recruit a homogeneous patient population progressing at a specific rate; this will likely impact trials in the future. Generalizability of results on limited populations remains a concern. Although clinical outcomes remain the most appropriate primary outcome measures, fluid markers reflecting biologically important processes will assume more importance as more is learned about the association between such markers and clinical end points. The benefit of use of analytic strategies, such as responder analyses, is still uncertain.

Trial of Antisense Oligonucleotide Tofersen for SOD1 ALS.

BACKGROUND: The intrathecally administered antisense oligonucleotide tofersen reduces synthesis of the superoxide dismutase 1 (SOD1) protein and is being studied in patients with amyotrophic lateral sclerosis (ALS) associated with mutations in SOD1 (SOD1 ALS). METHODS: In this phase 3 trial, we randomly assigned adults with SOD1 ALS in a 2:1 ratio to receive eight doses of tofersen (100 mg) or placebo over a period of 24 weeks. The primary end point was the change from baseline to week 28 in the total score on the ALS Functional Rating Scale-Revised (ALSFRS-R; range, 0 to 48, with higher scores indicating better function) among participants predicted to have faster-progressing disease. Secondary end points included changes in the total concentration of SOD1 protein in cerebrospinal fluid (CSF), in the concentration of neurofilament light chains in plasma, in slow vital capacity, and in handheld dynamometry in 16 muscles. A combined analysis of the randomized component of the trial and its open-label extension at 52 weeks compared the results in participants who started tofersen at trial entry (early-start cohort) with those in participants who switched from placebo to the drug at week 28 (delayed-start cohort). RESULTS: A total of 72 participants received tofersen (39 predicted to have faster progression), and 36 received placebo (21 predicted to have faster progression). Tofersen led to greater reductions in concentrations of SOD1 in CSF and of neurofilament light chains in plasma than placebo. In the faster-progression subgroup (primary analysis), the change to week 28 in the ALSFRS-R score was -6.98 with tofersen and -8.14 with placebo (difference, 1.2 points; 95% confidence interval [CI], -3.2 to 5.5; P = 0.97). Results for secondary clinical end points did not differ significantly between the two groups. A total of 95 participants (88%) entered the open-label extension. At 52 weeks, the change in the ALSFRS-R score was -6.0 in the early-start cohort and -9.5 in the delayed-start cohort (difference, 3.5 points; 95% CI, 0.4 to 6.7); non-multiplicity-adjusted differences favoring early-start tofersen were seen for other end points. Lumbar puncture-related adverse events were common. Neurologic serious adverse events occurred in 7% of tofersen recipients. CONCLUSIONS: In persons with SOD1 ALS, tofersen reduced concentrations of SOD1 in CSF and of neurofilament light chains in plasma over 28 weeks but did not improve clinical end points and was associated with adverse events. The potential effects of earlier as compared with delayed initiation of tofersen are being further evaluated in the extension phase. (Funded by Biogen; VALOR and OLE ClinicalTrials.gov numbers, NCT02623699 and NCT03070119; EudraCT numbers, 2015-004098-33 and 2016-003225-41.).

Design of a Randomized, Placebo-Controlled, Phase 3 Trial of Tofersen Initiated in Clinically Presymptomatic SOD1 Variant Carriers: the ATLAS Study.

Despite extensive research, amyotrophic lateral sclerosis (ALS) remains a progressive and invariably fatal neurodegenerative disease. Limited knowledge of the underlying causes of ALS has made it difficult to target upstream biological mechanisms of disease, and therapeutic interventions are usually administered relatively late in the course of disease. Genetic forms of ALS offer a unique opportunity for therapeutic development, as genetic associations may reveal potential insights into disease etiology. Genetic ALS may also be amenable to investigating earlier intervention given the possibility of identifying clinically presymptomatic, at-risk individuals with causative genetic variants. There is increasing evidence for a presymptomatic phase of ALS, with biomarker data from the Pre-Symptomatic Familial ALS (Pre-fALS) study showing that an elevation in blood neurofilament light chain (NfL) precedes phenoconversion to clinically manifest disease. Tofersen is an investigational antisense oligonucleotide designed to reduce synthesis of superoxide dismutase 1 (SOD1) protein through degradation of SOD1 mRNA. Informed by Pre-fALS and the tofersen clinical development program, the ATLAS study (NCT04856982) is designed to evaluate the impact of initiating tofersen in presymptomatic carriers of SOD1 variants associated with high or complete penetrance and rapid disease progression who also have biomarker evidence of disease activity (elevated plasma NfL). The ATLAS study will investigate whether tofersen can delay the emergence of clinically manifest ALS. To our knowledge, ATLAS is the first interventional trial in presymptomatic ALS and has the potential to yield important insights into the design and conduct of presymptomatic trials, identification, and monitoring of at-risk individuals, and future treatment paradigms in ALS.

Medical therapies for amyotrophic lateral sclerosis-related respiratory decline: an appraisal of needs, opportunities and obstacles.

A roundtable convened in July 2020 examined issues concerning respiratory support in amyotrophic lateral sclerosis (ALS), with reference to the potential for an early-phase orally administered medication that might either postpone the introduction of noninvasive ventilation (NIV) and/or enhance the benefits to be gained from it. Attention was also given to the impact of the COVID-19 pandemic on usual practice in the assessment and management of ALS-related respiratory difficulties. Implementation of NIV marks a step-change in clinical status for patients and a major increase in burden for caregivers. All means to ease this transition should be explored: an oral therapy that supported respiratory function and patients' independence and sense of well-being would aid discussions to facilitate the eventual successful introduction of NIV. Assessment of a candidate oral therapy that might support respiratory function in ALS patients would be aided by the development of improved patient-reported outcome measures for robust quantification of treatment effect and quality of life. Such instruments could also be used to monitor patients' status during the COVID-19 pandemic, averting some of the risks of face-to-face assessment plus the patient burden and costs of traditional methods. Several oral candidate therapies have recently failed to meet their primary endpoints in clinical trials. However, understanding of the underlying physiology and appropriate trial design have grown and will inform future developments in this field.

Prescription and acceptance of durable medical equipment in FORTITUDE-ALS, a study of reldesemtiv in ALS: post hoc analyses of a randomized, double-blind, placebo-controlled clinical trial.

Objective: To evaluate the possible effect of reldesemtiv, a fast skeletal muscle troponin activator, on prescription and acceptance of durable medical equipment (DME) in the FORTITUDE-ALS trial. Methods: Health economic outcome information was collected in FORTITUDE-ALS (NCT03160898); sites recorded if and when DME, specifically manual or power wheelchairs, gastrostomy tubes, noninvasive ventilators, or augmentative language devices, was prescribed by a physician and accepted by the patient (DME-PAP) during the trial. Acceptance was defined as the patient agreeing the item was needed. Cox regression analysis compared time to DME-PAP for each reldesemtiv dose with placebo. Post hoc analyses evaluated all reldesemtiv doses compared with placebo. Results: At least one DME item was prescribed and accepted by 33/114 (28.9%) of placebo patients, 19/112 (17.0%) of patients receiving reldesemtiv 150 mg bid, 24/113 (21.2%) receiving 300 mg bid, and 29/117 (24.8%) receiving 450 mg bid. The proportion of new DME-PAP was significantly lower in patients receiving reldesemtiv 150 mg bid vs placebo (17.0% vs 28.9%, p = 0.032). The hazard ratio versus placebo for accepting at least one DME item for all reldesemtiv doses combined was 0.61 (confidence interval: 0.39, 0.96, p = 0.032). 25% of placebo patients were prescribed and agreed to obtain a DME item by 84 days; this threshold was met for reldesemtiv-treated patients at 120 days. Conclusions: Results suggest ALS patients receiving reldesemtiv may have lower risk of and delayed need for DME related to impaired mobility, breathing, swallowing, or speaking; this delay is consistent with other measures indicating delay in disease progression.

Adaptive Platform Trials to Transform Amyotrophic Lateral Sclerosis Therapy Development.

Current therapeutic development in amyotrophic lateral sclerosis (ALS) relies on individual randomized clinical trials to test a specific investigational product in a single patient population. This approach has intrinsic limitations, including cost, time, and lack of flexibility. Adaptive platform trials represent a novel approach to investigate several interventions for a single disease in a continuous manner. Already in use in oncology, this approach is now being employed more often in neurology. Here, we describe a newly launched platform trial for ALS. The Healey ALS Platform Trial is testing multiple investigational products concurrently in people with ALS, with the goal of rapidly identifying novel treatments, biomarkers, and trial endpoints. ANN NEUROL 2022;91:165-175.

Noninvasive ventilation use by patients enrolled in VITALITY-ALS.

Objectives: To evaluate the prescribing practices of noninvasive ventilation (NIV) and patient compliance during VITALITY-ALS. Methods: VITALITY-ALS enrolled patients with a slow vital capacity (SVC) ≥70% of predicted who were not using NIV at screening. Physicians prescribed NIV without restriction following randomization. Reason(s) for NIV prescription, dates prescribed and initiated, and compliance were recorded. Compliance was recorded as prescribed but never initiated, used ≥2 h/24 h, used ≥4 h/24 h, or used ≥22 h/24 h. In addition to other outcome measures, SVC and the revised ALS functional rating scale (ALSFRS-R) were performed at all visits. Patients were followed up to 56 weeks. Results: 565 patients were randomized and dosed with placebo or tirasemtiv in VITALITY-ALS; 195 (34.5%) were prescribed NIV: of these, 78.5% used it for ≥2 h/24 h, 71.3% for ≥4 h/24 h, and 11.8% for ≥22 h/24 h. The three most common reasons NIV was prescribed were decline in vital capacity, respiratory symptoms, and sleep-related symptoms. During the trial, 179/565 (31.7%) patients had a decline of SVC below 50%; of these patients, 122/179 (68.2%) were prescribed NIV. Reasons for prescribing NIV were different for patients from North America compared with Europe. Conclusions: Despite allowing for NIV initiation at any point following randomization in VITALITY-ALS, only slightly more than two out of three patients whose SVC fell below 50% were prescribed NIV; this was similar in Europe and in North America. Underutilization of NIV could influence survival outcomes in patients with ALS including those involved in clinical trials.

Reldesemtiv in Patients with Spinal Muscular Atrophy: a Phase 2 Hypothesis-Generating Study.

This phase 2, double-blind, placebo-controlled, hypothesis-generating study evaluated the effects of oral reldesemtiv, a fast skeletal muscle troponin activator, in patients with spinal muscular atrophy (SMA). Patients ≥ 12 years of age with type II, III, or IV SMA were randomized into 2 sequential, ascending reldesemtiv dosing cohorts (cohort 1: 150 mg bid or placebo [2:1]; cohort 2: 450 mg bid or placebo [2:1]). The primary objective was to determine potential pharmacodynamic effects of reldesemtiv on 8 outcome measures in SMA, including 6-minute walk distance (6MWD) and maximum expiratory pressure (MEP). Changes from baseline to weeks 4 and 8 were determined. Pharmacokinetics and safety were also evaluated. Patients were randomized to reldesemtiv 150 mg, 450 mg, or placebo (24, 20, and 26, respectively). The change from baseline in 6MWD was greater for reldesemtiv 450 mg than for placebo at weeks 4 and 8 (least squares [LS] mean difference, 35.6 m [p = 0.0037] and 24.9 m [p = 0.058], respectively). Changes from baseline in MEP at week 8 on reldesemtiv 150 and 450 mg were significantly greater than those on placebo (LS mean differences, 11.7 [p = 0.038] and 13.2 cm H2O [p = 0.03], respectively). For 6MWD and MEP, significant changes from placebo were seen in the highest reldesemtiv peak plasma concentration quartile (Cmax > 3.29 µg/mL; LS mean differences, 43.3 m [p = 0.010] and 28.8 cm H2O [p = 0.0002], respectively). Both dose levels of reldesemtiv were well tolerated. Results suggest reldesemtiv may offer clinical benefit and support evaluation in larger SMA patient populations.