Trial of Sodium Phenylbutyrate–Taurursodiol for Amyotrophic Lateral Sclerosis

A multicenter, randomized, double blind, placebo-controlled clinical trial of dl-3-butylphthalide in treatment of amyotrophic lateral sclerosis.

The prognostic value of slow vital capacity (SVC) in relation to respiratory function decline and disease progression in patients with amyotrophic lateral sclerosis (ALS) is not well understood. To investigate the rate of decline in percentage predicted SVC and its association with respiratory-related clinical events and mortality in patients with ALS. This retrospective study included 893 placebo-treated patients from 2 large clinical trials (EMPOWER and BENEFIT-ALS, conducted from March 28, 2011, to November 1, 2012, and from October 23, 2012, to March 21, 2014, respectively) and an ALS trial database (PRO-ACT, containing studies completed between 1990 and 2010) to investigate the rate of decline in SVC. Data from the EMPOWER trial (which enrolled adults with possible, probable, or definite ALS; symptom onset within 24 months before screening; and upright SVC at least 65% of predicted value for age, height, and sex) were used to assess the relationship of SVC to respiratory-related clinical events; 456 patients randomized to placebo were used in this analysis. The 2 clinical trials included patients from North America, Australia, and Europe. Clinical events included the earlier of time to death or time to decline in the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) respiratory subdomain, time to onset of respiratory insufficiency, time to tracheostomy, and all-cause mortality. Among 893 placebo-treated patients with ALS, the mean (SD) patient age was 56.7 (11.2) years, and the mean (SD) SVC was 90.5% (17.1%) at baseline; 65.5% (585 of 893) were male, and 20.5% (183 of 893) had bulbar-onset ALS. In EMPOWER, average decline of SVC from baseline through 1.5-year follow-up was -2.7 percentage points per month. Steeper declines were found in patients older than 65 years (-3.6 percentage points per month [P = .005 vs <50 years and P = .007 vs 50-65 years) and in patients with an ALSFRS-R total score of 39 or less at baseline (-3.1 percentage points per month [P < .001 vs >39]). When the rate of decline of SVC was slower by 1.5 percentage points per month in the first 6 months, risk reductions for events after 6 months were 19% for decline in the ALSFRS-R respiratory subdomain or death after 6 months, 22% for first onset of respiratory insufficiency or death after 6 months, 23% for first occurrence of tracheostomy or death after 6 months, and 23% for death at any time after 6 months (P < .001 for all). The rate of decline in SVC is associated with meaningful clinical events in ALS, including respiratory failure, tracheostomy, or death, suggesting that it is an important indicator of clinical progression.

Edaravone is recommended for amyotrophic lateral sclerosis (ALS) based on a study showing an effect on a defined subset of patients. To document the effect of edaravone in a cohort of ALS patients from India to find out if, after starting edaravone, there is a plateau period or significant slowing from baseline to compare results with existing literature. This was a single-center, prospective observational study with no control arm (due to ethical reasons). ALS patients >18 years of age, not requiring respiratory support or tube feeding, were included. All patients were given edaravone infusion in addition to standard of care and oral riluzole 50 mg twice daily. This consisted of giving the drug in monthly cycles over 6 months. The first cycle consisted of daily infusion of the drug for 14 days followed by a drug-free interval for the remaining part of the month. From cycle 2 to cycle 6, the patients received the drug for the first 10 days of the month followed by a drug-free interval for the remaining part of the month. The primary outcome was a significant change in Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) score from baseline at 6 months. Secondary outcomes were monthly change in ALSFRS-R scores when compared with the previous month and baseline, change in the first 3 months compared to the change in the next 3 months, adverse drug effects, and number of deaths. The study was registered with the Indian Council of Medical Research Clinical Trial Registry of India with the trial number CTRI/2019/11/021838. Paired t-test was used for statistical analysis. Thirty patients received the drug along with riluzole. Twenty-three patients completed all six monthly infusions. Two died (3 months), two developed adverse reactions (3 months) and did not want further infusions (one had breathing difficulty and the other had hypotension during infusion). Two withdrew consent due to perceived poor effectiveness of the drug. The mean ALSFRS-R at baseline was 35.17 [standard deviation (SD) 8.01; range 20-46]. The primary outcome showed a significant decline in the mean last available ALSFRS-R score 6 months by -4.9 (SD 1.21) (p < 0.01). For the secondary outcome measure, mean monthly ALSFRS-R score was calculated before each infusion after excluding dropouts. There was a significant monthly decline in ALSFRS-R score: -0.93 (SD 0.58), -1.0 (-0.52), -0.90 (SD 0.71), -0.87 (SD 0.61), -0.82 (SD 0.57), -0.95 (SD 0.63), respectively (p < 0.001). There was also a progressive monthly decline when compared to baseline. The rate of decline in the first 3 months was the same as in the remaining 3 months: -2.5 (SD 0.73) vs -2.6 (SD 0.98) (p = 0.3). Edaravone infusion does not stop or significantly slow progression of disease from baseline but is safe.

Amyotrophic lateral sclerosis (ALS) is a fatal disease. The sigma-1 (σ1) receptor emerged as a target for intervention. To determine the effects of pridopidine, a σ1-receptor agonist, in ALS. Pridopidine was tested as a regimen of the HEALEY ALS Platform Trial, a phase 2/3, multicenter, randomized, double-blind, platform trial. The study was conducted at 54 sites in the US from January 2021 to July 2022 (final follow-up, July 14, 2022). A total of 163 participants with ALS were randomized to receive pridopidine or placebo. An additional 122 concurrently randomized participants were assigned to receive placebo in other regimens and included in the analyses. Eligible participants were randomized 3:1 to receive oral pridopidine 45 mg twice daily (n = 121) or matching oral placebo (n = 42) for a planned duration of 24 weeks. The primary efficacy outcome was change from baseline through week 24 in ALS disease severity, analyzed using a bayesian shared parameter model, which has components for function (Revised Amyotrophic Lateral Sclerosis Functional Rating Scale [ALSFRS-R]) and survival that were linked through an integrated estimate of treatment-dependent disease slowing across these 2 components. This was denoted as the disease rate ratio (DRR), with DRR less than 1 indicating a slowing in disease progression on pridopidine relative to placebo. There were 5 key secondary end points: time to 2-point or greater reduction in ALSFRS-R total score among participants with bulbar dysfunction at baseline, rate of decline in slow vital capacity among participants with bulbar dysfunction at baseline, percentage of participants with no worsening in the ALSFRS-R bulbar domain score, time to 1-point or greater change in the ALSFRS-R bulbar domain score, and time to death or permanent assisted ventilation. Among 162 patients (mean age, 57.5 years; 35% female) who were randomized to receive the pridopidine regimen and included in the primary efficacy analysis, 136 (84%) completed the trial. In the primary analysis comparing pridopidine vs the combined placebo groups, there was no significant difference between pridopidine and placebo in the primary end point (DRR, 0.99 [95% credible interval, 0.80-1.21]; probability of DRR <1, 0.55) and no differences were seen in the components of ALSFRS-R or survival. There was no benefit of pridopidine on the secondary end points. In the safety dataset (pridopidine, n = 121; placebo, n = 163), the most common adverse events were falls (28.1% vs 29.3%, respectively) and muscular weakness (24.0% vs 31.7%, respectively). In this 24-week study, pridopidine did not impact the progression of ALS. ClinicalTrials.gov Identifiers: NCT04297683, NCT04615923.

Bioenergetic failure has been proposed as a driver of amyotrophic lateral sclerosis (ALS). CNM-Au8 is a suspension of gold nanocrystals that catalyzes the conversion of nicotinamide adenine dinucleotide hydride into NAD+, resulting in an increase of cellular adenosine triphosphate production. To determine the effects of CNM-Au8 on ALS disease progression. CNM-Au8 was tested as a regimen of the HEALEY ALS Platform Trial, a phase 2/3, multicenter, randomized, double-blind platform trial. The study was conducted at 54 sites in the US from July 2020 to March 2022 (final follow-up, March 17, 2022). A total of 161 participants with ALS were randomized to receive CNM-Au8 (n = 120) or regimen-specific placebo (n = 41). Data from 123 concurrently randomized placebo participants in other regimens were combined for analyses. Eligible participants were randomized in a 3:3:2 ratio to receive CNM-Au8 60 mg daily (n = 61), CNM-Au8 30 mg daily (n = 59), or matching placebo (n = 41) for 24 weeks. The primary efficacy outcome was change from baseline through week 24 in ALS disease severity measured by a bayesian shared parameter model of function (based on the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale) and survival, which provided an estimate of the rate of disease progression measured by the disease rate ratio (DRR), with a DRR of less than 1 indicating treatment benefit. Secondary end points included a Combined Assessment of Function and Survival using a joint-rank test, rate of decline in slow vital capacity (percent predicted), and survival free of permanent assisted ventilation. Among 161 participants who were randomized within the CNM-Au8 regimen (mean age, 58.4 years; 61 [37.9%] female), 145 (90%) completed the trial. In the primary analysis comparing the combined CNM-Au8 dosage groups vs the combined placebo groups, the primary end point (DRR, 0.97 [95% credible interval, 0.783-1.175]; posterior probability of DRR <1, 0.65) and the 3 secondary end points suggested no benefit or harm of CNM-Au8. In the active (n = 120) vs placebo (n = 163) groups, the most common adverse events were diarrhea (23 [19%] vs 12 [7%]), nausea (17 [14.2%] vs 14 [8.6%]), fatigue (12 [10.8%] vs 30 [18.4%]), and muscular weakness (24 [20%] vs 45 [27.6%]). No benefit of CNM-Au8 on ALS disease progression was observed at 24 weeks. ClinicalTrials.gov Identifiers: NCT04297683, NCT04414345.

In preclinical studies, the anti-inflammatory drug colchicine, which has never been tested in amyotrophic lateral sclerosis, enhanced the expression of autophagy factors and inhibited accumulation of transactive response DNA-binding protein 43 kDa, a known histopathological marker of amyotrophic lateral sclerosis. This multicentre, randomized, double-blind trial enrolled patients with probable or definite amyotrophic lateral sclerosis who experienced symptom onset within the past 18 months. Patients were randomly assigned in a 1:1:1 ratio to receive colchicine at a dose of 0.005 mg/kg/day, 0.01 mg/kg/day or placebo for a treatment period of 30 weeks. The number of positive responders, defined as patients with a decrease lesser than 4 points in the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised total score during the 30-week treatment period, was the primary outcome. Disease progression, survival, safety and quality of life at the end of treatment were the secondary clinical outcomes. Secondary biological outcomes included changes from baseline to treatment end of stress granule and autophagy responses, transactive response DNA-binding protein 43 kDa, neurofilament accumulation and extracellular vesicle secretion, between the colchicine and placebo groups. Fifty-four patients were randomized to receive colchicine (n = 18 for each colchicine arm) or placebo (n = 18). The number of positive responders did not differ between the placebo and colchicine groups: 2 out of 18 patients (11.1%) in the placebo group, 5 out of 18 patients (27.8%) in the colchicine 0.005 mg/kg/day group (odds ratio = 3.1, 97.5% confidence interval 0.4–37.2, P = 0.22) and 1 out of 18 patients (5.6%) in the colchicine 0.01 mg/kg/day group (odds ratio = 0.5, 97.5% confidence interval 0.01–10.2, P = 0.55). During treatment, a slower Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised decline was detected in patients receiving colchicine 0.005 mg/kg/day (mean difference = 0.53, 97.5% confidence interval 0.07–0.99, P = 0.011). Eight patients experienced adverse events in placebo arm (44.4%), three in colchicine 0.005 mg/kg/day (16.7%) and seven in colchicine 0.01 mg/kg/day arm (35.9%). The differences in adverse events were not statistically significant. In conclusion, colchicine treatment was safe for amyotrophic lateral sclerosis patients. Further studies are required to better understand mechanisms of action and clinical effects of colchicine in this condition.

Background: This parallel-group single-blind trial evaluates the safety and efficacy of Edaravone, as a free radical scavenger, in a highly selective subgroup of Iranian patients with amyotrophic lateral sclerosis (ALS). Methods: The study was registered in ClinicalTrials.gov (registration number: NCT03272802) and Iranian Registry of Clinical Trials (registration number: IRCT20190324043105N). Patients were included into the study, who were diagnosed as probable or definite ALS (according to revised El Escorial criteria), mildly to moderately affected by the disease [according to Amyotrophic Lateral Sclerosis Health State Scale (ALS/HSS)], scored ≥ 2 points on all items of the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R), and had forced vital capacity (FVC) of at least 80%. 20 patients (10 cases, 10 controls) were observed for 12 cycles (each cycle lasted four weeks). Cases received Edaravone for the first 14 days in the first cycle and for the first 10 days in the next cycles. In addition, all patients received Riluzole. The 40-item Amyotrophic Lateral Sclerosis Assessment Questionnaire (ALSAQ-40), ALSFRS-R, and Manual Muscle Testing (MMT) scores were measured every 3 cycles to evaluate the physical and functional status of the patients. Besides, injection reactions, adverse events (AEs), and serious adverse events (SAEs) were measured during the study. Results: ALSAQ-40, ALSFRS-R, and MMT scores were not significantly different between cases and controls in 5 different time points. During the study, no injection reactions were observed. AEs and SAEs were not significantly different between cases and controls. Conclusion: Our data did not demonstrate efficacy of Edaravone in ALS treatment, but showed its safety for use in patients with ALS. Further studies are necessary to investigate Edaravone efficacy in patients with ALS before prescribing this new drug outside Japan.

Additional therapies for amyotrophic lateral sclerosis (ALS) are urgently needed. Immune-mediated complement activation may be involved in ALS pathogenesis as evidenced by the upregulation of terminal components; thus, complement inhibition could potentially slow progression. To evaluate the safety and efficacy of the terminal complement C5 inhibitor ravulizumab in adults with ALS. This double-blind, placebo-controlled, parallel-group, multinational, randomized, phase 3 clinical trial was conducted from March 30, 2020, to October 17, 2021, in 81 ALS specialty centers across 17 countries. A preplanned, unmasked, nonbinding interim futility analysis was conducted when 33% of participants had completed week 26, wherein a conditional power of less than 10% would halt the trial. A total of 478 individuals were screened, and 96 were excluded. Inclusion criteria were weight of 40 kg or more, fulfillment of the El Escorial diagnostic criteria, and a minimal prestudy Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) progression score of -0.3 points per month. Study treatment consisted of placebo or a weight-based dose of intravenous ravulizumab every 8 weeks until week 42. Participants could continue standard-of-care treatment. The primary end point was change from baseline in ALSFRS-R score at week 50 based on the Combined Assessment of Function and Survival (CAFS). A total of 382 participants were randomly assigned 2:1 to receive ravulizumab (n = 255; mean [SD] age, 58.6 [10.6] years; 94 female [36.9%] and 161 male [63.1%]) or placebo (n = 127; mean [SD] age, 58.0 [11.0] years; 58 female [45.7%] and 69 male [54.3%]). The interim analysis showed that the observed mean change from baseline in ALSFRS-R at week 50 was -14.67 points (SE, 0.89 points; 95% CI, -16.42 to -12.91 points) for ravulizumab and -13.33 points (SE, 1.22 points; 95% CI, -15.72 to -10.93 points) for placebo, with no significant difference between the groups (mean [SE] difference, -1.34 [1.46] points; 95% CI, -4.21 to 1.53 points). Based on these data, the trial was terminated for futility. The primary analysis at week 50 showed no significant difference in CAFS between groups (mean [SE], 5.5 [10.8] points; 95% CI, -15.7 to 26.6 points; P = .61). Overall incidence rates for treatment-emergent adverse events were similar for ravulizumab (204 participants [80.0%]) and placebo (108 participants [85.0%]). This trial rapidly showed that terminal complement C5 inhibition with ravulizumab did not slow functional decline in participants with ALS and that the safety profiles of ravulizumab and placebo were similar. Highly effective, novel treatments are critically needed to slow functional decline and extend survival in patients with ALS. ClinicalTrials.gov Identifier: NCT04248465.

Utilizing the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) as a Tool in Nutrition Assessment of Patients With Amyotrophic Lateral Sclerosis

Rate of disease progression (ΔFS), measured as change in the revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) and body mass index (BMI), are predictors of survival in amyotrophic lateral sclerosis (ALS). Our aim in this study was to assess the utility of these clinical biomarkers along with neurophysiological measures, such as the split hand index (SI), in monitoring disease progression. Clinical trial data were collected from 107 patients recruited into the Tecfidera in ALS trial. The prognostic utility of clinical and neurophysiological measures, including ΔFS, BMI, SI, and neurophysiological index (NPI), were assessed cross-sectionally and longitudinally (40 weeks). The outcome measures of disease severity and progression included: (i) ALSFRS-R score; (ii) Medical Research Council (MRC) score; and (iii) forced vital capacity and sniff nasal inspiratory pressure. Fast-progressor ALS patients (ΔFS ≥1.1) exhibited significantly lower ALSFRS-R and total MRC scores at baseline. A baseline ΔFS score ≥1.1 was associated with a greater reduction in ALSFRS-R (P=.002) and MRC (P=.002) scores over 40 weeks. Baseline BMI <25 was also associated with faster reduction of ALSFRS-R and MRC scores. SI and NPI were associated with disease severity at baseline, but not with subsequent rate of disease progression. Implementation of the assessed clinical and neurophysiological biomarkers may assist in patient management and stratification into clinical trials.

Amyotrophic lateral sclerosis (ALS) is a disease with high morbidity and mortality that adversely affects the activities of daily living. Disease progression in ALS is characterized by loss of function in bulbar, motor, and respiratory parameters. The revised amyotrophic lateral sclerosis functional rating scale (ALSFRS-R), which consists of 12 criteria, is used to determine disease effects on each of these functions. While each criterion is equally important when calculating the total ALSFRS-R score, the importance levels of the 12 criteria may vary in clinical practice. In this classical approach, the relationships among the parameters are not considered and the effects of bulbar, spinal, and respiratory dysfunctions on a patient's activities of daily living may be different. In this study, we aimed to evaluate ALS cases with the ALSFRS-R fuzzy method. Although each subheading in the ALSFRS-R had the same score, the disease score was determined by the fuzzy ALSFRS-R method, based on whether a subheading had priority in management of the disease. While creating the functional rating scale ALSFRS-R approach, fuzzy ALSFRS-R score values were obtained by creating fuzzy models for each main group and integrating the fuzzy model results of each main group into a separate model. In total, 50 patients with definite ALS according to the El Escorial criteria (33 men [66%] and 17 women [34%]; mean age, 58.49±10.01 years) were included in the study. When ALSFRS-R results and fuzzy ALSFRS-R results were compared, the prioritization order of 45 patients increased using the fuzzy ALSFRS-R score, while the prioritization order of five patients remained the same in both evaluations. The approach obtained by using fuzzy membership functions and decision rules, formed in accordance with expert opinion, was applied to the data of 50 patients from a large-scale hospital. In total, 90% of the patients had increased prioritization when using the fuzzy ALSFRS-R scoring method. Our results showed that the fuzzy approach provided more accurate information regarding a patient's condition.

ObjectiveThe global, phase 3, randomized, placebo-controlled PHOENIX trial evaluated the safety and efficacy of an oral, fixed-dose combination of sodium phenylbutyrate and taurursodiol (PB&TURSO) in amyotrophic lateral sclerosis (ALS). BackgroundIn the phase 2 CENTAUR trial, PB&TURSO significantly slowed functional decline and prolonged survival duration compared with placebo in adults with definite ALS (revised El Escorial criteria), symptom onset 18 months, and baseline slow vital capacity (SVC) >60%.PHOENIX was designed to evaluate PB&TURSO in a larger population of people living with ALS over a longer placebo-controlled duration than in CENTAUR (48 weeks vs 24 weeks, respectively). Design/MethodsAdults with clinically definite or clinically probable ALS, symptom onset <24 months, and SVC 55% were enrolled from 69 European sites and US sites and randomized 3:2 to receive PB&TURSO or placebo for 48 weeks.The primary end point was change from baseline to week 48 in ALS Functional Rating Scale-Revised (ALSFRS-R) total score, evaluated using the mortality adjusted mixed-effects model, known as Mortality Adjusted Progression.Secondary end points included change from baseline to week 48 in the 40-item ALS Assessment Questionnaire and in SVC, change from baseline to week 24 in ALSFRS-R total score, and overall survival (to be assessed over longer-term follow-up at the final data analysis).Safety assessments included adverse event incidence and severity. ResultsSix hundred sixty-four participants (Europe, n = 552; the United States, n = 112) with a mean (SD) age of 59.5 (10.81) years were enrolled.Most identified as male (62%) and White (83%); 22% had bulbar-onset disease.Mean (SD) time since ALS symptom onset was 14.4 (5.30) months.At screening, 92% and 3% of participants were receiving stabledose riluzole and edaravone, respectively. ConclusionsTopline results including primary efficacy and safety data will be presented at the Annual Meeting of the American Academy of Neurology pending data availability.Study Supported By: Amylyx Pharmaceuticals

Objective: To investigate the clinical and electrophysiological characteristics of patients with amyotrophic lateral sclerosis (ALS) with positive repetitive nerve stimulation (RNS) test results on the accessory nerve and negative needle electromyography (EMG) test results on the sternocleidomastoid with the goal to enrich the knowledge of disease progression in patients with ALS. Methods: The clinical data of 612 patients diagnosed with ALS at the Neurology Department of the First Medical Center, Chinese PLA General Hospital from June 2016 to August 2022 were collected. In total, 267 cases had undergone EMG tests on the sternocleidomastoid following a positive 3 Hz RNS test result on the accessory nerve, who were selected as the study subjects. The differences in clinical indicators were compared between RNS (+)/EMG (-) group and RNS (+)/EMG (+) group. A binomial distribution model with multiple variables was built to quantitatively analyze the major factors and their effects. Results: At the initial visit, 15.8% of patients with ALS were 3 Hz RNS (+) on the accessory nerve and EMG (-) on the ipsilateral sternocleidomastoid, accounting for 36.3% of RNS (+) patients. The decremental range of the 3 Hz RNS test delivered to the accessory nerve in these patients [-14% (-19%, -12%)] was lower than that in patients with RNS (+)/EMG (+) [-17% (-23%, -13%)] (P<0.05), while the ratio of upper limb onset (64.9%) and non-definite diagnosis (28.9%) were higher [54.7% and 13.5% for patients with RNS (+)/EMG (+), P<0.05]. Furthermore, the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) score [40 (37, 42)], body mass index (BMI) [23.8 (22.0, 25.4) kg/m2] and forced vital capacity (FVC) [92.8% (76.6%, 103.8%)] were higher in patients with RNS(+)/EMG(+) (P<0.05). The multivariate model suggested that, in patients with RNS (+)/EMG (-), the ratio of upper limb onset to lower limb onset was 1.04, while that of upper limb onset to bulbar onset was 2.02, and that of lower limb onset to bulbar onset was 1.94. The ratio of non-definite ALS to definite ALS was 1.13. The ALSFRS-R score, BMI, and FVC had a protective contribution to the electrophysiological function of the motor neurons. The ratio of the effect size of the ALSFRS-R or BMI to that of FVC was 3.37 and 1.14, respectively. Conclusions: Patients with ALS that were 3 Hz RNS (+) on the accessory nerve and EMG (-) on the ipsilateral sternocleidomastoid had a smaller decremental range of the compound muscle action potential amplitude, and a higher proportion of upper limb onset and non-definite ALS. A higher ALSFRS-R score, BMI, and FVC have a protective effect to the electrophysiological function of motor neurons. The effect size of the ALSFRS-R score is the largest, followed by BMI and FVC.

In this issue of the Journal, Paganoni et al.1 describe the results of a well-designed, multicenter, phase 2 trial of a fixed-dose combination of 6 g per day of sodium phenylbutyrate and 2 g per day of taurursodiol, also known as tauroursodeoxycholic acid, in patients with definite amyotrophic lateral sclerosis (ALS) according to El Escorial criteria who were enrolled within 18 months after symptom onset. The trial showed a difference of 0.42 points per month between the active-drug group and the placebo group in the mean rate of change in the total score on the Amyotrophic Lateral Sclerosis Functional Rating .

Strong evidence suggests that endoplasmic reticulum stress plays a critical role in the pathogenesis of amyotrophic lateral sclerosis (ALS) through altered regulation of proteostasis. Robust preclinical findings demonstrated that guanabenz selectively inhibits endoplasmic reticulum stress-induced eIF2α-phosphatase, allowing misfolded protein clearance, reduces neuronal death and prolongs survival in in vitro and in vivo models. However, its safety and efficacy in patients with ALS are unknown.To address these issues, we conducted a multicentre, randomized, double-blind trial with a futility design. Patients with ALS who had displayed an onset of symptoms within the previous 18 months were randomly assigned in a 1:1:1:1 ratio to receive 64 mg, 32 mg or 16 mg of guanabenz or placebo daily for 6 months as an add-on therapy to riluzole. The purpose of the placebo group blinding was to determine safety but not efficacy. The primary outcome was the proportion of patients progressing to higher stages of disease within 6 months as measured using the ALS Milano-Torino staging system, compared with a historical cohort of 200 patients with ALS. The secondary outcomes were the rate of decline in the total revised ALS functional rating scale score, slow vital capacity change, time to death, tracheotomy or permanent ventilation and serum light neurofilament level at 6 months.The primary assessment of efficacy was performed using intention-to-treat analysis. The treatment arms using 64 mg and 32 mg guanabenz, both alone and combined, reached the primary hypothesis of non-futility, with the proportions of patients who progressed to higher stages of disease at 6 months being significantly lower than that expected under the hypothesis of non-futility and a significantly lower difference in the median rate of change in the total revised ALS functional rating scale score.This effect was driven by patients with bulbar onset, none of whom (0/18) progressed to a higher stage of disease at 6 months compared with those on 16 mg guanabenz (4/8; 50%), the historical cohort alone (21/49; 43%; P = 0.001) or plus placebo (25/60; 42%; P = 0.001). The proportion of patients who experienced at least one adverse event was higher in any guanabenz arm than in the placebo arm, with higher dosing arms having a significantly higher proportion of drug-related side effects and the 64 mg arm a significantly higher drop-out rate. The number of serious adverse events did not significantly differ between the guanabenz arms and the placebo. Our findings indicate that a larger trial with a molecule targeting the unfolded protein response pathway without the alpha-2 adrenergic related side-effect profile of guanabenz is warranted.