A randomized, double-blind, placebo-controlled trial was performed at 19 ALS clinical centers of the Chinese ALS association. All patients provided written informed consent. The ethics committee of Peking Union Medical College Hospital approved the study protocol. The registration number of the clinical trial was ChiCTR-IPR-15007365.
Participants
Patients with definite or probable ALS according to the revised version of the El Escorial World Federation of Neurology criteria were recruited into the study (4). Included patients displayed onset of progressive weakness within 18 months prior to the study. The age at onset was between 20 and 75 years old. The forced vital capacity (FVC) was more than 70% of the predicted normal value. Patients had not taken Riluzole or Edaravone in the 3 months before recruitment. All patients were capable of understanding the information provided and giving full informed consent.
The exclusion criteria were as follows: electromyography showed motor nerve conduction block and abnormal sensory nerve conduction; computed tomography or magnetic resonance imaging revealed lesions that may explain the patient's clinical presentation; dementia or mental disorder; serious heart, liver, kidney, or other related disease; participation may endanger the patient’s life; gastrointestinal disorders or gastrointestinal surgery that may affect gastrointestinal absorption; a history of allergies, especially medication allergies; patients requiring ventilator-assisted breathing or tracheotomy; patients who were breast feeding or pregnant; patients who had received or were currently receiving Riluzole treatment; presentation of bulbar or thoracic symptoms or signs at onset; or patients who had difficulty taking medicine.
Sample size calculation
The sample size was calculated according to a previously published clinical trial of ALS patients (5). To provide 80% power to detect an adjusted mean difference between groups of 3 points on the ALSFRS-R score(30.2±8.9 vs 33.2±8.0) and considering a dropout rate of 25% at the last visit, with a 1:1 randomization ratio between NBP and placebo group, at a two-sided alpha level of 0.05, we calculated that a sample size of 312 patients would be required approximately (156 in the NBP group and 156 in the placebo group).
Treatment group
Patients eligible for admission were randomized, using SAS statistical analysis to generate A randomized arrangement of 312 subjects receiving treatment (study drug versus control drug) in A 1:1 ratio between group A and group B. That is, list the serial number, the corresponding treatment assignment, and follow this compilation blind.
Patients randomly assigned to groups A or B were treated with butylphthalide soft capsules (100mg/ tablet) or placebo (A placebo with physical characteristics such as appearance, size, color, dosage form, weight, taste and smell as similar as possible to the experimental drug, but without the active ingredients of the experimental drug).NBP group patients were given two soft capsules(200mg) three times a day for 12 months. Placebo group patients were given two placebo soft capsules three times a day for 12 months.
Evaluation of functional status
All patients were evaluated before treatment with NBP or placebo and then followed up for 12 months. A functional evaluation was conducted every 3 months after enrollment and included the ALSFRS-R, survival and tracheotomy incidence, total Medical Research Council (MRC) score, respiratory function, and clinical global impression (CGI) scale reported by the patient.
The ALSFRS-R score was evaluated according to a questionnaire. The maximum ALSFRS-R score was 48. The total MRC score was calculated as the sum of the muscle strength in 24 muscle movements, including neck flexion, neck extension, bilateral shoulder abduction, elbow flexion, elbow extension, wrist flexion, wrist extension, thumb extension, hip flexion, knee flexion, knee extension, ankle dorsiflexion, and ankle plantar flexion. Each muscle movement was evaluated with the MRC scale (0–5); the total MRC score was 120. Respiration function was monitored with an FVC test and was expressed as a percentage of the expected value. The CGI scale was used to assess disease severity and was evaluated by patients using a visual analogue scale ranging from no symptoms to the most serious symptoms (0 to 7 points).
Outcomes
The primary endpoint was the ALSFRS-R score after 12 months of treatment. The secondary efficacy outcomes were survival, tracheotomy, total MRC score, FVC, and the CGI score reported by the patient.
Adverse events
The investigator observed patients for adverse events every 3 months after treatment and instructed patients to report any events at any time. After patients routinely or prematurely terminated the study, adverse events were monitored for 3 months.
Statistical analysis
The qualitative factors among the baseline data were analyzed using the χ2 test, and the quantitative data were analyzed using the two independent-samples t test. The outcome measures were the changes in the ALSFRS-R score, percentage of predicted FVC, total MRC score, and CGI score from baseline to 12 months. To estimate the treatment effects, comparisons between groups were performed using the Mann–Whitney U-test for two sets of independent samples, as the data did not follow a normal distribution. Statistical analyses were performed using SPSS 17.0 software (SPSS, Inc., Chicago, IL, USA). All statistical tests were two-sided, and a value of P<0.05 was considered to indicate a statistically significant difference.