Objective The primary lateral sclerosis ( PLS ) consensus diagnostic criteria and functional rating scale ( PLSFRS ) were recently established to facilitate and optimize future PLS clinical trials. We examined the trajectory of the PLSFRS and other functional outcome measures and biomarkers in the PLS Natural History Study ( PLS NHS ) to understand their performance in this prospective cohort. Methods The PLS NHS is a prospective, longitudinal, multicenter study of people living with PLS in different diagnostic categories: early (disease duration <2 years); probable (2–4 years); and definite PLS (4–15 years). PLSFRS scores and other functional outcome measures were collected at baseline, 3‐, 6‐, 9‐, and 12‐month follow‐up visits. Baseline characteristics were compared between the groups. The slopes of the PLSFRS and other functional outcome measures over 12 months were examined in the overall cohort and subgroups using linear mixed‐effect models. The associations between baseline characteristics and the rate of PLSFRS decline were analyzed with linear regression models. Results A total of 76 participants were included: early (n = 6); probable (n = 26); and definite (n = 44) PLS . Baseline PLSFRS total scores were highest in the early PLS group, followed by the probable and definite PLS groups. In the overall cohort, the PLSFRS total score declined by 0.33 points/month (95% confidence interval [0.27–0.39], adjusted p < 0.05). The rate of decline was steepest in the early PLS group, followed by the probable and definite PLS groups. Baseline neurofilament light chain level was associated with the rate of PLSFRS decline over 1 year ( p = 0.001). Interpretation In PLS, the rate of functional decline, as measured by the PLSFRS total score, is faster during the early phase of the disease. Neurofilament light might serve as a prognostic biomarker in PLS. ANN NEUROL 2026;99:418–428
Toward therapeutic trials in primary lateral sclerosis
Placebo‐Controlled, Randomized Double‐Blind N‐Of‐1 Trial to Study Safety and Potential Efficacy of TJ‐68 for Improving Muscle Cramps in Patients With Amyotrophic Lateral Sclerosis: A Pilot Study
ABSTRACTIntroduction/AimsMuscle cramps are a common symptom in amyotrophic lateral sclerosis (ALS). Ameliorating muscle cramps may improve quality of life in devastating diseases like ALS. A traditional Japanese medicine (Kampo, TJ‐68) is widely prescribed in Japan for muscle cramps. However, it is not available in the USA. This study evaluated the safety, tolerability, and efficacy of TJ‐68 in ALS.MethodsThis study was a double‐blind, randomized, placebo‐controlled crossover trial, consisting of four periods, conducted at three centers in the USA. Safety was evaluated using multiple measures. The primary efficacy outcome was the Visual Analog Scale for Muscle Cramps Affecting Overall Daily Activity (item #5 of the Muscle Cramp Scale (MCS)). The secondary outcomes included the remaining items of the MCS and the Clinical Global Impression of Changes (CGIC), among others. The study was planned to enroll 22 participants with ALS within 2 years.ResultsThe enrollment was slow and was completed with 11 participants. There were no serious safety issues and TJ‐68 was well tolerated. Although the primary outcome measure did not reach statistical significance (p = 0.35), several secondary measures showed significant results: MCS #1 triggering of cramps (p = 0.01), MCS #2 cramp frequency (p = 0.03), MCS Additional 1 change of motor behaviors (p = 0.02), and CGIC assessed by the evaluator (p = 0.009). Other outcome measures did not reach statistical significance.DiscussionThe study revealed that N‐of‐1 trial design can detect changes in a small sample size, and TJ‐68 appeared to be safe. Larger studies are needed to confirm the efficacy of TJ‐68.
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.
Abstract 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 this patient population may sustain quality of life longer. A traditional Japanese medicine, shakuyakukanzoto (TJ-68) is widely prescribed in Japan for managing muscle cramps in a variety of conditions. The Japanese ALS Management Guideline mentions TJ-68 for difficult muscle cramps in ALS. Therefore, this clinical trial is designed to test the safety and efficacy of TJ-68 in participants with ALS reporting serious muscle cramps using a personalized N-of-1 approach. If successful, we can introduce TJ-68 for muscle cramps in ALS to Western medicine. Methods: With FDA-IND approval, we are conducting 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 was sized to detect a one-point shift on the Columbia Muscle Cramp Scale (MCS) item #5 with 85% power under a four-period crossover design.The secondary assessment includes 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 MCS in rare disorders. If TJ-68 proves safe and efficacious, we will work to introduce this product to Western medicine for treatment of patients with ALS and disabling muscle cramps. Trial Registration: This clinical trial has been registered with ClinicalTrials.gov (NCT04998305).
Primary lateral sclerosis natural history study – planning, designing, and early enrollment