RESUME-1: a Phase III study of tolperisone in the treatment of painful, acute muscle spasms of the back.

Tolperisone is a nonopioid, centrally acting muscle relaxant in clinical development in the USA for the treatment of symptoms associated with acute, painful muscles spasms of the back. CLN-301, RESUME-1, is a 14-day double-blind, randomized, placebo-controlled, parallel-group Phase III study of the efficacy and safety of tolperisone administered orally three-times daily in 1000 male and female subjects at approximately 70 clinical sites in the USA experiencing back pain due to or associated with muscle spasm of acute onset. Tolperisone is a promising therapeutic for managing acute, painful muscle spasms of the back as it appears to lack the off-target CNS effects often seen with conventional skeletal muscle relaxants. Clinical Trials registration number: NCT04671082.

Tolperisone for the Treatment of Acute Muscle Spasm of the Back: Results from the Dose-Ranging Phase 2 STAR Study (NCT03802565).

OBJECTIVE: Use of skeletal muscle relaxants (SMRs) for acute muscle spasm is confounded by central nervous system adverse events (AEs), including somnolence. Tolperisone is an SMR that does not appear to be associated with somnolence. The aim of this study was to assess the safety and efficacy of tolperisone versus placebo in subjects with acute muscle spasm of the back. METHODS: STAR (NCT03802565) was a double-blind, randomized, placebo-controlled phase 2 study in subjects with back pain due to acute muscle spasm. Subjects were randomized 1:1:1:1:1 to tolperisone 50, 100, 150, or 200 mg three times daily (TID) or placebo for 14 days. The primary efficacy endpoint was subject-rated pain "right now" using a numeric rating scale on day 14. RESULTS: Subjects (tolperisone, n=337; placebo, n=78) were enrolled at 38 US clinical sites. Tolperisone was well tolerated, with AEs in 18.1% of subjects receiving tolperisone versus 14.1% of subjects receiving placebo. Headache (7.1%) and diarrhea (2.4%) were the most frequent AEs in tolperisone-treated subjects versus 3.8% and 0%, respectively, in placebo-treated subjects. Somnolence was reported in 1.2% and 2.6% of subjects treated with tolperisone and placebo, respectively. Mean change from baseline in numeric rating scale score of pain "right now" on day 14 was -3.5 for placebo versus -4.2, -4.0, -3.7, and -4.4 for tolperisone 50, 100, 150, and 200 mg TID, respectively (linear test of trend on the least-squares mean difference [treatment-placebo]; p=0.0539). In an analysis of pairwise estimates (treatment-placebo), the greatest numerical difference and significance were observed for tolperisone 200 mg TID (p=0.0040). Several secondary endpoints trended toward significance for tolperisone 200 mg TID versus placebo. CONCLUSION: Tolperisone 200 mg TID may be a promising treatment for acute muscle spasm, without the somnolence associated with SMRs. The safety and efficacy of tolperisone should be evaluated in a phase 3 trial.

An assessment of the centrally acting muscle relaxant tolperisone on driving ability and cognitive effects compared to placebo and cyclobenzaprine.

WHAT IS KNOWN AND OBJECTIVE: Tolperisone is a centrally acting muscle relaxant under development in the United States as a treatment for acute and painful symptoms of muscle spasms. The objective of this three-way, randomized, blinded, three-period crossover study was to assess the safety and cognitive effects of tolperisone compared to placebo and the widely used muscle relaxant cyclobenzaprine in healthy volunteers. METHODS: Subjects were randomized to 1 of 3 treatment arms to receive tolperisone (150 mg), cyclobenzaprine (10 mg) or placebo 3 times per day (TID) in 3 separate study periods. Subjects completed a driving test on the Cognitive Research Corporation's Driving Simulator (CRCDS Mini-Sim), a validated driving simulator, on day 1 at time to maximum plasma concentration, on day 2 before the morning dose of study drug and on day 3 at steady state following the morning dose. Subjects were assessed on various driving parameters and on a computer-administered digit-symbol substitution test (CogScreen symbol digit coding test). The driving scenario is a monotonous 100 km highway route on which subjects are instructed to maintain speed and lane position. RESULTS AND DISCUSSION: The performance of subjects who had received tolperisone was not significantly different from those who had received placebo in terms of the primary end point: standard deviation of lateral position, a measure of weaving. Subjects who had received tolperisone also performed comparably to those who had received placebo on a range of secondary measures assessing driving ability, cognition and psychomotor performance. In contrast, subjects who had received cyclobenzaprine showed significant impairment compared to placebo (P < .01) on the primary end point of standard deviation of lateral position and on the majority of the secondary end points of driving ability. Despite their markedly poorer driving performance after receiving cyclobenzaprine, few subjects reported feeling unsafe to drive on day 1 (10.3%) and day 2 (3.4%). The incidence of adverse events was similar for tolperisone (36.4%) and placebo (29.0%) and was greater for cyclobenzaprine (45.4%). WHAT IS NEW AND CONCLUSION: Subjects who received tolperisone (150 mg TID) experienced no impact on various measures of driving, self-reported sleepiness and cognition measures compared to placebo, in contrast to those who received the widely used muscle relaxant cyclobenzaprine (10 mg TID).

PRISM: a novel research tool to assess the prevalence of pseudobulbar affect symptoms across neurological conditions.

BACKGROUND: Pseudobulbar affect (PBA) is a neurological condition characterized by involuntary, sudden, and frequent episodes of laughing and/or crying, which can be socially disabling. Although PBA occurs secondary to many neurological conditions, with an estimated United States (US) prevalence of up to 2 million persons, it is thought to be under-recognized and undertreated. The PBA Registry Series (PRISM) was established to provide additional PBA symptom prevalence data in a large, representative US sample of patients with neurological conditions known to be associated with PBA. METHODS: Participating clinicians were asked to enroll ≥20 consenting patients with any of 6 conditions: Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), Parkinson's disease (PD), stroke, or traumatic brain injury (TBI). Patients (or their caregivers) completed the Center for Neurologic Study-Lability Scale (CNS-LS) and an 11-point scale measuring impact of the neurological condition on the patient's quality of life (QOL). Presence of PBA symptoms was defined as a CNS-LS score ≥13. Demographic data and current use of antidepressant or antipsychotic medications were also recorded. RESULTS: PRISM enrolled 5290 patients. More than one third of patients (n = 1944; 36.7%) had a CNS-LS score ≥13, suggesting PBA symptoms. The mean (SD) score measuring impact of neurological condition on QOL was significantly higher (worse) in patients with CNS-LS ≥13 vs <13 (6.7 [2.5] vs. 4.7 [3.1], respectively; P<0.0001 two-sample t-test). A greater percentage of patients with CNS-LS ≥13 versus <13 were using antidepressant/antipsychotic medications (53.0% vs 35.4%, respectively; P<0.0001, chi-square test). CONCLUSIONS: Data from PRISM, the largest clinic-based study to assess PBA symptom prevalence, showed that PBA symptoms were common among patients with diverse neurological conditions. Higher CNS-LS scores were associated with impaired QOL and greater use of antipsychotic/antidepressant medications. These data underscore a need for greater awareness, recognition, and diagnosis of PBA.

Pseudobulbar affect: an under-recognized and under-treated neurological disorder.

INTRODUCTION: Pseudobulbar affect (PBA) is a neurologic syndrome of emotional affect disinhibition, characterized by uncontrollable, exaggerated, and often inappropriate emotional outbursts, which may cause severe distress, embarrassment, and social dysfunction. However, the US prevalence of PBA remains unknown. METHODS: An online survey was conducted primarily to estimate the US prevalence of PBA in patients with the six most commonly associated conditions: Alzheimer's disease, amyotrophic lateral sclerosis, multiple sclerosis, Parkinson's disease, stroke, and traumatic brain injury. Invitations to participate were randomly sent online to adults (aged ≥ 18 years) registered in the Harris Poll Online Panel who were patients or belonged to a household with a patient diagnosed with one of the six conditions (identified through previous screening by Harris Interactive). Participants were screened for PBA using the Pathological Laughing and Crying Scale (PLACS) and the Center for Neurologic Study-Lability Scale (CNS-LS). PBA estimates were made using a cut-off score of ≥ 13 on the PLACS and two different cut-off thresholds on the CNS-LS, a lower one of ≥ 13 and a more rigorous one of ≥ 21. Existing US prevalence data for the six underlying conditions were used to estimate US prevalence of PBA. RESULTS: Of 38,000 individuals invited to participate, 8876 responded (23%) and 2318 (26%) completed the questionnaire. Mean prevalence of PBA across all six conditions was 10.1%, 9.4%, and 37.5% with the PLACS ≥ 13, CNS-LS ≥ 21, and CNS-LS ≥ 13 thresholds, respectively. Using disease population estimates from government agencies and professional organizations, the estimated US population with PBA ranged from 1.8 to 7.1 million. Among patients who discussed their laughing and/or crying episodes with a physician, 41% were diagnosed, and about half received a medication for their episodes. CONCLUSIONS: The overall prevalence of PBA was estimated to be about 10% across these commonly associated underlying neurological conditions and appears to be under-recognized.

Dextromethorphan plus ultra low-dose quinidine reduces pseudobulbar affect.

OBJECTIVE: To evaluate dextromethorphan combined with ultra low-dose quinidine (DMq) for treating pseudobulbar affect (PBA) in patients with amyotrophic lateral sclerosis (ALS) or multiple sclerosis (MS). METHODS: In a 12-week randomized, double-blind trial, ALS and MS patients with clinically significant PBA (a baseline score ≥13 on the Center for Neurologic Studies-Lability Scale [CNS-LS]) were maintained, twice daily, on placebo, DMq at 30/10mg (DMq-30), or DMq at 20/10mg (DMq-20). RESULTS: In 326 randomized patients (of whom 283, or 86.8%, completed the study), the PBA-episode daily rate was 46.9% (p < 0.0001) lower for DMq-30 than for placebo and 49.0% (p < 0.0001) lower for DMq-20 than for placebo by longitudinal negative binomial regression, the prespecified primary analysis. Mean CNS-LS scores decreased by 8.2 points for DMq-30 and 8.2 for DMq-20, vs 5.7 for placebo (p= 0.0002 and p= 0.0113, respectively). Other endpoints showing statistically significant DMq benefit included, for both dosage levels, the likelihood of PBA remission during the final 14 days and, for the higher dosage, improvement on measures of social functioning and mental health. Both dosages were safe and well tolerated. INTERPRETATION: DMq markedly reduced PBA frequency and severity, decreasing the condition's detrimental impact on a patient's life, with satisfactory safety and high tolerability. The findings expand the clinical evidence that DMq may be an important treatment for patients suffering from the socially debilitating symptoms of PBA.