Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial.

BACKGROUND AND OBJECTIVES: Primary mitochondrial myopathies (PMMs) encompass a group of genetic disorders that impair mitochondrial oxidative phosphorylation, adversely affecting physical function, exercise capacity, and quality of life (QoL). Current PMM standards of care address symptoms, with limited clinical impact, constituting a significant therapeutic unmet need. We present data from MMPOWER-3, a pivotal, phase-3, randomized, double-blind, placebo-controlled clinical trial that evaluated the efficacy and safety of elamipretide in participants with genetically confirmed PMM. METHODS: After screening, eligible participants were randomized 1:1 to receive either 24 weeks of elamipretide at a dose of 40 mg/d or placebo subcutaneously. Primary efficacy endpoints included change from baseline to week 24 on the distance walked on the 6-minute walk test (6MWT) and total fatigue on the Primary Mitochondrial Myopathy Symptom Assessment (PMMSA). Secondary endpoints included most bothersome symptom score on the PMMSA, NeuroQoL Fatigue Short-Form scores, and the patient global impression and clinician global impression of PMM symptoms. RESULTS: Participants (N = 218) were randomized (n = 109 elamipretide; n = 109 placebo). The m0ean age was 45.6 years (64% women; 94% White). Most of the participants (n = 162 [74%]) had mitochondrial DNA (mtDNA) alteration, with the remainder having nuclear DNA (nDNA) defects. At screening, the most frequent bothersome PMM symptom on the PMMSA was tiredness during activities (28.9%). At baseline, the mean distance walked on the 6MWT was 336.7 ± 81.2 meters, the mean score for total fatigue on the PMMSA was 10.6 ± 2.5, and the mean T score for the Neuro-QoL Fatigue Short-Form was 54.7 ± 7.5. The study did not meet its primary endpoints assessing changes in the 6MWT and PMMSA total fatigue score (TFS). Between the participants receiving elamipretide and those receiving placebo, the difference in the least squares mean (SE) from baseline to week 24 on distance walked on the 6MWT was -3.2 (95% CI -18.7 to 12.3; p = 0.69) meters, and on the PMMSA, the total fatigue score was -0.07 (95% CI -0.10 to 0.26; p = 0.37). Elamipretide treatment was well-tolerated with most adverse events being mild to moderate in severity. DISCUSSION: Subcutaneous elamipretide treatment did not improve outcomes in the 6MWT and PMMSA TFS in patients with PMM. However, this phase-3 study demonstrated that subcutaneous elamipretide is well-tolerated. TRIAL REGISTRATION INFORMATION: Trial registered with clinicaltrials.gov, Clinical Trials Identifier: NCT03323749; submitted on October 12, 2017; first patient enrolled October 9, 2017. CLINICALTRIALS: gov/ct2/show/NCT03323749?term = elamipretide&draw = 2&rank = 9. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that elamipretide does not improve the 6MWT or fatigue at 24 weeks compared with placebo in patients with primary mitochondrial myopathy.

Sublingual Dexmedetomidine for the Treatment of Acute Agitation in Adults With Schizophrenia or Schizoaffective Disorder: A Randomized Placebo-Controlled Trial.

Objective: Determine if sublingual dexmedetomidine, a selective α2 adrenergic receptor agonist, reduces symptoms of acute agitation associated with schizophrenia or schizoaffective disorder.Methods: This phase 3, randomized, double-blind, placebo-controlled study was conducted in adults diagnosed with schizophrenia or schizoaffective disorder per the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria. The study was conducted at 15 US sites between January 23, 2020, and May 8, 2020. Participants were randomized to sublingual dexmedetomidine 180 µg, 120 µg, or matching placebo. The primary efficacy endpoint was mean change from baseline in the Positive and Negative Syndrome Scale-Excited Component (PEC) total score at 2 hours postdose.Results: Altogether, 380 participants (mean age 45.6 years, 63.4% identifying as male, 77.9% identifying as Black or African American) were randomized; 380 (100%) self-administered study medication, and 372 (97.9%) completed the study. The mean PEC total score at baseline (17.6) indicated mild to moderate agitation. At 2 hours postdose, the least squares mean changes (SE) from baseline were -10.3 (0.4) for sublingual dexmedetomidine 180 µg, -8.5 (0.4) for 120 µg, and -4.8 (0.4) for placebo. Least squares mean differences (97.5% confidence intervals) in the sublingual dexmedetomidine groups were -5.5 (-6.7 to -4.3) for 180 µg and -3.7 (-4.9 to -2.5) for 120 µg (both P < .001 vs placebo). The most commonly encountered adverse events with dexmedetomidine (incidence ≥ 5% and ≥ 2× rate observed with placebo) were somnolence, dry mouth, and hypotension for the 120 µg dose, and somnolence, dizziness, orthostatic hypotension, and oral hypoesthesia for the 180 µg dose.Conclusions: Treatment with sublingual dexmedetomidine 180 µg or 120 µg was more efficacious than placebo in reducing acute agitation associated with schizophrenia as measured by PEC scores at 2 hours postdose.Trial Registration: ClinicalTrials.gov identifier: NCT04268303.

Effect of Sublingual Dexmedetomidine vs Placebo on Acute Agitation Associated With Bipolar Disorder: A Randomized Clinical Trial.

Importance: Acute agitation is common in patients with bipolar disorder and requires urgent management to relieve distress and to prevent escalation to aggressive behavior. Objective: To evaluate the effect of orally absorbed, sublingual dexmedetomidine, a selective α2A-adrenergic receptor agonist on symptoms of acute agitation in patients with bipolar disorder. Design, Setting, and Participants: Phase 3, randomized, double-blind, placebo-controlled trial conducted in 15 sites in the US with enrollment between February 24, 2020, and April 27, 2020, and final follow-up on May 21, 2020. A total of 380 adults with bipolar I or II disorder were randomized and 362 completed the study. Interventions: Participants were randomized to 3 groups: sublingual dexmedetomidine 180 µg (n = 127), sublingual dexmedetomidine 120 µg (n = 127), or placebo (n = 126). Main Outcomes and Measures: The primary efficacy end point was the mean change from baseline at 2 hours for the Positive and Negative Syndrome Scale-Excited Component (PEC) total score. The range of possible total scores is 5 (absence of agitation) to 35 (extremely severe). The secondary end point was the earliest time of a statistically significant change in PEC total score from baseline for the drug vs placebo. On the primary efficacy end point, to account for multiplicity associated with comparing 2 sublingual dexmedetomidine doses with placebo, the 2-sided significance level for each dose vs placebo was set at .025. Results: Of 380 patients randomized (mean age, 45.6 years; 54.8% women; and 56.1% Black individuals), 378 (99.5%) self-administered the study medication and completed the study. Baseline agitation was mild to moderate, with an overall mean PEC total score of 18.0. Two hours after taking the medication, the mean changes from baseline in PEC total score were -10.4 for sublingual dexmedetomidine 180 µg, -9.0 for sublingual dexmedetomidine 120 µg, and -4.9 for placebo. Least-square mean differences from placebo in the sublingual dexmedetomidine groups at 2 hours were -5.4 (97.5% CI, -6.6 to -4.2) for 180 µg and -4.1 (97.5% CI, -5.3 to -2.9) for 120 µg (both doses P < .001 vs placebo). Treatment effects began 20 minutes after taking the medication among patients in the sublingual dexmedetomidine groups (least-square mean difference for 180 µg, -1.1 [97.5% CI, -2.0 to -0.2]; P = .007; for 120 µg, -1.0 [97.5% CI, -1.9 to -0.1]; P = .009). Adverse events occurred in 35.7% of patients taking 180 µg of dexmedetomidine, 34.9% taking 120 µg, and 17.5% taking placebo. The most common adverse events (≥5%) in the respective 180 µg, 120 µg, and placebo groups were somnolence (21.4% and 20.6% vs 4.8%); dry mouth (4.8% and 7.1% vs 0.8%); hypotension (6.3% and 4.8% vs 0%); and dizziness (5.6% and 5.6% vs 0.8%). Conclusions and Relevance: Among patients with mild to moderate agitation associated with bipolar disorder, treatment with a sublingual film formulation of dexmedetomidine 120 µg or 180 µg, compared with placebo, resulted in significantly greater reduction in the agitation score at 2 hours. Further research is needed to understand the spectrum of patients for whom this treatment would be effective and feasible and to better understand the clinical importance of the observed effect size. Trial Registration: ClinicalTrials.gov Identifier: NCT04276883.