Trofinetide for the treatment of Rett syndrome: a randomized phase 3 study.

Rett syndrome is a rare, genetic neurodevelopmental disorder. Trofinetide is a synthetic analog of glycine-proline-glutamate, the N-terminal tripeptide of the insulin-like growth factor 1 protein, and has demonstrated clinical benefit in phase 2 studies in Rett syndrome. In this phase 3 study ( https://clinicaltrials.gov identifier NCT04181723 ), females with Rett syndrome received twice-daily oral trofinetide (n = 93) or placebo (n = 94) for 12 weeks. For the coprimary efficacy endpoints, least squares mean (LSM) change from baseline to week 12 in the Rett Syndrome Behaviour Questionnaire for trofinetide versus placebo was -4.9 versus -1.7 (P = 0.0175; Cohen's d effect size, 0.37), and LSM Clinical Global Impression-Improvement at week 12 was 3.5 versus 3.8 (P = 0.0030; effect size, 0.47). For the key secondary efficacy endpoint, LSM change from baseline to week 12 in the Communication and Symbolic Behavior Scales Developmental Profile Infant-Toddler Checklist Social Composite score was -0.1 versus -1.1 (P = 0.0064; effect size, 0.43). Common treatment-emergent adverse events included diarrhea (80.6% for trofinetide versus 19.1% for placebo), which was mostly mild to moderate in severity. Significant improvement for trofinetide compared with placebo was observed for the coprimary efficacy endpoints, suggesting that trofinetide provides benefit in treating the core symptoms of Rett syndrome.

Adjunctive Pimavanserin in Patients with Major Depressive Disorder: Combined Results from Two Randomized, Double-Blind, Placebo-Controlled Phase 3 Studies.

Objective: In a phase 2 study, pimavanserin demonstrated efficacy as adjunctive treatment for major depressive disorder (MDD). Subsequently, two phase 3 studies (NCT03968159 in the US; NCT03999918 in Europe) were initiated to examine the efficacy and safety of adjunctive pimavanserin in subjects with MDD and inadequate response to antidepressant treatment. Studies were combined with a prespecified statistical analysis plan owing to recruitment challenges related to the COVID-19 pandemic. Experimental design: The randomized, double-blind studies enrolled 298 patients with MDD and inadequate response to current antidepressants. Patients were randomly assigned 1:1 to pimavanserin or placebo added to current antidepressant for 6 weeks. Primary endpoint was change from baseline to week 5 in the Hamilton Rating Scale for Depression, 17-item version (HAM-D-17). Principal observations: There was no effect of pimavanserin in change from baseline to week 5 in the HAM-D-17 (pimavanserin [n = 138]: least-squares mean [LSM] [standard error {SE}], -9.0 [0.58]; placebo [n = 135]: -8.1 [0.58]; mixed-effects model for repeated measures LSM [SE] difference, -0.9 [0.82], P = 0.2956). Nominal improvement with pimavanserin was observed on 2 secondary endpoints: Clinical Global Impressions-Severity scale, Karolinska Sleepiness Scale. Treatment-emergent adverse events occurred in 58.1% of pimavanserin-treated and 54.7% of placebo-treated patients. Conclusions: Adjunctive pimavanserin did not significantly improve depressive symptoms, although pimavanserin was well tolerated.

A Phase 1, Open-Label Study to Evaluate the Effects of Food and Evening Dosing on the Pharmacokinetics of Oral Trofinetide in Healthy Adult Subjects.

BACKGROUND AND OBJECTIVE: Trofinetide, a synthetic analog of tripeptide glycine-proline-glutamate, is an investigational agent for the treatment of Rett syndrome, a neurodevelopmental disorder with affected individuals requiring lifelong support. Food can affect the pharmacokinetic profile of a drug, and this phase 1 study assessed the potential effect of food on the pharmacokinetics of trofinetide. The study also evaluated the potential effect of evening dosing on trofinetide bioavailability and characterized the pharmacokinetic profile of trofinetide in urine. METHODS: A 60 mL oral solution of trofinetide (12 g) was administered in three dosing periods: morning fasted (A; reference), morning fed (B), and evening fasted (C). Healthy adult subjects (18-45 years) were randomized to sequence ABC (n = 19) or BAC (n = 22). Blood and urine samples were collected at scheduled timepoints for trofinetide pharmacokinetic analysis. Bioequivalence was confirmed if 90% confidence intervals for geometric mean ratio between B/A or C/A fell within 80-125% equivalence limits for area under the concentration-time curve (AUC) and maximum concentration (Cmax) in whole blood. RESULTS: Bioequivalence criteria were met for all conditions (i.e., morning fed vs. morning fasted and evening fasted vs. morning fasted) except Cmax in the fed versus fasted condition, which was just below the bioequivalence limit (75.49%), suggesting a negligible food effect and lack of diurnal variation on bioavailability. Trofinetide was primarily excreted unchanged in urine. Trofinetide was well tolerated, and there were no significant changes in vital signs or laboratory parameters. CONCLUSION: This study supports dosing of trofinetide without regard to food.