Randomized clinical trial: A phase 2b controlled study of the efficacy and safety of trazpiroben (TAK-906) for idiopathic or diabetic gastroparesis

BACKGROUND

Previous clinical studies of trazpiroben, a dopamine D2 /D3 receptor antagonist for long-term treatment of moderate-to-severe idiopathic and diabetic gastroparesis, have shown improved symptoms of fullness. This study assessed trazpiroben efficacy, safety, and tolerability in adults with idiopathic and diabetic gastroparesis versus placebo.

METHODS

This global, multicenter, double-blind, parallel-group, phase 2b study (NCT03544229) enrolled eligible adults aged 18-85 years with symptomatic idiopathic or diabetic gastroparesis. Randomized participants received either oral placebo or trazpiroben 5, 25, or 50 mg, administered twice daily over 12 weeks, and completed the American Neurogastroenterology and Motility Society Gastroparesis Cardinal Symptom Index-Daily Diary. Change in weekly composite score from baseline to week 12 (primary endpoint) and treatment-emergent adverse events were assessed. Data were summarized descriptively.

KEY RESULTS

Overall, 242 participants were enrolled (mean [standard deviation] age 55.7 [14.2] years; 75.6% female); 193 completed the study. No significant differences in change from baseline in weekly average of the daily diary composite score occurred at week 12 between placebo (least-squares mean [standard error] -1.19 [0.12]) and trazpiroben (5, 25, and 50 mg: -1.11 [0.22], -1.17 [0.12], and -1.21 [0.12], respectively). Overall, 41.4% of participants receiving trazpiroben reported treatment-emergent adverse events (placebo, 39.7%). No serious events were considered trazpiroben-related; no life-threatening or fatal events were reported.

CONCLUSIONS & INFERENCES

There was no clinically meaningful difference in efficacy between trazpiroben and placebo in treating gastroparesis, based on the primary endpoint analysis. Trazpiroben was well tolerated with no new safety concerns identified, strengthening evidence supporting its favorable safety profile. NCT number: NCT03544229.

Evaluating the Safety, Tolerability, and Disposition of Trazpiroben, a D2 /D3 Receptor Antagonist: Phase I Single- and Multiple-Ascending Dose Studies in Healthy Japanese Participants

Trazpiroben (TAK‐906) is a peripherally selective dopamine D₂/D₃ receptor antagonist being developed to treat chronic gastroparesis. This phase I, randomized, double‐blind, placebo‐controlled, single‐ and multiple‐ascending dose, parallel‐group study evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of trazpiroben in healthy Japanese men. Findings were compared with those from a prior US trial in healthy individuals. Overall, 24 participants were enrolled into 3 cohorts (each n = 8). Per cohort, 6 participants received trazpiroben (cohort 1, 50 mg; 2, 100 mg; 3, 10 mg) once on day 1 and twice daily on days 3 through 7, and two received placebo. Trazpiroben was well tolerated, with no clinically meaningful adverse events observed. Following single‐ and multiple‐dose administration, trazpiroben was rapidly absorbed and eliminated (mean elimination half‐life, 1.89‐6.45 hours; median time to maximum serum concentration [steady state], 1.00‐1.25 hours). Serum prolactin increased with trazpiroben treatment (mean maximum serum concentration 93.32 ng/mL [10 mg] vs. 10.83 ng/mL [placebo]), illustrating receptor target engagement. Results reflected those from healthy US participants, indicating a lack of differences between these ethnic populations in trazpiroben disposition and safety profile. Trazpiroben may represent a promising therapy for chronic gastroparesis across different populations, with further evaluation ongoing in a phase IIb study (NCT03544229).