Framingham, Massachusetts-based Tortugas Neuroscience reported positive Phase IIb results for obuprazine (TRTL-107) in acute schizophrenia, with all three tested dose groups meeting the primary endpoint versus placebo. The results, generated in China by the drug's original developer, Hansoh Pharmaceutical Group (HKEX: 3692), support Tortugas' plans to file a US Investigational New Drug (IND) application.
The randomized, double-blind, placebo- and active-reference-controlled Phase IIb trial enrolled 363 Chinese adults with acute schizophrenia requiring hospitalization within two months before screening across 24 clinical centers. Patients were assigned to one of five groups: three obuprazine dose ranges (1.5–3.0 mg, 4.5–6.0 mg, and 6.0–9.0 mg), aripiprazole, or placebo. The primary endpoint — change from baseline in Positive and Negative Syndrome Scale (PANSS) total score at Day 42 — was met by all three obuprazine dose groups versus placebo (p<0.0001 for each). The 1.5–3.0 mg group produced a placebo-adjusted difference of -16.7 points (least-squares mean change: -28.6 vs. -11.9 for placebo), while the 4.5–6.0 mg and 6.0–9.0 mg groups showed placebo-adjusted differences of -13.2 and -14.7 points, respectively.
Tortugas said each obuprazine dose group also produced statistically significant and clinically meaningful improvements versus placebo on the Positive and Negative Syndrome Scale (PANSS) positive symptom, negative symptom and Marder cognitive factor subscales at Day 42. At the 1.5–3.0 mg dose, placebo-adjusted improvements were 5.3 points on the positive subscale and 4.4 points on the negative subscale (both p<0.0001). Tortugas also said obuprazine was numerically more efficacious than aripiprazole across multiple endpoints, including the primary endpoint, but the release provided no comparative figures. PANSS responder rates (≥50% reduction from baseline) for the 1.5–3.0 mg and 4.5–6.0 mg groups were described as notably higher than for placebo and aripiprazole as early as Day 14, though detailed rates were not given.
Obuprazine was generally well tolerated; treatment discontinuation due to adverse events was approximately 2.1% for obuprazine-treated patients versus 2.5% for placebo. No other safety data were disclosed in the release.