Tortugas Neuroscience and its partner Hansoh Pharma have reported that their Phase IIb clinical trial of obuprazine (TRTL-107) for acute schizophrenia achieved its primary endpoint.
The double-blind, randomised study evaluated 363 adult patients across 24 clinical centres in China who had required hospitalisation within two months prior to screening.
Participants received placebo, aripiprazole, or one of three daily doses of obuprazine: 1.5–3.0mg, 4.5–6.0mg, or 6.0–9.0mg.
At day 42, each obuprazine arm achieved statistically significant reductions from baseline in Positive and Negative Syndrome Scale (PANSS) total scores compared with placebo.
The 1.5–3.0mg cohort recorded the largest reduction, showing a least-squares mean drop of 28.6 points compared with 11.9 points for placebo, reflecting a placebo-adjusted difference of -16.7 points.
Placebo-adjusted differences were -13.2 points for the 4.5–6.0mg cohort and -14.7 points for the 6.0–9.0mg cohort.
Obuprazine demonstrated numerically greater efficacy than aripiprazole across several trial measures, including the primary endpoint.
By Day 14, responder rates, defined as at least a 50% reduction in PANSS total score, were higher in the 1.5–3.0mg and 4.5–6.0mg groups than in both the aripiprazole and placebo groups.
At Day 42, each obuprazine arm also showed statistically significant improvements over placebo across PANSS positive symptom, negative symptom, and Marder cognitive factor scores.
The 1.5–3.0mg dose produced placebo-adjusted reductions of 5.3 points on the positive symptom subscale and 4.4 points on the negative symptom subscale.
Study discontinuations were 2.5% for placebo and around 2.1% among obuprazine-treated patients.
Tortugas Neuroscience CEO Jeff Jonas said: “These Phase IIb trial results represent one of the most compelling efficacy datasets reported in schizophrenia in recent years and provide strong evidence for the potential of obuprazine to deliver clinically meaningful efficacy across symptom domains, with an early onset of clinical response.
“We believe the consistency and breadth of these results position obuprazine as a potentially differentiated treatment option in a market with significant unmet need. These data represent a major milestone for Tortugas and strengthen our confidence as we advance the programme toward the next stage of development.”
Tortugas intends to file an investigational new drug (IND) application in the US and will submit complete trial findings to a peer-reviewed journal.
Obuprazine functions as a dopamine D2/D3 receptor partial agonist, a 5-Hydroxytryptamine 1A (5-HT1A) receptor partial agonist, and a 5-HT2A receptor antagonist.
Hansoh Pharma conducted the Phase IIb trial, while Tortugas holds commercial development rights outside Greater China.
