Tortugas Neuroscience has announced positive phase 2b trial results for obuprazine (TRTL-107), the company’s investigational treatment for schizophrenia.
Results from the trial conducted by Tortugas’ partner, Hansoh Pharma, and presented at the 2026 European College of Neuropsychopharmacology Congress (ECNP), demonstrated statistically significant and clinically meaningful improvements in Positive and Negative Syndrome Scale (PANSS) Total Score for each dose group, rapid onset of clinical response, broad improvements across multiple symptom domains, and a generally favourable tolerability profile.
Each obuprazine dose group demonstrated statistically significant and clinically meaningful improvements versus placebo on the primary endpoint of change from baseline in PANSS Total Score at Day 42, with evidence of rapid onset of clinical response. The 1.5-3.0 mg dose group produced the largest treatment effect, with a least-squares mean change from baseline of -28.6 points compared with -11.9 points for placebo, representing a placebo-adjusted difference of -16.7 points. The 4.5-6.0 mg and 6.0-9.0 mg dose groups demonstrated placebo-adjusted differences of -13.2 and -14.7 points, respectively. Based on PANSS responder rates, the 1.5-3 mg and 4.5-6 mg dose groups demonstrated a notable increase in responder rates compared with both placebo and aripiprazole as early as day 14.
“These phase 2b 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,” said Jeff Jonas, CEO of Tortugas Neuroscience.
“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 program toward the next stage of development.”
The randomised, double-blind, placebo- and active-reference-controlled phase 2b trial enrolled 363 Chinese adults with acute schizophrenia requiring hospitalisation within two months prior to screening across 24 clinical centres.
Obuprazine demonstrated numerically greater efficacy than aripiprazole across multiple endpoints, including the primary endpoint. It was generally well tolerated, with discontinuation rates comparable to placebo (2.5% for placebo vs. approximately 2.1% for obuprazine-treated patients).
“We believe that obuprazine’s differentiated pharmacology, including its functional modulation of dopamine D2, D3, and 5-HT1A receptors, coupled with potent antagonism of serotonin 5-HT2A receptors, may support broad control across multiple symptom domains while potentially addressing tolerability limitations,” said Al Robichaud, president and head of R&D at Tortugas.
“Importantly, the phase 2b results are consistent with this pharmacologic profile, with obuprazine demonstrating robust results across multiple symptom domains and a favourable tolerability profile. We are particularly encouraged by the results observed across dose levels, which may provide physicians flexibility to optimize treatment based on individual patient needs.”
The company plans to submit a U.S. Investigational New Drug (IND) application for TRTL-107. Detailed results from the study are expected to be submitted for publication in a peer-reviewed journal.