Tortugas Neuroscience (“Tortugas”), a clinical-stage biotechnology company focused on developing transformative therapies for central nervous system (CNS) disorders, today announced positive Phase 2b trial results for obuprazine (TRTL-107), the company’s investigational treatment for schizophrenia. Results from the Phase 2b trial conducted by Tortugas’ partner, Hansoh Pharma, and presented this past weekend 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 favorable 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 (p<0.0001). 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 (p<0.0001), respectively. Based on PANSS responder rates (≥50% reduction from baseline), 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, Chief Executive Officer 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 randomized, double-blind, placebo- and active-reference-controlled Phase 2b trial enrolled 363 Chinese adults with acute schizophrenia requiring hospitalization within two months prior to screening across 24 clinical centers. Patients were randomized to one of five treatment groups: 1.5–3.0 mg, 4.5–6.0 mg, 6.0–9.0 mg, aripiprazole, or placebo. The primary endpoint was change from baseline in PANSS total score at Day 42.

Key Study Highlights:

  • Each dose group achieved statistically significant and clinically meaningful improvement versus placebo.

  • The 1.5-3.0 mg dose demonstrated a 16.7-point placebo-adjusted improvement in PANSS total score at Day 42 (p<0.0001). The 4.5-6.0 mg and 6.0-9.0 mg groups demonstrated placebo-adjusted improvements of 13.2 and 14.7 points (p<0.0001), respectively.

  • Based on PANSS responder rates (≥50% reduction from baseline), the 1.5-3 mg and 4.5-6 mg dose groups demonstrated a notable increase in responder rates versus both placebo and aripiprazole as early as Day 14, supporting a rapid onset of clinical response.

  • At Day 42, each obuprazine dose group demonstrated statistically significant and clinically meaningful improvement versus placebo across PANSS positive symptom subscale, negative symptom subscale, and Marder cognitive factor scores. At 1.5-3.0 mg, placebo-adjusted improvements were 5.3 points on the PANSS positive symptom subscale and 4.4 points on the PANSS negative symptom subscale (both p<0.0001).

  • Obuprazine demonstrated numerically greater efficacy than aripiprazole across multiple endpoints, including the primary endpoint.

  • Obuprazine 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, Ph.D., President and Head of Research & Development at Tortugas. “Importantly, the Phase 2b results are consistent with this pharmacologic profile, with obuprazine demonstrating robust results across multiple symptom domains and a favorable 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 Phase 2b study are expected to be submitted for publication in a peer-reviewed journal.

About Obuprazine (TRTL-107)

Obuprazine (or TRTL-107), Tortugas’ most advanced product candidate, is a dopamine D2/D3 receptor partial agonist, 5-HT2A receptor antagonist and 5-HT1A receptor partial agonist for the treatment of schizophrenia. Tortugas holds global commercial development rights for obuprazine, excluding Greater China. Hansoh Pharma has successfully completed multiple clinical trials for obuprazine to date, including this recent Phase 2b trial.

Despite the availability of multiple antipsychotic therapies, many patients continue to experience persistent symptoms, inadequate response, treatment discontinuation, and functional impairment, underscoring the need for new treatments that can deliver broad symptom control while maintaining favorable tolerability. The efficacy and tolerability profile demonstrated in this study support the potential for obuprazine to become a differentiated treatment option for patients living with schizophrenia.

About Tortugas Neuroscience

Tortugas Neuroscience is a clinical-stage CNS-focused biotech company dedicated to developing medicines that address diseases of the brain. With a strategic focus on clinically validated mechanisms of action with well-defined development and regulatory pathways, Tortugas Neuroscience is committed to creating therapies with meaningful impact for patients worldwide. For more information, please visit: https://www.tortugasneuro.com

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