Tortugas Neuroscience’s schizophrenia drug from Hansoh Pharma has proven its worth in a phase 2b study, validating the fledgling biotech’s neurology strategy.
The company was launched by a pair of Sage Therapeutics veterans in the spring with $106 million to hand and a pipeline headed up by obuprazine. The drug, also known as TRTL-107, is a D2/D3 partial agonist and 5-HT2A antagonist licensed from China’s Hansoh.
Hansoh has been evaluating obuprazine in the phase 2b study of 363 Chinese adults with acute schizophrenia who had required hospitalization within two months prior to screening. Patients either received one of a range of five doses of obuprazine or the approved antipsychotic aripiprazole or placebo.
Each obuprazine dose cohort demonstrated statistically significant and clinically meaningful improvements in Positive and Negative Syndrome Scale (PANSS) total score, a measure of schizophrenia symptoms, compared to placebo at Day 42—hitting the trial’s primary endpoint.
The largest benefit was seen by the 1.5-3 mg dose cohort, who were tied to a placebo-adjusted reduction in PANSS score of 16.7, Tortugas explained in the Oct. 12 release.
For the 4.5-6 mg and 6-9 mg dose groups, the placebo-adjusted reductions were 13.2 and 14.7 points, respectively.
There was a “notable increase” in responder rates for the 1.5-3 mg and the 4.5-6 mg dose groups when compared to both placebo and aripiprazole at Day 14. This suggested a “rapid onset of clinical response,” according to Tortugas.
When it came to safety, obuprazine was generally well tolerated, with a discontinuation rate of 2.1% slightly below the 2.5% for the placebo group.
“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,” Tortugas’ Head of R&D Al Robichaud, Ph.D., said in the release.
“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,” Robichaud said.
“We are particularly encouraged by the results observed across dose levels, which may provide physicians flexibility to optimize treatment based on individual patient needs,” he added.
Tortugas' plan now is to secure FDA go-ahead to run a trial of obuprazine in the U.S.
The biotech’s pipeline consists of three other licensed assets, all of which are in phase 2. They include a GABA receptor-positive allosteric modulator from Hansoh that is aimed at treating tinnitus, as well as GAT-1 inhibitor for focal epilepsy and a PDE9 inhibitor for reversible encephalopathies, which are both licensed from Japan’s Eisai.
When Tortugas launched in April, the Framingham, Massachusetts-based biotech explained that its strategy was to focus on developing “medicines with clear regulatory paths to approval.” To this end, Tortugas has opted for small molecules with “derisked mechanisms of action” that can be developed as once-daily, oral formulations for “large and well-defined indications.”
The company is headed up by Robichaud and CEO Jeff Jonas, M.D., who previously worked together at Sage.
The company’s name—the Spanish word for tortoises—reflects the biotech’s approach to neuroscience drug development that “combines enduring patience with precise, purposeful momentum,” according to its website.
The schizophrenia space was shaken up in 2024 when Bristol Myers Squibb’s Cobenfy secured regulatory approval, boasting the first new mechanism of action in the space in decades. The Big Pharma paid $14 billion for Karuna Therapeutics to get its hands on the non-dopaminergic antipsychotic med. More recently, Maplight went public via a $250 million IPO to fund its own potential rival to Cobenfy.
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