FDA Clears Celon Pharma's Novel PDE10A Inhibitor CPL-936 for Phase 3 Schizophrenia Trials
Key Insights
The FDA has cleared Celon Pharma's CPL-936 (search), a novel second-generation PDE10A (search) inhibitor, to advance into Phase 3 trials for schizophrenia (search) treatment following positive regulatory feedback.
The Phase 3 program will include two 28-day randomized, double-blind trials in patients with acute schizophrenia (search) episodes and a 12-month safety extension study.
CPL-936 (search) demonstrated robust efficacy in a 189-patient Phase 2 trial, with the 40 mg dose showing 6.3-point improvement in positive PANSS scores and 16.4-point reduction in total PANSS scores.
Celon Pharma S.A. has received FDA clearance to advance its lead neuroscience candidate CPL-936 (search) into Phase 3 development for schizophrenia (search), marking a significant regulatory milestone for the novel second-generation PDE10A (search) inhibitor. The FDA provided positive feedback following a Type B meeting, confirming that the company's existing preclinical data are sufficient to initiate pivotal studies.
Phase 3 Program Design
The FDA endorsed Celon Pharma's proposed Phase 3 program, which includes two 28-day randomized, double-blind trials in patients with acute schizophrenia (search) episodes and a 12-month open-label extension to establish long-term safety. The regulatory agency agreed that "treatment of schizophrenia" is the appropriate indication for CPL-936 (search), confirming the compound's potential for broad labeling at registration.
The FDA also supported the company's plan to conduct required supportive studies—including drug-drug interaction (DDI), QTc, and mass balance studies—concurrently with the pivotal trials, provided key safety measures are in place. This parallel development approach is expected to streamline timelines and maintain strategic flexibility.
Strong Phase 2 Efficacy Data
CPL-936 (search) previously demonstrated robust and clinically meaningful efficacy in a 189-patient Phase 2 trial, with both the 20 mg and 40 mg doses producing statistically significant improvements versus placebo across positive and total PANSS scores. The 40 mg dose also showed early signs of cognitive benefit.
At Week 4, the positive PANSS subscale improved by 3.7 points for the 20 mg dose (p<0.001; Cohen's d=0.73) and 6.3 points for the 40 mg dose (p<0.001; Cohen's d=1.38). For total PANSS score—a key secondary endpoint—reductions were 9.7 and 16.4 points, respectively (both p<0.001).
Differentiated Mechanism of Action
CPL-936 (search) is a selective phosphodiesterase 10A (PDE10A (search)) inhibitor with an improved fast-off pharmacodynamic profile designed to modulate dopaminergic and glutamatergic neurotransmission. These results underscore the compound's differentiated mechanism of action, which addresses the broad symptom spectrum of schizophrenia (search) including positive, negative, and cognitive symptoms.
Expansion into Additional Indications
"This validates both the strength of our scientific foundation and the robustness of our clinical program," said Maciej Wieczorek, Ph.D., Chief Executive Officer of Celon Pharma. "With FDA alignment in place, we are advancing CPL-936 (search) into Phase 3 development and expanding its potential across CNS disorders, including Levodopa-Induced Dyskinesia (search) in Parkinson's disease (search)."
The company is also being evaluated for Levodopa-Induced Dyskinesia (search) (LiD) in Parkinson's disease (search), representing a potential expansion of the program into additional CNS indications.
Next Steps and Timeline
Celon Pharma plans to finalize its Phase 3 protocols incorporating FDA feedback and expects to initiate pivotal studies in 2026. The company is also advancing regulatory preparations and exploring global partnerships to support development and potential commercialization of this novel therapeutic approach for schizophrenia (search) treatment.