Celon Pharma S.A. has received FDA clearance to advance its lead neuroscience program, CPL’36, into pivotal Phase 3 clinical trials for schizophrenia. The decision follows a positive Type B meeting, in which the agency confirmed that the company’s existing preclinical data are sufficient to initiate pivotal studies.

The Phase 3 program will include two 28-day randomized, double-blind trials in patients experiencing acute schizophrenia episodes, alongside a 12-month open-label extension to assess long-term safety. The FDA agreed that “treatment of schizophrenia” is the appropriate indication and endorsed Celon Pharma’s plan to conduct supportive studies—including drug-drug interaction, QTc, and mass balance assessments—concurrently with the pivotal trials, provided safety measures are in place.

Maciej Wieczorek, chief executive officer of Celon Pharma, said: “This validates both the strength of our scientific foundation and the robustness of our clinical program. With FDA alignment in place, we are advancing CPL’36 into Phase 3 development and expanding its potential across CNS disorders, including Levodopa-Induced Dyskinesia in Parkinson’s disease.”

CPL’36 is a selective phosphodiesterase 10A (PDE10A) inhibitor with a fast-off pharmacodynamic profile, designed to modulate dopaminergic and glutamatergic neurotransmission. It demonstrated clinically meaningful efficacy in a 189-patient Phase 2 trial, with both 20 mg and 40 mg doses showing statistically significant improvements versus placebo across positive and total PANSS scores. The 40 mg dose also indicated early cognitive benefits.

At Week 4, improvements in the positive PANSS subscale were 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). Reductions in total PANSS score—a key secondary endpoint—were 9.7 and 16.4 points, respectively (both p<0.001). These results underscore CPL’36’s differentiated mechanism targeting multiple neurotransmission pathways to address the broad spectrum of schizophrenia symptoms.

Celon Pharma plans to finalise Phase 3 protocols incorporating FDA feedback, with study initiation expected in 2026. The company is also exploring global partnerships to support development and potential commercialisation.