Cereno Scientific focuses on the development of treatments for rare cardiovascular and lung diseases. Their lead candidate, CS1, is a histone deacetylase inhibitor (HDAC inhibitor) that acts through epigenetic modulation and addresses the underlying mechanisms of pulmonary arterial hypertension (PAH), such as pathological vascular changes. PAH is a progressive and life-threatening disease with limited treatment options, with current therapies mainly focusing on symptom relief.
Following successful results from the company's Phase IIa study, which showed good safety, tolerability and positive efficacy signals, it has now also presented follow-up data from the Expanded Access Program (EAP), which includes 10 patients from the Phase IIa study who continued CS1 treatment under an FDA-approved protocol.
Consistent results strengthen CS1's potential
The new 4-month data from EAP confirm the observations of the Phase IIa study, where CS1 demonstrated a favorable safety and tolerability profile without serious drug-related adverse events. The results are particularly significant as safety and tolerability are major challenges for existing PAH treatments, with several development programs recently discontinued due to adverse events. Rahul Agrawal, Chief Medical Officer and Head of R&D at Cereno Scientific, commented:
“The safety and tolerability profile of CS1 observed during the first four months of the Expanded Access Program is in line with the results of our three-month Phase IIa study, which is a promising outcome in this progressive disease. The combination of a favorable safety profile and early signs of efficacy underscores the potential of CS1 in this rare and serious disease.”
The EAP program, also known as CS-004, is designed to collect long-term safety and efficacy data for CS1 treatment, with follow-up at 4, 8, and 12 months. The program includes a sub-study that uses the medical technology company Fluidda's non-invasive imaging diagnostics to visualize how long-term CS1 treatment affects structural changes in pulmonary vessels, which may provide further insights into the candidate's disease-modifying potential. The program runs over 12 months, with full results expected in the first quarter of 2026.
Patient-driven demand and the next steps
Sten R. Sorensen, CEO of Cereno Scientific, emphasizes that the EAP was initiated at the request of both patients and their physicians following the Phase IIa study, indicating strong confidence in CS1's potential:
– I am pleased that we have been able to enable continued CS1 treatment through the EAP program for the PAH patients who participated in our Phase IIa study. This was at the request of both patients and their physicians, which is a very promising indication of CS1's potential. We are now allowing the EAP program to continue to its conclusion, and look forward to the results that will provide insights into the long-term use of CS1 after up to 12 months of treatment.
Cereno Scientific is now preparing a global, placebo-controlled Phase IIb study, scheduled to start in the first half of 2026, to more comprehensively evaluate the clinical efficacy of CS1. The study builds on the Phase IIa results, which showed that 40,9 percent of patients improved their REVEAL Risk Score 2.0, 71 percent reported improved quality of life according to the Minnesota Living with Heart Failure Questionnaire, and 25 percent showed significant reductions in pulmonary vascular resistance (>30 percent), consistent with CS1's mechanism of action aimed at reversing vascular changes.
