Cereno Scientific (Nasdaq First North: CRNO B), a Swedish biotech company developing treatments for rare cardiovascular and pulmonary diseases, announced on Monday that it has received approval from the US Food and Drug Administration (FDA) to commence a Phase IIb trial of its lead drug candidate CS1 for the treatment of pulmonary arterial hypertension (PAH).

This approval allows the company to advance toward first patient in (FPI) in the second quarter of 2026. Top-line data is expected around the fourth quarter of 2028, subject to enrolment timelines.

The clearance builds on the favourable safety, tolerability and encouraging disease-modifying signals observed in the Phase IIa study. CS1 has also been granted Orphan Drug Designation and Fast Track designation in the US.

Approximately 126 patients with PAH who are stable on background therapy will take part in the global, multicentre trial. During the first 36 weeks of treatment, participants will be randomised to receive once-daily CS1 capsules at one of two dose levels or matching placebo. The total study duration is 60 weeks, including screening and follow-up.

The study will evaluate the effect of CS1 on pulmonary vascular resistance (PVR) at Week 36 via right-heart catheterisation, changes in 6-minute walk distance at Week 36, and a range of additional evaluations including measures of heart function, biomarker changes, clinical worsening, patient-reported outcomes, and pharmacokinetics. This dose-finding trial is expected to be conducted across 10-12 countries in the US, Europe and South America at approximately 65 investigative sites.