Phase 2b trial plans for CS1 as PAH treatment endorsed by FDA
Experimental therapy aims to reverse vascular remodeling inherent in disease
Plans for a Phase 2b clinical trial that will test CS1, Cereno Scientific‘s experimental treatment for pulmonary arterial hypertension (PAH), have been endorsed by the U.S. Food and Drug Administration (FDA).
The FDA’s endorsement comes just a few weeks after a meeting between Cereno and the FDA to discuss next steps for the development of CS1.
“The endorsement from the FDA for CS1 validates that the development plans have sound rationale to be able to support documentation for future marketing approval and adds credibility to our scientific and clinical capabilities,” Sten R. Sörensen, CEO of Cereno, said in a company press release. “These are important factors in the dialogues we have with potential partners, but also other stakeholders we interact with such as collaborators, investors, and the scientific community.”
“We are keen to progress [toward] the initiation of the Phase IIb trial to further evaluate CS1 as a PAH treatment with favorable safety and tolerability and disease-modifying capacity,” Sörensen added. “Our ultimate ambition is to be able to develop a treatment that could enhance and extend life of patients.”
Trial to evaluate therapy’s effects on right heart function
PAH is marked by high pressure in the vessels that carry blood from the heart through the lungs. This pressure puts strain on the right side of the heart, which is responsible for pumping blood to the lungs to pick up oxygen that can then be carried out to the rest of the body.
In PAH, the cells that line lung blood vessels grow abnormally, and this vascular remodeling causes the vessels to become narrower, which increases blood pressure. CS1 aims to treat the disease by reversing this vascular remodeling. Specifically, CS1 is a reformulation of valproic acid, an antiseizure treatment that targets histone deacetylases, or HDAC, a group of enzymes that suppress gene activity. It serves as an epigenetic modulator, which means it regulates gene activity without altering the DNA sequence.
An earlier Phase 2a trial (NCT05224531) tested three doses of CS1 in 25 adults with PAH. Data from that study indicated the therapy was generally well tolerated and that it improved right heart function and stabilized or reduced risk scores associated with death from PAH. Participants who completed the Phase 2a study could continue CS1 treatment as part of an expanded access program which is collecting data on the therapy’s long-term effects.
According to Cereno, the upcoming Phase 2b trial will test CS1 against a placebo in a larger group of PAH patients, and evaluate the therapy’s effects on vascular remodeling and right heart function. The company didn’t give details about the trial’s design, but noted that it is expected to launch in the first half of 2026.
“The plans for the Phase IIb trial are in alignment with the expectations of the FDA, meaning that we have high confidence that the Phase IIb trial design will include the relevant criteria contributing to the development program’s marketing approval process,” said Rahul Agrawal, MD, Cereno’s chief medical officer and head of research and development. “We are now continuing steps for preparations ahead of the Phase IIb trial in PAH.”
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