Clinical Trials Arena

Seyltx buys Algernon’s Phase II chronic cough therapy

Seyltx bought the programme for $2m and 20% equity and plans to advance ifenprodil in Phase II trials this year.

US-based Seyltx has closed an agreement to acquire Algernon Pharmaceuticals’ chronic cough therapy, ifenprodil (NP-120).

Algernon received a purchase price of $2m along with a 20% equity position in Selytx. Following the close of the acquisition, Algernon’s stock rose by more than 25% in trading today. The deal was first announced in November 2023.

Ifenprodil is an N-methyl-D-aspartate (NMDA) receptor antagonist that specifically targets the NMDA type subunit 2B (GluN2B). The data from the Phase II trial of the therapy in Australia and New Zealand in patients with idiopathic pulmonary fibrosis (IPF) and chronic cough showed a decline in cough count, compared to baseline.

Seyltx plans to start the Phase II trial for ifenprodil by the end of this year. This is in line with Algernon’s earlier plans to start the placebo-controlled trial in Q3 2024. The study will enrol approximately 180 participants with IPF and chronic cough. The participants will be randomised 1:1:1 to receive either 20mg or 40mg of ifenprodil thrice daily or placebo for 12 weeks.

There are no US Food and Drug Administration (FDA) approved therapies for chronic cough, which is defined as a cough that lasts more than eight weeks. Multiple companies have applied for approval of chronic cough therapies but were ultimately rejected by the FDA.

In December 2023, Merck & Co (Merck) received its second rejection for gefapixant for the treatment of refractory chronic cough (RCC) or unexplained chronic cough (UCC) in adults. The FDA stated that there was not enough ‘substantial’ evidence of the drug’s effectiveness, with the FDA advisory committee saying that there was ‘little difference’ between the placebo group and the gefapixant group from a trial.

Another chronic cough therapy in the late stage of development is GSK’s camlipixant, a twice-daily oral P2X3 receptor antagonist. GSK added the drug to its portfolio as part of the $2bn acquisition of Canadian Bellus Health. Camlipixant is currently being evaluated in a Phase III trial, with GSK anticipating regulatory approval and launch of the drug in 2026.

Another drug in Algernon’s pipeline is depression treatment N,N-Dimethyltryptamine (DMT). The therapy is being evaluated in an investigator-initiated clinical trial by Yale University.