Actio Biosciences raised $66 million in a series B on Wednesday to progress its two lead candidates, ABS-1230 and ABS-0871, into clinical proof-of-concept studies for separate rare diseases: KCNT1-related epilepsy and Charcot-Marie-Tooth disease type 2C (CMT2C), respectively. The financing, co-led by the venture arm of Regeneron Pharmaceuticals and Deerfield Management, will support Phase I studies of the two programmes. Existing investors Canaan, Droia Ventures and Euclidean Capital also participated in the round. "We have made tremendous progress since our launch and series A, advancing two lead programmes," Actio CEO David Goldstein told FirstWord. He described ABS-1230 and ABS-0871 — which inhibit KCNT1 and TRPV4, respectively — as "expected first-in-class oral small molecules with strong preclinical evidence." The company has already begun enrolling healthy volunteers in a Phase I safety study of ABS-0871; it plans to begin recruiting patients with TRPV4-positive CMT2C for the Phase Ib portion next year. In patients with the disease, mutations in the TRPV4 gene can disrupt the blood-neural barrier and lead to increased activity in the corresponding TRPV4 ion channel, which regulates the concentration of calcium inside cells, a vital role to keep cellular processes running smoothly. "We believe ABS-0871 will potentially be able to counter the TRPV4 channel overactivity in all patients with CMT2C," Goldstein said. The candidate, he added, "represents a precision therapy that we hope will directly counter the cause of disease and therefore alleviate symptoms and arrest disease progression."For ABS-1230, a healthy volunteer Phase I study is expected to start next half, with the Phase Ib portion in epilepsy patients scheduled to launch in early 2026. KCNT1-related epilepsy is an often fatal pediatric epileptic encephalopathy that has no approved disease modifying therapies. The genetic disease is characterised by overactivation of the KCNT1 potassium ion channel, which regulates the flow of electricity to the brain, leading to abnormal electrical brain activity and a high frequency of daily seizures. "By inhibiting the overactive ion channel with ABS-1230, we believe we can address the underlying genetic cause of disease and reduce seizure frequency," Goldstein said. He added that in mouse models of KCNT1-related epilepsy, the candidate rapidly reduced seizure frequency.