A serious adverse event has led Icagen to stop enrolling patients into a clinical trial evaluating up to 600 mg doses of its lead ion-channel drug candidate, ICA-105665, in participants with photosensitive epilepsy. The firm said the adverse event occurred in the 600 mg patient cohort after completion of the 500 mg dosing cohort. It plans to discuss the situation with both clinical advisors and FDA.
Icagen had previously completed a multiple ascending dose study with ICA-105665 in healthy volunteers who received daily doses of 500 mg and 600 mg for a period of seven days. This trial resulted in no serious adverse events, although a final review of laboratory data is pending, Icagen points out.
The decision to increase the dose of ICA-105665 in another trial with photosensitive epilepsy patients followed on from positive results in a study evaluating a 400 mg dose of ICA-105665 in equivalent patient cohorts. Back in April Icagen reported that FDA had agreed to a second study of up to two additional cohorts of photosensitive epilepsy patients receiving higher doses of ICA-105665, and a second study of higher doses of ICA-105665 in a multiple ascending dose trial of healthy volunteers. The objective of both of the studies was to evaluate higher doses of ICA-105665 in order to optimize dose selection for subsequent larger clinical trials.
Icagen is focused on discovery, development, and commercialization of orally administered small molecule drugs that modulate ion-channel targets. ICA-105665 is designed to selectively open certain subtypes of KCNQ potassium channels that the firm says have been validated as playing important roles in certain conditions characterized by abnormal neuroexcitability, such as seizures, and potentially also chronic pain disorders.
In July Icagen received a $3 million milestone payment from Pfizer on the initiation of a Phase I study of a number of compounds developed through the partners' sodium-channel program for pain and related disorders.