Investors are stocking up on Stoke Therapeutics, sending the biotech’s shares jumping over 90% in premarket trading on the back of positive phase 1/2a data for a seizure disorder medicine.
The data come from a study of the antisense oligonucleotide STK-001 in children and adolescents aged between 2 and 18 years with Dravet syndrome who were already taking the “best available anti-seizure medicines,” Stoke reported Monday afternoon.
The eight patients who received a single 70-mg dose of STK-001 reported a median 43% reduction in the frequency of their convulsive seizures from baseline after three months, rising to 57% after six months for seven evaluable patients.
A total of 11 patients received two or three 70-mg doses. The 10 patients evaluated at three months reported a 85% reduction in seizures, dropping to 74% in the nine patients evaluated at six months.
“STK-001 is the first medicine in development to demonstrate substantial and durable reductions in seizure frequency and improvements in multiple measures of cognition and behavior,” CEO Edward Kaye, M.D., said in a March 25 release. “These effects were observed in patients who were already taking the best available anti-seizure medicines, which confirms our highly differentiated mechanism of action and approach to treating this disease.”
“We look forward to meeting with regulatory agencies to discuss our plans for a randomized, controlled registrational study and to providing an update coming out of those discussions later in 2024,” Kaye added.
Stoke said yesterday that the FDA has granted clearance for patients to receive three 70-mg doses of STK-001 before switching to 45 mg. Thanks to the data, the company can now meet with the agency to plan a registrational study with the 70-mg and then 45-mg dosing.
Dosing was a key question for analysts on an afternoon investor call yesterday. Stoke previously amended the protocol after a patient experienced suspected unexpected serious adverse reactions related to the treatment.
The meteoric rise in share price is a nice reversal for Stoke, which in July 2023 saw shares drop 30% on news that 32% (24) of the 74 patients taking STK-001 experienced an adverse event tied to the investigational treatment.
In the latest data release, Stoke said there were no new safety findings related to the therapy and doses up to 70 mg were generally well tolerated. Across the phase 1/2a studies conducted to date, Stoke has seen 30% treatment-emergent adverse events, with cerebrospinal fluid protein elevations and procedural vomiting the most commonly reported, as well as 22% treatment-emergent serious adverse events. Just one patient had a treatment-emergent serious adverse event that was considered related to the study drug.
In two open-label extension studies, 74% of patients had cerebrospinal fluid elevations but there have been no clinical manifestations. Just one patient discontinued due to the elevations, which can be indicative of an issue in the central nervous system.