What happened
Shares of Stoke Therapeutics (STOK 6.16%) were down more than 34% as of 1:45 p.m. ET on Tuesday. The clinical-stage biotech company released positive early trial news regarding its lead therapy, but the stock hit a new 52-week low at $6.12 a share. Stoke's shares are down 31% this year.
So what
Stoke focuses on upregulating protein expression with RNA-based therapies to treat severe diseases, especially those of the central nervous system and the eye. The company's lead pipeline candidate, STK-001, is being tested in phase 1/2 trials as a treatment for Dravet syndrome, a progressive genetic epilepsy disorder. STK-001 works by restoring protein levels in patients who have the haploinsufficiency that causes the syndrome.
The drop was due to two factors. The first was the typical selling on positive news. However, not all the news was positive, which is why the stock really dropped. There were no significant safety issues raised by STK-001, though there were some adverse events in the trials that included vomiting, irritability, and elevated CSF protein levels. Of the 74 patients in the trial, 20% had some type of treatment-emergent serious adverse event, but not so serious they discontinued their trial participation.
The biggest problem from the results was, at the 45-milligram dose given in three monthly injections, it had an average reduction of only 18% in convulsive seizures, compared to the baseline. The drug did fare better in a 70-milligram dose, showing a median reduction of 53% compared to the baseline.
Now what
The results weren't so negative that the company will halt trials. It's likely that the big stock price drop will reverse somewhat in the next few days. The company also has another prospective therapy, STK-002, to treat autosomal dominant optic atrophy, the most common optic nerve disorder.
As of the first quarter, the company said it had $254.2 million in cash, enough, it said, to fund operations through the end of 2025.
