The FDA has applied its fast-track designation to GW Pharmaceuticals’ Epidiolex, a cannabinoid treatment for a rare form of epilepsy.

The drug, derived from cannabis, is designed to suppress seizures in patients with Dravet syndrome, a treatment-resistant type of childhood epilepsy. The disease can have catastrophic effects on patients, GW said, beginning in the first year of life and leading to repeated, prolonged seizures. Dravet affects about 5,440 patients in the U.S. and 6,710 in Europe, according to the company.

Now, on FDA’s fast track, Epidiolex will get expanded access to regulators to speed its way toward a final agency decision. GW has already filed an investigational new drug application for the treatment, and the company said it’s on schedule to kick off a Phase II/III study in the second half of this year.

The biotech’s shares jumped about 7% on the news Friday morning.

Beyond Dravet syndrome, GW is developing Epidiolex for the rare Lennox-Gastaut syndrome, another severe, drug-resistant form of childhood epilepsy, and the company received an FDA orphan drug designation for that indication in February.

The U.K.’s GW has crafted a pipeline based around its proprietary cannabinoid development platform, anchored by the Bayer-partnered Sativex, which is approved in Europe to treat muscle spasms in multiple sclerosis patients. In the U.S., GW is working with Otsuka Pharmaceuticals to get the spray-delivered treatment FDA-approved to treat cancer pain.

GW’s wholly owned candidates include cannabis-derived therapies for Type 2 diabetes, glioma and ulcerative colitis.

Read more: GW hits the FDA fast track with its cannabis-based epilepsy drug – FierceBiotech