The US Food and Drug Administration (FDA) has granted orphan drug designation to Inhibikase Therapeutics’ imatinib for treatment of progressive multifocal leukoencephalopathy (PML).

PML is a rare side-effect of small molecule and antibody drugs given to patients with autoimmune diseases such as arthritis and multiple sclerosis (MS) and it occurs in 1%-3% of clinical acquired immune deficiency syndrome (AIDS) patients.

According to the company, certain drugs used to treat autoimmune disease suppress the ability of a patient to fight infection, particularly for John Cunningham (JC) virus.

JC lives inside most people, but when the immune system is suppressed, it can occasionally migrate into the brain, ‘blowing up’ certain brain cells. This results in a debilitating loss of cognitive and motor neuron function, often culminating in a patient’s death.

"To succeed, we’re talking re-engineering how imatinib is absorbed and distributed in the body."

MS Center of Atlanta director of clinical research neurologist Jeffrey English said multiple sclerosis (MS) can be a disabling disease.

"There are ways to screen for PML early, but we have no effective treatments for this disease," English said.

"If there was a way to treat PML, this would open up a pathway for many more patients to receive Tysabri, the most effective treatment for MS."

The company said that imatinib is a host-directed protein kinase inhibitor that disrupts the ability of JC virus to reproduce in the patient.

Imatinib is the active ingredient in Inhibikase’s lead product IkT-001Pro, as well as in the anti-cancer drug Gleevec, developed by Novartis.

Inhibikase president and CEO Milton Werner said the anti-JC virus activity of imatinib cannot be achieved by simply altering the frequency or amount of Gleevec given to patients.

"Early trial work has already shown this," Werner said. "To succeed, we’re talking re-engineering how imatinib is absorbed and distributed in the body.

"The granting of orphan drug designation is a pivotal milestone in the development of IkT-001Pro to treat this rare and debilitating illness.

"The designation will enable resources for continued development, but more importantly the designation provides an additional avenue for discussion with the FDA on the best path for bringing IkT-001Pro to market."