Although three new drugs for Parkinson’s disease have been approved over the last year, plans generally are sticking with the drugs they’ve included on formularies for several years, most of which are generic, experts tell AIS Health.

That may change in the long term as new gene therapies that currently are in development are approved and come online. But none of those potential new treatments are close to market right now, says Mesfin Tegenu, R.Ph., president of PerformRx.

“Many commonly used therapies for Parkinson’s disease — carbidopa-levodopa, MAO-Bs, dopamine agonists — have available generics, which on most plans would be considered formulary options, or one generic product within each class would be selected as formulary,” Tegenu tells AIS Health.

The FDA in August approved Kyowa Kirin, Inc.’s Nourianz (istradefylline) tablets as an add-on treatment to levodopa/carbidopa in adult patients with Parkinson’s disease experiencing motor fluctuations. In February, the FDA approved Osmotica Pharmaceutical US LLC’s Osmolex ER (amantadine) for the treatment of Parkinson’s disease. And in late December, the FDA approved Accorda Therapeutics’ Inbrija (levodopa inhalation powder) for intermittent treatment of off episodes in people with Parkinson’s disease taking carbidopa/levodopa.

Still, plans are stocking their formularies with less expensive generic medications. Parkinson’s disease treatment generally progresses through drugs that have a moderate effect but fewer side effects to drugs that are more effective, but have more significant side effects, Tegenu says.

“Choice of which pharmacotherapy to use initially is individualized based on the characteristics of the patient, the disease and the drugs,” he says. “There is no single preferred therapy, and trade-offs are common.”

Plans aren’t expected to cover Inbrija, Tegenu says. “Members would be able to request an exception through the prior authorization process for these products,” he adds. For Osmolex ER, plans generally require failure on trials of immediate-release amantadine.