Inbrija (CVT-301) is an investigational, inhaled levodopa (L-dopa) therapy being developed by Acorda Therapeutics to treat symptoms of “off” periods in people with Parkinson’s disease who are using carbidopa/levodopa.

Parkinson’s patients are unable to produce a healthy quantity of dopamine in their brains, which impairs communication between brain cells and is the underlying cause of Parkinson’s symptoms.

Patients often experience “off” periods, which are debilitating periods of decreased motor and non-motor functions when the medication wears off between doses and symptoms of the disease re-emerge.

How Inbrija works

The time it takes for an oral medication to act varies between patients, as the drug must be absorbed through the digestive tract before reaching the brain.

Inbrija, as an inhaled drug, was designed to deliver a precise dose of a dry powder formulation of levodopa to the lungs, bypassing the digestive system while en route to the brain and decreasing the time it takes to act.

Levodopa treatment has been shown to be effective in the treatment of Parkinson’s because once it reaches the brain, enzymes are able to convert it into dopamine, increasing the amount of dopamine in brain cells.

Inbrija in clinical trials

Acorda is currently recruiting up to 350 participants to join a 12-month Phase 3 clinical trial (NCT02242487) to assess the effect of two inhaled doses of Inbrija (low or high) for the treatment of “off” episodes (up to five per day) in Parkinson’s patients. All participants receive active treatment, but patients are blinded to dose level.

The company completed another Phase 3 study called the SPAN-PD trial (NCT02240030) testing the efficacy and safety of inhaled Inbrija. The results of this trial showed that, compared to placebo, the drug significantly improved movement in Parkinson’s patients during “off” periods. Inbrija was also able to return patients back to the “on” state and maintain it for at least an hour.

SPAN-PD was a 12-week, randomized, placebo-controlled, double-blind study in 339 Parkinson’s patients experiencing “off” periods. Patients received either 84 mg or 60 mg of Inbrija or placebo throughout the day during “off” episodes.

At week 12, patients who took 84 mg of Inbrija showed significant movement improvements compared to those taking placebo.

In an earlier Phase 2 study (NCT01777555), Inbrija was also shown to be safe and well-tolerated by 86 trial participants, as well as effective in improving motor function and reducing “off” times. Patients enrolled in this study used Inbrija an average of 2.1 times per day and the treatment effect was noticeable after 10 minutes of the drug’s administration.

Other information

Acorda announced the filing of a New Drug Application (NDA), seeking  U.S. Food and Drug Administration (FDA) approval of Inbrija as a Parkinson’s treatment in late June. The company is planning to submit a similar request, called a Marketing Authorization Application (MAA), to the European Medicines Agency (EMA) by the end of the year.

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