Levodopa Inhalation Powder: A Review in Parkinson's Disease

Levodopa inhalation powder (Inbrija^®) is approved for the intermittent treatment of OFF episodes in patients with Parkinson's disease (PD) treated with levodopa/dopa-decarboxylase inhibitor (LD-DCI) in the EU and specifically with carbidopa/levodopa in the USA. The approved dosage is 84 mg taken as needed up to five times a day. Administered via a breath-actuated inhaler, this formulation enables levodopa to bypass the gastrointestinal (GI) tract and, instead, rapidly enter the bloodstream through the pulmonary system. In the 12-week, double-blind, placebo-controlled, phase III SPAN-PD trial, as-needed levodopa inhalation powder 84 mg improved motor symptoms during OFF periods in PD patients (aged 30-86 years) treated with levodopa and carbidopa or benserazide. The likelihood of achieving an ON state 60 min postdose was significantly higher in the levodopa inhalation powder than the placebo group, with most patients in the levodopa inhalation powder group experiencing improvements in PD symptoms. Findings from longer-term, 52-week phase III studies were consistent with those from the SPAN-PD trial with regards to the treatment of OFF episodes. Levodopa inhalation powder was generally well tolerated and did not noticeably affect pulmonary function in PD patients. Providing a nonintrusive, convenient treatment method, levodopa inhalation powder is a promising option for the intermittent treatment of OFF episodes in patients with PD treated with a LD-DCI.