Study Comparing Intravenous and Subcutaneous Infudopa With Intestinal Duodopa in Patients With Parkinson's Disease

In patients with Parkinson's disease, the characteristic motor symptoms, i.e., slowness of movement (bradykinesia), tremor and rigidity, are consequences of the progressive degeneration of neurons containing and releasing dopamine. The first-line treatment of Parkinson´s is oral administration of levodopa - a precursor to dopamine that (unlike dopamine) passes the blood brain barrier. After the first few years of treatment with levodopa, many patients do however develop a highly variable response to the drug characterised by rapid shifts between impaired locomotion and drug induced dyskinesias (referred to as the on-off syndrome). This is cased by the marked variation in serum levodopa levels following per oral administration, and it is known that intravenous administration of levodopa give a more stable level of levodopa with improved on-off symptoms. Levodopa-carbidopa intestinal gel (LCIG) - under the name of Duodopa® - is delivered directly to the proximal jejunum via a tube connected to a portable infusion pump. Infusion of Duodopa in the jejunum bypasses gastric emptying, helping to avoid the fluctuation in plasma levodopa levels. However, while clearly confirming that an even administration of levodopa is of considerable benefit to Parkinson patients with on-off symptomatology, the LCIG approach is marred by the need for surgery (for the insertion of the intestinal tube) and various possible complications following this, as well as by side effects such as abdominal pain. Researchers have now succeeded in producing a physiologically acceptable levodopa solution (called Infudopa) in a concentration allowing for a continuous intravenous (i.v.) or subcutaneous (s.c.) administration of therapeutic doses to humans. Early experience of this strategy confirms that both s.c. and i.v. administration of this solution results in even serum levodopa levels and markedly improved motor functioning. The aim of this study is to compare the pharmacokinetic profile of Infudop