Constant V.M. Verschuur, M.D., from Amsterdam Neuroscience, and colleagues randomly assigned patients with early Parkinson disease to receive either levodopa (three times per day) in combination with carbidopa for 80 weeks (early-start group) or placebo for 40 weeks followed by levodopa in combination with carbidopa for 40 weeks (delayed-start group; 222 and 223 patients, respectively).

(HealthDay)—For patients with early Parkinson disease, treatment with levodopa combined with carbidopa has no disease-modifying effect, according to a study published in the Jan. 24 issue of the New England Journal of Medicine.

The researchers found that the change in the Unified Parkinson’s Disease Rating Scale (UPDRS) score was −1.0 ± 13.1 and −2.0 ± 13.0 points in the early-start and delayed-start groups, respectively, from baseline to week 80 (difference, 1.0 point; 95 percent confidence interval, −1.5 to 3.5; P = 0.44). Between weeks 4 and 40, the rate of symptom progression as measured in UPDRS points per week was 0.04 ± 0.23 and 0.06 ± 0.34 in the early-start and delayed-start groups, respectively (difference, −0.02; 95 percent confidence interval, −0.07 to 0.03). Between weeks 44 and 80, the corresponding rates were 0.10 ± 0.25 and 0.03 ± 0.28 (difference, 0.07; two-sided 90 percent confidence interval, 0.03 to 0.10); the difference did not meet the criterion for noninferiority of early versus delayed receipt of levodopa.

“Whether higher doses of the drug, longer periods of administration, or initiation of the drug at later stages of the disease could alter the course of Parkinson disease warrants evaluation in future trials,” the authors write.

Several authors disclosed financial ties to pharmaceutical companies, including Merck.