In this trial, patients received levodopa 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).
An editorial discusses the limitations of the trial such as of the 223 patients in the delayed-start group, 39% needed symptomatic relief during phase 1 and proceeded to receive levodopa early; this limits the power of the comparison between the groups in assessing the effect of disease modification. However, a per-protocol analysis that included only patients who completed their originally assigned treatment also did not show evidence of slowing of progression of symptoms with early initiation of levodopa, but the editorial suggests the trial was probably insufficiently powered to allow firm conclusions. It concludes that this trial, therefore, supports current practice and that there is no evidence early initiation of levodopa slows progression of the disease; though on the other hand, there is no reason to delay therapy when it is clinically indicated.