The FDA is evaluating data from several clinical trials that suggests that Stalevo, a popular ParkinsonÃ¢â‚¬â„¢s drug, may cause increased heart risks when compared with competitor treatment Sinemet. Both drugs contain a combination of the medicines carbidopa and levodopa, but only Stalevo includes a third ingredient, entacapone. Though entacapone itself appears to have no effect on the symptoms of ParkinsonÃ¢â‚¬â„¢s, combining it with carbidopa/levodopa has been shown to be a more effective treatment than carbidopa/levodopa alone.
The agency is taking a closer look at the results of several studies comparing Stalevo and Sinemet. Concerns were raised when the results of one trial, known as STRIDE-PD, showed that roughly 2% of the Stalevo patients surveyed experienced adverse heart issues. In contrast, none of the Sinemet patients included in the survey experienced such problems.
The disparity in the STRIDE-PD results led the FDA to examine data from fourteen other similar studies that also compared Stalevo to Sinemet. Combined with the data from the STRIDE-PD trial, the results indicated that patients being treated with Stalevo were nearly two and a half times more likely to experience adverse heart issues than those taking Sinemet .
Several factors, however, undermine the definitiveness of these results, and the FDA has not recommended that patients taking Stalevo discontinue treatment. Most notably, the results of the STRIDE-PD trials disproportionately accounted for the heightened risk seen in the composite data set; when the STRIDE-PD results are removed, the data suggests that Stalevo is only 1.67 times as likely to result in heart complications Ã¢â‚¬â€œa statistically insignificant difference. Also, the trials being analyzed were not designed to assess heart risks, most of the patients involved had preexisting risk factors for heart disease, and no data was available on treatment discontinuation or trial discontinuation. Finally, eleven of the trials included in the study lasted fewer than six months, while seven out of eight of the instances of heart damage seen in Stalevo patients from the STRIDE-PD trial came after six months of treatment.