FDA Evaluating Stalevo Clinical Trial Data
FDA is evaluating clinical trial data that may suggest that patients taking Stalevo, a Parkinson's disease medication, may be at an increased risk for developing prostate cancer. In this trial, patients taking Stalevo were compared to those taking carbidopa and levodopa (sold as Sinemet), a combination medication also used to treat Parkinson's disease.
At this time, FDA's review of Stalevo is ongoing and no new conclusions or recommendations about the use of this drug have been made.
Stalevo contains a combination of the active ingredients entacapone, carbidopa, and levodopa. Entacapone is also available as a single-ingredient product sold under the brand name Comtan. Both Stalevo and Comtan are used to treat symptoms of Parkinson's disease.
The data being reviewed are from a long-term clinical trial called Stalevo Reduction in Dyskinesia Evaluation - Parkinson's Disease (STRIDE-PD). STRIDE-PD evaluated the time to onset of dyskinesia (difficulty controlling voluntary movement) in patients with Parkinson's disease taking Stalevo compared to those taking only carbidopa/levodopa. An unexpected finding in the trial was that a greater number of patients taking Stalevo were observed to have prostate cancer compared to those taking carbidopa/levodopa.
The agency is exploring additional ways to better understand if Stalevo actually increases the risk of prostate cancer. Previous controlled clinical trials of shorter duration evaluating Stalevo in Parkinson's disease have not found an increased risk of prostate cancer, and prostate cancer is most commonly diagnosed in men who are of the same age as men included in the STRIDE-PD trial.
According to FDA, health care professionals should be aware of this possible risk and follow current guidelines for prostate cancer screening. Patients should not stop taking their medication unless directed to do so by their health care professional.
The STRIDE-PD trial was a double blind, randomized, parallel group, controlled clinical trial conducted at 77 centers in 14 countries, including 31 sites in the United States, between September 2004 and November 2008. The purpose of the trial was to evaluate the time to onset of dyskinesia (difficulty controlling voluntary movement) in patients with Parkinson's disease taking Stalevo compared to those taking only carbidopa/levodopa. A total of 745 patients with Parkinson's disease were enrolled in the trial and 541 completed treatment. Of the patients who completed treatment, 265 patients received Stalevo and 276 received carbidopa/levodopa. Treatment lasted between 2.6 years and 4 years (mean duration: 2.7 years). The average age of patients in the trial was approximately 60 years. The majority of subjects were Caucasian (95.2 percent) and male (62.7 percent).
A total of 467 men received randomized treatment in the trial. Among those who received treatment, there was a higher number of cases of prostate cancer in patients in the Stalevo group compared those in the carbidopa/levodopa group. Specifically, nine out of 245 males (3.7 percent, 95 percent Confidence Interval: 1.69 percent - 6.86 percent) had prostate cancer in the Stalevo group compared to the two out of 222 males (0.9 percent) in the carbidopa/levodopa group. The incidence rate of prostate cancer was 14 cases/1,000 patient years for Stalevo and 3.2 cases/1,000 patient years for carbidopa/levodopa. The odds ratio for the occurrence of prostate cancer in males taking Stalevo was 4.19 (95 percent Confidence Interval: 0.90– 19.63). Duration of therapy prior to diagnosis of prostate cancer in the Stalevo-treated group ranged from 148 days to 949 days (mean: 664 days).
STRIDE-PD is the first long-term clinical trial evaluating Stalevo in Parkinson's disease. Previous clinical trials with Stalevo did not find an increased risk for prostate cancer. Most of these trials evaluating this drug were conducted for less than a year, whereas STRIDE-PD was conducted over a 4 year period, with a mean duration of exposure of 2.7 years.