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Rasagiline Effective in Lowering Adverse Events

Authors

Tim Casey

Prague—In a meta-analysis of clinical trials evaluating the safety profiles of monotherapeutic treatments, researchers found that patients with early Parkinson’s disease (PD) who were treated with rasagiline had a lower risk for adverse events (AEs) and lower dropout rates (DRs) than those treated with pramipexole or ropinirole. The results were presented at the ISPOR European Congress during a poster session titled Indirect Comparison of Adverse Events for Early Parkinson’s Disease (PD) Monotherapy Trials: Pramipexole, Ropinirole and Rasagiline. The authors mentioned that all 3 therapies produce AEs such as gastrointestinal (GI) or cognitive disorders, so they were interested in performing an indirect comparison of the drugs by choosing relevant studies selected via the Cochrane Guidelines. When selecting the studies, the authors had several criteria based on publication (peer-reviewed articles published in English until April 2010); design (randomized, blinded, placebo-controlled clinical trials); population (patients diagnosed with PD in early stages); treatments (1 mg of rasagiline, ≤4.5 mg of pramipexole, or ≤8 mg of ropinirole vs placebo); duration (≥10 weeks); blinding (single or double); principal outcomes (AEs and DRs); measurement (binary); and covariates/confounders (study length and age). The authors extracted relevant AEs and DRs from the studies. They categorized the AEs into cognitive (hallucination, confusion, amnesia, concentration impairment, depression, delusion, and illusion), GI (nausea and constipation), and sleep/fatigue (somnolence, insomnia, fatigue, and asthenia). They performed indirect comparison safety profiles using effect measures that calculate comparisons of relative risk (RR) against placebo as well as statistical pairwise comparison of differences. RR was defined as the ratio of the risk in the exposed group to the risk in the nonexposed group. In this study, the RR indicated the strength of association between AEs and DRs in the treatment and placebo groups. An RR of 1 indicated no difference between the groups, an RR >1 indicated the risk of developing AEs or DRs was higher in the treatment group, and an RR <1 indicated the risk of developing AEs or DRs was lower in the treatment group. Of the 208 studies identified, only 6 met the authors’ inclusion criteria. The main reasons for exclusion were non-PD studies and noncompliant designs such as nonrandomized designs, no placebo controls, open-label studies, or patients with advanced PD, sleep disorders, or concomitant levodopa treatment. The results showed that patients treated with ropinirole exhibited the highest risk for GI AEs, sleep/fatigue AEs, and DRs, while those treated with pramipexole had the highest risk for cognitive AEs. Patients treated with rasagiline had no more AEs and significantly lower DRs than the placebo group. Subjects who took rasagiline also had the lowest RRs with ≥90% confidence in all categories. In addition, the cognitive AEs in the ropinirole group were similar compared with the placebo group. The authors noted the results from the fixed and random effects statistical models were not significantly different. Study limitations included that the results were based on a small number of trials, indicating a low power to find statistical differences. There were also some methodologic and reporting differences among studies although they passed the inclusion/exclusion criteria. The authors also mentioned they could not adjust for baseline disease severity because some studies did not measure the baseline scores.

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