HealthDay News — For patients with metastatic castration-resistant prostate cancer (mCRPC) with at least 1 risk factor for seizure at baseline, treatment with enzalutamide is not associated with increased incidence of seizure, according to research published online December 7 in JAMA Oncology.

Susan Slovin, MD, PhD, from Memorial Sloan Kettering Cancer Center in New York City, and colleagues examined the incidence of seizure among patients receiving enzalutamide for mCRPC. A total of 366 patients receiving treatment with oral enzalutamide (160mg/day) were evaluated. 

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The researchers found that medication that lowered seizure threshold, history of brain injury, and history of cerebrovascular accident or transient ischemic attack were risk factors for seizure at baseline (57.2, 26.5, and 22.2%, respectively). Within 4 months of enzalutamide initiation, four patients (1.1%) had at least one confirmed seizure; three additional patients (0.8%) experienced a seizure within four months following the 4-month study period. The incidence of confirmed seizure was 2.6 per 100 patient-years. Overall, 84.4% of patients receiving enzalutamide experienced at least 1 treatment-emergent adverse event.

“Incidence of seizure is similar in patients with mCRPC and similar seizure risk factors with or without enzalutamide exposure,” the authors write. “The risk profile presented, along with the previously established efficacy of enzalutamide, suggests that enzalutamide can benefit patients with a history of seizures or other predisposing factors, but each patient should be closely monitored for the duration of treatment.”

Several authors disclosed financial ties to pharmaceutical companies, including Astellas Pharma and Medivation, co-developers of enzalutamide.

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