SILVER SPRING, MD—An increased incidence of prostate cancer was observed in Parkinson’s disease (PD) patients treated with entacapone during a pre-approval randomized clinical trial, according to a new study which noted that the relationship had not yet been intensely investigated.

Entacapone is used with levodopa and carbidopa to prolong the effects in the brain.

In response, researchers from the U.S. Food and Drug Administration (FDA) sought to investigate whether entacapone is associated with prostate cancer and whether the drug is linked to advanced disease at the time of cancer diagnosis. Results were published in the journal Parkinsonism & Related Disorders.1

The FDA team used data from the VA’s healthcare system, focusing on Parkinson’s patients treated with add-on entacapone or add-on dopamine agonist/monoamine oxidase B inhibitors between January 2000 and December 2014. Veterans were followed on treatment for occurrence of prostate cancer, which was identified through linkage to the VA cancer registry.

Overall, 17,666 patients, mean age 74, met study criteria, with the entacapone-treated group including 5,257 subjects. Over mean follow-up time of 3.1 and 4.0 years in the entacapone and control cohort, respectively, 23 prostate cancer cases occurred in the entacapone cohort and 97 in the control cohort.

Results indicated that the overall incidence of prostate cancer was 1.8 per 1,000 person-years of risk. No difference in risk of prostate cancer was detected between the cohorts for increased duration of entacapone intake (adjusted HR: 1.08; 95% confidence interval: 0.46–2.51 for cumulative exposure of two or more years). Furthermore, researchers noted, Time since starting drug therapy and cumulative dose (mg) also did not point to a difference in prostate cancer risk between cohorts.

“Prolonged therapy with entacapone was not associated with increased prostate cancer incidence; however, findings suggest a higher severity of prostate cancer,” study authors concluded.

1. Major JM, Dong D, Cunningham F, By K, Hur K, Shih DC, Jiang R, Podskalny GD, Wei X, Pinheiro S, Bird ST, Keeton S, Graham DJ. Entacapone and prostate cancer in Parkinson’s disease patients: A large Veterans Affairs healthcare system study. Parkinsonism Relat Disord. 2018 May 5. pii: S1353-8020(18)30220-7. doi: 10.1016/j.parkreldis.2018.04.035. [Epub ahead of print] PubMed PMID: 29759929.