Dataset Information

Deep and ongoing response of castrate-resistant prostate cancer on very low-dose enzalutamide in an elderly chemotherapy-naive patient: a case report.

ABSTRACT:

Background

Enzalutamide is an orally administered drug that blocks signaling in the androgen receptor with clinical activity in both chemotherapy-naive and post-chemotherapy patients with castrate-resistant prostate cancer (CRPC). Enzalutamide is generally well-tolerated, but dose reductions are nonetheless needed in case of side effects.

Case

An 82-year-old patient with chemotherapy-naive metastatic castration-resistant prostate cancer was treated with a very low dose of 40 mg enzalutamide once daily. The trough levels of enzalutamide and the active metabolite N-desmethylenzalutamide were 4.5 mg/L and 3.0 mg/L, respectively. This exposure provided a long-term response without any significant side effects.

Conclusion

Low doses of enzalutamide may be efficacious, while also reducing the risk of side effects. Furthermore, employing a lower dose would reduce healthcare costs and increase access to enzalutamide. Studies exploring the efficacy of lower enzalutamide doses are warranted.

SUBMITTER: Boerrigter E

PROVIDER: S-EPMC8149336 | biostudies-literature | 2021 Jul

REPOSITORIES: biostudies-literature

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Publications

Deep and ongoing response of castrate-resistant prostate cancer on very low-dose enzalutamide in an elderly chemotherapy-naïve patient: a case report.

Boerrigter Emmy E Havenith Thomas T van Erp Nielka P NP Schnog John-John B JB

Cancer chemotherapy and pharmacology 20210404 1

<h4>Background</h4>Enzalutamide is an orally administered drug that blocks signaling in the androgen receptor with clinical activity in both chemotherapy-naive and post-chemotherapy patients with castrate-resistant prostate cancer (CRPC). Enzalutamide is generally well-tolerated, but dose reductions are nonetheless needed in case of side effects.<h4>Case</h4>An 82-year-old patient with chemotherapy-naive metastatic castration-resistant prostate cancer was treated with a very low dose of 40 mg en ...[more]

PMID: 33817752

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Project description:IntroductionEnzalutamide significantly improved clinical outcomes compared with placebo in patients with chemotherapy-naïve metastatic castration-resistant prostate cancer (mCRPC) with disease progression despite androgen deprivation therapy (ADT) in the PREVAIL study. However, few patients from Asia were enrolled. Our study (NCT02294461) aimed to evaluate the safety and efficacy of enzalutamide in this disease setting in patients in mainland China, Korea, Taiwan, and Hong Kong.MethodsIn this double-blind, phase III study, patients with asymptomatic/mildly symptomatic metastatic prostate cancer and disease progression despite ADT were randomized to enzalutamide (160 mg/day) or placebo. The primary endpoint was time to prostate-specific antigen (PSA) progression. Secondary endpoints included overall survival, radiographic progression-free survival, time to first skeletal-related event (SRE), time to initiation of cytotoxic chemotherapy, PSA response ≥ 50%, best overall soft-tissue response, and safety. Pre-planned interim analysis was scheduled following approximately 175 PSA-progression events (67% of targeted total of 261 events). An additional 5-year landmark analysis of overall survival, time to antineoplastic therapy, and safety was performed.ResultsThe double-blind study period was stopped after interim analysis owing to the benefit of enzalutamide over placebo. Overall, 388 patients were randomized (enzalutamide, n = 198; placebo, n = 190). Baseline characteristics were balanced between treatment groups. Enzalutamide significantly reduced risk of PSA progression vs placebo (hazard ratio 0.38; 95% CI 0.27-0.52; P < 0.0001). Median time to PSA progression was 8.31 months with enzalutamide and 2.86 months with placebo. Secondary endpoints, including 5-year overall survival, were significantly improved with enzalutamide, except time to first SRE. Adverse-event incidence was similar between enzalutamide and placebo. Fatigue was the most common drug-related adverse event in both treatment groups.ConclusionEnzalutamide significantly reduced risk of PSA progression, improved secondary efficacy endpoints, and was well tolerated in chemotherapy-naïve Asian patients with mCRPC with disease progression despite ADT.Trial registrationwww.Clinicaltrialsgov NCT02294461.

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