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Conference Coverage

Adverse Events in Patients With Prostate Cancer Receiving Apalutamide or Enzalutamide

February 16, 2021

Results from a study presented at the virtual 2021 ASCO Genitourinary Cancers Symposium highlight the importance of considering safety and tolerability of second-generation androgen receptor inhibitors during treatment decision-making for prostate cancer.

Apalutamide and enzalutamide are second generation androgen receptor inhibitors approved for the treatment of non-metastatic castration-resistant prostate cancer in the United States.

This study aimed to describe the frequency and management of adverse events (AEs) and the resulting health care resource utilization among patients with prostate cancer treated with these drugs.

A total of 43 US sites were included in the retrospective chart review study. In which, 43 physicians identified 699 patients initiating treatment with apalutamide (n = 368), enzalutamide (n = 333), or both (n = 2) between February 1, 2018 and December 21, 2018. AEEs were collected and reported in regular clinical practice.

A representative subset of patients, experiencing at least 1 AE for either apalutamide (n = 125) or enzalutamide (n = 125), were selected randomly from the initial cohort to describe the management of AEs.

In the initial 699 patients identified, 368 (72%) men receiving apalutamide and 333 (78.7%) men receiving enzalutamide experienced ≥1 AE. The most common AEs were fatigue/asthenia (apalutamide, 30.2%; enzalutamide, 38.7%), hot flush (14.1% and 13.5%, respectively), and arthralgia (14.4% and 12.9%, respectively). Cognitive and mental changes were observed in 5.4% receiving apalutamide and 7.8% receiving enzalutamide.

In the subset analysis, actions to address AEs included treatment of the AE (apalutamide, 36.8%; enzalutamide, 39.2%) treatment discontinuation (8% and 12.8%, respectively), dose reduction (7.2% and 8%, respectively), and hospitalization (5.6% and 4%, respectively). AEs were not resolved in 43.6% receiving apalutamide and 39.4% receiving enzalutamide. The median duration of days to resolved AEs were 60 and 56, respectively.

“This real-world study highlights the clinical and resource use burden of AEs among nmCRPC patients treated with apalutamide and enzalutamide,” concluded study authors.

“The results demonstrate the importance of safety and tolerability as key considerations in shared clinician-patient decision-making regarding second-generation androgen receptor inhibitor therapy in non-metastatic castration-resistant prostate cancer,” they added.Janelle Bradley


Jiang S, Varghese D, Appukkuttan S. Frequency, management, and resource use of adverse events (AEs) in nonmetastatic castrate-resistant prostate cancer (nmCRPC) patients receiving apalutamide or enzalutamide: A real-world study. Presented at: the virtual 2021 ASCO Genitourinary Cancers Symposium; February 11-13, 2021. Abstract 217.

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