Enzalutamide‐induced severe thrombocytopenia complicated by a seizure in a 76‐year‐old man with castration‐resistant prostate cancer

Abstract

Introduction Adverse events with enzalutamide widely used for men with castration‐resistant prostate cancer are of interest. Case presentation A 76‐year‐old man developed castration‐resistant prostate cancer. He received 160 mg of enzalutamide daily. On the 13th day after treatment, severe thrombocytopenia was observed (platelet count: 1.9 × 104/μL). Normal coagulation and fibrinolytic systems suggested thrombocytopenia induced by enzalutamide. Enzalutamide was withdrawn immediately, and platelet count uneventfully recovered to 7.0 × 104/μL and 28.8 × 104/μL 9 and 30 days after discontinuation, respectively. He restarted enzalutamide therapy without thrombocytopenia recurrence. However, 81 days after restarting enzalutamide, he experienced a seizure. There were no significant findings from brain computed tomography, which suggested that the seizure was also an enzalutamide‐associated adverse event. Conclusion Thrombocytopenia may occur early following enzalutamide therapy, and blood analysis within 2 weeks after treatment may facilitate its management. Enzalutamide‐induced thrombocytopenia, complicated by seizure, has not been reported.

A case of castration-resistant metastatic prostate cancer who continued treatment with enzalutamide after epileptic seizure

“…In a case presented by Murata et al 7 , seizure and severe thrombocytopenia developed during the ongoing enzalutamide treatment, after thrombocytopenia were mentioned. Enzalutamide administration was discontinued completely after the patients developed seizures since it was assumed that enzalutamide would continue to trigger the seizure.…”

Stevens-Johnson Syndrome Caused by Enzalutamide: A Case Report and Literature Review

“…The mechanism of enzalutamide-induced cutaneous adverse events is unknown, but it may be mediated by immunological mechanisms ( 16 ). One published case report of enzalutamide-induced thrombocytopenia observed a significant platelet count decline two weeks after starting enzalutamide, which recovered 30 days after enzalutamide withdrawal ( 18 ). Similarly, adverse reactions occurred about two weeks after the induction of enzalutamide therapy, suggesting that patients should be monitored with clinical symptom checks and blood tests within two weeks after starting enzalutamide therapy.…”

Profils d’effets indésirables sous abiratérone et enzalutamide : analyse descriptive des données de la base nationale de pharmacovigilance

“…Rapportées dans plusieurs essais cliniques et en post-AMM [12][13][14][15], leur incidence en vie en réelle chez des patients traités et présentant des facteurs de risque de convulsion semblait similaire à celle observée chez des patients présentant un cancer de prostate résistant à la castration mais non exposés à la molécule [16]. La survenue d'un épisode convulsif doit faire réévaluer l'utilisation ultérieure du médicament au cas par cas [8].…”