Apalutamide

Apalutamide, sold under the brand name Erleada, is a nonsteroidal antiandrogen (NSAA) medication which is used in the treatment of prostate cancer. It is specifically indicated for use in conjunction with castration in the treatment of non-metastatic castration-resistant prostate cancer (NM-CRPC). It is taken by mouth. Side effects of apalutamide when added to castration include fatigue, nausea, abdominal pain, diarrhea, high blood pressure, rash, falls, bone fractures, and an underactive thyroid. Rarely, it can cause seizures. The medication has a high potential for drug interactions. Apalutamide is an antiandrogen, and acts as an antagonist of the androgen receptor, the biological target of androgens like testosterone and dihydrotestosterone. In doing so, it prevents the effects of these hormones in the prostate gland and elsewhere in the body. Apalutamide was first described in 2007, and was approved for the treatment of prostate cancer in February 2018. It was the first medication to be approved specifically for the treatment of NM-CRPC. Apalutamide is used in conjunction with castration, either via bilateral orchiectomy or gonadotropin-releasing hormone analogue (GnRH analogue) therapy, as a method of androgen deprivation therapy in the treatment of NM-CRPC. It is also a promising potential treatment for metastatic castration-resistant prostate cancer (mCRPC), which the NSAA enzalutamide and the androgen synthesis inhibitor abiraterone acetate are used to treat. Apalutamide is provided in the form of 60 mg oral tablets. It is taken at a dosage of 240 mg once per day (four tablets) when used in the treatment of NM-CRPC. Contraindications of apalutamide include pregnancy and a history of or susceptibility to seizures. Apalutamide has been found to be well-tolerated in clinical trials, with the most common side effects reported when added to surgical or medical castration including fatigue, nausea, abdominal pain, and diarrhea. Other side effects have included rash, falls and bone fractures, and hypothyroidism, as well as seizures (in 0.2%), among others. Apalutamide is an expected teratogen and has a theoretical risk of birth defects in male infants if taken by women during pregnancy. It may impair male fertility. When used as a monotherapy (i.e., without surgical or medical castration) in men, NSAAs are known to produce additional, estrogenic side effects like breast tenderness, gynecomastia, and feminization in general by increasing estradiol levels. Similarly to the related second-generation NSAA enzalutamide but unlike first-generation NSAAs like flutamide and bicalutamide, elevated liver enzymes and hepatotoxicity have not been reported with apalutamide. There is no known antidote for overdose of apalutamide. General supportive measures should be undertaken until clinical toxicity, if any, diminishes or resolves.