The Food and Drug Administration has approved Erleada (apalutamide) as the first treatment for nonmetastatic, castration-resistant prostate cancer. Apalutamide blocks the effects on the tumor of androgens, such as testosterone, which promote tumor growth.
Apalutamide was studied in a randomized, placebo-controlled clinical trial of 1,207 men with nonmetastatic, castration-resistant prostate cancer. The study participants were treated with apalutamide or placebo, plus hormone therapy (gonadotropin-releasing hormone analog therapy) or surgery to lower the amount of testosterone in their bodies (surgical castration). Those receiving apalutamide were metastasis-free for longer than those receiving placebo (a median of 40.5 months versus a median of 16.2 months).
Apalutamide is metabolized by the cytochrome P-450 (CYP) 2C8 and CYP3A4 isoenzyme systems. The presence of other drugs also metabolized by these systems may alter the circulating levels of apalutamide.
The most common adverse effects of apalutamide, occurring in more than 10% of those taking the drug, include fatigue, hypertension, rash, diarrhea, nausea, weight loss, arthralgia, falls, hot flushes, decreased appetite, fracture, and peripheral edema. Seizures occurred in 0.2% of patients receiving apalutamide in a clinical trial. The drug can also cause fetal harm or loss of pregnancy.
Nurses should complete a drug history and confirm, using an electronic database, that patients are not receiving medications that will increase CYP2C8 or CYP3A4 enzyme activity, as these drugs may decrease apalutamide's effectiveness. Patients prescribed apalutamide should be taught to swallow the tablets whole, with or without food. Patients should also be advised of the possible adverse effects of therapy. Nurses should evaluate patients for fall and fracture risk because both can occur in patients receiving apalutamide. Nurses should consult with the prescriber regarding the use of bone-targeted agents that could be given to the patient according to established guidelines. If the patient develops a seizure while taking apalutamide, it is recommended the drug be discontinued. Patients taking apalutamide and their female partners of reproductive age should be advised to use effective contraception. If the patient's partner is pregnant, a condom should be used during apalutamide treatment. For complete prescribing information, see http://www.accessdata.fda.gov/drugsatfda_docs/label/2018/210951s000lbl.pdf.