Enzalutamide is a non-steroidal anti-androgen for metastatic prostate cancer. It has a consistent influence on several cytochromes’ activity; therefore, co-administration of ART (antiretroviral therapy) is strongly contraindicated considering the high risk of virological failure.

We are describing how we successfully used Therapeutic Drug Monitoring (TDM) to modify ART dosing in an HIV-infected patient affected by metastatic prostate cancer who needed long-term treatment with enzalutamide.