Endocrine Pharmacology USMLE Step 1 Practice Question

A 72-year-old man with a 3-year history of metastatic prostate cancer presents to his oncology clinic for routine follow-up. His blood pressure is 128/76 mmHg, heart rate is 82/min, and respiratory rate is 16/min. Physical examination reveals no palpable gynecomastia or breast tenderness, and his testes are of normal size bilaterally. Urinalysis is within normal limits. His PSA is significantly elevated at 18 ng/mL, and repeat bone scan confirms osseous metastases. He reports no prior hormonal or androgen-deprivation therapy. His oncologist initiates a nonsteroidal antiandrogen agent that competitively blocks both testosterone and dihydrotestosterone at the androgen receptor level without suppressing central gonadotropin release. Which of the following drugs was most likely prescribed?