In the TITAN and SPARTAN studies, deep and rapid PSA responses with apalutamide were associated with prolonged time to deterioration in HRQoL, Functional Assessment of Cancer Therapy – Prostate (FACT-P) physical wellbeing, Brief Pain Inventory-Short Form (BPI-SF) worst pain intensity, and Brief Fatigue Inventory (BFI) worst fatigue intensity in patients with advanced prostate cancer [29]. This evidence concerns the gene KLK3 and prostate cancer.