Background
Androgen deprivation therapy (ADT) combined with apalutamide, abiraterone acetate plus prednisone, enzalutamide, or docetaxel are the standard treatments for advanced castration-sensitive prostate cancer (CSPC). We investigated ADT-free alternatives for advanced CSPC.
Patients and methods
LACOG 0415 is a phase 2, open-label, non-comparative, randomized trial. Patients with advanced CSPC were randomized (1:1:1) to receive goserelin plus abiraterone acetate and prednisone (ADT plus AAP arm), apalutamide (APA arm), or apalutamide plus abiraterone acetate and prednisone (APA plus AAP arm). The primary endpoint was the proportion of patients with PSA of ≤0.2 ng/mL at week 25 in the modified intention-to-treat population. Safety analyses were performed in all patients with at least one dose of the study drug.
Results
Of 128 randomized patients, 120 patients were evaluable for PSA response at week 25; 17.2% had a high-risk biochemical recurrence, 8.6% had locally advanced disease, and 74.2% had distant metastases. At week 25, PSA of ≤0.2 ng/mL was observed in 75.6% (95%CI 59.7%–87.6%), 60.0% (95%CI 43.3%–75.1%), and 79.5% (95%CI 63.5%–90.7%) of patients in ADT plus AAP, APA, and APA plus AAP arms, respectively. PSA decline of ≥80% was observed in 100%, 90.0%, and 97.4%, respectively. Grade 3–4 AEs were observed in 31.0%, 21.4% and 36.4%, respectively. Testosterone levels increased significantly in the APA arm and decreased significantly in ADT plus AAP and APA plus AAP arms.
Conclusions
ADT-free alternatives provide a high PSA response in advanced CSPC, although the APA arm did not reach the expected rate of PSA of ≤0.2 ng/mL at week 25. These results warrant further investigation of ADT-free treatments as alternatives in advanced CSPC.
Source study registration