Adding abiraterone to standard of care significantly improves outcomes in men with high-risk nonmetastatic prostate cancer and metastatic castration-sensitive prostate cancer, according to separate studies presented at the ESMO Congress 2021.
One study, led by Gerhard Attard, MD, PhD, John Black Charitable Foundation Endowed Chair in Urological Cancer Research at University College London, UK, examined the effect of abiraterone plus prednisolone, with or without enzalutamide, used in combination with androgen deprivation therapy (ADT) in 1974 patients with nonmetastatic high-risk prostate cancer who participated in the STAMPEDE trial. Investigators randomly assigned patients to receive ADT with or without abiraterone (914 patients) or ADT with or without abiraterone plus enzalutamide (1060 patients) for 2 years. Recipients of ADT alone made up the control arm. Metastasis-free survival (MFS) was the primary endpoint.
Compared with ADT alone, abiraterone-based therapy was significantly associated with a 47% decreased risk for metastasis and a 40% decreased risk for death. The effect of treatment on MFS was similar for ADT with abiraterone and ADT with abiraterone plus enzalutamide. These combinations were significantly associated with 46% and 47% decreased risks for metastasis, respectively, compared with ADT alone.
The 6-year MFS rate increased from 69% to 82% and the 6-year overall survival rate increased from 77% to 86% compared with ADT alone.
“Based on these results, all men with high-risk nonmetastatic prostate cancer should be considered for 2 years of abiraterone,” Dr Attard said in an ESMO press release. “This will involve more hospital visits during this period to manage administration of the drug but by reducing subsequent relapse, may reduce the overall burden for both patients and health services.”
In the other study, the phase 3 PEACE-1 trial, Karim Fizazi, MD, of Institute Gustave Roussy in Villejuif, France, and colleagues found that adding abiraterone plus prednisone to ADT plus docetaxel improves overall survival (OS) in men with metastatic castration-sensitive prostate cancer (mCSPC).
Investigators randomly assigned 1173 men with de novo mCSPC to receive standard of care (SOC), SOC plus abiraterone-prednisone, SOC plus radiation therapy, or SOC plus abiraterone-prednisone plus radiation therapy. For 710 patients, SOC was ADT plus docetaxel. The median follow-up duration was 4.4 years.
Men treated with abiraterone in addition to ADT plus docetaxel had a significant 25% decreased risk for death compared with those who received ADT plus docetaxel alone, the investigators reported.
Previous PEACE-1 results presented at ASCO 2021 in June showed that abiraterone added to SOC significantly improved radiographic progression-free survival compared with SOC alone (median 4.5 vs 2.2 years), with a significant 46% risk reduction in disease progression.
In the ESMO press release, Maria De Santis, MD, Chair of Interdisciplinary Urological Oncology, Department of Urology, Charité Universitätsmedizin, Berlin, Germany, commented: “The findings have the potential to be implemented in our daily practice right away as we do not have to wait for the approval of a new drug. The clearly positive results are reassuring and should convince patients and physicians to intensify the treatment of patients with metastatic and high-risk locally advanced hormone/castration-sensitive prostate cancer early on. I expect this kind of treatment intensification to be implemented as a standard of care.”
Disclosure: These studies were supported by Janssen, Astellas, Ipsen, Sanofi, and PHRC. Please see the original references for a full list of disclosures.
Attard G, Brown LC, Clarke N, et al. Abiraterone acetate plus prednisolone (AAP) with or without enzalutamide (ENZ) added to androgen deprivation therapy (ADT) compared to ADT alone for men with high-risk non-metastatic (M0) prostate cancer (PCa): Combined analysis from two comparisons in the STAMPEDE platform protocol. Presented at: ESMO Congress 2021, September 16-21, 2021. Abstract LBA4_PR.
Fizazi K, Galceran JC, Foulon S, et al. A phase III trial with a 2×2 factorial design in men with de novo metastatic castration-sensitive prostate cancer: Overall survival with abiraterone acetate plus prednisone in PEACE-1. Abstract LBA5-PR. Presented at: ESMO Congress 2021, September 16-21.
Fizazi K, Moldonado X, Foulon S, et al. A phase 3 trial with a 2×2 factorial design of abiraterone acetate plus prednisone and/or local radiotherapy in men with de novo metastatic castration-sensitive prostate cancer (mCSPC): First results of PEACE-1.Presented at ASCO 2021, June 4-8, 2021. Abstract 5000.
New combination of old drugs improves survival in patients with prostate cancer [press release]. ESMO; September 19, 2021.