Adding abiraterone to the current standard of care (SOC) prolonged radiographic progression-free survival (rPFS) compared with SOC alone in patients with metastatic castration-sensitive prostate cancer (mCSPC), according to results of the phase 3 PEACE-1 trial presented at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting.
In fact, the rPFS results demonstrated a 2.5-year difference in favor of abiraterone plus SOC, said Karim Fizazi, MD, PhD, of Institut Gustave Roussy in Villejuif, France, when presenting the study at the meeting.
The phase 3 trial (ClinicalTrials.gov Identifier: NCT01957436) included 1173 patients with de novo mCSPC who were randomly assigned to the following treatment arms:
- SOC, which was androgen deprivation therapy (ADT) alone or ADT plus docetaxel
- SOC plus abiraterone (given with prednisone)
- SOC plus radiotherapy
- SOC plus radiotherapy and abiraterone (with prednisone).
The trial was amended as the SOC evolved over time. The SOC was initially ADT alone (Nov. 2013-2015), then ADT with docetaxel permitted (2015-2017), followed by ADT with mandatory docetaxel (2017-Dec. 2018).
Data from the abiraterone arms were pooled because there was no interaction between abiraterone and radiotherapy. The median follow-up was 36 months.
Abiraterone plus SOC significantly prolonged rPFS over SOC alone. The median rPFS was 4.5 years and 2.2 years, respectively (hazard ratio [HR], 0.54; 95% CI, 0.46-0.64; P <.0001).
In patients who received ADT plus docetaxel as the SOC, the addition of abiraterone prolonged rPFS. The median rPFS was 4.5 years with abiraterone and 2.0 years without it (HR, 0.50; 95% CI, 0.40-0.62; P <.0001).
Abiraterone also improved castration-resistant prostate cancer (CRPC)–free survival. In the overall population, the median CRPC–free survival was 3.8 years with abiraterone plus SOC and 1.5 years with SOC alone (HR, 0.40; 95% CI, 0.35-0.47; P <.0001).
In patients who received ADT plus docetaxel as the SOC, the median CRPC–free survival was 3.2 years with abiraterone plus SOC and 1.4 years with SOC alone (HR, 0.38; 95% CI, 0.31-0.47; P <.0001).
“Abiraterone resulted in a very clear and significant improvement of CRPC-free survival, with a 60% reduction in the risk of developing castration resistance or death in both the overall population and the ADT plus docetaxel population,” Dr Fizazi said.
The overall survival data are not yet mature.
Grade 3-5 liver toxicity and hypertension were more common in the abiraterone-SOC arm, but the frequencies of febrile neutropenia and neutropenia were similar to the SOC-alone arm.
“Adding abiraterone and prednisone to ADT plus docetaxel clearly improves radiographic PFS in men with de novo metastatic prostate cancer,” Dr Fizazi said in closing.
He added that, although the overall survival data are maturing, “regardless of survival results, these data question whether we should deny patients approximately 2.5 years without radiographic progression or death, or whether combining ADT plus docetaxel and abiraterone-prednisone should simply become the new standard of care for men with de novo metastatic prostate cancer.”
Disclosures: This research was supported by UNICANCER, Janssen-Cilag Ltd., Ipsen, Sanofi, and the European Organisation for Research and Treatment of Cancer. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Fizazi K, Maldonado 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. J Clin Oncol. 2021;39:(suppl 15; abstr 5000). doi:10.1200/JCO.2021.39.15_suppl.5000
This article originally appeared on Cancer Therapy Advisor