Men aged 70 years or older benefit less from the addition of abiraterone acetate plus prednisone (AAP) to standard of care for de novo metastatic hormone-sensitive prostate cancer (mHSPC) compared with younger men, according to findings from a post-hoc analysis of the randomized PEACE-1 trial presented at the American Society of Clinical Oncology’s 2023 Genitourinary Cancers Symposium in San Francisco, California.
Results of the PEACE-1 trial, which were published in 2022 in The Lancet, found that the triplet therapy of AAP combined with standard of care (androgen deprivation therapy [ADT] with or without docetaxel) significantly improved radiographic progression-free survival (rPFS) and overall survival.
The post-hoc analysis, which included 741 men younger than 70 years and 431 aged 70 years or older, showed that the older patients had nonsignificant 35% and 5% decreased risks for radiographic progression and death, respectively, whereas the younger patients had significant 51% and 27% decreased risks for these outcomes, respectively, according to Loic Mourey, MD, of Institut Universitaire du Cancer-Oncopole in Toulouse, France, who presented study findings on behalf of his team.
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Among men fit to receive standard of care consisting of ADT plus docetaxel, the rPFS benefit of adding abiraterone was comparable in the younger and older groups, Dr Mourey reported. With respect to overall survival, however, addition of abiraterone was associated with a nonsignificant 20% decrease in death risk among the older men and a significant 29% decreased risk of death among the younger men.
The frequency of severe adverse events was higher among older men receiving abiraterone plus prednisone compared with younger men (69% vs 61%), the investigators reported. They observed no difference between the older and younger men who did not receive abiraterone plus prednisone.
The decreased benefit observed among the older men is likely due to more toxicity leading to more frequent and earlier drug discontinuation, Dr Mourey said. Importantly, among the older men fit enough to receive ADT plus docetaxel, the benefit of adding abiraterone to standard of care was comparable to that of the younger men.
For patients aged 70 years or older being considered for triplet therapy, the investigators recommended careful evaluation (such as G8 screening and assessment of comorbidities and polypharmacy) and “close follow-up to maintain benefit and preserve quality of life and autonomy.”
Disclosure: This research was partly supported by Janssen-Cilag, Ipsen, and Sanofi. Please see the original reference for a full list of disclosures.
References
Mourey L, Boyle H, Roubaud G, et al. Efficacy and safety of abiraterone acetate plus prednisone and androgen deprivation therapy +/- docetaxel in older patients (≥70 years), with de novo metastatic-castration sensitive prostate cancer, compared to younger patients (<70 years): The PEACE-1 trial. Presented at: ASCO GU 2023, San Francisco, California, February 16-18. Abstract 20.
Fizazi K, Foulon S, Carles J, et al. Abiraterone plus prednisone added to androgen deprivation therapy and docetaxel in de novo metastatic castration-sensitive prostate cancer (PEACE-1): a multicentre, open-label, randomised, phase 3 study with a 2 × 2 factorial design. Lancet. 2022;399(10336):1695-1707. doi:10.1016/S0140-6736(22)00367-1
