Long-Term Trial Data Show Triplet Therapy Extends Survival in Metastatic Prostate Cancer

Men whose prostate cancer has already spread by the time it is diagnosed may gain a lasting survival advantage when abiraterone is added to their initial treatment, according to long-term results from the academically led phase 3 PEACE-1 trial presented at the ESMO Congress 2026 in Lugano and Madrid. After almost eight years of follow-up, the addition of abiraterone to standard therapy reduced the risk of death by 25 percent compared with standard treatment alone, a benefit that investigators say grows stronger the longer patients are followed.

The findings address one of the most common and challenging scenarios in prostate cancer: de novo metastatic castration-sensitive prostate cancer, or mCSPC, in which the disease has already reached distant sites in the body at the moment of first diagnosis. For these men, treatment has long been anchored in androgen deprivation therapy, or ADT, which lowers testosterone to starve the tumour of the hormonal signals that drive its growth. In recent years, two strategies have been shown to improve survival on top of ADT: adding docetaxel chemotherapy, or adding a second-generation hormonal therapy such as abiraterone. A direct comparison of those two doublet approaches found no significant difference in overall survival between them, leaving clinicians to weigh toxicity, patient fitness and preferences when choosing between them.

PEACE-1 set out to test whether combining both intensification strategies would deliver more than either alone. The trial enrolled 1,173 men with de novo metastatic castration-sensitive prostate cancer. All received standard of care, meaning ADT with or without docetaxel chemotherapy, and were then randomly assigned to one of four additional options: no further treatment, abiraterone plus prednisone, radiotherapy to the prostate, or both abiraterone plus prednisone and radiotherapy. Overall, 57 percent of participants had high-volume disease, indicating more extensive cancer spread throughout the body. An earlier analysis of the trial had already shown that adding abiraterone to standard of care improved overall survival; the new report extends that finding deep into the follow-up period.

With a median follow-up of 7.7 years, the survival gap between the groups had widened rather than narrowed. Adding abiraterone reduced the risk of death by 25 percent, with a hazard ratio of 0.75 and a 95 percent confidence interval of 0.65 to 0.87, reaching a p-value of 0.0001. In practical terms, median overall survival was 6.1 years for men who received abiraterone compared with 4.6 years for those who did not, a difference of a year and a half in the median. With a median follow-up of 7.7 years, that sustained separation of survival curves is what gives the result its weight.

The most striking numbers emerged in the subgroup of 710 men who received ADT plus docetaxel as their doublet backbone. When abiraterone plus prednisone was added to that combination, creating a triplet regimen, the risk of death fell by 32 percent, with a hazard ratio of 0.68 and a 95 percent confidence interval of 0.56 to 0.82. Median survival rose from 4.4 years with doublet therapy to 6.2 years with triplet therapy. At the eight-year mark, 40.3 percent of men on triplet therapy were still alive, compared with 27.1 percent of those on doublet therapy alone. In other words, nearly one in eight additional men was still living eight years after diagnosis simply because a third drug had been included from the start.

The benefit was not confined to one disease extent. Survival outcomes favoured triplet therapy in both low- and high-volume metastatic disease, and a formal statistical test found no significant difference in the size of the benefit between the two groups, with an interaction test p-value of 0.56. Among men with high-volume disease, median survival was 4.6 years with triplet therapy versus 3.5 years with doublet therapy, a hazard ratio of 0.68 with a 95 percent confidence interval of 0.54 to 0.85, and almost twice as many men were alive at eight years, 38 percent versus 20 percent.

Lead author Dr Karim Fizazi of Centre Oscar Lambret in Lille, France, framed the magnitude of the effect in blunt terms. “There is a major survival benefit, with almost two years of additional life for patients receiving the three treatments, which is of course highly significant,” he said. “In our opinion, this makes this triplet treatment a strong standard of care for these patients.” He also pointed to the unusual length of the follow-up as a strength in itself. “Most clinical trials, especially when led by pharma companies, tend to stop their follow-up early,” Fizazi added. “This long-term analysis demonstrated that the survival benefit becomes greater with time: for instance, in men with multiple metastases at diagnosis, there are almost twice as many long-term survivors with triplet therapy.”

The trial also offered a clue about the best timing of intensified treatment. Among men in the control groups whose cancer eventually progressed, 86 percent went on to receive an androgen receptor pathway inhibitor, the same class of drug as abiraterone. The investigators suggest this pattern supports starting such treatment early rather than holding it in reserve until the disease advances, since many patients ultimately receive the drug anyway but only after their cancer has had time to progress. On safety, no new long-term concerns were identified over the extended follow-up.

Independent commentators welcomed the data while cautioning that important questions remain. “For patients and clinicians, these data mean that modern, intensified systemic treatment, particularly triplet therapy with ADT, docetaxel and abiraterone, can translate into a substantially improved chance of long-term disease control and survival, with toxicity that is generally manageable,” said Dr Ursula Vogl of the Oncology Institute of Southern Switzerland in Bellinzona, who was not involved in the study. She noted, however, that PEACE-1 did not directly compare triplet therapy with ADT plus a newer hormone therapy without chemotherapy, which is another established treatment option for these patients. The decision to add docetaxel therefore depends on individual factors, including other health conditions, age and patient preferences, and it remains unclear which patients gain the greatest additional benefit from chemotherapy, underscoring the need for personalised treatment selection.

Taken together, the results support triplet therapy with ADT, docetaxel and abiraterone as a strong standard of care for the men studied, although PEACE-1 did not directly compare triplet therapy with ADT plus a newer hormone therapy without chemotherapy, leaving room for clinical judgement in cases where chemotherapy may not be appropriate.

Subject of Research: Long-term survival outcomes of adding abiraterone to androgen deprivation therapy and docetaxel in the PEACE-1 phase 3 trial for metastatic prostate cancer

Article Title: Adding abiraterone to ADT and docetaxel improves survival in metastatic prostate cancer

Article References: Adding abiraterone to ADT and docetaxel improves survival in metastatic prostate cancer. Original publication (Bibliographic details unavailable.)

Image Credits: AI Generated

DOI: Not provided

Keywords: prostate cancer, PEACE-1 trial, abiraterone, docetaxel, androgen deprivation therapy, triplet therapy, metastatic cancer, overall survival, ESMO Congress 2026, clinical trial, castration-sensitive prostate cancer, treatment intensification