ASCO GU 2026: Comparison of Docetaxel Triplet Therapy with ARPI Doublet in US Veterans with mHSPC.

(UroToday.com) The 2026 American Society of Clinical Oncology Genitourinary (ASCO GU) cancers symposium held in San Francisco, CA, between February 26^th and 28^th, 2026, was host to the Poster Session A: Prostate Cancer. Dr. Abigail Chu presented Poster 185: Comparison of docetaxel triplet therapy with ARPI doublet in US veterans with metastatic hormone-sensitive prostate cancer (mHSPC).

As Dr. Chu highlighted, combination intensification has improved survival in randomized trials such as ARASENS and PEACE-1.^1,2 However, there are no head-to-head studies directly comparing docetaxel-based triplet therapy with ARPI doublet therapy. This retrospective analysis aimed to address that gap using contemporary real-world data.

The study included US veterans diagnosed with mHSPC who initiated an ARPI within four months of diagnosis after July 1, 2021. Docetaxel triplet therapy was defined as docetaxel administered within 90 days of ARPI initiation. Patients were stratified by disease presentation, synchronous versus metachronous, and by disease volume using CHAARTED criteria. Propensity score matching was performed based on age, the highest PSA within six months, and disease volume.

After matching, 608 veterans were included, with no significant baseline differences between groups. The mean age was approximately 69 years in both cohorts. High-volume disease was present in roughly 70 percent of patients, and the majority had synchronous presentation. Median PSA was 107 ng/mL in the triplet group and 84.9 ng/mL in the doublet group. After matching, 608 veterans were included, with no significant baseline differences between groups. The mean age was approximately 69 years in both cohorts. High-volume disease was present in roughly 70 percent of patients, and the majority had synchronous presentation. Median PSA was 107 ng/mL in the triplet group and 84.9 ng/mL in the doublet group.
With a median follow-up of 24.1 months, median overall survival had not yet been reached in either group. Dr. Chu reported that triplet therapy was associated with a significantly lower risk of death compared with doublet therapy (HR 0.60, 95% CI 0.43 to 0.82).

The survival benefit was most pronounced in patients with synchronous disease (HR 0.51, 95% CI 0.35 to 0.74). In contrast, no significant difference was observed in metachronous disease (HR 1.00, 95% CI 0.49 to 2.03)

Again, the survival benefit was most pronounced in patients with high-volume disease (HR 0.55, 95% CI 0.38 to 0.79), and no survival benefit was observed in low-volume cases (HR 0.77, 95% CI 0.38 to 1.54).
An exploratory analysis among triplet-treated patients showed that darolutamide-based therapy was associated with improved overall survival compared with abiraterone-based triplet therapy (HR 0.52, 95% CI 0.30 to 0.91).

Summarizing the implications of this analysis, Dr. Chu emphasized:

In this real-world veteran cohort, docetaxel triplet therapy was associated with lower mortality compared with ARPI doublet therapy.
The benefit appeared greatest in patients with de novo and high-volume mHSPC.
No clear advantage was observed in metachronous or low-volume disease.
Darolutamide-based triplet therapy may be associated with improved survival compared with abiraterone-based triplet therapy, though this finding is exploratory.
Prospective studies are needed to validate these findings and better define optimal patient selection.

Presented by: Abigail Chu, BS, Saint Louis University School of Medicine, St. Louis, MO

Written by: Julian Chavarriaga, MD – Urologic Oncologist, Department of Urology at Penn State Health. @chavarriagaj on Twitter during the 2026 American Society of Clinical Oncology Genitourinary (ASCO GU) cancers symposium held in San Francisco, CA, between February 26^th and 28^th, 2026.

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