Triplet therapy in mHSPC: the survival gain is in high-volume disease

Design

Updated systematic review and frequentist random-effects network meta-analysis, CINeMA certainty

Population

23 randomised trials, 18,689 men with metastatic hormone-sensitive prostate cancer

Primary outcome

Progression-free and overall survival versus ARPI plus ADT

Effect

No significant OS benefit for any triplet in all-comers; docetaxel + ARPI + ADT in high-volume disease HR 0.76 (95% CI 0.61 to 0.95), high certainty

Twenty-three randomised trials and 18,689 men were combined to compare first-line combinations in metastatic hormone-sensitive prostate cancer, with certainty graded by CINeMA.

In all-comers, no triplet significantly improved overall survival over an androgen receptor pathway inhibitor plus androgen deprivation. Docetaxel added to that pair, and a PARP inhibitor added to it, both suggested progression-free survival gains that did not reach significance. The one result with high certainty is narrower: in high-volume disease, docetaxel plus ARPI plus ADT improved overall survival, hazard ratio 0.76.

Safety is the other half of the decision and the analysis could not settle it. Severe adverse events did not differ significantly with either addition, but the estimates were imprecise enough that a clinically meaningful increase in toxicity cannot be excluded. Certainty was downgraded for open-label designs and inconsistent prior docetaxel exposure across comparator arms — which is to say the evidence base for intensification is messier than the number of trials suggests.

• Reserve the docetaxel triplet for high-volume disease, where the survival evidence is graded high certainty.
• Do not offer triplet intensification to all-comers on the basis of progression-free survival.
• Assess fitness for docetaxel explicitly; toxicity estimates here are too imprecise to reassure with.
• PARP inhibitor combinations rest partly on phase 2 data with small samples — biomarker selection matters.
• Access and cost decide much of this in Indian practice; an ARPI plus ADT backbone remains the defensible default.

Why it matters

It narrows intensification from a general strategy to a decision about disease volume and fitness.

Don't overread it

The all-comer results are indirect comparisons from open-label trials with inconsistent prior docetaxel exposure.

The statistics, in plain English

A hazard ratio of 0.66 for progression-free survival with an interval of 0.43 to 1.01 is a clinically interesting estimate that crosses 1.0 by a whisker — by convention not significant, and the right response is to treat it as unresolved rather than to argue the interval. The high-volume overall survival result (0.76, 0.61 to 0.95) is the one estimate with high certainty, and even that is a subgroup: subgroup findings are where network meta-analyses are weakest, which makes the CINeMA grading the important part of the report.

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