CAPItello-291
In HR-positive/HER2-negative advanced breast cancer progressing on aromatase-inhibitor therapy, does capivasertib plus fulvestrant improve PFS?
Trial design and population
708 patients with HR-positive/HER2-negative advanced breast cancer progressing during/after aromatase inhibitor therapy; 40.8% had PIK3CA, AKT1 or PTEN alterations.
Capivasertib 400 mg orally twice daily, 4 days on/3 days off, plus fulvestrant vs placebo plus fulvestrant.
708
PFS in overall population and AKT-pathway-altered subgroup
Key results
Median PFS in overall population was 7.2 vs 3.6 months (HR 0.60, 95% CI 0.51–0.71; P<.001). In AKT-pathway-altered tumours, median PFS was 7.3 vs 3.1 months (HR 0.50, 95% CI 0.38–0.65).
Source-reported outcome visualization
Median progression-free survival · Primary analysis
Source-reported endpoint and unit. Median survival is not converted into an NNT.
Absolute Effect
Median PFS difference 3.6 months is not an NNT. Effect was stronger in the prespecified AKT-pathway-altered subgroup.
NNT: Not calculated; median PFS difference is not a valid NNT. Do not convert median survival differences into NNT.
NNH: Not quantifiable. Grade ≥3 rash about 12%, diarrhoea 9% and hyperglycaemia 2% with capivasertib; these were uncommon with placebo. Rash, diarrhoea and glucose monitoring are central to delivery.
Safety and treatment burden
Grade ≥3 rash about 12%, diarrhoea 9% and hyperglycaemia 2% with capivasertib; these were uncommon with placebo. Rash, diarrhoea and glucose monitoring are central to delivery.
Follow-up, maturity and limitations
Primary analysis median follow-up approximately 16 months.
Molecular testing is required for biomarker-selected use. Overall and altered-subgroup results should not be conflated; prior CDK4/6 exposure and local approval affect application.
Clinical interpretation
Current-practice context · reviewed 20 October 2026
Historical evidence is separated from current sequencing. Confirm current guidelines, local regulatory status, biomarkers, prior therapies and patient-specific contraindications. Newer treatments may have changed the preferred sequence; where NNT/NNH cannot be defensibly quantified, no surrogate calculation is made.