PIK3CA and breast cancer: Preliminary clinical activity was seen with capivasertib monotherapy in heavily pre-treated patients with AKT1-mutant solid cancers, including oestrogen receptor-positive breast cancer, but very low single-agent activity in patients with PIK3CA-mutant breast and gynaecological cancers.13, 14 In the phase 2 BEECH trial, capivasertib did not enhance the efficacy of paclitaxel in oestrogen receptor-positive advanced breast cancer, although endocrine therapy was not permitted in this study as is standard practice.15