We hypothesized that triplet combination of immunotherapy with PARP and PI3K-AKT pathway inhibition is tolerable and may demonstrate activity in pts with relevant pathway defects. We investigated the safety and tolerability, pharmacodynamics (PD) and antitumor activity of Durv+Ola, with escalating doses of Cap. 1 pt with PIK3CA E545K mutant breast Ca had stable disease (SD) for 5 months, and 1 pt with PTEN loss and BRCA1 mutant breast Ca had SD of 6 months despite prior progression on PARP inhibitor. Triplet Cap+Ola+Durv is tolerable with evidence of PD and antitumor activity.