A two-part phase III trial (a safety run-in cohort, followed by a randomized placebo-controlled cohort) is ongoing (EPIK-B2; NCT04208178) to evaluate the efficacy and safety of alpelisib, a PI3K inhibitor, in combination with dual HER2 inhibition with trastuzumab and pertuzumab in patients with HER2+ (any HR status) advanced breast cancer in the “maintenance” setting (a similar trial design as in the PATINA clinical trial, cf. Above) following completion of taxane chemotherapy combined with dual HER2 antibody therapy129. The gene discussed is ERBB2; the disease is breast cancer.