What this Trial Is About

This is a multicenter, prospective, open-label, randomized phase II study to evaluate the CCCA assessed by Ki67 drop below \<2.7% from baseline to week 2 (window of opportunity) and to week 10 with capivasertib plus fulvestrant compared with fulvestrant alone as neoadjuvant treatment for primary high-risk lobular breast cancer patients. 120 patients will be randomized to receive: \- Capivasertib (400 mg po twice daily d1-4 followed by 3 days off) for 2 weeks followed by capivasertib (400 mg po twice daily d1-4 followed by 3 days off) and fulvestrant (500 mg i.m. q28d, with an additional 500 mg dose given two weeks after the initial dose) for additional 8 weeks (overall 4 administrations of fulvestrant) or \- Fulvestrant (500mg i.m. q28d, with an additional 500 mg dose given two weeks after the core biopsy and the initial dose) for 10 weeks (overall 4 administrations) Treatment will be given until surgery/core-biopsy, disease progression, unacceptable toxicity, or withdrawal of consent of the patient. All patients will undergo core-biopsies, under treatment and after completing study therapy in order to assess Ki67%. Further treatment including surgery, (neo)adjuvant chemotherapy, radiotherapy, and (neo)adjuvant endocrine therapy will be administered at the discretion of the investigator and according to standard of care outside the clinical trial.

Capivasertib Plus Fulvestrant vs. Fulvestrant in Primary High-risk Lobular Breast Cancer