Phase II Neoadjuvant Study of Capivasertib Plus Fulvestrant Versus Fulvestrant Alone in Primary High-risk Lobular Breast Cancer

What this Trial Is About

Researchers are evaluating the effect of adding capivasertib to fulvestrant compared with fulvestrant alone as neoadjuvant treatment for women with primary high-risk lobular breast cancer that is hormone receptor positive and HER2 negative. This phase II, open-label, randomized study focuses on measuring the complete cell cycle arrest CCCA by assessing Ki67 levels at baseline, week 2, and week 10. The study aims to identify patients who may benefit from combined treatment and potentially avoid chemotherapy, considering the unique characteristics of invasive lobular breast cancer. Participants are randomly assigned to one of two treatment groups. One group receives capivasertib orally twice daily for 4 days followed by a 3-day break for 2 weeks, then continues this capivasertib schedule combined with fulvestrant injections every 28 days for an additional 8 weeks, totaling four doses of fulvestrant. The other group receives fulvestrant injections alone on the same schedule for 10 weeks. Treatment continues until surgery, disease progression, unacceptable side effects, or patient withdrawal. During the study, all patients will undergo core biopsies before and after treatment to measure Ki67 levels. Researchers will assess safety, pathological response, breast conservation rates, and survival outcomes. Patients will be monitored throughout treatment and follow-up, which may last up to two years to assess invasive disease-free survival and overall survival. Additional therapies such as surgery, chemotherapy, or radiotherapy will be given as needed outside the trial according to standard care.

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