Phase II neoadjuvant study evaluating capivasertib plus fulvestrant vs fulvestrant in patients with primary high-risk lobular breast cancer- LOBSTER
Introduction
This is a multicenter, prospective, open-label, randomized phase II study to evaluate the Complete Cell Cycle Arrest (CCCA) assessed by Ki67 drop to 2.7% or lower from baseline to week 2 (window of opportunity) and to week 10 with capivasertib plus fulvestrant compared to fulvestrant alone as neoadjuvant treatment in 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)
The treatment will be given until surgery/core-biopsy, change in neoadjuvant treatment, disease progression, unacceptable toxicity, or withdrawal of patient consent.
All patients will undergo core-biopsy during treatment and in the absence of subsequent surgery after completing study therapy 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.
News
The study will be open for recruiting in July 2024. At the moment no new sites will be added. The trial will be conducted in Germany, there are no plans to include additional countries.
Design
The patients will be randomized 1:1 into one of two treatment groups. The schema below shows the treatment with Capivasertib as monotherapy for the first two weeks, followed by combination of Capivasertib with Fulvestrant or Fulvestrant alone.
Capivasertib is available in tablet form, which the patient can take at home. The initial dose will be 800mg daily (2x 200mg in the morning and 2x 200mg in the evening) for 4 days followed by 3 days pause.
Fulvestrant will be administered via syringes by the site staff at a dose of 500mg intramuscularly. The injections will be administered every 28 days, with exception of the first 2 weeks.
The patient will receive a total of 4 Fulvestrant injections in each arm.
Further information on the study
The LOBSTER trial is sponsored by German Breast Group (GBG). The IMP Supplier is AstraZeneca.
EUCT number: 2023-5092992-17-00
Contact
Christina Müller-Weisbrod
