CDK4/6 Inhibitor Plus Letrozole for High-Risk Luminal B Breast Cancer
Posted: Wednesday, February 5, 2020
Using neoadjuvant treatment with the CDK4/6 inhibitor ribociclib and the aromatase inhibitor letrozole in the treatment of patients with high-risk luminal B breast cancer achieved similar response rates as multiagent chemotherapy. Moreover, the novel combination therapy did so with less toxicity than chemotherapy. These findings from the SOLTI-1402/CORALLEEN trial were presented by Joaquin Gavilá, MD, of the Instituto Valenciano de Oncologia, Valencia, Spain, at the 2019 San Antonio Breast Cancer Symposium (Abstract GS2-06) and simultaneously published in The Lancet Oncology.
“We believe that this combination is worth exploring as an alternative to chemotherapy for patients with high-risk luminal B breast cancer,” said Dr Gavilá.
The study included 106 patients who were randomly assigned 1:1 to receive either six 28-day cycles of ribociclib plus daily letrozole or multiagent chemotherapy. Surgical samples from 95% of these patients were analyzed.
At the time of surgery, 48% of the ribociclib-plus-letrozole group had a low risk of recurrence versus 47.1% of the chemotherapy group. Intrinsic subtype conversion to luminal A disease at surgery occurred in 88% of patients in the ribociclib-and-letrozole group versus 84.3% in the chemotherapy group.
In those who received ribociclib plus letrozole, the rate of minimal residual cancer burden (of 0 or 1) was 8%, and a Preoperative Endocrine Prognostic Index (PEPI) of 0 was 24%. In the chemotherapy group, the rate of minimal residual cancer burden (0 or 1) was 11.8%, and PEPI of 0 was 17.6%. Grade 3 or 4 toxicities were observed in 54.9% of the patients in the ribociclib-and-letrozole group versus 69.2% in the chemotherapy group.
“Future studies in high-risk early breast cancer evaluating the survival outcomes and quality of life of this combination in the absence of cytotoxic therapy are justified,” stated Dr. Gavilá. However, Dr. Gavilá cautioned that the results are preliminary and need to be confirmed in future clinical trials.
Disclosure: For full disclosures of the study authors, visit abstractsonline.com.