image: Santiago Escrivá, Medical Oncologist at the Vall d’Hebron University Hospital (HUVH) and Clinical Investigator of VHIO’s Breast Cancer Group.
Credit: VHIO
- Results from an international Phase IIa study point to the promise of adding bispecific HER2-targeted antibody zanidatamab to the combination of CDK4/6 inhibitor palbociclib plus hormone therapy with fulvestrant in heavily pretreated patients with HER2+/HR+ metastatic breast cancer.
- The targeting of all 3 pathways has achieved encouraging results which show promising progression-free survival at 6 months and median progression-free survival with durable responses. These primary data further support the development of a novel chemotherapy-free treatment regimen for this patient population.
- Selected as late breaking data, results of this study were presented by first author Santiago Escrivá, Medical Oncologist at the Vall d’Hebron University Hospital (HUVH) and Clinical Investigator of VHIO’s Breast Cancer Group, at the San Antonio Breast Cancer Symposium (SABCS), 05-09 December.
Led by VHIO investigators, this Phase IIa international and multicenter study was designed to evaluate the efficacy of adding the bispecific HER2-targeted antibody zanidatamab to the combination of CDK4/6 inhibitor palbociclib plus hormone therapy fulvestrant for the treatment of heavily pretreated patients with HER2+/HR+ metastatic breast cancer (mBC).
Reported at SABCS 2023, primary results show that 67% of patients treated with this triplet combination were progression-free at 6 months, with a median progression-free survival of 12 months, and durable responses of a median of 15 months.
“In the majority of cases, HER2+ metastatic breast cancer remains incurable. Identifying and developing novel HER2-directed therapies including less toxic chemotherapy-free strategies will ultimately improve outcomes for an increasing number of our patients,” said Santiago Escrivá, Clinical Investigator of VHIO’s Breast Cancer Group directed by Cristina Saura, and lead author of this study.
Zanidatamab is a bispecific HER2-targeted antibody that binds HER2 in a unique trans configuration, driving multiple mechanisms of antitumor activity. Approximately 50% of HER2+ metastatic breast cancers are also hormone receptor-positive (HR+), making the estrogen pathway an additional cancer drug target. The CDK4/6 inhibitor palbociclib plus hormone therapy with fulvestrant is approved for HER2+/HR+ mBC.
By targeting these three pathways at the same time, zanidatamab in combination with palbociclib plus fulvestrant showed promising progression-free survival results with a median of 12 months with durable responses and a manageable safety profile in this patient population.
“These primary results support the continued development of this new chemotherapy-free regimen for heavily pretreated patients with HER2+ HR+ metastatic breast cancer,” concluded Escrivá.
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About the San Antonio Breast Cancer Symposium®
Since 1977, the San Antonio Breast Cancer Symposium® (SABCS®) has been the leading scientific conference for basic scientists, physician-scientists, clinical investigators and breast care providers, and advocates seeking an exchange of new information in experimental biology, etiology, prevention, diagnosis, and therapy of premalignant breast disease and breast cancer. Founded, owned, and operated by UT Health San Antonio, the symposium has grown to a five-day event attended by an international audience of academic investigators and private physicians from over 80 countries to attain information through abstract presentations, panel discussions, research findings, and state-of-the-art educational sessions. UT Health San Antonio, with co-sponsor the American Association for Cancer Research, supports SABCS, which provides education and accessibility to the latest information regarding the prevention, diagnosis, and treatment of premalignant breast cancer and breast disease. For more information on SABCS, visit: www.sabcs.org.