You are here

Sandra M. Swain, MD, FACP, FASCO

Professor of Medicine
Associate Dean of Research Development
Vice-President of Genetic Medicine
Georgetown University Medical Center
Washington, D.C.

Current Research

Goal: To understand the underlying mechanism in variable response to ribociclib in patients of African descent (African American) compared to women of European descent (Caucasian). 

Impact: Ribociclib, in combination with other medications, is FDA-approved for the treatment of select patients with advanced hormone receptor (HR)-positive breast cancer. Evidence suggests a benefit for the general population, however individual patients may have unique characteristics that result in different responses. Due to historical under-representation in clinical trials, determination of these unique characteristics in African American women is hampered. Dr. Swain is conducting studies to address this disparity by examining the mechanisms behind the variable responses to ribociclib in African American compared to Caucasian women. 

What’s next: Dr. Swain and her colleagues will conduct a study that analyzes the genetics and blood of African Americans and Caucasians who are taking ribociclib to treat their breast cancer. 

Treatments for hormone receptor-positive advanced breast cancer include ribociclib in combination with fulvestrant, an anti-estrogen drug. Variable responses have been demonstrated due to the differences in the way ribocicllib is metabolized. Dr. Swain is investigating how genetic and ethnic differences in patients affect the pharmacokinetics of ribociclib. She and her colleagues will analyze the genetics and blood of African Americans and Caucasians who are taking ribociclib to gain a better understanding of the differences in responses. She hopes these studies will provide a foundation for future clinical treatment strategies. 

Full Research Summary

Research area: To determine the differences in the metabolism and toxicity of ribociclib in African American and Caucasian patients with hormone receptor-positive breast cancer and their effect on treatment response. 

Impact: Ribociclib is FDA approved as a treatment, in combination with hormonal therapy, for patients with advanced hormone receptor (HR)-positive breast cancer. Despite demonstration of improved responses compared to placebo, additional challenges remain, such as inter-individual variation in response. One reason for this variation is thought to be due to the differences in how patients metabolize ribociclib. Ribociclib is predominantly metabolized by the CYP3A enzyme, genetic variants of which differ greatly between racial and ethnic groups. The effect of race on the safety of ribociclib is unknown since only 3 percent of the clinical trial population that led to the drug’s FDA approval was African American. Dr. Swain is investigating how the genetic variation in the CYP3A gene between African American and Caucasian patients contributes to the variability in response and patient outcome.

Current investigation: Dr. Swain and her team will collect blood samples from African American and Caucasian patients with advanced HR-positive breast cancer during treatment with ribociclib. They will examine the variation in genes that regulate the drug’s metabolism and transport genes between patient populations. These studies will help guide the treatment of HR-positive breast cancer patients particularly African American patients. Since ribociclib is the therapeutic option used in hormone receptor-positive metastatic breast cancer, the findings from this study will provide urgent information that could directly impact patient outcomes.


Dr. Sandra M. Swain is an internationally-recognized breast cancer medical oncologist, and clinical translational researcher. She has authored nearly 300 articles in numerous peer-reviewed medical journals, such as the New England Journal of Medicine, Lancet Oncology, and the Journal of Clinical Oncology, on topics including inflammatory breast cancer, adjuvant treatment of breast cancer, the treatments of metastatic HER2-positive breast cancer, cardiotoxicity, and health care disparities.

Throughout her career, Swain has held many advisory and leadership positions with professional oncology societies and organizations across the globe. From 2012 through 2013, she served as President of the American Society of Clinical Oncology where she championed efforts to promote the advancement of women in medicine and that she continues today through her service on the board of Conquer Cancer, the ASCO foundation, and the Women Who Conquer Cancer initiative she established. Currently, she is a professor at the Georgetown University School of Medicine, the Associate Dean for Research Development at Georgetown University Medical Center, and the Vice President of MedStar Genetic Medicine–roles in which she works to improve patients’ access to cutting-edge treatments and technologies by expanding medical research opportunities across the MedStar Health system. She is also co-chair of the Early Breast Cancer Trialists’ Collaborative Group in Oxford and a visiting professor of clinical oncology at the University of Oxford, UK.

BCRF Investigator Since


Donor Recognition

The Ann Taylor and LOFT Award

Area(s) of Focus