Titles and Affiliations

Associate Chief, Division of Breast Oncology, Susan F. Smith Center for Women's Cancers
Clinical Research Director, Breast Oncology Center
Senior Physician
Associate Professor of Medicine, Harvard Medical School
Dana-Farber Cancer Institute
Boston, Massachusetts

Research area

A clinical trial testing new immunotherapy combinations for HER2-positive breast cancer.


HER2-positive breast cancer can be highly aggressive when it progresses to an advanced stage. Drugs that specifically target HER2, such as trastuzumab, have improved outcomes, but metastatic HER2-positive breast cancer is still incurable and resistance to trastuzumab and other HER2-directed agents remains a critical problem. Researchers are exploring potential combinations of trastuzumab with other therapies and immunotherapies are a compelling option. Trastuzumab acts by causing an anti-tumor immune response against HER2-bearing tumor cells, but tumors are highly effective at blunting immune activity. Immunotherapies are designed to reactivate the immune system in tumors, and Dr. Krop and colleagues designed a clinical trial testing the benefit of immunotherapy in combination with trastuzumab and a chemotherapy, in advanced HER2-positive breast cancer.

Progress Thus Far

The AVIATOR trial is underway to explore if the addition of a PD-L1-targeting immunotherapy drug called avelumab (Bavencio®) can improve response to trastuzumab. The trial is comparing standard therapy (trastuzumab plus chemotherapy) with avelumab versus standard therapy alone. A total of 100 patients will be enrolled. 

What’s next

The study is open at 17 clinical sites and has recruited 87 patients to date. It will continue two of the study arms, testing therapy against standard therapy with avelumab. In addition, patient samples were collected throughout the study which will provide important biological information on how the drugs performed, which can help guide future trial design.


Ian Elliott Krop, MD, PhD, is the Associate Chief, Division of Breast Oncology. He is also an Associate Professor of Medicine at Harvard Medical School.

Dr. Krop is a translational investigator focused on the development of novel molecularly targeted therapies and immunotherapies for breast cancer, and elucidating the mechanisms of resistance to these treatments. The majority of his effort is concentrated in the area of HER2+ breast cancer. He was a leader in the development of the antibody-drug conjugate trastuzumab emtansine (T-DM1).

Dr. Krop currently serves as Chief Scientific Officer for the Translational Breast Cancer Research Consortium. He is a member of the National Cancer Institute’s Breast Cancer Steering Committee and co-chairs its Immuno-Oncology Working Group. He is also the co-vice chair for correlative science for the Alliance for Clinical Trials in Oncology. He is a member of the Eastern Cooperative Oncology Group Data Monitoring Committee.

Dr. Krop is a graduate of Johns Hopkins University and Johns Hopkins University School of Medicine. He trained at Johns Hopkins Hospital, Dana-Farber Cancer Institute, Harvard Medical School, and Brigham and Women’s Hospital. He completed a medical oncology fellowship at Dana-Farber.