Single Dose of Trastuzumab Kick Starts Immune Response in Certain Breast Cancers

“A tumor’s immune response to a single dose of the HER2 inhibitor trastuzumab predicted which patients with HER2-positive breast cancer would respond to the drug on a more long-term basis, according to the results of a study published recently in Clinical Cancer Research.

“In addition, Vinay Varadan, PhD, assistant professor at Case Western Reserve University School of Medicine and member of the Case Comprehensive Cancer Center, and his colleagues found that women with the HER2-enriched subtype of HER2-positive breast cancer—a subtype that is estrogen and progesterone receptor negative—had the highest rate of immune response to treatment with trastuzumab, with significant increases in immune response after a single dose of the drug.

“ ‘Our study showed, for the first time, that the immune-cell–activating properties of trastuzumab are likely related to the subtypes of breast cancer,’ Varadan said. ‘Knowing this can inform future trials studying the usefulness of adding immunotherapy drugs to trastuzumab.’ “


To Predict Responses to Checkpoint Blockade, an Understanding of Immune Responses Is Needed

“Spreading the success of cancer immunotherapy beyond those patients currently enjoying powerful, long-term responses to treatment requires greater understanding of the immune response to tumors, two leaders in the field note in a review in the April 3 Science.

” ‘Identifying in advance who will benefit from treatment and developing combination therapies to improve and expand on current results will require us to decipher the dynamics of human immune response to tumors and their surrounding microenvironment,’ said co-author Padmanee Sharma, M.D., Ph.D., professor of Genitourinary Medical Oncology and Immunology at The University of Texas MD Anderson Cancer Center.

“Immune checkpoint blockade, the unleashing of immune response against cancer by blocking molecules on T cells that shut down those attacking cells, produces durable results and long-term survival in a substantial fraction of patients with some cancers. For example, 22 percent of advanced melanoma patients treated with ipilimumab (Yervoy®), the first checkpoint inhibitor, live for four years or longer. Right now there’s no way to identify those most likely to benefit.