Novel Triple-Negative Breast Cancer Immunotherapy Trial Under Way at UH Seidman Cancer Center

Preliminary results may be available in December 2019

Innovations in Cancer - Winter 2019

Women with metastatic triple-negative breast cancer have few good treatment options. However, there may be new hope for these patients, thanks to a novel clinical trial under way at University Hospitals Seidman Cancer Center. 

Joseph Baar, MD, PhD, Director of Clinical Breast Cancer Research at UH Seidman Cancer Center and Associate Professor of Medicine, Case Western Reserve University School of Medicine, is leading an investigator-initiated trial evaluating combining immunotherapy with chemotherapy. Jame Abraham, MD, is also enrolling patients in the trial at Cleveland Clinic.

 Joseph Baar, MD

“Up until now, women with triple-negative breast cancer have only had one treatment option, which is chemotherapy,” Dr. Baar says. “However, more recently, we’ve seen that the immune modulator pembrolizumab (Keytruda) improves outcomes in patients with metastatic triple-negative breast cancer. As a result, it is now critical to explore how the addition of pembrolizumab to chemotherapy might improve survival in patients with this type of breast cancer.”

“When the first data came out just using pembrolizumab by itself, there was already evidence that women with metastatic triple-negative breast cancer who had received many prior treatments were responding just to the antibody itself,” Dr. Baar adds. “With the addition of the chemotherapy, we’re hoping at the very least that there will be an additive effect, if not a synergistic effect.”

As triple-negative breast cancer progresses, tumor cells express a protein ligand called PD-L1, which interacts with the PD-1 receptor on T-cells. The PD-L1 to PD-1 interaction prevents the T-cell from responding to the tumor as a threat. Pembrolizumab binds to the T-cell’s PD-1 receptors and therefore blocks the PD-1 to PD-L1 interaction, allowing the T-cells to be activated against the tumor cells. Dr. Baar hypothesizes that the addition of such an immunotherapeutic agent to chemotherapy will allow the body’s natural immune response to reduce disease recurrence to a greater extent than either modality alone.

Dr. Baar and the medical oncology team at UH Seidman Cancer Center are enrolling 30 patients with metastatic triple-negative breast cancer in the Merck-funded trial. 

“We’ve enrolled 23 patients, so we’re in the home stretch,” he says. “We’ve had really good enrollment on this trial because there’s nothing else out there. We should have the enrollment portion completed by this summer.”

The chemotherapy drugs being evaluated in this trial are carboplatin and nab-paclitaxel, in addition to the immunotherapeutic agent pembrolizumab. The primary outcome measure is the overall response rate – a composite of complete response, partial response, progressive disease and stable disease. Secondary outcome measures include progression-free survival, disease control rate and duration of response. 

Patients eligible for the trial must have radiologically measurable and documented metastatic triple negative breast cancer, be functional day to day as measured by an ECOG performance status of between zero and one, must not have received more than two prior therapies for this disease, and must be willing to undergo a preliminary biopsy for research purposes.

Dr. Baar says he hopes to report preliminary results at the San Antonio Breast Cancer Symposium in December 2019.

For more information about this clinical trial, please email Joseph.Baar@UHhospitals.org.