Intratumoral Immune Therapy for Recurrent Breast Cancer

By: Sarah Campen, PharmD
Posted: Monday, January 31, 2022

Intratumoral immune therapy with the monoclonal antibody tremelimumab and the immunostimulant poly ICLC, in combination with systemic durvalumab, appears to be safe and may have clinical utility in women with recurrent breast cancer, according to data presented at the 2021 Society for Immunotherapy of Cancer (SITC) Annual Meeting (Abstract 337) and published in the Journal for ImmunoTherapy of Cancer. “Clinical response was associated with longer survival and increased CD8 T-cell proliferation,” explained Craig Slingluff, MD, of the University of Virginia, Charlottesville, and colleagues. “The therapy enhances intratumoral immune effectors and markers of T-cell function in hypothesis-generating data that warrant confirmatory studies.”

In this basket trial, 19 patients with treatment-refractory recurrent breast cancer—with a median 4 prior lines of therapy—received poly ICLC intratumorally at 1 mg for 6 doses, then intramuscularly for 3 doses, combined with intravenous durvalumab at 1,500 mg every 4 weeks. Most patients were assigned to cohorts also receiving tremelimumab at 10 mg intratumorally or 75 mg intravenously.

Objective clinical responses were observed in 5 patients (26%), including 2 of 9 patients with triple-negative breast cancer and 3 of 10 patients with non–triple-negative breast cancer. Of those who responded, two remain alive at 34 and 40 months. In injected tumors, there was a significant increase from days 0 to 29 in immune response, including numbers of CD8-positive T cells, CD20-positive B cells, mature dendritic cells, macrophages, and CD56-positive natural killer cells.

The most common treatment-related adverse events were fatigue, injection-site pain, and chills. There was one dose-limiting toxicity reported in a patient who received tremelimumab intravenously; she died of severe hyponatremia and progressive disease.

Disclosure: No information regarding conflicts of interest was provided.

Journal for ImmunoTherapy of Cancer

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