Combining IL-7 With Pembrolizumab in Metastatic Triple-Negative Breast Cancer
Posted: Thursday, July 2, 2020
The long-acting interleukin-7, GX-I7, appeared to be well tolerated when used in combination with pembrolizumab and did not result in an increase in immune-related adverse events in patients with metastatic triple-negative breast cancer. GX-I7 works to increase the number of T cells in the tumor microenvironment as well as in the peripheral blood. These findings from the phase Ib/II KEYNOTE-899 trial were presented during the ASCO20 Virtual Scientific Program by Joohyuk Sohn, MD, PhD, of Yonsei University College of Medicine, Seoul, South Korea, and colleagues (Abstract 1072).
This study enrolled 24 patients with recurrent or refractory metastatic triple-negative breast cancer whose disease had failed to respond to standard chemotherapy. All patients had been treated with up to three previous lines of chemotherapy. Patients were administered GX-I7 intramuscularly, either every 9 weeks or every 12 weeks, with or without cyclophosphamide preconditioning, plus intravenous pembrolizumab every 3 weeks.
By January 2020, 17 of the 24 patients were evaluable for efficacy. Patients had received a median of three cycles of pembrolizumab and GX-I7. In these patients still receiving treatment, one had a partial response, two had stable disease, and one had a durable unconfirmed progressive disease. GX-I7 was found to induce dose-dependent proliferation of lymphocytes in the peripheral blood, producing a fourfold lymphocyte increase in the highest tested doses.
Treatment was discontinued in 13 patients, primarily as a result of progressive disease. There were no dose-limiting toxicities reported in any of the dosing groups. Grade 1 or 2 treatment related adverse events occurred in 91.7% of patients, and 9.1% of patients experienced a grade 3 adverse event. No grade 4 events were recorded. The most common side effects included injection-site reactions (39%) and fever (13%). The grade 3 toxicities seen included elevation in liver aminotransferases and an infusion-related reaction, each reported in one patient.
Disclosure: For full authors’ disclosures, visit coi.asco.org.
