Compassionate use of recombinant human IL-7-hyFc as a salvage treatment for restoring lymphopenia in patients with recurrent glioblastoma

Abstract Purpose Lymphopenia is frequently observed and is associated with poor prognosis in glioblastoma (GBM) patients. Restoring lymphopenia in cancer patients has been suggested as a novel immunotherapeutic strategy. As interleukin-7 (IL-7) is necessary for proliferation of lymphocytes and to amplify the total lymphocyte count (TLC), IL-7 therapy has been tried for various cancers, although the results are inconclusive. Here, we describe the clinical results of recurrent GBM treated with long-acting engineered version of recombinant human IL-7 (rhIL-7-hyFc). Methods This prospective case series based on compassionate use was approved by the Ministry of Food and Drug Safety in South Korea. Patients with recurrent GBM were enrolled to Seoul St. Mary’s Hospital. Primary outcomes were the safety profile and elevated total lymphocyte count (TLC). Secondary outcomes were overall survival (OS) and progression-free survival (PFS). The duration of median follow-up was 372.6 days (range 98–864 days). Results Among 18 patients enrolled, 10 received rhIL-7-hyFc with temozolomide, 5 received rhIL-7-hyFc with bevacizumab, 1 received rhIL-7-hyFc with PCV chemotherapy, and 2 received rhIL-7-hyFc alone. The mean TLC of enrolled patients after the first treatment with rhIL-7-hyFc was significantly increased from 1,131 cells/mm 3 (range 330-2,989) at baseline to 4,356 cells/mm 3 (range 661-22,661). Similar increase was observed in 16 of 18 patients (88.8%), only after the first treatment of rhIL-7-hyFc. TLCs of these patients were maintained higher while rhIL-7-hyFc was repeatedly administered. Most common adverse events were injection sites reactions (64.7%) including urticaria and itching sensation, however, there were no serious adverse events more than grade III. Median OS and PFS were 378 days (range 107-864 days) and 231 days (55-726 days), respectively. Conclusion Our study first reports that IL-7 immunotherapy can restore lymphopenia and maintain TLC with various salvageable chemotherapies in recurrent GBM patients without serious adverse toxicities. This outcome warrants further larger and randomized clinical trials to validate the clinical benefits of rhIL-7-hyFc for GBM patients.