CTIM-24. PHASE II TRIAL OF RHIL-7-HYFC IN PATIENTS WITH HIGH-GRADE GLIOMA DEMONSTRATED ACCEPTABLE SAFETY PROFILE AND REDUCED LYMPHOPENIA

Abstract BACKGROUND Lymphopenia, a common finding in patients with high-grade gliomas (HGGs), is associated with poor outcomes including worse survival, fatigue, and in some cases, increased opportunistic infections. Interleukin-7 (IL-7) is a cytokine crucial for lymphocyte survival and proliferation. We previously demonstrated long-acting IL-7 (rhIL-7-hyFc, efineptakin alfa, NT-I7) increases absolute lymphocyte counts (ALCs) and extends survival in preclinical murine models of HGG. Here, we report results using rhIL-7-hyFc to effectively reduce lymphopenia in patients with HGG. METHODS We performed a phase II randomized, placebo-controlled, double-blind study of rhIL-7-hyFc in patients with newly diagnosed HGGs (82% IDH-wildtype glioblastoma in both groups). Patients received rhIL-7-hyFc (720mcg/kg) or placebo one-week post-radiation and temozolomide, with subsequent doses at weeks 13, 25, and 37. The primary endpoint was ALC four weeks post-initial administration; exploratory endpoints included CD4 count, progression-free survival (PFS), and overall survival (OS). RESULTS We enrolled 22 patients (median age 59.5 years, range 33-74; 40.9% female) with HGG. Both groups exhibited comparable demographics, including MGMT methylation status, and received a median of 2 doses of rhIL-7-hyFc or placebo. At 4 weeks, the pre-specified primary endpoint, ALC significantly increased relative to baseline in the treatment group, compared to placebo (median percent change=148% vs. 16.7%, p=0.007), as did CD4 count (121% vs. 10.5%, p=0.011). There were no treatment-related grade 4/5 adverse events. Exploratory endpoints of PFS and OS will be reported at time of conference. CONCLUSIONS rhIL-7-hyFc is safe and effective in improving ALC and CD4 count in patients with newly diagnosed HGG undergoing temozolomide and concurrent radiation therapy. This study was powered to meet the primary endpoint; larger trials will likely be required to demonstrate clinical efficacy. Nevertheless, these data support the continued exploration of rhIL-7-hyFc as an adjunct to standard therapy to mitigate lymphopenia and potentially extend survival for patients with HGG.