Guard-01: A prospective study of efbemalenograstim alfa as primary prophylaxis for concurrent chemo-radiotherapy induced neutropenia.

Abstract

e24100 Background: Concurrent chemo-radiotherapy (CCRT) holds a crucial role in the therapeutic regimen for diverse malignant tumors, yet it often leads to substantial hematologic toxicity, notably leukopenia and neutropenia. To assess the efficacy and safety of efbemalenograstim alfa, a novel long-acting formulation of G-CSF, when employed as primary prophylaxis during CCRT, Guard-01 study was performed. Methods: This study aims to enroll 120 patients who are scheduled to undergo definitive CCRT for various malignancies. Participants will be randomized in a 1:1 ratio to either the study or control group. In the study group, patients will receive efbemalenograstim alfa the completion of chemotherapy. Conversely, patients assigned to the control group will not receive G-CSF prophylaxis unless febrile neutropenia or dose-limiting neutropenic events develop during their previous chemotherapy cycles. The primary endpoint is the incidence of grade 3/4 neutropenia (ANC < 1.0 × 10 9 /L) throughout the entire duration of CCRT. Results: As of January 09, 2025, 72 patients (median age: 57.5 years; 44.4% female) were enrolled (36 in study group, 36 in control group).Five patients (13.89%) in the efbemalenograstim alfa arm experienced grade 3/4 neutropenia, compared to 15 patients (41.67%) in the control arm, yielding a statistically significant difference of -27.78% (90% confidence interval [CI]: -43.79%, -10.64%; p = 0.0058). Across the first chemotherapy cycle, the incidence of grade 3/4 neutropenia was 5.56% in the study group and 41.67% in the control group (p = 0.0002). Among 14 patients receiving etoposide or docetaxel based chemotherapy, two patients (28.57%) in the study group experienced grade 3/4 neutropenia, while four patients (57.14%) in the control group did. For 23 patients receiving paclitaxel or pemetrexed based chemotherapy, grade 3/4 neutropenia was observed in two patients (16.67%) of the study group, compared to seven (63.64%) of the control group. The incidence of grade 3/4 neutropenia in the 35 patients receiving cisplatin mono-chemotherapy was 5.88% (one patient) and 22.22% (four patients) in the study and control groups, respectively. The median duration of grade 3/4 neutropenia was 0 days (interquartile range [IQR]: 0-0) in the study group compared with 0 days (IQR: 0-4.5) in the control group (p = 0.0027). The absolute neutrophil count (ANC) nadir was significantly higher in the study group than in the control group (3.32 [0.26-8.45] × 10 9 /L vs. 1.16 [0.06-7.11] × 10 9 /L; p < 0.001). The most frequently observed treatment-emergent adverse events (TEAEs) in the study group were anemia (55.66%), thrombocytopenia (47.22%) and leukopenia (36.11%). No grade ≥3 treatment-related adverse events (TRAEs) was reported in either group. Conclusions: Efbemalenograstim alfa is safe and efficacious in preventing grade 3/4 neutropenia in patients undergoing CCRT. Clinical trial information: ChiCTR2300077504 .