Guard-02: Safety and efficacy of prophylactic use of novel long-acting G-CSF efbemalenograstim α on same-day of chemotherapy in breast cancer patients.

Abstract

e24088 Background: Granulocyte colony-stimulating factor (G-CSF) is widely used for prevention of chemotherapy-induced neutropenia (CIN), there is controversy over whether G-CSF can be given within 24 hours after chemotherapy yet. Efbemalenograstim α is a novel long-acting G-CSF contains two G-CSF fused to a hIgG2-Fc fragment, approved by FDA in 2023. Guard-02 trial (ChiCTR2300078792) was to evaluate the efficacy and safety of efbemalenograstim α for prevention of CIN within 24 hours after chemotherapy. Methods: This was a prospective, multicenter, single-arm, two-stage clinical study. Breast cancer patients who received chemotherapy with epirubicin (90 mg/m 2 ) and cyclophosphamide (600 mg/m 2 ) (EC therapy) for 4 cycles were enrolled. Patients received efbemalenograstim α (20 mg per dose, subcutaneous injection) at 24±4 hours (d2) after chemotherapy in first cycle and at 4±1 hours (d1) after chemotherapy in subsequent cycles. The primary endpoint was the incidence of grade 3-4 neutropenia (ANC <1× 10 9 /L) in cycles 1-2. The safety profile was evaluated. Results: By end of Nov 2024, 37 patients whose median age at 50 years old (range.33-65) has been recruited. The incidence of grade 3-4 neutropenia in cycles 1-2 and cycles 1-4 were 16.22% (90% CI: 7.31%-29.52%) and 21.62% (95% CI: 9.83%-38.21%), both lower than that in phase III trial administering efbemalenograstim α at 48 ± 4 hours (d3) after EC chemotherapy (NCT04174599, whose incidence of grade 3-4 neutropenia in cycles 1-2 and cycles 1-4 were 34.45% and 43.70%). Besides, administering efbemalenograstim α within 24 hours after chemotherapy was well tolerated and safe. The most frequently adverse event (AE) considered related to the study drug was muscle pain (5.41%), the incidences of AEs were low in all patients and no serious adverse event (SAE) was related to study drug. Conclusions: Administering long-acting G-CSF on same-day of chemotherapy was as safe and effective as on day 3 of chemotherapy in reducing the risk of CIN. In patients with daytime chemotherapy, efbemalenograstim α provides oncologists an alternative for simplifying the management of CIN. Clinical trial information: ChiCTR2300078792 . Summary of efficacy endpoints by cycle. Cycles 1-2(n=37) Cycle 1(n=37) Cycle 2(n=32) Cycle 3(n=24) Cycle 4(n=21) Cycles 1-4(n=37) Incidence of grade 3-4 neutropenia in each cycle (%, 95% CI) 16.22 (6.19, 32.01) 8.11 (1.70, 21.91) 9.38 (1.98, 25.02) 8.33 (1.03, 27.00) 14.29 (3.05, 36.34) 21.62 (9.83, 38.21) Incidence of febrile neutropenia (FN) in each cycle (%, 95% CI) 2.70 (0.07, 14.16) / 3.13 (0.08, 16.22) / / 2.70 (0.07, 14.16) Duration in days of grade 3-4 neutropenia in each cycle (median, 95% CI) 0 (0,0) 0 (0,0) 0 (0,0) 0 (0,0) 0 (0,0) 0 (0,0) Depth of ANC nadir (median(95% CI), × 10 9 /L) / 4.10 (3.06, 5.44) 3.37 (2.55, 4.07) 2.10 (1.27, 2.70) 1.90 (1.20, 2.98) 1.90 (1.43, 2.69)