Low‐dose pegylated recombinant human granulocyte‐colony stimulating factor as hematopoietic support for adjuvant chemotherapy in Chinese patients with breast cancer: An open‐label, randomized, non‐inferiority trial

Abstract Aims The recommended dosage of pegylated recombinant human granulocyte‐colony stimulating factor (PEG‐rhG‐CSF) for Western chemotherapy patients is 6 mg per cycle. However, for Eastern Asians, the optimal dose remains unknown. Methods This open‐label, randomized, non‐inferiority trial (NCT05283616) enrolled Chinese female breast cancer patients receiving adjuvant chemotherapy. Participants were randomized to receive either 3 or 6 mg of PEG‐rhG‐CSF per cycle, stratified by body weight (BW; ≤60 kg vs . >60 kg). The primary endpoint was timely absolute neutrophil count (ANC) recovery before the second cycle of chemotherapy. Results A total of 122 patients were randomized and 116 were included for efficacy analyses. The timely ANC recovery rate in the 3 mg arm was 89.8%, compared to 93.0% in the 6 mg arm (one‐sided 95% confidence interval CI lower limit for difference: −11.7%), meeting the prespecified non‐inferiority margin of 15%. The rate was 93.3% with PEG‐rhG‐CSF 3 mg and 96.6% with 6 mg in patients with BW ≤ 60 kg, and 86.2% and 89.3%, respectively, in those with BW > 60 kg. Although the incidence of severe neutropenia was similar across arms, the occurrence of excessively high ANC and white blood cell counts was higher in the 6 mg arm. No grade ≥3 adverse events related to PEG‐rhG‐CSF occurred. Conclusion Three milligrams of PEG‐rhG‐CSF per cycle provided non‐inferior neutrophil protection and attenuated neutrophil overshoot compared to 6 mg doses. This low‐dose regimen could be a new supportive care option for Chinese breast cancer patients receiving anthracycline‐based adjuvant chemotherapy.