BACKGROUND: The chemotherapy regimens recommended for both rhabdomyosarcoma (RMS) and Ewing sarcoma (ES) patients are myelosuppressive and can reduce the absolute neutrophil count (ANC) and subsequently increase the risk of febrile neutropenia (FN). However, only a few studies have focused on the efficacy and safety of granulocyte-colony stimulating factor (G-CSF) drugs in pediatric and adolescent patients with RMS and ES. Our objective was to investigate the efficacy and safety of mecapegfilgrastim, a biosimilar of pegfilgrastim, in prophylaxis of FN for pediatric and adolescent patients with RMS or ES.
METHODS: In this single-arm, single-center, prospective study, pediatric and adolescent patients with RMS or ES were enrolled to receive either VAC (vincristine, cyclophosphamide, dactinomycin) regimen or VDC (vincristine, cyclophosphamide, doxorubicin) regimen in a 3-week cycle, followed by treatment with mecapegfilgrastim (100 μg/kg, maximum 6 mg) given at 24 h after completing chemotherapy. The primary endpoint was the incidence rate of FN. Secondary endpoints included the incidence rate of grade 4 neutropenia, duration of ANC ≤ 0.5 × 109/L, incidence rate of chemotherapy delay or reduction, use of antibiotics, and safety profile.
RESULTS: In total, 2 of the 30 (6.7%, 95% CI: 0.82-22.07) patients experienced FN after the first cycle of chemotherapy. Eight (26.7%, 95% CI: 12.28-45.89) patients experienced grade 4 neutropenia after receiving prophylactic mecapegfilgrastim. Eight patients experienced ANC ≤ 0.5 × 109/L with a median duration of 4.5 days; among them, 6 patients reached the lowest point of their ANC level on day 7, and 5 of them recovered by day 10. No dose reductions, delays, or discontinuation of chemotherapy was reported. Twenty-one (70.0%) patients received antibiotics during the treatment period. No patient experienced FN in the 0-5 years and the 13-18 years groups, and 2 patients experienced FN in the 6-12 years group. Two patients, 6 patients, and no patient experienced grade 4 neutropenia in the 0-5 years, 6-12 years, and 13-18 years groups, respectively.
CONCLUSIONS: Mecapegfilgrastim showed acceptable efficacy and safety profile in pediatric and adolescent patients with RMS or ES. Further randomized studies with large sample size are warranted.
BACKGROUND: This clinical trial was registered at Chictr.org.cn (No.ChiCTR1900022249). Registered on March 31, 2019.

OBJECTIVE: 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.
CONCLUSIONS: 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.

A single injection of 12 mg pegfilgrastim was used to mobilize peripheral blood progenitor cells (PBPCs) from healthy donors in some studies. The purpose of this study was to determine if 6 mg of pegfilgrastim was effective and safe for mobilizing CD34+ cells in donors for allogeneic hematopoietic stem cell transplantation. We conducted a retrospective case-matched design. A single dosage of 6 mg pegfilgrastim was used to mobilize PBPCs from 60 healthy donors. Granulocyte colony-stimulating factor (G-CSF, 10 μg/kg) was administered daily to the matched donors. Leukapheresis was scheduled to commence on day 4 of the mobilization regimen. The median yielded CD34+ cell in the pegfilgrastim group was higher than those in the G-CSF group, at 5.06 × 106/kg recipient weight. The 73.3% of donors mobilized with pegfilgrastim yielded >4 × 106 cells/kg CD34+ cells in a single apheresis procedure when compared to the 33.3% of donors mobilized with G-CSF (P < 0.001). The myeloid-derived suppressor cells (MDSC) proportion in the pegfilgrastim group was significantly higher than that in the G-CSF group (P < 0.001). The cumulative incidence of grade II-IV acute graft-versus-host disease (aGVHD) was higher in the G-CSF group than that in the pegfilgrastim group (26.7% vs. 11.7%), without statistical difference. In comparison to the G-CSF group, the pegfilgrastim group had a reduced median pain intensity numerical rating scale score (1 vs. 2). A single 6 mg dosage of pegfilgrastim is effective and safe for allogeneic PBPCs collection from healthy donors. Pegfilgrastim may decrease the incidence of aGVHD by boosting MDSCs, which need further investigation.

An optimal strategy for mobilizing hematopoietic stem cells in poorly mobilizing patients with multiple myeloma (MM) and lymphoma has not yet been determined.
We retrospectively analyzed the efficacy and safety of etoposide combined with cytarabine (etoposide 75 mg/m2, daily d1∼2; Ara-C 300 mg/m2, every 12 h d1∼2), plus pegfilgrastim (6 mg d6) in 32 patients with MM or lymphoma, among whom 53.1% were defined as \"proven poor mobilizers.\"
This approach resulted in adequate mobilization (≥2.0 × 106 CD34+ cells/kg) in 93.8% of patients and optimal mobilization (≥5.0 × 106 CD34+ cells/kg) in 71.9% of patients. A total of 100% of patients with MM reached at least 5 × 106 CD34+ cells/kg collected, the amount required for double autologous stem cell transplant. In total, 88.2% of patients with lymphoma reached at least 2 × 106 CD34+ cells/kg collected, the amount required for a single autologous stem cell transplant. This was achieved with a single leukapheresis in 78.1% of cases. A median peak number of 42.0/μL circulating CD34+ cells and a median number of blood CD34+ cells counts in 6.7 × 106/L were collected among 30 successful mobilizers. Approximately 6.3% of patients required plerixafor rescue, which was successful. Nine (28.1%) of the 32 patients suffered grade 2∼3 infections, and 50% required platelet transfusions.
We conclude that chemo-mobilization with etoposide, Ara-C and pegfilgrastim in poorly mobilizing patients with MM or lymphoma is very effective and has acceptable toxicity.

OBJECTIVE: To compare the efficacies and costs between pegfilgrastim and filgrastim prophylaxis for FN post-ASCT for lymphoma and multiple myeloma patients.
METHODS: 43 patients who received pegfilgrastim (6 mg) were compared to a retrospective cohort of 129 patients that had received filgrastim post-ASCT. Hematopoietic recovery time, FN incidence and treatment costs were assessed and compared.
RESULTS: The mean time to absolute neutrophil count engraftment was 8.72 ± 2.38 days for the prospective pegfilgrastim group and 9.87 ± 3.13 days for the retrospective filgrastim group (P = 0.027). The incidence of FN was 18.60% and 50.39% in prospective pegfilgrastim and retrospective filgrastim groups, respectively (P = 0.000). The mean cost of filgrastim was $617.22 ± 37.87, compared with $525.78 for pegfilgrastim (P = 0.032).
CONCLUSIONS: Convenience, effectiveness, and safety of prophylaxis for FN in the prospective pegfilgrastim group were significantly improved compared to the retrospective filgrastim group in ASCT patients.
CONCLUSIONS: Pegfilgrastim prophylaxis was more effective and convenient than filgrastim for FN prophylaxis in patients post-ASCT, especially for MM patients.

BACKGROUND: An ECCOPG (Eastern China Cooperative Oncology Pharmacy Group) funded study was designed to compare the effect of 3 versus 6 mg pegfilgrastim for primary prevention of febrile neutropenia (FN) in Chinese breast cancer patients retrospectively.
METHODS: Patients undergoing a docetaxel and cyclophosphamide chemotherapy regimen, followed by pegfilgrastim, for primary prevention during 2018 and 2020 were retrospectively enrolled in the present study. The patients were divided into 2 groups according to the dose of pegfilgrastim. The incidence of severe neutropenia (absolute neutrophil count <0.5×109/L), incidence of FN, and recovery time were calculated to compare the efficacy of different groups. P<0.05 was considered statistically significant.
RESULTS: A total of 295 patients were enrolled, 150 in the 3 mg pegfilgrastim group and 145 in the 6 mg pegfilgrastim group. No significant differences were found in the incidence of severe neutropenia (3 vs. 6 mg, 39.3% vs. 34.5%, P=0.401) and the incidence of FN (3 vs. 6 mg, 7.3% vs. 8.3%, P=0.830). Median recovery time was 2 days for both groups (P=0.485).
CONCLUSIONS: 3 mg pegfilgrastim may be effective and safe for Chinese breast cancer patients as the primary prevention for FN. Prospective studies are needed to further confirm the prophylactic effect of 3 mg pegfilgrastim.

The mobilization of hematopoietic stem cells (HSCs) using granulocyte colony-stimulating factor is a classic method. Recently, a single injection of pegfilgrastim was used to mobilize CD34+ cells in some small-sample studies. To confirm the efficacy and safety of pegfilgrastim in the mobilization of CD34+ cells from healthy donors, we conducted a retrospective multicenter study. A total of 146 healthy donors who all received subcutaneous pegfilgrastim (12 mg) on day 1 were enrolled in our study. Donor HSC apheresis was conducted on day 5. The primary endpoint was the percentage of donors from whom ≥4 × 106 CD34+ cells/kg were collected in a single apheresis session. The median number of CD34+ cells in donors was significantly higher on day 5 than that on day 4 (82.26 μL vs. 51.65 μL, P ¡ 0.001). In 111 of the 146 donors, an optimal number of CD34+ cells (≥4 × 106 kg) were collected in a single apheresis procedure. Bone pain and headache were the main adverse events, but the side effects did not require treatment. The number of white blood cells in most donors dropped to normal levels within 1 week after apheresis. Nearly 97% of patients achieved neutrophil and platelet engraftment. Pegfilgrastim for mobilization could be used to obtain an optimal number of CD34+ cells in a single session. Pegfilgrastim-induced mobilization not only was effective and safe but also avoided the pain of multiple injections and apheresis procedures in donors. However, prospective randomized controlled trials should be conducted in the future.

Autologous stem cell transplantation (ASCT) is the only curable therapy for multiple myeloma (MM), while its success primarily relies on mobilization to obtain sufficient hematopoietic stem/progenitor cells (HPC). Although the role of Pegfilgrastim (PEG), a novel PEGylated form of the recombinant G-CSF filgrastim (FIL), in mobilization has been demonstrated, it remains unclear whether this approach is cost-effective in MM treatment. Here, we performed a real-world analysis to evaluate the efficacy and cost of PEG for mobilization in a cohort of MM patients, of which 53% carried high-risk cytogenetic abnormalities. A total of 91 patients who received either a single dose of PEG (6 or 12 mg, n = 42) or multiple dosing of 10 μg/kg/day FIL (n = 49) after chemotherapy for HPC mobilization were included. The yield of MNCs and CD34+ cells per milliliter of blood collected via apheresis was significantly greater in the PEG group than that in the FIL group (P = 0.014 and P = 0.038). Mobilization with PEG yielded significantly higher median number of collected CD34+ cells than FIL (5.56 vs. 4.82 × 106/kg; P = 0.038). Moreover, the average time-to-recovery of leukocytes and platelets after transplantation was markedly shorter in the PEG group than that in the FIL group (leukocyte, 11.59 ± 1.98 vs 12.93 ± 2.83 days, P = 0.019; platelet, 12.86 ± 2.62 vs 14.80 ± 5.47, P = 0.085). However, the total cost of mobilization and apheresis using PEG or FIL was comparable (P = 0.486). Of note, mobilization with 12 mg PEG further shortened time-to-recovery of leukocytes (10.64 ± 0.51 vs. 12.04 ± 2.26 days, P = 0.05) and platelets (10.60 ± 2.89 vs. 13.33 ± 2.35 days, P = 0.031) compared with 6 mg PEG. Our results support a notion that PEG (especially 12 mg) combined with chemotherapy is a cost-effective and convenient regimen of mobilization, which might improve the outcome of ASCT in MM.

OBJECTIVE: The role of long-acting hematopoietic growth factor in supporting dose-dense chemotherapy and minimizing hematologic toxicity has not been established. We investigated the efficacy and safety of once-per-cycle pegfilgrastim in breast cancer patients receiving neoadjuvant dose-dense epirubicin and cyclophosphamide (ddEC).
METHODS: Newly diagnosed stage I to III breast cancer patients received four cycles of ddEC (E, 100 mg/m2 and C, 600 mg/m2 every 2 weeks) and 6 mg of subcutaneous pegfilgrastim on day 2 of each cycle. The primary endpoint was to evaluate the incidence of chemotherapy delay. Secondary endpoints include the incidences of febrile neutropenia (FN) and grade 3/4 neutropenia during the four ddEC cycles.
RESULTS: A total of 240 patients were enrolled and 913 ddEC cycles were administered in the study. Chemotherapy delay occurred in 15 patients (6.3% of patients, 95% CI 3.2-9.4%) for 17 cycles (1.9% of cycles, 95% CI 1.0-2.8%). The most frequent cause of chemotherapy delay was transaminase elevation (10 patients, 12 cycles). A total of 12 patients (5.0%, 95% CI 2.2-7.8%) developed 13 episodes of FN. Of the 221 patients that completed four ddEC cycles with pegfilgrastim support, 209 patients (94.6%, 95% CI 91.6-97.6%) had a 100% relative dose intensity (RDI). A RDI ≥ 85% was achieved in 217 of 221 patients (98.2%, 95% CI 96.5-99.9%). Bone pain of any grade was recorded in 85 of 220 evaluable patients (38.6%, 95% CI 32.2-45.0%).
CONCLUSIONS: Pegfilgrastim is effective and safe in facilitating four cycles of neoadjuvant ddEC, with low incidences of chemotherapy delay and febrile neutropenia.

BACKGROUND: To compare the effect of xinruibai (Pegfilgrastim) and filgrastim injections on white blood cell and platelet (PLT) recovery, adverse events, post-operative complications, and cost effectiveness after allogeneic hematopoietic stem cell transplantation (allo-HSCT).
METHODS: Children who underwent allo-HSCT at our hospital from January 2014 to May 2017 due to thalassemia major, aplastic anemia, leukemia, and mucopolysaccharidosis were included. Among the children, 53 received xinruibai injections and 33 received filgrastim injections.
RESULTS: There were no significant differences in the average time to neutrophil and platelet recovery, the incidence of post-operative complications after allo-HSCT, the number of red blood cell and PLT infusions, or the incidence of adverse events related to the injection between two groups (P >  0.05). The pain score was 3.06 (SD 0.41) for the xinruibai group and 25.18 (SD 6.22) for the filgrastim group, indicating significant differences between the two groups (P <  0.001). No difference was found in the hospitalization cost. The cost of the granulocyte-colony stimulating factor (G-CSF) was 257.11 ± 61.87 Euro in the xinruibai group and 214.79 ± 0.00 Euro in the filgrastim group, showing significant difference (P <  0.001).
CONCLUSIONS: Xinruibai injection was more convenient, simple, effective, and safer than filgrastim.