Granulocyte Colony-Stimulating Factor (Neupogen®; Filgrastim) Accelerates Neutrophil Recovery in a Rodent Model of Sulfur Mustard-Induced Hematologic Toxicity.

OBJECTIVE: Evidence of myelosuppression has been negatively correlated with patient outcomes following cases of high dose sulfur mustard (SM) exposure. These hematologic complications can negatively impact overall immune function and increase the risk of infection and life-threatening septicemia. Currently, there are no approved medical treatments for the myelosuppressive effects of SM exposure. METHODS: Leveraging a recently developed rodent model of SM-induced hematologic toxicity, post-exposure efficacy testing of the granulocyte colony-stimulating factor drug Neupogen® was performed in rats intravenously challenged with SM. Before efficacy testing, pharmacokinetic/pharmacodynamic analyses were performed in naïve rats to identify the apparent human equivalent dose of Neupogen® for efficacy evaluation. RESULTS: When administered 1 d after SM-exposure, daily subcutaneous Neupogen® treatment did not prevent the delayed onset of hematologic toxicity but significantly accelerated recovery from neutropenia. Compared with SM controls, Neupogen®-treated animals recovered body weight faster, resolved toxic clinical signs more rapidly, and did not display transient febrility at time points generally concurrent with marked pancytopenia. CONCLUSIONS: Collectively, this work corroborates the results of a previous pilot large animal study, validates the utility of a rodent screening model, and provides further evidence for the potential clinical utility of Neupogen® as an adjunct treatment following SM exposure.

Biosimilar Use Among 38 ASCO PracticeNET Practices, 2019-2021.

PURPOSE: Biosimilars offer increased patient choice and potential cost-savings, compared with originator biologics. We studied 3 years of prescribed biologics among US physician practices to determine the relationship of practice type and payment source to oncology biosimilar use. METHODS: We acquired biologic utilization data from 38 practices participating in PracticeNET. We focused on six biologics (bevacizumab, epoetin alfa, filgrastim, pegfilgrastim, rituximab, and trastuzumab) for the period from 2019 to 2021. We complemented our quantitative analysis with a survey of PracticeNET participants (prescribers and practice leaders) to reveal potential motivators and barriers to biosimilar use. We implemented logistic regression to evaluate the biosimilar use for each biologic, with covariates including time, practice type, and payment source, and accounted for clusters of practices. RESULTS: Use of biosimilars increased over the 3-year period, reaching between 51% and 80% of administered doses by the fourth quarter of 2021, depending on the biologic. Biosimilar use varied by practice, with independent physician practices having higher use of biosimilars for epoetin alfa, filgrastim, rituximab, and trastuzumab. Compared with commercial health plans, Medicaid plans had lower biosimilar use for four biologics; traditional Medicare had lower use for five biologics. The average cost per dose decreased between 24% and 41%, dependent on the biologic. CONCLUSION: Biosimilars have, through increased use, lowered the average cost per dose of the studied biologics. Biosimilar use differed by originator biologic, practice type, and payment source. There remains further opportunity for increases in biosimilar use among certain practices and payers.

Effect of concomitant use of G-CSF and myelosuppressive chemotherapy on bone marrow and peripheral granulocytes in a mouse model.

Granulocyte-colony stimulating factor (G-CSF) stimulates bone marrow progenitor cell proliferation and enhances neutrophil production. Exogenous G-CSF administration is indicated for chemotherapy-induced neutropenia management. However, there is a paucity of basic research examining the effects of the concomitant use of G-CSF and chemotherapy on myeloid cells in vivo. Whether concomitant G-CSF and chemotherapy adversely affect myeloid cell proliferation have not been determined. Herein, we examined the effects of the concomitant use of pegfilgrastim and 5-fluorouracil on myeloid cells and peripheral blood cells in mouse models. Balb/c mice were treated intraperitoneally with 5-fluorouracil (20 µg/g b.w.) or a vehicle as a control for 5 days, and pegfilgrastim was administered subcutaneously at 1 µg/g b.w. on day 3. As a result, we demonstrated that the concomitant use of pegfilgrastim suppressed the 5-fluorouracil-induced decrease of granulocytic cells in both bone marrow and peripheral blood in mice. To assess the clinical efficacy of early administration of pegfilgrastim during docetaxel, cisplatin, and 5-fluorouracil therapy in patients with esophageal cancer, we retrospectively identified 42 consecutive patients treated with this regimen. The incidence of both febrile neutropenia and grade 4 neutropenia was significantly lower in patients who received pegfilgrastim than in those who did not receive it (P = 0.002 and P = 0.002, respectively). These results suggest that the concomitant use of pegfilgrastim and chemotherapy, consisting of continuous infusions of 5-fluorouracil, improved chemotherapy-induced neutropenia without detrimental effects on proliferating myeloid granulocytic cells.

Filgrastim, fibrinolysis, and neovascularization.

Segmental recanalization of chronically occluded arteries was observed in patients with chronic limb-threatening ischemia (CLTI) treated with Filgrastim, a granulocyte colony stimulating factor, every 72 h for up to a month, and an infra-geniculate programmed compression pump (PCP) for 3 h daily. Molecular evidence for fibrinolysis and neovascularization was sought. CLTI patients were treated with PCP alone (N = 19), or with Filgrastim and PCP (N = 8 and N = 6, at two institutions). Enzyme-Linked Immunosorbent Assay was used to measure the plasma concentration of plasmin and of fibrin degradation products (FDP), and the serum concentration of proteins associated with neovascularization. In the PCP-alone group, blood was sampled on Day 1 (baseline) and after 30 days of daily PCP. In the Filgrastim and PCP group, blood was drawn on Day 1, and 1 day after the 5th and the 10th Filgrastim doses. Each blood draw occurred before and after 2 h of supervised PCP. Significant (p < 0.01) PCP independent increases in the plasma concentration of plasmin (>10-fold) and FDP (>5-fold) were observed 1 day after both the 5th and the 10th Filgrastim doses, compared to Day 1. Significant (p < 0.05) increases in the concentration of pro-angiogenic proteins (e.g., HGF, MMP-9, VEGF A) were also observed. Filgrastim at this novel dosimetry induced fibrinolysis without causing acute hemorrhage, in addition to inducing a pro-angiogenic milieu conducive to NV. Further clinical testing is warranted at this novel dosimetry in CLTI, as well as in other chronically ischemic tissue beds. Trial registration. https://clinicaltrials.gov/ct2/show/NCT02802852.

Filgrastim (r-met-hu G-CSF) enhances the efficiency of spermatogenesis in prepubertal Bos indicus bulls.

This study aimed to test the effects of the drug r-met-hu-G-CSF (filgrastim) on spermatogenic efficiency in prepubertal Brahman bulls. Twelve intact, healthy prepubertal bulls were administered 0, 1 (LD = low dose) or 4 (HD = high dose) µg/Kg r-met-hu-G-CSF (daily for 4 days), and haematological analysis was performed. Bulls were castrated (D0 or D60). BW (body weight) and SC (scrotal circumference) were recorded. Testis weight and volume were taken at castration with samples for testis histology and stereology: germ cell types, spermatids count and DSP (daily sperm production per gram)/g of testicular parenchyma. Testicular weight, volume, BW, SC and gonadosomatic index (GSI) were NS (LD-HD; p > .05). At D0 (age 11 months), the most advanced germ cell types (maGCt) ranged from intermediate spermatogonia to pachytene spermatocytes. After 2 months, control animals had round spermatids as maGCt, LD animals 75% round spermatids and 25% elongated spermatids, and HD animals round spermatids. Spermatids/testis were higher in LD (1.23 ± 0.2 millions) than in controls (0.65 ± 0.1 millions, p < .05). Spermatogenic efficiency (DSP/g) was higher in LD (5.4 ± 0.4 million) than in controls (3.2 ± 0.2 million, p < .01). In conclusion, r-met-hu-G-CSF raises spermatogenic efficiency in prepubertal Brahman bulls.

Use of prophylactic pegfilgrastim for chemotherapy-induced neutropenia in the US: A review of adherence to present guidelines for usage.

Evidence-based US guidelines provide recommendations for the use of granulocyte colony-stimulating factor (G-CSF) as supportive therapy in patients with cancer receiving chemotherapy. Pegfilgrastim is recommended for FN prophylaxis in patients with non-myeloid malignancies receiving a high-risk chemotherapy regimen, or an intermediate-risk regimen if one or more risk factors are present. The guidelines highlight the patient characteristics and chemotherapy regimens for solid tumors and hematologic malignancies that may influence a patient's overall risk of FN and may benefit from pegfilgrastim support. This review aimed to evaluate how pegfilgrastim use in patients with cancer receiving myelosuppressive chemotherapy in routine clinical practice aligns with evidence-based US guidelines. Examination of the literature revealed widespread deviation in relation to under- and over-prescribing, and timing of administration in US clinical practice. Pegfilgrastim is often over-prescribed in patients receiving palliative chemotherapy and those at low risk of FN. Potential under-prescribing of pegfilgrastim was also observed. In this literature search, data that appear to support same-day administration of pegfilgrastim were from uncontrolled studies that were limited in size. Analyses of healthcare claims data clearly favored next-day use, with statistically significant increases in FN incidence among patients receiving same-day pegfilgrastim versus those treated 1-4 days post-chemotherapy. Earlier-than-recommended administration typically occurs at the physician's discretion where next-day administration might present barriers to the patient receiving supportive therapy.There is a need to ensure appropriate prescribing to optimize patient outcomes, as deviation from the guideline recommendations was associated with increased incidence of FN and hospitalization.

Meloxicam with Filgrastim may Reduce Oxidative Stress in Hematopoietic Progenitor Cells during Mobilization of Autologous Peripheral Blood Stem Cells in Patients with Multiple Myeloma.

Autologous stem cell transplantation (ASCT) is a potentially curative therapy but requires collection of sufficient blood stem cells (PBSC). Up to 40 % of patients with multiple myeloma (MM) fail to collect an optimum number of PBSC using filgrastim only and often require costly plerixafor rescue. The nonsteroidal anti-inflammatory drug meloxicam mobilizes PBSC in mice, nonhuman primates and normal volunteers, and has the potential to attenuate mobilization-induced oxidative stress on stem cells. In a single-center study, we evaluated whether a meloxicam regimen prior to filgrastim increases collection and/or homeostasis of CD34+ cells in MM patients undergoing ASCT. Mobilization was not significantly different with meloxicam in this study; a median of 2.4 × 106 CD34+ cells/kg were collected in the first apheresis and 9.2 × 106 CD34+ cells/kg were collected overall for patients mobilized with meloxicam-filgrastim, versus 4.1 × 106 in first apheresis and 7.2 × 106/kg overall for patients mobilized with filgrastim alone. CXCR4 expression was reduced on CD34+ cells and a higher CD4+/CD8+ T-cell ratio was observed after mobilization with meloxicam-filgrastim. All patients treated with meloxicam-filgrastim underwent ASCT, with neutrophil and platelet engraftment similar to filgrastim alone. RNA sequencing of purified CD34+ cells from 22 MM patients mobilized with meloxicam-filgrastim and 10 patients mobilized with filgrastim only identified > 4,800 differentially expressed genes (FDR < 0.05). Enrichment analysis indicated significant attenuation of oxidative phosphorylation and translational activity, possibly mediated by SIRT1, suggesting meloxicam may counteract oxidative stress during PBSC collection. Our results indicate that meloxicam was a safe, low-cost supplement to filgrastim mobilization, which appeared to mitigate HSPC oxidative stress, and may represent a simple means to lessen stem cell exhaustion and enhance graft quality.

Comparison of peripheral blood stem cell mobilization with filgrastim versus pegfilgrastim in lymphoma patients - single center experience.

PURPOSE: The purpose of this study was to evaluate mobilization outcomes with biosimilar pegfilgrastim versus filgrastim in association with chemotherapy as a mobilization strategy for lymphoma patients. METHODS: In the current study we included 32 lymphoma patients that received mobilization therapy and PBSC harvesting at the Bone Marrow Transplantation Department of Fundeni Clinical Institute, Bucharest, Romania between January and December 2019. RESULTS: Pegfilgrastim had beneficial effect when compared to filgrastim in reducing grade IV neutropenia both in the univariate and multivariate logistic models. Additionally, similar efficacy, as mobilization rate, after both filgrastim and pegfilgrastim was observed and no differences were noted between the two groups considering the need for platelet or red blood cell support. CONCLUSION: The use of biosimilar pegfilgrastim is a viable alternative to filgrastim in PBSC mobilization for lymphoma patients.

A whole-body circulatory neutrophil model with application to predicting clinical neutropenia from in vitro studies.

A circulatory model of granulopoiesis and its regulation is presented that includes neutrophil trafficking in the lungs, liver, spleen, bone marrow, lymph nodes, and blood. In each organ, neutrophils undergo transendothelial migration from vascular to interstitial space, clearance due to apoptosis, and recycling via the lymphatic flow. The model includes cell cycling of progenitor cells in the bone marrow, granulocyte colony-stimulating factor (G-CSF) kinetics and its neutrophil regulatory action, as well as neutrophil margination in the blood. From previously reported studies, 111 In-labeled neutrophil kinetic data in the blood and sampled organs were used to estimate the organ trafficking parameters in the model. The model was further developed and evaluated using absolute neutrophil count (ANC), band cell, and segmented neutrophil time course data from healthy volunteers following four dose levels of pegfilgrastim (r2  = 0.77-0.99), along with ANC time course responses following filgrastim (r2  = 0.96). The baseline values of various cell types in bone marrow and blood, as well as G-CSF concentration in the blood, predicted by the model are consistent with available literature reports. After incorporating the mechanism of action of both paclitaxel and carboplatin, as determined from an in vitro bone marrow studies, the model reliably predicted the observed ANC time course following paclitaxel plus carboplatin observed in a phase I trial of 46 patients (r2  = 0.70). The circulatory neutrophil model may provide a mechanistic framework for predicting multi-organ neutrophil homeostasis and dynamics in response to therapeutic agents that target neutrophil dynamics and trafficking in different organs.

Cost saving, patient centered algorithm for progenitor cell mobilization for autologous hematopoietic cell transplantation.

Administration of plerixafor with granulocyte-colony stimulating factor (G-CSF) mobilizes CD34+ cells much more effectively than G-CSF alone, but cost generally limits plerixafor use to patients at high risk of insufficient CD34+ cell collection based on low peripheral blood (PB) CD34+ counts following 4 days of G-CSF. We analyzed costs associated with administering plerixafor to patients with higher day 4 CD34+ cell counts to decrease apheresis days and explored the use of a fixed split dose of plerixafor instead of weight-based dosing. We analyzed 235 patients with plasma cell disorders or non-Hodgkin's lymphoma who underwent progenitor cell mobilization and autologous hematopoietic cell transplantation (AHCT) between March 2014 and December 2017. Two hundred ten (89%) received G-CSF plus Plerixafor and 25 (11%) received G-CSF alone. Overall, 180 patients (77%) collected in 1 day, 53 (22%) in 2 days and 2 (1%) in 3 days. Based on our data, we present a probabilistic algorithm to identify patients likely to require more than one day of collection using G-CSF alone. CD34+ cell yield, ANC and platelet recovery were not significantly different between fixed and standard dose plerixafor. Plerixafor enabled collection in 1 day and with estimated savings of $5000, compared to patients who did not receive plerixafor and required collection for three days. While collection and processing costs and patient populations vary among institutions, our results suggest re-evaluation of current algorithms.

Establishing Pediatric Mouse Models of the Hematopoietic Acute Radiation Syndrome and the Delayed Effects of Acute Radiation Exposure.

Medical countermeasures (MCMs) for hematopoietic acute radiation syndrome (H-ARS) should be evaluated in well-characterized animal models, with consideration of at-risk populations such as pediatrics. We have developed pediatric mouse models of H-ARS and delayed effects of acute radiation exposure (DEARE) for efficacy testing of MCMs against radiation. Male and female C57BL/6J mice aged 3, 4, 5, 6, 7 and 8 weeks old (±1 day) were characterized for baseline hematopoietic and gastrointestinal parameters, radiation response, efficacy of a known MCM, and DEARE at six and 12 months after total-body irradiation (TBI). Weanlings (age 3 weeks) were the most radiosensitive age group with an estimated LD50/30 of 712 cGy, while mice aged 4 to 8 weeks were more radioresistant with an estimated LD50/30 of 767-787 cGy. Female weanlings were more radiosensitive than males at 3 and 4 weeks old but became significantly more radioresistant after the pubertal age of 5 weeks. The most dramatic increase in body weight, RBC counts and intestinal circumference length occurred from 3 to 5 weeks of age. The established radiomitigator Neulasta® (pegfilgrastim) significantly increased 30-day survival in all age groups, validating these models for MCM efficacy testing. Analyses of DEARE among pediatric survivors revealed depressed weight gain in males six months post-TBI, and increased blood urea nitrogen at 12 months post-TBI which was more severe in females. Hematopoietic DEARE at six months post-TBI appeared to be less severe in survivors from the 3- and 4-week-old groups but was equally severe in all age groups by 12 months of age. Similar to our other acute radiation mouse models, there was no appreciable effect of Neulasta used as an H-ARS MCM on the severity of DEARE. In summary, these data characterize a pediatric mouse model useful for assessing the efficacy of MCMs against ARS and DEARE in children.

Effects of Ocimum tenuiflorum on Induced Testicular Degeneration by Filgrastim in Wistar Rats.

Since the creation of man on earth, herbal remedies have been used as an invaluable, safe, and available natural source of medicine for the treatment of several dysfunctions in living animals and human beings. The pharmacological properties of these herbs are commonly known to include analgesic, antidiabetic, antispasmodic, hepatoprotective, reproductive, and cardioprotective potentials. Various nutritional, environmental, and physiological factors can affect the male reproductive system. Several herbal remedies are reported to target the testis at the spermatogenesis and hormonal level. Most of the chemotherapy drugs used for treating cancers cause adverse effects on male reproductive functions. Filgrastim is used for the treatment of cancer in patients suffering from neutropenia. Ocimum tenuiflorum is one of the herbal remedies used as a natural antioxidant substance for protecting the body organs against the toxic effects of chemotherapy drugs. Therefore, the current study was designed to investigate the possible productive effects of the O. tenuiflorum against adverse effects of filgrastim on testicular tissues in male Wistar rats. In total, 40 adult male rats were selected and randomly divided into four groups (n=10). Group 1 was treated with intraperitoneal administration of filgrastim at a dose of 30.83 µg/kg/day for 1 week. Group 2 received O. tenuiflorum suspended in corn oil and administered by gavages at 20 mg/kg/day for 1 week. Group 3 was intraperitoneally injected with filgrastim at a dose of 30.83 µg/kg/day for 1 week and treated with O. tenuiflorum at similar manure to group 2. Finally, group 4 was treated with placebo (0.9% saline solution). The results showed that filgrastim administration leads to the degeneration of spermatozoa and germ cells in the testicles of rats. The results of the current study showed that O. tenuiflorum has some ameliorating effects on the testicles and fertility of the rats which were treated with filgrastim. Finally, the recorded data showed that O. tenuiflorum has protective effects on testis tissues and reproductive functions in male rats.

Biosimilarity Assessment of 2 Filgrastim Therapeutics in Healthy Volunteers.

This study aimed to compare the pharmacokinetic, pharmacodynamic, and safety profiles of a proposed biosimilar and innovator filgrastim therapeutics in healthy volunteers. In a crossover design, 23 subjects received a single subcutaneous injection of 300-µg filgrastim, followed by a 7-day washout period. Assessed pharmacokinetic parameters were the maximum observed filgrastim serum concentration (Cmax ), time to reach Cmax (tmax ), the area under the concentration-time curve (AUC), and elimination half-life. Pharmacodynamics were assessed by the maximum observed absolute neutrophil count effect (Emax ), tmax,E (time to reach Emax ), and the area under the effect of the absolute neutrophil count -time curve. The test/reference ratio (90% confidence intervals) of Cmax of 0.992 (0.860-1.143), AUC0-inf of 0.995 (0.891-1.111), Emax of 0.952 (0.841, 1.078), and area under the effect of the absolute neutrophil count -time curve from time zero to 96 hours of 0.939 (0.854-1.032), were all well within the predefined equivalence boundaries of 80% and 125%. Obtained values for tmax (∼4 hours), tmax,E (∼15 hours), and elimination half-life (∼3.5 hours) were comparable between 2 treatment groups. The local tolerability and incidence of adverse events were comparable, with no clinically meaningful difference between biosimilar and innovator products. Altogether, the results suggested a high similarity of the proposed biosimilar to the innovator filgrastim in healthy volunteers.

Efficacy and safety of lipegfilgrastim versus pegfilgrastim in elderly patients with aggressive B cell non-Hodgkin lymphoma (B-NHL): results of the randomized, open-label, non-inferiority AVOID neutropenia study.

BACKGROUND: Lipegfilgrastim has been shown to be non-inferior to pegfilgrastim for reduction of the duration of severe neutropenia (DSN) in breast cancer patients. This open-label, non-inferiority study assessed the efficacy and safety of lipegfilgrastim versus pegfilgrastim in elderly patients with aggressive B cell non-Hodgkin lymphoma (NHL) at high risk for chemotherapy-induced neutropenia. PATIENT AND METHODS: One hundred and one patients (median age, 75 years) were randomized to lipegfilgrastim or pegfilgrastim (6 mg/cycle) during six cycles of R-CHOP21. RESULTS: Lipegfilgrastim was non-inferior to pegfilgrastim for the primary efficacy endpoint, reduction of DSN in cycle 1. In the per-protocol population, mean (standard deviation) DSN was 0.8 (0.92) and 0.9 (1.11) days in the two groups, respectively; the adjusted mean difference between groups was - 0.3 days (95% confidence interval, - 0.70 to 0.19). Non-inferiority was also demonstrated in the intent-to-treat population. The incidence of severe neutropenia in cycle 1 was 51% (21/41) in the lipegfilgrastim group and 52% (23/44) in the pegfilgrastim group. Very severe neutropenia (ANC < 0.1 × 109/L) in cycle 1 was reported by 5 (12%) patients in the lipegfilgrastim group and 8 (18%) patients in the pegfilgrastim group. However, over all cycles, febrile neutropenia (strict definition) was reported by only 1 (2%) patient in each treatment group (during cycle 1 in the lipegfilgrastim group and cycle 6 in the pegfilgrastim group). The mean time to absolute neutrophil count recovery (defined as ≥ 2.0 × 109/L) was 8.3 and 9.4 days in the two groups, respectively. Serious adverse events occurred in 46% of patients in each group; none were considered treatment-related. Eight patients died during the study (2 in the lipegfilgrastim group, 5 in the pegfilgrastim group, and 1 who died before starting study treatment). No deaths occurred during the treatment period, and all were considered to be related to the underlying disease. CONCLUSIONS: This study shows lipegfilgrastim to be non-inferior to pegfilgrastim for the reduction of DSN in elderly patients with aggressive B cell NHL receiving myelosuppressive chemotherapy, with a comparable safety profile. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier NCT02044276; EudraCT number 2013-001284-23.

Mobilization characteristics, blood graft composition, and outcome in diffuse large B-cell lymphoma after autologous stem cell transplantation: Results from the prospective multicenter GOA study.

BACKGROUND: Diffuse large B-cell lymphoma (DLBCL) is a common indication for autologous stem cell transplantation (auto-SCT). STUDY DESIGN AND METHODS: This prospective noninterventional study aimed to evaluate the impact of mobilization characteristics and graft cellular content on hematologic recovery and outcome after auto-SCT among 68 patients with DLBCL. RESULTS: Better mobilization capacity as manifested by blood CD34+ cell count >32 × 106 /L and CD34+ cell yield of the first apheresis >2.75 × 106 /kg correlated with faster neutrophil (P = .005 and P = .017) and platelet (P = .002 and P < .001) recovery. A higher number of infused CD34+ cells (> 2.65 × 106 /kg) was associated with better 5-year overall survival (OS; 95% vs 67%, P = .012). The graft CD34+ CD133+ CD38- cell count >0.07 × 106 /kg was predictive of better 5-year OS (87% vs 63%; P = .008) and higher graft CD3+ cell count (>23.1 × 106 /kg) correlated also with better 5-year OS (80% vs 40%, P = .008). In multivariate analysis only disease status of CR I at auto-SCT was associated with better progression-free survival (P = .014) and OS (P = .039). CONCLUSION: The mobilization capacity of CD34+ cells impacted on early hematologic recovery in patients with DLBCL after auto-SCT. Higher graft CD34+ cell count and both CD34+ CD133+ CD38- and CD3+ cells were also associated with better OS. The effect of optimal graft cellular composition on outcome in DLBCL should be evaluated in a randomized study.

Eflapegrastim's enhancement of efficacy compared with pegfilgrastim in neutropenic rats supports potential for same-day dosing.

Eflapegrastim (Rolontis) is a long-acting granulocyte colony-stimulating factor (G-CSF) with an IgG4 Fc fragment and short polyethylene glycol linker. Current G-CSF products are administered 24 hours after chemotherapy. The present study compares the duration of neutropenia (DN) with eflapegrastim or pegfilgrastim at 0, 2, 5, or 24 hours post chemotherapy. Eflapegrastim was evaluated by G-CSF receptor binding and bone marrow cell proliferation assays in vitro. Eflapegrastim-Fc component binding to Fcγ receptors C1q and FcRn was assessed by enzyme-linked immunosorbent assay. Neutropenia was induced in rats via intraperitoneal cyclophosphamide or docetaxel/cyclophosphamide. Rats received chemotherapy followed by vehicle, pegfilgrastim, or eflapegrastim at 2, 5, or 24 hours. The difference in DN after treatment was assessed. In vitro binding to G-CSF receptor of both agents was similar. Binding to FcRn and no binding to Fcγ receptors or C1q were observed with eflapegrastim. Studies in chemotherapy-induced neutropenic rats revealed shorter DN with eflapegrastim versus pegfilgrastim. Increased levels of G-CSF in serum and marrow were observed in groups treated with eflapegrastim versus those treated with pegfilgrastim. Although eflapegrastim and pegfilgrastim have similar in vitro binding affinity, the Fc fragment in eflapegrastim increases the uptake into bone marrow, resulting in increased therapeutic potential for chemotherapy-induced neutropenia. Eflapegrastim's greater marrow resident time provided a pharmacodynamic advantage over pegfilgrastim, translating into shortened duration of neutropenia. Our findings support eflapegrastim same-day administration with chemotherapy, warranting further evaluation in patients undergoing myelosuppressive chemotherapy.

Effect of rhG-CSF Combined With Decitabine Prophylaxis on Relapse of Patients With High-Risk MRD-Negative AML After HSCT: An Open-Label, Multicenter, Randomized Controlled Trial.

PURPOSE: Relapse is a major cause of treatment failure after allogeneic hematopoietic stem-cell transplantation (allo-HSCT) for high-risk acute myeloid leukemia (HR-AML). The aim of this study was to explore the effect of recombinant human granulocyte colony-stimulating factor (rhG-CSF) combined with minimal-dose decitabine (Dec) on the prevention of HR-AML relapse after allo-HSCT. PATIENTS AND METHODS: We conducted a phase II, open-label, multicenter, randomized controlled trial. Two hundred four patients with HR-AML who had received allo-HSCT 60-100 days before randomization and who were minimal residual disease negative were randomly assigned 1:1 to either rhG-CSF combined with minimal-dose Dec (G-Dec group: 100 µg/m2 of rhG-CSF on days 0-5 and 5 mg/m2 of Dec on days 1-5) or no intervention (non-G-Dec group). The primary outcome was relapse after transplantation, and the secondary outcomes were chronic graft-versus-host disease (cGVHD), safety of the treatment, and survival. RESULTS: The estimated 2-year cumulative incidence of relapse in the G-Dec group was 15.0% (95% CI, 8.0% to 22.1%), compared with 38.3% (95% CI, 28.8% to 47.9%) in the non-G-Dec group (P < .01), with a hazard ratio (HR) of 0.32 (95% CI, 0.18 to 0.57; P < .01). There was no statistically significant difference between the G-Dec and non-G-Dec groups in the 2-year cumulative incidence of cGVHD without relapse (23.0% [95% CI, 14.7% to 31.3%] and 21.7% [95% CI, 13.6% to 29.7%], respectively; P = .82), with an HR of 1.07 (95% CI, 0.60 to 1.92; P = .81). After rhG-CSF combined with minimal-dose Dec maintenance, increasing numbers of natural killer, CD8+ T, and regulatory T cells were observed. CONCLUSION: Our findings suggest that rhG-CSF combined with minimal-dose Dec maintenance after allo-HSCT can reduce the incidence of relapse, accompanied by changes in the number of lymphocyte subtypes.

Feasibility and efficacy of low-dose pegfilgrastim for CD34+ cell mobilization in lymphoma.

BACKGROUND: Pegfilgrastim has equivalent efficacy to daily granulocyte colony-stimulating factor (G-CSF) in enhancing neutrophil recovery after chemotherapy, but data on its use for peripheral blood stem cell (PBSC) mobilization are limited. We evaluated the safety and efficacy of CD34+ PBSC mobilization by low-dose (3.6 mg) pegfilgrastim after chemotherapy in patients with malignant lymphoma. STUDY DESIGN AND METHODS: Twenty patients with malignant lymphoma were enrolled in this study. Cytotoxic chemotherapy was started on day 1, and 3.6 mg of pegfilgrastim was subcutaneously administered on day 7. CD34+ cells were counted in the peripheral blood daily from days 11 to 14 using a flow cytometric analysis. RESULTS: In 19 of the 20 patients (95%), the CD34+ cell counts in the peripheral blood exceeded 10 × 106/L, with a mean value of 20.3 on day 11, 38.0 on day 12, 40.3 on day 13, and 40.1 on day 14. Older age was associated with lower maximum CD34+ cell mobilization. The most frequent adverse events associated with pegfilgrastim were back pain, nausea, appetite loss, and lactate dehydrogenase elevation. CONCLUSION: Our data indicated that a single dose of 3.6 mg pegfilgrastim on day 7 after chemotherapy safely and effectively mobilized CD34+ cells.

Evaluation of Structural, Biological, and Functional Similarity of Biosimilar Granulocyte Colony Stimulating Factor to its Reference Product.

PURPOSE: Granulocyte colony stimulating factor (GCSF; also known as filgrastim) is a growth factor used to induce production of granulocytes. As the first locally developed and approved biosimilar medicine of Turkey, Fraven® being a biosimilar of filgrastim has been ab initio manufactured from cell to finished product at two different production facilities. Comprehensive structural, biological and functional characterization studies were performed to compare Fraven® from two different production sites and its reference product Neupogen® sourced from Turkey. METHODS: Primary and higher-order protein structures were analyzed by high performance liquid chromatography electrospray ionization-time of flight mass spectrometry, circular dichroism, and two-dimensional nuclear magnetic resonance spectroscopy. Isoelectric focusing, SDS-Page, size exclusion chromatography, and related proteins analyses were used to compare impurities. In order to assess functional similarity, surface plasmon resonance (SPR) was used. In vitro cell proliferation assay was also performed to show dose related drug response in NFS-60 cell line. RESULTS: Primary, secondary and tertiary structures of biosimilar Fraven® manufactured at both sites were found to be highly similar to the reference Neupogen®. Product related substances and impurities were also highly similar to the reference. Comparability of GCSF receptor binding affinities of each product was shown using the KD values of SPR analysis. In vitro cell proliferation similarity was also evaluated and proven by PLA. CONCLUSION: Based on the similarity assessment, despite being manufactured at two different production sites, biosimilar Fraven® is highly similar to the reference product Turkey originated Neupogen®.

Quantification and Qualification of Stem Cells From Blood After Mobilization With Filgrastim, and Concentration Using a Platelet-Rich Plasma System.

PURPOSE: To determine the cellular composition of a product created with peripheral blood harvested after systemic mobilization with filgrastim and processed with one point-of-care blood concentrating system, i.e., a platelet-rich plasma (PRP) system. The second purpose was to compare mobilized platelet-rich plasma (M-PRP) with a concentrated bone marrow aspirate (cBMA) and a PRP created from the same subjects with the same PRP system. METHODS: Ten healthy volunteer subjects were recruited for collection and analysis of 3 tissue sources: non-treated peripheral blood, bone marrow aspirate, and filgrastim-mobilized peripheral blood, involving 4 doses of weight-based filgrastim. One point-of-care blood and bone marrow concentrating system was used to create 3 products: PRP, cBMA, and M-PRP. Automated hematologic analysis was performed on all products to quantify total red blood cells, white blood cells (WBCs), monocyte, platelet, and hematopoietic progenitor cell (HPC) concentrations. Flow cytometry was used to determine hematopoietic and mesenchymal progenitor cell populations. Lastly, concentrates were cultured and fibroblast colony-forming units (CFU-F) and morphology of adherent cells were evaluated. RESULTS: M-PRP contained a greater concentration of WBC (mean difference = 53.2 k/µL; P < .0001), monocytes (mean difference = 8.3 k/µL; P = .002), and a trend toward a greater concentration of HPC (mean difference = 200.5 /µL; P = .060) when compared with PRP. M-PRP contained a greater concentration of monocytes (mean difference = 5.5 k/µL; P = .017) and a trend toward a greater concentration of platelets (mean difference = 348 k/µL; P = .051) and HPC (mean difference = 193.4 /µL; P = .068) when compared with cBMA. M-PRP had a similar concentration of platelets to PRP (mean difference = 110 k/µL; P = .051) and PRP had a greater concentration than cBMA (mean difference = 458 k/µL; P = .003). cBMA remained the only product capable of producing CFU-Fs (446 ± 247 /mL) as neither the M-PRP nor PRP produced CFU-Fs. M-PRP produced colonies consistent with WBC. CONCLUSIONS: M-PRP, produced with filgrastim mobilized blood and a proprietary PRP system, contained more total WBCs, monocytes, platelets, and HPCs than cBMA and more WBCs, monocytes, and HPCs than PRP. CLINICAL RELEVANCE: Filgrastim mobilized PRP may be an alternative to cBMA for use as a point-of-care product for orthopaedic treatments.