Filgrastim-Mediated Neutrophil Recovery in Patients with Breast Cancer Treated with Docetaxel and Doxorubicin

Justification for a Fixed Dose of Eflapegrastim, a Long-Acting G-CSF, in Patients Receiving Docetaxel-Cyclophosphamide Chemotherapy

Eflapegrastim (Rolontis) is a long-acting granulocyte colony-stimulating factor (G-CSF) produced by conjugating a human G-CSF analogue and a human immunoglobulin G4 Fc fragment, linked via a polyethylene glycol linker. Weight-based doses of 45 to 270 μg/kg eflapegrastim (12.3-73.6 μg/kg as G-CSF) were evaluated in a phase 2 study in patients. Based on these results, a fixed dose of 13.2 mg eflapegrastim (3.6 mg G-CSF) was compared with pegfilgrastim (6 mg G-CSF) in 2 phase 3 studies and in a pharmacokinetic single-arm multicenter study. Absolute neutrophil count (ANC) data from these 3 studies were evaluated in patients with early-stage breast cancer who were treated with docetaxel and cyclophosphamide (n = 669). Serum concentrations of eflapegrastim were determined by enzyme-linked immunosorbent assay. Eflapegrastim systemic exposures were higher in cycle 1 than in cycle 3, likely attributable to the higher ANC in cycle 3, increasing neutrophil-mediated clearance. Eflapegrastim elicited a greater effect on ANC than pegfilgrastim in patients at ∼60% of the G-CSF dose. Body weight had no clinically significant effect on response, justifying administration of a fixed dose of eflapegrastim. The results from 2 phase 3 studies demonstrate that eflapegrastim at a fixed dose of 13.2 mg (3.6 mg G-CSF) administered once per chemotherapy cycle is effective in prophylactic treatment of chemotherapy-induced neutropenia.

Clinical confirmation to demonstrate similarity for a biosimilar pegfilgrastim: a 3-way randomized equivalence study for a proposed biosimilar pegfilgrastim versus US-licensed and EU-approved reference products in breast cancer patients receiving myelosuppressive chemotherapy

Background

Chemotherapy-induced neutropenia is a common result of myelosuppressive chemotherapy treatment. Infections such as febrile neutropenia (FN) are sensitive to the duration of neutropenia as well as the depth of absolute neutrophil count (ANC) at nadir. Filgrastim, a granulocyte colony stimulating factor (G-CSF), can stimulate the function of mature neutrophils. Pegfilgrastim, a long-acting form of filgrastim, has been shown to reduce FN to a greater extent compared to filgrastim. G-CSF agents have been recommended for prophylactic administration with chemotherapy. Apotex developed a proposed pegfilgrastim biosimilar. This study was conducted to confirm that no clinically meaningful efficacy or safety differences exist between Apotex’s proposed biosimilar and its reference product.

Methods

589 breast cancer patients were randomized and dosed with the proposed pegfilgrastim biosimilar, US-licensed pegfilgrastim reference product, or EU-approved pegfilgrastim reference product. The primary endpoint assessed was the duration of severe neutropenia (DSN) and secondary endpoints included rate of FN and ANC nadir.

Results

Data showed that the mean DSN, the primary endpoint measured, was comparable across all three treatments. The As Treated arm had a 95% confidence interval within the equivalence range for the proposed pegfilgrastim biosimilar with the US-licensed and EU-approved pegfilgrastim reference products. Secondary endpoints, which included depth and peak of ANC nadir, time to ANC recovery post-nadir and rates of FN, also showed similarity between the three different treatment groups. The adverse event incidence was similar across treatment arms and there were no unexpected safety events.

Conclusions

Overall, these results show that the proposed pegfilgrastim biosimilar is similar to Amgen’s US-licensed and EU-approved pegfilgrastim reference products with regard to the clinical efficacy and safety endpoints assessed.

Trial registration EMA: European Union Clinical Trials Register: (https://www.clinicaltrialsregister.eu/ctr-search/search?query=eudract_number:2011-002678-21) Eudract # 2011-002678-21 Registered: 01/10/2012

Development of a new G-CSF product based on biosimilarity assessment

BACKGROUND

Zarzio, a new recombinant human granulocyte colony-stimulating factor (filgrastim), was evaluated in healthy volunteers and neutropenic patients in phase I and III studies.

PATIENTS AND METHODS

Healthy volunteers in randomized, two-period crossover studies received single- and multiple-dose s.c. injections of 1 microg/kg (n = 24), 2.5 microg/kg (n = 28), 5 microg/kg (n = 28), or 10 microg/kg (n = 40), as well as single-dose i.v. infusions of 5 microg/kg (n = 26), of Zarzio or the reference product (Neupogen). Filgrastim serum levels were monitored; pharmacodynamic parameters were absolute neutrophil count (all studies) and CD34(+) cells (multiple-dose studies). Supportive efficacy and safety data were obtained from an open phase III study in 170 breast cancer patients undergoing four cycles of doxorubicin and docetaxel (Taxotere) chemotherapy, receiving Zarzio (300 or 480 microg) as primary prophylaxis of severe neutropenia.

RESULTS

The results of the studies in healthy volunteers confirm the comparability of the test and reference products with respect to their pharmacodynamics and pharmacokinetics. Confidence intervals were within the predefined equivalence boundaries. In the phase III study in breast cancer patients, the administration of Zarzio was efficacious and safe, triggering no immunogenicity.

CONCLUSION

The results of these studies demonstrate the biosimilarity of Zarzio with its reference product Neupogen.

Modeling the Cost Effectiveness of Secondary Febrile Neutropenia Prophylaxis During Standard-Dose Chemotherapy

Purpose

Current guidelines (ie, by the American Society of Clinical Oncology and the European Organisation for Research and Treatment of Cancer) do not recommend secondary infection prophylaxis, whereas, in contrast, caregivers prefer secondary prophylaxis to chemotherapy dose reduction after an episode of febrile neutropenia (FN). Because granulocyte colony-stimulating factor (G-CSF) is expensive, this study investigates the economic consequences of secondary prophylactic use of different prophylactic strategies (antibiotics, antibiotics plus G-CSF, and a combined sequential approach) in a population at risk of FN, using a Markov model.

Methods

The input for the model is mainly based on the clinical outcome and patient-based cost data set (adopting the health care payer's perspective for the Netherlands) derived from a randomized study on primary prophylaxis in small-cell lung cancer (SCLC) patients; establishing mean cost of an episode FN of €3,290 and prophylaxis of €79 (antibiotics) ± €1,616 (G-CSF) per cycle. The economic analysis was analyzed probabilistically using first- and second-order Monte Carlo simulation. The incremental cost-effectiveness ratio (ICER) was defined as cost per FN-free cycle.

Results

Secondary prophylaxis with antibiotics was the least expensive strategy (mean, €4,496/patient). The strategy antibiotics plus G-CSF was most expensive (mean, € 8,998/patient). Comparison of these two strategies resulted in an unacceptably high ICER (€343,110 per FN-free cycle) in the Dutch context. In scenarios using higher FN-related costs (as found in the United States), the strategies are less distinct in their monetary effects, but still favor antibiotics.

Conclusion

This model-based economic analysis demonstrates that in the Netherlands and most likely also in the United States, if secondary prophylaxis is preferred, the strategy with antibiotics is recommended.

Comparison of pegfilgrastim with filgrastim on febrile neutropenia, grade IV neutropenia and bone pain: a meta-analysis of randomized controlled trials

BACKGROUND AND OBJECTIVE

While head-to-head clinical trials demonstrate pegfilgrastim to be as efficacious as filgrastim in reducing chemotherapy-induced neutropenia, these studies lacked the statistical power to demonstrate better outcomes with one therapy compared to the other. Our objective was to obtain a pooled estimate of the effect of pegfilgrastim compared with filgrastim on incidence of febrile neutropenia (FN), and related outcomes among patients with solid tumors and malignant lymphomas receiving myelosuppressive chemotherapy.

RESEARCH DESIGN AND METHODS

We searched PubMed and EMBASE for articles published from January 1, 1990 to August 31, 2006 reporting on randomized controlled trials (RCTs) that compared the efficacy and safety of pegfilgrastim versus filgrastim. We only accepted studies in which filgrastim (5 microg/kg/day) and pegfilgrastim (100 microg/kg or a fixed dose of 6 mg) were administered at approved doses indicated on the package insert. Pooled relative risk (RR) was estimated using the conservative random effects, empirical Bayesian method of Hedges and Olkin.

MAIN OUTCOME MEASURES

Rates of grade IV neutropenia and of FN, time to absolute neutrophil count (ANC) recovery, and bone pain.

RESULTS

We identified five RCTs, with a total of 617 patients, evaluating the efficacy of a single dose of pegfilgrastim per cycle versus daily filgrastim injections. Although only one study had a statistically significant difference in FN reductions favoring pegfilgrastim over filgrastim (relative risk reduction of 50%; p = 0.027), the pooled RR showed a statistically significant favorable result for pegfilgrastim (RR = 0.64; 95% CI, 0.43-0.97). Grade IV neutropenia rates (for cycle 1: RR = 0.99; 95% CI, 0.91-1.08; cycle 2: RR = 0.88; 95% CI, 0.70-1.11; cycle 3: RR = 0.80; 95% CI, 0.47-1.36; cycle 4: RR = 0.90; 95% CI, 0.71-1.13), time to ANC (SMD = 0.11, 95% CI, -0.34-0.56), and incidence of bone pain (RR = 0.95; 95% CI, 0.76-1.19) were similar between the two G-CSFs. The included trials varied in the type of cancer, chemotherapy regimen and type of trial.

CONCLUSION

A single dose of pegfilgrastim performed better than a median of 10-14 days of filgrastim in reducing FN rates for patients undergoing myelosuppressive chemotherapy.

Granulocyte colony-stimulating factors in the management of chemotherapy-induced neutropenia: evidence based review

(1) Neutropenia is a frequent complication of chemotherapy associated with life-threatening infections, hospitalisation, and chemotherapy dose reductions and delays.(2) Primary prophylaxis with granulocyte colony-stimulating factors has been shown to reduce the incidence and duration of neutropenia, febrile neutropenia, infections, hospitalisation and antibiotic use.(3) Recent randomised clinical trials of filgrastim, lenograstim and pegfilgrastim showed variable results across patient groups at different risks of febrile neutropenia.(4) Pegfilgrastim is at least as effective as filgrastim in the prophylaxis of chemotherapy-induced neutropenia and has improved pharmacokinetics requiring reduced administration.

Cost-Effectiveness of Adding Granulocyte Colony-Stimulating Factor to Primary Prophylaxis With Antibiotics in Small-Cell Lung Cancer

Purpose

Recently, a Dutch, randomized, phase III trial demonstrated that, in small-cell lung cancer patients at risk of chemotherapy-induced febrile neutropenia (FN), the addition of granulocyte colony-stimulating factor (GCSF) to prophylactic antibiotics significantly reduced the incidence of FN in cycle 1 (24% v 10%; P = .01). We hypothesized that selecting patients at risk of FN might increase the cost-effectiveness of GCSF prophylaxis.

Methods

Economic analysis was conducted alongside the clinical trial and was focused on the health care perspective. Primary outcome was the difference in mean total costs per patient in cycle 1 between both prophylactic strategies. Cost-effectiveness was expressed as costs per percent-FN-prevented.

Results

For the first cycle, the mean incremental costs of adding GCSF amounted to 681 euro (95% CI, −36 to 1,397 euro) per patient. For the entire treatment period, the mean incremental costs were substantial (5,123 euro; 95% CI, 3,908 to 6,337 euro), despite a significant reduction in the incidence of FN and related savings in medical care consumption. The incremental cost-effectiveness ratio was 50 euro per percent decrease of the probability of FN (95% CI, −2 to 433 euro) in cycle 1, and the acceptability for this willingness to pay was approximately 50%.

Conclusion

Despite the selection of patients at risk of FN, the addition of GCSF to primary antibiotic prophylaxis did not result in cost savings. If policy makers are willing to pay 240 euro for each percent gain in effect (ie, 3,360 euro for a 14% reduction in FN), the addition of GCSF can be considered cost effective.

Use of Filgrastim among Febrile Inpatients who Received Outpatient Filgrastim or Pegfilgrastim

Purpose

To characterize the inpatient use of filgrastim in cancer patients hospitalized for management of post-chemotherapy fever after receiving either outpatient filgrastim or pegfilgrastim.

Method

Retrospective review of chart records in a single-center, tertiary-care, teaching hospital and outpatient oncology center of cancer patients hospitalized for fever after outpatient chemotherapy and proactive administration of filgrastim or pegfilgrastim. Patients with the following tumor types were included: breast cancer, cervical cancer, colon cancer, Hodgkin disease, intermediate- or high-grade non-Hodgkin lymphoma, small cell or non-small cell lung cancer, and ovarian cancer.

Result

Billing data identified 1,438 outpatient chemotherapy patients treated with filgrastim or pegfilgrastim; 261 (18.2%) of whom were hospitalized for fever. All patients in the filgrastim groups, and 78% of those in the pegfilgrastim group, were given inpatient filgrastim. Duration of filgrastim administration in the inpatient setting was significantly shorter ( P < 0.001) for the pegfilgrastim group.

Conclusions

Filgrastim was frequently administered to cancer patients hospitalized for fever, even after outpatient pegfilgrastim was administered as an adjunct to chemotherapy. Patients treated with once-per-cycle pegfilgrastim in an outpatient setting do not require filgrastim if they are hospitalized for fever before neutrophil recovery. Thus, hospitals could realize immediate cost savings by not treating those patients with filgrastim. This study illustrates the need to develop operational procedures in institutions to rapidly identify prior outpatient pegfilgrastim administration as a patient is admitted for post-chemotherapy fever.

Prevention of chemotherapy-induced febrile neutropenia by prophylactic antibiotics plus or minus granulocyte colony-stimulating factor in small-cell lung cancer: a Dutch Randomized Phase III Study

PURPOSE

Febrile neutropenia (FN) is a major complication of chemotherapy. Antibiotics as well as granulocyte colony-stimulating factor (G-CSF) are effective in preventing FN. This multicenter randomized phase III trial determines whether the addition of G-CSF to antibiotic prophylaxis can further reduce the incidence of FN in patients with small-cell lung cancer (SCLC) at the risk of FN.

PATIENTS AND METHODS

Patients (N = 175) were stratified for stage of disease, performance status, age, and prior chemotherapy treatment, and were randomly assigned for treatment with cyclophosphamide, doxorubicin, and etoposide (CDE), followed by prophylactic antibiotics alone (ciprofloxacin and roxithromycin) or by antibiotics in combination with G-CSF on days 4 to 13.

RESULTS

In cycle 1, 20 patients (24%) in the antibiotics group developed FN compared with nine patients (10%) in the antibiotics plus G-CSF group (P = .01). In cycles 2 to 5, the incidences of FN were practically the same in both groups (17% v 11%). Only the treatment parameters (odds ratio, 0.33; 95% CI, 0.14 to 0.78) and age (1.067 per year; 95% CI, 1.013 to 1.0124) were related to the probability of FN in cycle 1.

CONCLUSION

Primary G-CSF prophylaxis added to primary antibiotic prophylaxis is effective in reducing FN and infections in SCLC patients at the risk of FN with the first cycle of CDE chemotherapy. For patients with similar risk of FN, the combined use of prophylactic antibiotics plus G-CSF can be considered, specifically in the first cycle of chemotherapy.

Increasing chemotherapy dose density and intensity: phase I trials in non-small cell lung cancer and non-Hodgkin's lymphoma

Dose densification and dose escalation of cytotoxic chemotherapy may be important in improving the cure rates of chemotherapy-responsive cancers. We conducted two phase I studies, in non-small cell lung cancer (NSCLC) and in lymphoma, to explore the possibility of intensifying chemotherapy by compressing the delivery of and escalating the dose of standard combination chemotherapy. One study used etoposide and cisplatin chemotherapy in patients with unresectable stage III or IV NSCLC, intensifying chemotherapy by reducing the cycle length. The second study used cyclophosphamide, doxorubicin, vincristine, and prednisone, CHOP chemotherapy, in the treatment of stage II-IV intermediate or immunoblastic high-grade lymphoma, intensifying chemotherapy first by reducing the cycle length and then by escalating the dosages of cyclophosphamide and doxorubicin. Filgrastim support was used during dose intensification. Fifty-five patients with NSCLC and 49 with non-Hodgkin's lymphoma (NHL) were enrolled and treated in successive cohorts. At standard dosages and intervals of chemotherapy, filgrastim support resulted in incidences of grade 3 and 4 neutropenia that were between 62% and 77% lower than those in the no-filgrastim control; the mean duration of neutropenia was, likewise, more than 80% lower. Absolute neutrophil counts were >/=2 x 10(9)/l at day 14 in virtually 100% of patients receiving filgrastim. In the NSCLC trial, etoposide and cisplatin were intensified by >50%, and in the lymphoma trial, cyclophosphamide was intensified by 270% and doxorubicin was intensified by 87%. Chemotherapy reductions or delays for neutropenia were rare in the groups receiving filgrastim; but at higher chemotherapy intensities, dose-limiting thrombocytopenia was encountered. We conclude that the delivery of myelosuppressive chemotherapy in both a dose-intense and a dose-dense manner is feasible with filgrastim support.

6,7-Dihydroxy-3-phenylcoumarin inhibits thromboplastin induced disseminated intravascular coagulation

6,7-Dihydroxy-3-phenylcoumarin (DHPC) was tested to determine whether it had any effect on vitamin K inhibition, by investigating the prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen level and platelet count. The anticoagulant and antithrombotic effects of DHPC were compared with those of warfarin by conducting a 4 h acute trial on thromboplastin-induced disseminated intravascular coagulation (DIC), investigating various haemostatic and antioxidant system parameters and performing a haemogram. Of most significance was that in the 5-d DHPC trial on healthy controls, PT, APTT, fibrinogen, platelet count remained within normal levels. In the 4-h DIC trial, both DHPC (0.025 mg/kg, i.v.) and warfarin (0.25 mg/kg, i.v.) significantly inhibited DIC, by reducing the PT, APTT, and fibrin degradation products and increasing fibrinogen levels and platelet count. In the DIC drug groups, lipid peroxidation significantly increased only in the warfarin group and glutathione significantly increased only in the DHPC group. However leucocyte count was significantly higher in the DHPC than the warfarin group. Further investigation is required for why DHPC is effective on the parameters investigated, at doses one-tenth of those of warfarin.