Safety Profile of Biosimilar Filgrastim (Zarzio/Zarxio): A Combined Analysis of Phase III Studies

Filgrastim biosimilar (EP2006): A review of 15 years' post-approval evidence

Filgrastim is approved for several indications, including reduction of the incidence and duration of chemotherapy-induced neutropenia and for stem cell mobilization. The filgrastim biosimilar, EP2006, has been available in Europe since 2009, and in the United States since 2015. In this time, preclinical and clinical data used to support the approval of EP2006 have been published. These data established the biosimilarity of EP2006 to reference filgrastim in terms of structure, pharmacokinetics, pharmacodynamics, efficacy, safety, and immunogenicity. Additional real-world evidence studies have also demonstrated equivalent efficacy and safety of EP2006 compared with reference filgrastim, both in the reduction of neutropenia and in stem cell mobilization in clinical practice. This review summarizes these preclinical, clinical, and real-world data, as well as the available cost-effectiveness data, for EP2006 since its approval 15 years ago.

BBCIC Research Network Analysis of First-Cycle Prophylactic G-CSF Use in Patients Treated With High-Neutropenia Risk Chemotherapy

BACKGROUND

Chemotherapy-induced febrile neutropenia (FN) is prevented or minimized with granulocyte colony-stimulating factors (G-CSFs). Several G-CSF biosimilars are approved in the United States. The Biologics and Biosimilars Collective Intelligence Consortium (BBCIC) is a nonprofit initiative whose objective is to provide scientific evidence on real-world use and comparative safety and effectiveness of biologics and biosimilars using the BBCIC distributed research network (DRN).

PATIENTS AND METHODS

We describe real-world G-CSF use in patients with breast or lung cancer receiving first-cycle chemotherapy associated with high FN risk. We assessed hospitalizations for FN, availability of absolute neutrophil counts, and G-CSF-induced adverse events to inform future observational comparative effectiveness studies of G-CSF reference products and their biosimilars. A descriptive analysis of 5 participating national health insurance plans was conducted within the BBCIC DRN.

RESULTS

A total of 57,725 patients who received at least one G-CSF dose were included. Most (92.5%) patients received pegfilgrastim. FN hospitalization rates were evaluated by narrow (<0.5%), intermediate (1.91%), and broad (2.99%) definitions. Anaphylaxis and hyperleukocytosis were identified in 1.15% and 2.28% of patients, respectively. This analysis provides real-world evidence extracted from a large, readily available database of diverse patients, characterizing G-CSF reference product use to inform the feasibility of future observational comparative safety and effectiveness analyses of G-CSF biosimilars. We showed that the rates of FN and adverse events in our research network are consistent with those reported by previous small studies.

CONCLUSIONS

Readily available BBCIC DRN data can be used to assess G-CSF use with the incidence of FN hospitalizations. Insufficient laboratory result data were available to report absolute neutrophil counts; however, other safety data are available for assessment that provide valuable baseline data regarding the effectiveness and safety of G-CSFs in preparation for comparative effectiveness studies of reference G-CSFs and their biosimilars.

Uptake and cost of biosimilar filgrastim among Medicare and Medicaid populations in 2015-2018

BACKGROUND: The first biosimilar product filgrastim-sndz was approved by the FDA in 2015, but real-world evaluations of its uptake and cost in nationally representative populations are limited. OBJECTIVE: To evaluate the uptake and cost of filgrastim-sndz, relative to its originator filgrastim and alternative biologic tbofilgrastim, among Medicare and Medicaid populations. METHODS: Using the annually aggregated, product-level utilization and cost data of biologic and biosimilar filgrastim products in 2015-2018 from CMS drug spending data, total number of claims and costs for all 3 filgrastim products were identified and extracted for Medicare Part B, Part D, and Medicaid reimbursement. Annual average cost per claim and per beneficiary of individual filgrastim products were also extracted, and their annual growth rates were calculated. RESULTS: Three years after entering the US market, use of filgrastim-sndz increased to 49.1% and 46.0% of all filgrastim claims paid by Medicare Parts B and D, respectively, and to 38.7% of filgrastim Medicaid claims in 2018. Total cost for filgrastim-sndz also reached 42.8%, 41.8%, and 26.9% of all filgrastim products paid by Medicare Parts B and D and Medicaid, respectively. Significant reductions in average cost per claim for filgrastim-sndz in 2017 and 2018 were observed in Medicare Part B and Medicaid. CONCLUSIONS: Significant uptake of biosimilar filgrastim in Medicare and Medicaid programs occurred during the first 3 years of marketing. Policymakers may use the evidence to evaluate existing barriers and policies regarding biosimilar adoption. DISCLOSURES: No outside funding supported this work. The author has no conflicts of interest to disclose.

Advances in the pharmacological management of neutropenia in solid tumors: the advent of biosimilars

Introduction: Severe neutropenia and infections are potentially life-threatening complications of cytotoxic antineoplastic therapies and often require hospitalization with a severe economic impact. Furthermore, hematological toxicity frequently results in chemotherapy dose reductions and delays that could interfere with disease control.Areas covered: This review provides an overview of granulocyte colony-stimulating factors (G-CSFs) including pegylated molecules, as well as more recent biosimilar G-CSFs, focusing on the toxicity, pharmacokinetics, and efficacy of these compounds.Expert opinion: The administration of hematopoietic growth factors in primary and secondary prophylaxis of neutropenia is a standard supportive care measure. Recently, several biosimilars have been developed. The market for biosimilar agents seems to be increasing over time thanks to their similar effectiveness and safety, compared with their originators, but lower costs.

NCCN Guidelines Insights: Hematopoietic Growth Factors, Version 1.2020

Management of febrile neutropenia (FN) is an integral part of supportive care for patients undergoing cancer treatment. The NCCN Guidelines for Hematopoietic Growth Factors provide suggestions for appropriate evaluation, risk determination, prophylaxis, and management of FN. These NCCN Guidelines are intended to guide clinicians in the appropriate use of growth factors for select patients undergoing treatment of nonmyeloid malignancies. These NCCN Guidelines Insights highlight important updates to the NCCN Guidelines regarding the incorporation of newly FDA-approved granulocyte-colony stimulating factor biosimilars for the prevention and treatment of FN.

Single-Dose Pharmacokinetics, Pharmacodynamics and Immunogenicity, and Multiple-Dose Immunogenicity of INTP5 (Pegfilgrastim Biosimilar) Versus Reference Pegfilgrastim in Healthy Subjects

BACKGROUND AND OBJECTIVE: INTP5 has been developed as a pegfilgrastim biosimilar. Single-dose, crossover study compared the pharmacokinetics and pharmacodynamics (PK/PD) of INTP5 (pegfilgrastim biosimilar) with reference pegfilgrastim (Neulasta^®, pegfilgrastim-ref) and a multiple-dose, parallel-group study compared the immunogenicity of INTP5 with pegfilgrastim-ref in healthy subjects as part of a complete clinical development plan.

METHODS

In the PK/PD study, subjects received a single subcutaneous 6 mg dose of INTP5 and pegfilgrastim-ref (N = 142) separated by a 6-week washout period. The primary endpoints were area under the serum concentration-time curve measured from time zero to infinity (AUC_0-∞) and maximum measured serum concentration (C_max) of pegfilgrastim and area under the absolute neutrophil count (ANC) versus time curve from time zero to t (AUEC_0-t) and maximum measured ANC (E_max) of baseline non-adjusted ANCs. In the immunogenicity study, subjects received two 6 mg doses of INTP5 (N = 100) or pegfilgrastim-ref (N = 100) separated by 21 days. The primary endpoints were incidence of anti-drug antibodies (ADAs) in the two treatment groups.

RESULTS

The primary PK endpoints [AUC_0-∞ (90% CI 108.59-123.11) and C_max (106.24-118.99)] and the primary PD endpoints [AUEC_0-t (99.07-102.32) and E_max (100.24-104.25)] met the acceptance criteria of 80-125%. The incidence of ADAs was 10.6% in the INTP5 arm and 9.0% in the pegfilgrastim-ref arm. The 90% CI for risk difference of the ADA incidence between INTP5 and pegfilgrastim-ref was 1.64% (- 5.40 to 8.68) and was within the 10% margin. No neutralizing antibodies were reported. Immunogenicity did not impact PK/PD parameters and subjects with aberrant PK/PD/safety did not show immunogenicity concerns. Incidence of adverse events (AEs) was similar with INTP5 and pegfilgrastim-ref in both studies. The most common AEs were musculoskeletal pain and headache.

CONCLUSION

INTP5 showed PK/PD equivalence with pegfilgrastim-ref following a single dose, no clinically meaningful difference in the immune response following multiple doses, and a comparable safety profile.

Extrapolation in Practice: Lessons from 10 Years with Biosimilar Filgrastim

Biosimilar filgrastim (Sandoz) was approved in Europe in 2009 and, in 2015, was the first biosimilar approved in the USA. These authorizations were based on the "totality of evidence" concept, an approach that considers data from structural and functional characterization and comparability analysis and non-clinical and clinical studies. For biosimilar filgrastim, phase III confirmatory clinical studies were performed in the most sensitive population, patients with breast cancer undergoing myelosuppressive chemotherapy. In Europe and the USA, approval was granted for all indications of the reference biologic. Hence, stem cell mobilization and severe chronic neutropenia indications were approved on the basis of extrapolation, with no clinical data available at the time of market authorization in the EU. Although extrapolation is well-accepted in biologic development and regulatory contexts, it remains a misunderstood part of the biosimilarity concept in the medical community. Since approval, more than a decade of obtained clinical experience supports the totality of evidence and reassures clinicians regarding the efficacy and safety of biosimilar filgrastim. This includes real-world data from MONITOR-GCSF, a multicenter, prospective, observational study describing treatment patterns and clinical outcomes of patients with cancer (n = 1447) receiving biosimilar filgrastim for the prophylaxis of chemotherapy-induced neutropenia in solid tumors and hematological malignancies. Evidence is also available from unrelated healthy donors and those with severe chronic neutropenia. Together, the experience from a decade of use of biosimilar filgrastim includes over 24 million patient-days of exposure, which can help reassure oncologists that extrapolation is based on strong scientific evidence and works in practice.

Efficacy and Safety of Supportive Care Biosimilars Among Cancer Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Biologics are widely used to manage the side effects of cancer treatment (e.g., epoetin alfa is used to treat chemotherapy-induced anemia [CIA] and granulocyte colony-stimulating factors [G-CSFs] are used to treat chemotherapy-induced neutropenia [CIN]). As several patents for biologics used in cancer treatment have expired, a number of companies have developed supportive care biosimilars (e.g., epoetin alfa biosimilar, filgrastim biosimilar, pegfilgrastim biosimilar).

OBJECTIVE

The objective of this study was to synthesize current evidence on the efficacy and safety of supportive care biosimilars compared with their reference biologics in oncology.

METHODS

We searched PubMed, Embase, the Cochrane library, ClinicalTrials.gov, ISI Web of Science and several Chinese databases from their inception dates to December 31, 2018 for randomized controlled trials (RCTs) or comparative observational studies that compared the efficacy and safety of supportive care biosimilars and their reference biologics in oncology. We pooled results separately for RCTs and observational studies, as such studies involve different patient populations and are designed differently. We pooled binary outcomes using risk ratios (RR) with confidence intervals (CIs) and continuous outcomes using weighted mean differences (WMD) with 95% CIs, then conducted subgroup and sensitivity analyses. We used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to rate the quality of evidence.

RESULTS

We identified 28 studies that compared biosimilars of G-CSF or epoetin alfa: one RCT and five cohort studies (total N = 2816) of epoetin alfa biosimilars, and 13 RCTs and 9 cohort studies (total N = 23,043) of G-CSF biosimilars [corrected]. Despite involving different populations, RCTs and observational studies comparing biosimilars and reference biologics indicated similar efficacy and safety results. Overall, there was no statistically significant difference in any efficacy or safety outcomes between any biosimilars and their corresponding original biologics (all p > 0.05). The quality of GRADE evidence of efficacy and safety outcomes was moderate or low. Findings were robust for all prespecified subgroup and sensitivity analyses.

CONCLUSION

Existing evidence suggests highly comparable efficacy and safety profiles for supportive care biosimilars and their reference biologics in oncology.