Background and methodology of MONITOR-GCSF, a pharmaco-epidemiological study of the multi-level determinants, predictors, and clinical outcomes of febrile neutropenia prophylaxis with biosimilar granulocyte-colony stimulating factor filgrastim

Treatment patterns and outcomes in patients with non-small cell lung cancer receiving biosimilar filgrastim for prophylaxis of chemotherapy-induced/febrile neutropaenia: Results from the MONITOR-GCSF study

Objective

Real‐world evidence data on the use of granulocyte colony‐stimulating factor (G‐CSF) in patients with non‐small cell lung cancer (NSCLC) are limited. MONITOR‐GCSF is a pan‐European, multicentre, prospective, non‐interventional study designed to describe patient characteristics, treatment patterns and clinical outcomes in patients receiving biosimilar filgrastim in the prophylaxis of chemotherapy‐induced neutropaenia (CIN) and febrile neutropaenia (FN).

Methods

In this subanalysis, patient characteristics, treatment patterns, and outcomes are described for 345 patients with stage 3 or 4 NSCLC, receiving up to six chemotherapy cycles. Patients were treated with biosimilar filgrastim as per their treating physician's best judgement.

Results

CIN (any grade) occurred in 13.6% of patients in Cycle 1 and in 36.5% of patients in all cycles. FN occurred in 1.4% of patients in Cycle 1 and in 5.2% of patients in all cycles. Grade 3–4 FN occurred in 1.2% of patients in Cycle 1 and in 3.8% of patients in all cycles.

Conclusion

Results show that in real‐life practice in patients with NSCLC, biosimilar filgrastim has similar effectiveness and safety to the known effectiveness and safety profile of reference filgrastim, supporting the use of biosimilar filgrastim for the real‐world treatment of neutropaenia in patients with NSCLC.

Chemotherapy-induced neutropenia/febrile neutropenia prophylaxis with biosimilar filgrastim in solid tumors versus hematological malignancies: MONITOR-GCSF study

Aim: This study aimed to report patterns of biosimilar filgrastim prophylaxis and outcomes of chemotherapy-induced neutropenia (CIN)/febrile neutropenia (FN) in patients with hematological malignancies or solid tumors. Patients & methods: MONITOR-GCSF is a real-world study of 1447 cancer patients receiving CIN/FN prophylaxis with biosimilar filgrastim (solid tumors: 77.2%; hematological malignancies: 22.8%). Results: Differences in prophylaxis intensity and day of initiation relative to guideline recommendations were observed. In hematology patients, higher rates of CIN and FN occurred at cycle level, and rate of FN was higher at patient level (9.1 vs 5.0% in solid tumor patients). Conclusion: Adequate GCSF support in hematology and solid tumor patients is important to prevent CIN/FN and related hospitalizations and chemotherapy disturbances.

Expanded access to cancer treatments from conversion to neutropenia prophylaxis with biosimilar filgrastim-sndz

Aim: Biosimilar medicines offer significant cost-savings potential over their reference products, which can be re-allocated to provide access to other cancer treatments on a budget-neutral basis. Methods: Simulation study using cost data for the USA under consideration of several prophylaxis patterns. Results: Potential savings from conversion from reference filgrastim to biosimilar filgrastim-sndz are significant. These savings expand budget-neutral access to novel immunotherapies (obinutuzumab; pembrolizumab) or supportive care (filgrastim-sndz). Conclusion: The combination of biosimilar savings and expanded access increases the value of cancer care as the same supportive care is provided at lower cost, additional cancer care is enabled at no additional cost, and more patients will have access to cancer care.

Over- and under-prophylaxis for chemotherapy-induced (febrile) neutropenia relative to evidence-based guidelines is associated with differences in outcomes: findings from the MONITOR-GCSF study

PURPOSE

In the MONITOR-GCSF study of chemotherapy-induced (febrile) neutropenia with biosimilar filgrastim, 56.6% of patients were prophylacted according to amended EORTC guidelines, but 17.4% were prophylacted below and 26.0% above guideline recommendations.

METHODS

MONITOR-GCSF is a prospective, observational study of 1447 evaluable patients from 140 cancers centers in 12 European countries treated with myelosuppressive chemotherapy for up to 6 cycles receiving biosimilar GCSF prophylaxis. Patients were classified as under-, correctly-, or over-prophylacted with GCSF relative to guideline recommendations based on their chemotherapy risk, individual risk factors, and type of GCSF prophylaxis (primary versus secondary).

RESULTS

Differences between under- (17.4%), correctly- (56.6%), or over-prophylacted (26.0%) groups were found in terms of patient risk factors (age, performance status, history of FN, comorbid conditions) as well as prophylaxis patterns (type of prophylaxis, day of GCSF initiation, and GCSF duration). Rates of chemotherapy-induced neutropenia (CIN) (all grades), FN, and CIN-related hospitalizations were consistently lower in over-prophylacted patients relative to under- and correctly-prophylacted patients. No differences were observed between under- and correctly-prophylacted patients except for CIN/FN-related chemotherapy disturbances. No GCSF safety differences were found between groups (except for headaches).

CONCLUSIONS

The real-world evidence provided by the MONITOR-GCSF study indicates that providing GCSF support may yield better CIN, FN, and CIN/FN-related hospitalization outcomes if patients are prophylacted at levels above guideline recommendations. Patients who are under-prophylacted are at higher risk for disturbances to their chemotherapy regimens. Our findings support the guideline recommendation that CIN/FN risk be assessed at the beginning of each chemotherapy cycle.

Chemotherapy-induced (febrile) neutropenia prophylaxis with biosimilar filgrastim in elderly versus non-elderly cancer patients: Patterns, outcomes, and determinants (MONITOR-GCSF study)

BACKGROUND

Myelotoxic chemotherapy is associated with chemotherapy-induced (febrile) neutropenia (CIN/FN). The MONITOR-GCSF study evaluated biosimilar filgrastim (Zarzio®) prophylaxis patterns, associated outcomes, and determinants. We performed stratified analyses comparing elderly and non-elderly patients.

METHODS

Comparative (elderly/non-elderly) analysis of demographics and clinical status, prophylaxis, associated CIN/FN outcomes (CIN grade 4 [CIN4], FN, CIN/FN-related hospitalizations and chemodisturbances, composite), and, per hierarchical modeling, determinants thereof evaluated at the patient- and cycle-level.

RESULTS

There were no significant differences between both cohorts in prophylaxis initiation/duration and associated outcomes, but proportionately more elderly patients were correctly-prophylacted and fewer over-prophylacted. Common determinants of poor CIN/FN outcomes included concomitant antibiotic prophylaxis, impaired performance status, and any grade CIN in a previous cycle, whereas common determinants of good outcomes included over-prophylaxis and prophylaxis initiation within 24-72h. In the elderly, female gender, liver/renal/cardiovascular disease, secondary prophylaxis, and under-prophylaxis were associated with poorer outcomes. In the non-elderly, CIN4 at baseline or in a prior cycle was associated with poorer CIN/FN outcomes, and higher biosimilar filgrastim dose and, perhaps counter-intuitively, under-prophylaxis with better outcomes.

CONCLUSION

Adequate GCSF support is essential for all patients, but especially for elderly patients with serious chronic disease, certainly, if concomitant antibiotic prophylaxis is indicated and if a CIN4 episode occurred in a prior cycle. The potential impact of impaired performance status, especially ECOG≥2 at chemotherapy start or a worsening to such during chemotherapy; under-prophylaxis, including inadequate secondary prophylaxis, should be considered in elderly patients. Timely GCSF initiation and over-prophylaxis is associated with lower rates of adverse CIN/FN events in elderly and non-elderly patients, and should be further evaluated in prospective randomized trials.

Predictive modeling of the outcomes of chemotherapy-induced (febrile) neutropenia prophylaxis with biosimilar filgrastim (MONITOR-GCSF study)

BACKGROUND

Risk models of chemotherapy-induced (CIN) and febrile neutropenia (FN) have to date focused on determinants measured at the start of chemotherapy. We extended this static approach with a dynamic approach of CIN/FN risk modeling at the start of each cycle.

DESIGN

We applied predictive modeling using multivariate logistic regression to identify determinants of CIN/FN episodes and related hospitalizations and chemotherapy disturbances (CIN/FN consequences) in analyses at the patient ('ever' during the whole period of chemotherapy) and cycle-level (during a given chemotherapy cycle). Statistical dependence of cycle data being 'nested' under patients was managed using generalized estimation equations. Predictive performance of each model was evaluated using bootstrapped c concordance statistics.

RESULTS

Static patient-level risk models of 'ever' experiencing CIN/FN adverse events and consequences during a planned chemotherapy regimen included predictors related to history, risk factors, and prophylaxis initiation and intensity. Dynamic cycle-level risk models of experiencing CIN/FN adverse events and consequences in an upcoming cycle included predictors related to history, risk factors, and prophylaxis initiation and intensity; as well as prophylaxis duration, CIN/FN in prior cycle, and treatment center characteristics.

CONCLUSIONS

These 'real-world evidence' models provide clinicians with the ability to anticipate CIN/FN adverse events and their consequences at the start of a chemotherapy line (static models); and, innovatively, to assess risk of CIN/FN adverse events and their consequences at the start of each cycle (dynamic models). This enables individualized patient treatment and is consistent with the EORTC recommendation to re-appraise CIN/FN risk at the start of each cycle. Prophylaxis intensity (under-, correctly-, or over-prophylacted relative to current EORTC guidelines) is a major determinant. Under-prophylaxis is clinically unsafe. Over-prophylaxis of patients administered chemotherapy with intermediate or low myelotoxicity levels may be beneficial, both in patients with and without risk factors, and must be validated in future studies.

Biosimilars: A Multidisciplinary Perspective

A biosimilar is an officially regulated and approved copy of an originator biologic therapy. Improved affordability and consequent wider patient access compared with biologics are a significant appeal of biosimilars. Regulatory guidelines for biosimilar development and approval are rigorous and undergoing constant refinement. The process of licensing approval for all biosimilars requires demonstration of comparability in quality, efficacy, and safety between the biosimilar and reference (originator) product, which is undertaken in a stepwise procedure of nonclinical and clinical evaluation. The approval of >20 biosimilars in Europe in several drug classes, including the first monoclonal antibody biosimilar, bears testimony to the increasing regulatory acceptance of these agents. In contrast, the clinical application of biosimilars remains underrecognized by physicians across therapy areas. Therefore, this article aims to provide a comprehensive review of the biosimilar development process and to provide multidisciplinary guidance on the potential therapeutic utility of biosimilars in clinical practice. Specifically, experts discuss clinical developments in the introduction of biosimilars across the disciplines of gastroenterology, nephrology, oncology, and rheumatology, and from a payer perspective, and also highlight a common need for ongoing pharmacovigilance, robust head-to-head clinical studies, and real-world data to establish the long-term risk-benefit profile of biosimilars. In conclusion, significant potential exists for biosimilars to revolutionize biologic therapy by widening patient access across therapy areas.

Clinical experience with Zarzio® in Europe: what have we learned?

Biosimilars are similar, but non-identical, versions of existing biological drugs for which patents have expired. Despite the rigorous approval process for biosimilars, concerns have been expressed about the efficacy and safety of these products in clinical practice. Biosimilars of filgrastim, based on the originator product Neupogen®, have been available since 2008 and are now in widespread clinical use in Europe and elsewhere. Three biosimilar G-CSFs have been approved based on a combination of physicochemical and biological protein characterisation, pharmacokinetic and pharmacodynamic assessment in healthy volunteers and efficacy and safety data in patients with cancer. To assess whether biosimilars are effective in the real-world clinical practice setting, a pooled analysis of five post-approval studies of biosimilar G-CSF (Zarzio®) that included 1,302 adult patients who received at least one cycle of chemotherapy with G-CSF support for the prevention of neutropenia was conducted. A total of 36 % of patients had a febrile neutropenia risk of >20 %, while 39.6 % had a risk of 10-20 % based on chemotherapy regimen. The occurrence of severe or febrile neutropenia was within the range of that observed in previous studies of originator G-CSF. In addition, the safety profile of Zarzio® was consistent with that reported for originator G-CSF and the known safety profile of G-CSF. Initial concerns about the use of biosimilars, at least with regard to biosimilar G-CSFs, appear to be unfounded. Adoption of cost-effective biosimilars should help reduce healthcare costs and improve patient access to biological treatments.

Clinical safety of biosimilar recombinant human granulocyte colony-stimulating factors

INTRODUCTION

A 'biosimilar', or 'similar biological medicinal product', is a biologic agent that is similar in terms of quality, safety and efficacy to an authorized reference biological medicine. Since the expiration of the filgrastim patent in Europe, three agents have received marketing authorization from the EMA: Tevagrastim, Zarzio and Nivestim. Tevagrastim has also been approved as a biologic by the FDA as tbo-filgrastim.

AREAS COVERED

Using the EMA dossiers (all three agents), the FDA dossier (Tevagrastim), and journal publications, this article reviews clinical safety data for these products with emphasis on serious/severe adverse events and special consideration of immunogenicity, bone pain, splenomegaly, allergic reactions, acute respiratory distress syndrome and mortality.

EXPERT OPINION

All three agents have similar safety profiles. None were statistically higher on safety parameters to what is known about originator filgrastim (Neupogen). What is known about filgrastim in general regarding safety can be extended to biosimilar filgrastim. Safety profiles may become more differentiated once long-term product-specific safety data are available. Large-sample, long-term, observational studies of real-world practice will provide the heterogeneity and statistical power to demonstrate product-specific safety profiles. Current evidence indicates that statistically no one product is less and no one product is more safe.

Follow-on biologics in oncology - the need for global and local regulations

The patent expiration for first-generation biological drugs has prompted the development of a new group of biopharmaceuticals – follow-on biologics. The extent of studies needed in the process of follow-on biologics approval is incomparably greater than in the case of generics but reduced in comparison to innovative biologics. The basis for the approval is to show the similarity sufficient to ensure the same quality, safety and efficacy as the reference medicine. In oncology, the most widely used among so far registered follow-on biologics are biosimilar granulocyte colony-stimulating factors, and in the hitherto clinical practice, there have been no concerns about their effectiveness and safety. It is expected that along with the patent expiry of next biologics, the number of follow-on biologics will increasingly grow, that implies the need to develop and implement specific regulations for this new class of medicine.

What do prescribers think of biosimilars?

Until recently, prescribers had to deal with generics, considered to be simple molecules that are easy to copy. But as discussed in this paper, the biodisponibility of generics remains a source of uncertainty. And now there are biosimilars, limited for the time being in the cancer setting to granulocyte-colony stimulating factors (G-CSFs) and epoetins. Soon there will be biosimilar monoclonal antibodies with anticancer activity. Prescribers will ask, as they did for generics, if such drugs have the same activity as originators, if their safety profile is the same, if quality of the production process is guaranteed. Prescribers will want to know if their patients are indeed receiving the prescribed product, and not another. Finally prescribers will want to check that the lower cost of biosimilars will allow them to adhere to international guidelines. This should benefit patients and the community.