Comparison of the pharmacokinetic and pharmacodynamic profiles of one US-marketed and two European-marketed epoetin alfas: a randomized prospective study

Satisfying QTPP of Erythropoietin Biosimilar by QbD through DoE-Derived Downstream Process Engineering

Well-characterized and scalable downstream processes for the purification of biologics are extremely demanding for delivering quality therapeutics to patients at a reasonable price. Erythropoietin (EPO) is a blockbuster biologic with diverse clinical applications, but its application is limited to financially well-off societies due to its high price. The high price of EPO is associated with the technical difficulties related to the purification challenge to obtain qualified products with a cost-effective defined process. Though there are reports for the purification of EPO there is no report of a well-characterized downstream process with critical process parameters (CPPs) that can deliver EPO consistently satisfying the quality target product profile (QTPP), which is a critical regulatory requirement. To advance the field, we applied the quality by design (QbD) principle and design of experiment (DoE) protocol to establish an effective process, which is scalable up to 100× batch size satisfying QTPP. We have successfully transformed the process from static mode to dynamic mode and validated it. Insignificant variation (p > 0.05) within and between 1×, 10×, and 100× batches showed that the process is reproducible and seamlessly scalable. The biochemical analysis along with the biofunctionality data ensures that the products from different scale batches were indifferent and comparable to a reference product. Our study thereby established a robust and scalable downstream process of EPO biosimilar satisfying QTPP. The technological scheme presented here can speed up the production of not only EPO but also many other life-saving biologics and make them available to the mass population at a reduced cost.

Analysis of Pharmacokinetic and Pharmacodynamic Parameters in EU- Versus US-Licensed Reference Biological Products: Are In Vivo Bridging Studies Justified for Biosimilar Development?

BACKGROUND

Bridging studies are mandatory in the EU and USA if the reference biological product used in the biosimilar comparability exercise is foreign sourced. However, it has been argued that the duplication of bridging studies may limit biosimilar development.

OBJECTIVE

The aim of the study was to explore whether it is necessary to conduct pharmacokinetic (PK)/pharmacodynamic (PD) bridging studies for biosimilars. This study examines similarities and differences between EU- and US-licensed reference biological products, based on literature-reported PK and/or PD data.

METHODS

We searched PubMed, Drugs@FDA, and European Medicines Agency (EMA) databases to identify biosimilar bridging studies designed to evaluate similarities between EU- and US-licensed reference biological products. PK and/or PD parameters were retrieved; the ratio of the parameter value of the EU-licensed product to that of the US-licensed product and its corresponding 90% confidence intervals (CIs) were calculated. Similarity was declared if the 90% CIs for the ratios of the PK or PD parameters were within the range of 80-125%.

RESULTS

Thirty-one bridging studies were identified for 11 biosimilars, including adalimumab (n = 10), bevacizumab (n = 4), epoetin alfa (n = 1), etanercept (n = 2), filgrastim (n = 1), infliximab (n = 3), insulin glargine (n = 1), insulin lispro (n = 1), PEGfilgrastim (n = 2), rituximab (n = 2), and trastuzumab (n = 4). Most studies showed PK and/or PD similarities between the EU- and US-licensed reference biological products. However, among the 31 studies, only three studies (accounting for two biologics, PEGfilgrastim and adalimumab) showed dissimilarity between the EU and US reference products. Although one bridging study on PEGfilgrastim (Sandoz) indicated dissimilar PKs (maximum observed plasma concentration [C_max] and area under the concentration-time curve [AUC]) between the reference products, the other study (Mylan) demonstrated similar PK. Moreover, two of ten studies involving adalimumab failed to demonstrate similarities between the reference products. However, for both cases, PK similarities were later confirmed in the follow-up bridging studies with larger sample sizes.

CONCLUSION

Our analysis reveals that, in most cases, the reference biological products originated from the EU and those from the USA are almost indistinguishable in terms of PK/PD properties. Additional in vivo bridging studies between reference products from different global regions may not be required if similar physicochemical and structural properties are evident in vitro.

Epoetin Biosimilars in the Treatment of Renal Anemia: What Have We Learned from a Decade of European Experience?

Biosimilars are biological medicines that are approved via stringently defined regulatory pathways on the basis that comparable safety, efficacy, and quality have been demonstrated to their reference medicine. The advantage of biosimilar drugs is that they may be less expensive than the reference medicine, allowing for greater patient access and cost savings in already stretched healthcare budgets. Biosimilar epoetins have been available in Europe for a decade. Complementing in vitro and preclinical characterization, and pharmacokinetic/pharmacodynamic studies, clinical trials provided the additional data needed to reassure European authorities that biosimilar epoetins were sufficiently similar to the reference epoetin to warrant approval. Post-approval, real-world studies have provided further evidence that biosimilar epoetins are an effective and well-tolerated option for the treatment of renal anemia, with ongoing pharmacovigilance and observational studies monitoring for any unexpected long-term signals that have not been identified in clinical development studies. As the evidence and experience with these products increase, many of the initial concerns are being alleviated. Nephrologists can be increasingly confident that European Medicines Agency-approved biosimilars offer high-quality, affordable, effective alternatives to existing reference medicines used to treat renal anemia, and may help yield cost savings and improve patient access.

Effectiveness of Switch to Erythropoiesis-Stimulating Agent (ESA) Biosimilars versus Maintenance of ESA Originators in the Real-Life Setting: Matched-Control Study in Hemodialysis Patients

BACKGROUND

In hemodialysis (HD), switching from erythropoiesis-stimulating agent (ESA) originators to biosimilars is associated with the need for doses approximately 10% higher, according to industry-driven studies.

OBJECTIVE

The aim of this study was to evaluate the efficacy on anemia control of switching from ESA originators to biosimilars in daily clinical practice.

METHODS

We retrospectively selected consecutive HD patients receiving stable intravenous ESA doses, and who had not been transfused in the previous 6 months, from 12 non-profit Italian centers. Patients switched from originators to biosimilars (n = 163) were matched with those maintained on ESA originators (n = 163) using a propensity score approach. The study duration was 24 weeks, and the primary endpoint was the mean dose difference (MDD), defined as the difference between the switch and control groups of ESA dose changes during the study (time-weighted average ESA dose minus baseline ESA dose).

RESULTS

Age (70 ± 13 years), male sex (63%), diabetes (29%), history of cardiovascular disease (40%), body weight (68 ± 14 kg), vascular access (86% arteriovenous fistula), hemoglobin [Hb] (11.2 ± 0.9 g/dL) and ESA dose (8504 ± 6370 IU/week) were similar in the two groups. Hb remained unchanged during the study in both groups. Conversely, ESA dose remained unchanged in the control group and progressively increased in the switch group from week 8 to 24. The time-weighted average of the ESA dose was higher in the switch group than in the control group (10,503 ± 7389 vs. 7981 ± 5858 IU/week; p = 0.001), leading to a significant MDD of 2423 IU/week (95% confidence interval [CI] 1615-3321), corresponding to a 39.6% (95% CI 24.7-54.6) higher dose of biosimilars compared with originators. The time-weighted average of Hb was 0.2 g/dL lower in the switch group, with a more frequent ESA hyporesponsiveness (14.7 vs. 2.5%). Iron parameters and other resistance factors remained unchanged.

CONCLUSIONS

In stable dialysis patients, switching from ESA originators to biosimilars requires 40% higher doses to maintain anemia control.

Development and 10-year history of a biosimilar: the example of Binocrit®

Patent expirations for several biological products have prompted the development of alternative versions, termed ‘biosimilars’, which have comparable quality, safety and efficacy to a licensed biological medicine (also referred to as the ‘reference’ medicine). The first biosimilars developed in oncology were the supportive-care agents filgrastim and epoetin. Binocrit^® (HX575) is a biosimilar version of epoetin alfa, indicated in the oncology setting for the treatment of chemotherapy-induced anemia (CIA). The process for development and approval of Binocrit^® as a biosimilar included extensive analytical characterization and comparison with the reference epoetin alfa. This was followed by a clinical development program comprising phase I pharmacokinetic/pharmacodynamic studies to show bioequivalence to the reference medicine and a confirmatory phase III study to confirm therapeutic effectiveness in CIA. Since its approval, Binocrit^® has been extensively used and studied in real-world clinical practice. The accumulated data confirm that Binocrit^® is an effective and well-tolerated option for the treatment of CIA in patients with cancer.

Structure-Function Relationships for Recombinant Erythropoietins: A Case Study From a Proposed Manufacturing Change With Implications for Erythropoietin Biosimilar Study Designs

Comparability studies used to assess a proposed manufacturing change for a biological product include sensitive analytical studies to confirm there are no significant differences in structural or functional attributes that may contribute to clinically meaningful changes in efficacy or safety. When a proposed change is relatively complex or when clinically relevant differences between the product before and after the change cannot be ruled out based on analytical studies, nonclinical and clinical bridging studies are generally required to confirm overall comparability. In this study, we report findings from a comparability assessment of epoetin alfa before and after a proposed manufacturing process change. Although differences in glycosylation attributes were observed, these were initially believed to be irrelevant to the product's pharmacology. This assumption was initially supported via nonclinical and clinical pharmacology studies, but a clinically meaningful difference in potency was ultimately observed in a phase 3 clinical study conducted in a sensitive patient population using a sensitive study design. These results indicate that the nonclinical assessments of structure-function relationships were insufficiently sensitive to identify clinically relevant differences resulting from differences in the glycosylation profile. This case study highlights important findings that may be relevant in the development of biosimilar epoetin alfa products.

Comparable pharmacokinetics and pharmacodynamics of two epoetin alfa formulations Eporon® and Eprex® following a single subcutaneous administration in healthy male volunteers

Purpose

This study aimed to assess and compare the pharmacokinetic (PK) and pharmacodynamic (PD) properties following a single subcutaneous injection of epoetin alfa (Eporon^®) with those of the comparator (Eprex^®) in healthy male subjects.

Subjects and methods

A randomized, double-blind, two-sequence, crossover study was conducted. Subjects were randomly assigned to receive a single dose, that is, 4,000 IU, of the test or comparator epoetin alfa. After 4 weeks, all subjects received the alternative formulation. The primary PK parameters, maximum observed concentration (C_max) and area under the curve extrapolated to infinity (AUC_inf), were calculated with the serum erythropoietin (EPO) concentrations from blood samples collected for 144 h after dosing. The reticulocyte, hematocrit, hemoglobin and red blood cell counts were measured up to 312 h as PD markers. The primary PD parameters, maximum observed effect (E_max) and area under the effect curve (AUEC), were obtained from the baseline-corrected reticulocyte count. The serum EPO concentration and the reticulocyte count were used to assess the concentration–response relationship. The tolerability and immunogenicity profiles were assessed together.

Results

Forty-two subjects completed the study. The mean EPO concentration–time profiles were comparable between the two formulations. The geometric mean ratios (90% CI) of the C_max and AUC_inf were 0.908 (0.843–0.978) and 1.049 (0.999–1.101), respectively, both of which were within the regulatory range of 0.80–1.25. Additionally, the PD and tolerability profiles were similar between the two formulations. The time-matched serum EPO concentration and PD markers presented a counterclockwise hysteresis, suggesting a time delay between the measured concentration and the response. Both formulations were well tolerated, and production of anti-drug antibodies was not observed.

Conclusion

The two epoetin alfa formulations had similar PK, PD and tolerability profiles. Furthermore, both formulations had a similar time-matched serum EPO concentration and erythropoietic response profile. Thus, the two formulations are expected to be used interchangeably in clinical settings.

Biosimilars - terms of use

The impending expiry of the patent on a number of leading biologic drugs has led to a surge in the development of 'biosimilar' or 'follow-on' products. However, in contrast to generic small-molecule medicines, biosimilars are not identical to their reference products. The differences and complexities surrounding both the molecular structure and the manufacturing process for biologics and biosimilars have resulted in a lack of clarity regarding the terms used in different parts of the world to define various aspects of development and utilization such as regulatory approval, pharmacovigilance, interchangeability and treatment-naivety. This makes quantitative evaluation of biosimilars a great challenge to both the scientific community and regulatory agencies. This manuscript attempts to clarify the terms used and address an important knowledge gap which is currently resulting in an increasing rush to position biosimilars for certain indications and patients in the absence of agreed upon definitions.

The approval process for biosimilar erythropoiesis-stimulating agents

A biosimilar drug or follow-on biologic drug is defined by the Public Health Service Act as a product that is "highly similar to the reference product notwithstanding minor differences in clinically active components and there are no clinically meaningful differences between the biologic product and the reference product in terms of the safety, purity and potency of the product." The advantage of biosimilar drugs is that they are significantly less expensive than the reference products, allowing for increased accessibility and cost savings. Recognizing these advantages, the US Congress passed the Biologics Price Competition and Innovation Act in 2009 as part of health care reform. The Biologics Price Competition and Innovation Act allows sponsors of biosimilar agents to seek approval by showing structural and functional similarity to the reference agent, with the extent of required clinical studies to be determined on the basis of the degree of biosimilarity with the reference product. The goal is to bring biosimilar agents to the market more efficiently while still protecting the safety of the public. The European Union has had such a process in place for a number of years. Two biosimilar epoetin agents have been approved in the European Union since 2007, and their companies are conducting trials to seek approval in the United States, because Amgen's patent protection for epoetin alfa expires in 2014. Trials completed for European Union approval of both agents showed similar efficacy and safety to the reference epoetin alfa. As with all biologics, immunogenicity concerns may persist because of the fragility of the manufacturing process and the worldwide experience with pure red cell aplasia as a result of epoetin therapy. The uptake of biosimilar epoetins after approval in the United States will depend on the balance of cost advantage against safety concerns. Competition in the marketplace will likely decrease the cost of the reference agent as well.

Biosimilars in the therapy of inflammatory bowel diseases

A biosimilar is a copy of an approved biological medicine whose patent protections have expired. Biosimilars of antibodies to tumour necrosis factor α (TNFα) are becoming important in the treatment of inflammatory bowel diseases (IBD). The first one introduced commercially is an infliximab biosimilar. The aim of this study was to provide an overview of anti-TNFα biosimilars. The literature on biosimilars of monoclonal anti-TNFα antibodies was reviewed, including their manufacture and approval pathways, concerns about efficacy, safety, immunogenicity, extrapolation, switching and labelling. Previous experience with biosimilars of epoetin and other growth factors was also reviewed. The infliximab biosimilar CT-P13 was the first biosimilar monoclonal antibody registered for the treatment of IBD. The major advantage of biosimilars is the reduced cost of therapy. Concerns have arisen, however, about the efficacy and safety of CT-P13 in IBD, the extrapolation of results from rheumatologic trials to IBD and the free interchangeability of CT-P13 with infliximab. Experience with simple peptide biosimilars, such as epoetins and growth factors, has generally been positive, with these biosimilars having similar efficacy and safety as the original products, although immunogenicity remains a major concern. Upcoming postregistration studies will address concerns on biosimilars in IBD, including their efficacy, safety, immunogenicity, switching and interchangeability. Biosimilars active against the same epitopes, but with improved pharmacokinetic properties that enhance their efficacy and/or safety, may be the next stage in the development of biosimilars. Anti-TNFα biosimilars represent promising new treatment options for patients with IBD. However, data on their efficacy and safety in IBD are needed.

Erythropoiesis-stimulating agents for the treatment of chemotherapy-induced anemia: comparisons from real-world clinical experience

Background

The purpose of this paper is to report real-world data on the relative effectiveness of a biosimilar erythropoiesis-stimulating agent (ESA; Binocrit^®), and other available ESAs for the treatment of chemotherapy-induced anemia.

Methods

Data were collected retrospectively from single centers in Spain (n=284) and Germany (n=145). Hemoglobin outcomes, transfusion requirements, and serious drug-related adverse events were assessed for each ESA.

Results

Hemoglobin outcomes and transfusion requirements were generally similar in the different ESA treatment groups assessed. No serious drug-related adverse events were recorded in any of the treatment groups.

Conclusion

These data confirm the real-world effectiveness and safety of a biosimilar ESA (Binocrit^®) for the treatment of cancer patients with chemotherapy-induced anemia.

Efficacy and safety data of subsequent entry biologics pertinent to nephrology practice: a systematic review

Background

Subsequent entry biologics (SEBs) may soon be a reality in Canadian nephrology practice. Understanding the worldwide experience with these agents will be valuable to Canadian clinicians.

Objectives

To compare the efficacy and safety data between SEBs used in nephrology practice and their reference biologic.

Design

Systematic review.

Sources of information

Ovid MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Database of Abstracts of Review of Effects, Cochrane Central Register of Controlled Trials.

Patients

Adult patients with chronic kidney disease (CKD).

Methods

Our systematic review follows the process outlined by Cochrane Reviews. For efficacy data, all randomized controlled trials (RCTs), quasi-RCTs and observational trials in nephrology practice were included. For safety data, case series, case reports, review articles in nephrology practice and pharmacovigilance programs were included as well.

Results

Only epoetin SEBs trials were published in the literature. Ten studies involving three different epoetin SEBs (epoetin zeta, HX575 and epoetin theta) were included. The mean epoetin dose used did not differ significantly between the SEBs and the reference product. For epoetin zeta and epoetin theta, the mean hemoglobin levels achieved in the studies were similar between the SEBs and the reference epoetin. The HX 575 studies reported a mean absolute change in hemoglobin within the predefined equivalence margin, when compared with the reference biologic. In terms of safety data, 2 cases of pure-red-cell aplasia were linked to the subcutaneous administration of HX 575. Otherwise, the rate of adverse drug reactions was similar when epoetin SEBs were compared with the reference biologic.

Limitations

Our analysis is limited by the paucity of information available on SEB use in nephrology with the exception of epoetin SEBs. Methodological flaw was found in one of the epoetin zeta studies which accounted for 45% of pooled results.

Conclusions

Little clinical difference was found between epoetin SEBs and the reference product. Although not deemed clinically important, the financial implication of a possible dose difference between epoetin zeta and reference product should be considered in pharmacoeconomic studies. Ongoing trials are expected to address the risk of pure-red-cell aplasia with HX 575.

Differentiating factors between erythropoiesis-stimulating agents: an update to selection for anaemia of chronic kidney disease

Erythropoiesis-stimulating agents (ESAs) have become a hallmark of anaemia therapy in patients with chronic kidney disease (CKD). Although different ESAs are available for the treatment of renal anaemia, each nephrologist should select a single ESA for an individual patient. Epoetin alfa and epoetin beta have been used 1-3 times weekly but extended-interval dosing up to every 4 weeks is also effective in a substantial majority of CKD patients. However, the epoetin dose necessary to achieve or maintain target haemoglobin (Hb) levels increases substantially as the dosing interval increases. Subcutaneous administration of short-acting ESAs is more effective than the intravenous route of administration. Darbepoetin alfa and the continuous erythropoietin receptor activator (CERA) have been developed as a treatment for anaemia with extended administration intervals (every 2 weeks and every 4 weeks, respectively). Dose requirements for these long-acting ESAs are independent of the route of administration. Patents of short-acting ESAs have expired, which has opened the field for biosimilars. Epoetin biosimilars approved by the European Medicines Agency (EMA) or the US Food and Drug Administration (FDA) have been shown to have a comparable efficacy and safety profile to their originators. An alarming increase in pure red cell aplasia (PRCA) in Thailand with follow-on epoetins manufactured in Asia (but also those manufactured in Latin America) indicates that stringent country-specific approval and pharmacovigilance protocols for ESAs manufactured in non-North American and non-EU European countries are urgently needed. Two PRCA cases occurring with subcutaneous HX575 (one certain, one likely) indicate that chances of inducing a more immunogenic product are unpredictable, even with a biosimilar epoetin approved under the EMA biosimilar approval pathway. Phase III clinical trials with peginesatide, a pegylated synthetic peptide-based ESA without any homology to erythropoietin raised safety concerns in non-dialysis CKD patients but not in dialysis patients.