Switching Between Epoetins: A Practice in Support of Biosimilar Use

Biosimilar-to-Biosimilar Switching: What is the Rationale and Current Experience?

Over time, clinicians have become increasingly comfortable embracing the prescription of biosimilars-highly similar versions of innovator or reference biological agents-for their patients with inflammatory diseases. Although a switch from a reference product to a licensed biosimilar version (or vice versa) is a medical decision robustly supported by the stepwise accumulation of clinical trial evidence concerning comparable safety, immunogenicity, and efficacy between these products, a switch from one biosimilar to another biosimilar of the same reference product, or a cross-switch, is not. Similarity among biosimilars of a reference product is not a regulatory agency concern and therefore is unlikely to be investigated in randomized controlled trials in the foreseeable future. Yet in clinical practice, across a diverse range of patients, the option to cross-switch from one biosimilar to another can and does arise for valid reasons such as convenience or tolerability issues, or driven by third parties (e.g., payers). In the absence of clinical trial data, clinicians must attempt to objectively evaluate the emerging real-world cross-switching evidence within the context of what is known about the science underpinning a designation of biosimilar. That knowledge then needs to be integrated with what clinicians know about their patients and their disease on a case-by-case basis. This review aims to consolidate relevant emerging real-world data and other key information about biosimilar-to-biosimilar cross-switching for prescribing clinicians. In the absence of clear clinical guidelines addressing this topic at present, this review may serve to facilitate discretionary and educated treatment decision making.

The "Square Box": Therapeutic Equivalence as a Foundation of the WHO Model List of Essential Medicines

Every two years, the World Health Organization (WHO) updates its Model List of Essential Medicines, intended as a guide for countries to adopt or adapt in accordance with local priorities and treatment guidelines, for the development of national essential medicines lists. When more than one therapeutic option is available for a given indication, the WHO Model List often includes a single medicine as representative of a group of equivalent and interchangeable medicines. The representative medicine of that group is listed with an accompanying ‘square box’ symbol. The intended purpose of the square box is to highlight pharmacological classes or groups of medicines for which countries, institutions and health professionals can assume homogeneous therapeutic efficacy and safety and select the most appropriate single medicine based on price, local availability, and acceptability. Though this concept of therapeutic equivalence within a therapeutic class has been endorsed by most authoritative textbooks of pharmacology since Goodman & Gilman’s The Pharmacological Basis of Therapeutics and evidence-based guidelines, marketing forces have often made claims on individual drugs to distinguish them beyond relevant differences shown by reliable evidence: this has generated the concept of “me-too drugs” with its double meaning—i.e., market latecomers differing minimally from products preceding them and whose marketing budgets have significant opportunity costs, or medicines which may be useful to substitute for equivalent products in the event of shortages. The square box concept is applied in the context of a comprehensive list: therapeutic equivalence or interchangeability cannot always be easily established. Different interpretations have been applied to different groups of medicines over the 40+ year history of the Model List. This paper presents the concept of the square box, provides key examples and guidance on how square box listings should be practically interpreted in the development and implementation of national essential medicine lists, considers the applicability of a square box listing concept to biologic medicines and proposes that an updated review of the square box concept and listings is warranted.

Effectiveness and Safety of Switching Originator and Biosimilar Epoetins in Patients with Chronic Kidney Disease in a Large-Scale Italian Cohort Study

Introduction

Real-world data on the comparative effectiveness and safety of switching among different epoetins (including originators and biosimilars) are limited. In light of current debate about interchangeability, prescribers, some patient groups and decision makers are calling for additional post-marketing evidence on the clinical effects of switching between originator and biosimilar epoetins in chronic kidney disease (CKD) patients.

Objective

The objective of this study was to evaluate the effectiveness and safety of switching versus non-switching and of switching from originator/biosimilar epoetin alpha (ESA α) to any other epoetin in CKD patients.

Methods

An observational, record-linkage, multi-database, retrospective cohort study was carried out in four Italian geographical areas. All subjects with at least one ESA α dispensing between 1 January 2009 and 31 December 2015 were retrieved. Switching was defined as any transition between originator/biosimilar ESA α to any other epoetin in a series of two consecutive prescriptions up to 2 years. Switchers were matched 1:1 with non-switchers by baseline propensity score and by duration of ESA α treatment. Switchers and non-switchers were followed up from switching date to a maximum of 1 year. Lack of effectiveness and safety of switching versus non-switching were evaluated through Cox regression models (hazard ratio [HR], 95% confidence interval [CI]). A direct comparison between the two switcher categories (switchers from originator/biosimilar ESA α to any other epoetin) was also performed.

Results

Overall, 14,400 incident users of ESA α for anaemia due to CKD (61.4% originator, 38.6% biosimilar) were available for analysis. During the follow-up, we found no differences on effectiveness (HR 1.02, 95% CI 0.79–1.31 originators; HR 1.16, 95% CI 0.75–1.79 biosimilars) and safety outcomes (HR 1.08, 95% CI 0.77–1.50 originators; HR 1.20, 95% CI 0.66–2.21 biosimilars) between switchers and non-switchers of ESA α. Cumulative probabilities of recording an adverse event, either in terms of lack of effectiveness or safety issue, were the same for two switching categories

Conclusions

In this large-scale Italian observational multi-database study, switching versus non-switching as well as switching from biosimilar/originator ESA α to any other epoetin in CKD patients is not associated with any effectiveness and safety outcomes.

Electronic supplementary material

The online version of this article (10.1007/s40264-019-00845-y) contains supplementary material, which is available to authorized users.

In Search of Predictors of Switching Between Erythropoiesis-Stimulating Agents in Clinical Practice: A Multi-Regional Cohort Study

BACKGROUND AND OBJECTIVES

Switching between different erythropoiesis-stimulating agents (ESAs) during the first year of therapy is frequent (15-20%), much more so toward reference products than biosimilars. The objectives of this study were to investigate the frequency and identify the potential predictors of switching between biosimilar and originator ESAs during the first year of treatment in patients with chronic kidney disease (CKD), or chemotherapy-related anemia from six large Italian geographic areas in the years 2009-2015.

METHODS

A retrospective cohort study was conducted using six Italian regional claims databases (≥ 13 million inhabitants) during 2009-2015. Among incident epoetin users, the frequency of single, multiple, and backward switch during the first year of treatment was evaluated. Using frailty Cox models, potential predictors of first switch were identified. All analyses were stratified by the main indications for use.

RESULTS

Among 102,240 incident epoetin users, 15,853 (15.5%) switched to another epoetin during the first year of therapy; only 18% of these switched to biosimilars. Single switch was more common (62.2% of the switchers) than multiple (23.5%) or backward switch (14.3%). In cancer, the cumulative number of transfusions and iron preparations dispensed, as well as hyperparathyroidism, were predictors of switching. In CKD, the cumulative number of transfusions, number of vitamin A/D preparations dispensed, and CKD severity increased the probability of switching.

CONCLUSIONS

Switching between ESAs was frequent in both CKD and cancer patients. The number of cumulative transfusions and severity of disease seemed to affect the switch.

Safety of Biologics, Including Biosimilars: Perspectives on Current Status and Future Direction

In recent years, marketing of highly innovative and costly biologics improved the management of high-burden diseases such as autoimmune diseases, cancers, and chronic renal failure. Several widely prescribed biologics have recently lost or will shortly lose their patents, thus opening avenues to the marketing of a growing number of biosimilars worldwide, which are products similar in terms of quality, safety, and efficacy to already licensed reference products, thus allowing for potential savings in pharmaceutical expenditure. Numerous debates about the interchangeability between biosimilars and reference products are still ongoing, owing to concerns about potential immunogenicity raised by switching, which may cause a lack of effect and toxicity. Patients successfully treated with biologic therapy may theoretically receive biosimilars to contain costs, if reference product and related biosimilar are judged as interchangeable. However, the positions of regulatory agencies on the interchangeability and automatic substitution of biologics with biosimilars are very different. The benefit-risk profile of biosimilars has been often questioned by clinicians owing to the limited amount of pre-marketing information on clinical efficacy and safety, despite biosimilarity being based on a comparability exercise with the reference product to gain the biosimilar approval. Nevertheless, after more than 10 years of marketing from the first biosimilar approval in Europe, no proof of differences in terms of the safety profile of biosimilars and originators has been reported. In this context, post-marketing evaluation of both biologics and biosimilars safety profiles through analyses from spontaneous reporting databases and claims databases is crucial. An important issue for the pharmacovigilance of biologics concerns the traceability, indicating the brand name and batch number in spontaneous adverse drug reaction reports, but this requirement is not frequently addressed. This review aims to provide an overview of the characteristics and potential challenges in the safety profile assessment of biologics with a focus on the post-marketing setting.

Epoetin Biosimilars in the Treatment of Chemotherapy-Induced Anemia: 10 Years' Experience Gained

High-quality, safe, and effective biosimilars have the potential to increase access to biological therapies worldwide and to reduce cancer care costs. The European Medicines Agency (EMA) was the first regulatory authority to establish legislative procedures for the approval of biosimilars when they published their guidelines on similar biological medicinal products in 2005. Biosimilar epoetins were first approved in 2007, and a wealth of data has been collected over the last decade. Two biosimilar epoetins (under five commercial names) have been approved by the EMA so far. The availability of epoetin biosimilars generated discussion among the oncology community regarding prescribing these products, their efficacy, and their safety. These agents are approved only if they are shown in extensive analytical and clinical testing to have comparable quality, safety, and efficacy to the reference medicine, and real-world studies provide further data that biosimilar epoetins are an effective and well-tolerated option for the treatment of chemotherapy-induced anemia in patients with cancer. Other countries have adopted similar regulatory pathways to those in Europe and have approved epoetin biosimilars. The now extensive European experience with biosimilar epoetins should reassure regulators from other territories.

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.

Studies on drug switchability showed heterogeneity in methodological approaches: a scoping review

BACKGROUND AND OBJECTIVE

Several drugs share the same therapeutic indication, including those undergoing patent expiration. Concerns on the interchangeability are frequent in clinical practice, challenging the evaluation of switchability through observational research. The objective of this study was to conduct a scoping review of observational studies on drug switchability to identify methodological strategies adopted to deal with bias and confounding.

METHODS

We searched PubMed, EMBASE, and Web of Science (updated January 31, 2017) to identify studies evaluating switchability in terms of effectiveness/safety outcomes or compliance. Three reviewers independently screened studies extracting all characteristics. Strategies to address confounding, particularly previous drug use and switching reasons, were considered. All findings were summarized in descriptive analyses.

RESULTS

Thirty-two studies, published in the last 10 years, met the inclusion criteria. Epilepsy, cardiovascular, and rheumatology were the most frequently represented clinical areas. Seventy-five percent of the studies reported data on effectiveness/safety outcomes. The most frequent study design was cohort (65.6%) followed by case-control (21.9%) and self-controlled (12.5%). Case-control and case-crossover studies showed homogeneous methodological strategies to deal with bias and confounding. Among cohort studies, the confounding associated with previous drug use was addressed introducing variables in multivariate model (47.3%) or selecting only adherent patients (14.3%). Around 30% of cohort studies did not report reasons for switching. In the remaining 70%, clinical parameters or previous occurrence of outcomes was measured to identify switching connected with lack of effectiveness or adverse events.

CONCLUSION

This study represents a starting point for researchers and administrators who are approaching the investigation and assessment of issues related to interchangeability of drugs.

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.

Real-world use of biological drugs in patients with psoriasis/psoriatic arthritis: a retrospective, population-based study of years 2010-2014 from Southern Italy

BACKGROUND

Biological drugs, such as infliximab, etanercept, adalimumab, ustekinumab, golimumab and certolizumab are third-line therapy for psoriasis (PsO) and psoriatic arthritis (PsA), but they may be used at earlier stage in severe forms. This study investigated the pattern of use and costs of biological drugs for PsO/PsA in a large population from Southern Italy during the years 2010-2014.

METHODS

This was a retrospective, population-based, drug-utilization study, using healthcare administrative databases of the ASL (Local Health Unit) and two hospitals of Messina Province (Sicily) in the years 2010-2014. Incident users of adalimumab, ustekinumab, infliximab, etanercept and golimumab for PsO/PsA were characterized. Yearly prevalence of use and costs, as well as time to treatment discontinuation and switch were assessed.

RESULTS

During the study period, 517 patients received at least one study drugs prescription for PsO/PsA and 304 (58.8%) were incident users, mostly treated with adalimumab (33.6%). Incident users were mostly males (59.8%), with a median age of 49 years. The prevalence of biological drugs users in PsO/PsA increased from 4.3 to 6.9 per 10,000 inhabitants from 2011 to 2014. Pharmaceutical expenditure of the study drugs almost doubled (from 2.6 to 4.7 million euros over 5 years of observation). During the first year of treatment, discontinuation occurred in 31.8% of incident users and switch was not infrequent (7.4%).

CONCLUSIONS

Prevalence of use and costs of biological drugs for PsO/PsA substantially increased in recent years in a large population of Southern Italy. Larger uptake of lowest cost biological drugs, and biosimilars whenever available, may help access to the most innovative drugs.

Pharmacoutilization of epoetins in naïve patients with hematological malignancies in an unselected Italian population under clinical practice setting: a comparative analysis between originator and biosimilars

Aim

The purpose of this study was to assess the prescription of epoetins and consumption of health care resources (in terms of drug treatments) in naïve patients with hematological malignancies in a real-world setting; in particular, we compared the results between reference product and biosimilar products.

Methods

An observational retrospective study based on administrative and laboratory databases of three local health units was conducted. All adults diagnosed with hematological malignancies and who had received at least one epoetin (either reference product or biosimilars) prescription for the first time between 1 January 2010 and 30 April 2012 (enrollment period) were included. The date of the first prescription of epoetin within the enrollment period was defined as index date (ID). Patients were followed up for 4 weeks after ID (follow-up period) and were investigated for the 1-year period before the ID. The difference between the last hemoglobin (Hb) measurement after ID and the one prior to ID (ΔHb) was evaluated. The drug cost analysis was conducted from the perspective of the Italian National Health System.

Results

Overall, 69 patients were included in the study; 48 of them received reference epoetin product and 21 received biosimilars as first prescription. Among reference product users, the mean ± standard deviation (SD) age was 62.5±14.7 years; this cohort of patients was slightly significantly younger than the biosimilar users (71.8±11.8 years). The mean ± SD overall Hb level prior to treatment was lower among patients who started with biosimilar products (9.6±1.1 g/dL) compared to those who started with a reference product (10.1±2.1 g/dL). No significant differences in ΔHb were observed between biosimilar and originator groups during the followup period. The mean ± SD cost per patient was €667.98±573.93 and €340.85±235.73 for the reference product and biosimilar users, respectively (p=0.065).

Conclusion

Our study showed that the use of biosimilar products might contribute to controlling health care costs (in terms of drug treatments) for patients with hematological malignancies being maintained by high-quality anemia therapy. Our findings also showed some discordances regarding the most appropriate therapeutic approach in daily clinical practice.