Comparative assessment of clinical response in patients with rheumatoid arthritis between PF-05280586, a proposed rituximab biosimilar, and rituximab

Non-TNF biologics and their biosimilars in rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic inflammatory rheumatic disease that affects both the articular and extra-articular structures, leading to significant joint damage, disability and excess mortality. The treatment algorithm of RA has changed tremendously in the past 1-2 decades because of the emergence of novel biological therapies that target different mechanisms of action in addition to TNFα.

AREAS COVERED

This article summarizes the evidence and safety of the non-TNF biological DMARDs in the treatment of RA, including those that target B cells, T-cell co-stimulation, interleukin (IL)-6 and granulocyte-monocyte colony-stimulating factor (GM-CSF). The targeted synthetic DMARDs such as the Janus kinase inhibitors are not included. The availability of the less costly biosimilars has enabled more patients to receive biological therapy earlier in the course of the disease. The evidence for the non-TNF biosimilar compounds in RA is also reviewed.

EXPERT OPINION

There are unmet needs of developing novel therapeutic agents to enhance the response rate and provide more options for difficult-to-treat RA. These include the newer generation biologic and targeted synthetic DMARDs. A personalized treatment strategy in RA requires evaluation of the cellular, cytokine, genomic and transcriptomic profile that would predict treatment response to biologic or targeted DMARDs of different mechanisms of action.

Exploring the effect on primary endpoints in trials testing targeted therapy interventions for rheumatoid arthritis: a meta-epidemiological study on the appropriate use of a core outcome set

OBJECTIVES

To explore which core domain is best associated with the American College of Rheumatology (ACR) 20% response in trials assessing the effect of targeted interventions in rheumatoid arthritis (RA).

METHODS

A meta-epidemiological study was performed on randomised trials investigating biologics and targeted agents compared with placebo or conventional disease-modifying antirheumatic drugs in patients with RA. The main outcome measures were ORs for the ACR 20% response and at least one of the eight core domains according to the existing RA core outcome set (COS) analysed based on standardised mean differences.

RESULTS

115 trials involving 55 422 patients with RA were eligible. The OR for achieving ACR 20% response was 3.19 (95% CI 2.96 to 3.44) for the experimental interventions relative to the comparators. The median number of COS domains reported was 6; 18 trials reported only 1 domain, 17 all 8. Univariable meta-regression analyses indicated that each of the eight core domains was significantly associated with ACR 20% response, yet improvements in physical disability explain a successful ACR 20% response the most. Including only trials reporting on all eight core domains, univariable meta-regression analyses proved improvement in fatigue to explain a successful ACR 20% response the most.

CONCLUSIONS

Within this dataset, it is evident that the conclusions concerning our primary objective were significantly influenced by both the amount and characteristics of missing data. Our data suggest that fatigue could be more important for the primary endpoint than previously assumed, but this is based on limited data.

Implications of Immunogenicity Testing for Therapeutic Monoclonal Antibodies: A Quantitative Pharmacology Framework

The interpretation of immunogenicity results for a mAb product and prediction of its clinical consequences remain difficult, despite enormous advances in methodologies and efforts toward the best practice for consistent data generation and reporting. To this end, the contribution from the clinical pharmacology discipline has been largely limited to comparing descriptively the pharmacokinetic (PK) profiles by antidrug antibodies (ADA) status or testing the significance of ADA as a covariate in a population PK setting, similar to the practice for small-molecule drugs in investigating the effect of an intrinsic/extrinsic factor on the drug disposition. There is a need for a mAb disposition framework that captures the dynamics of ADA formation and drug's interactions with the ADA and target as parts of the drug distribution and elimination. Here we describe such a framework and examine it against the PK, ADA, and clinical response data from a phase 3 trial in patients treated with adalimumab. The proposed framework offered a generalized understanding of how the dose, target affinity, and drug/ADA analyte forms affects the manifestation of ADA response with regard to its detections and alterations of drug disposition and effectiveness. Furthermore, as an example, its utility for dose considerations was demonstrated through predicting for late-stage trials of a PCSK9 inhibitor in terms of development in ADA incidence and titers, and consequences on the drug disposition, interaction with target, and downstream lowering effect on LDL-C.

A Randomized, Double-Blind, Efficacy and Safety Study of PF-05280586 (a Rituximab Biosimilar) Compared with Rituximab Reference Product (MabThera®) in Subjects with Previously Untreated CD20-Positive, Low-Tumor-Burden Follicular Lymphoma (LTB-FL)

Background

Biosimilars are highly similar to the licensed biologic (“reference product”), with no clinically meaningful differences in safety, purity, or potency between the two products.

Objective

This comparative 52-week clinical study evaluated the efficacy, safety, immunogenicity, pharmacokinetics (PK), and pharmacodynamics (PD) of PF-05280586 (Ruxience™ [a rituximab biosimilar]) versus rituximab reference product sourced from the EU (MabThera^®; rituximab-EU).

Patients and Methods

Subjects with CD20-positive, low-tumor-burden follicular lymphoma (LTB-FL) and an Eastern Cooperative Oncology Group performance status 0–1 were randomized (1:1) to PF-05280586 or rituximab-EU (375 mg/m² intravenously [once weekly for 4 weeks at days 1, 8, 15, and 22]), stratified using the Follicular Lymphoma International Prognostic Index 2 classification. The primary endpoint was overall response rate (ORR) at week 26 (percentage of subjects achieving complete response [CR] or partial response [PR]). Therapeutic equivalence was concluded if the two-sided 95% confidence interval (CI) for the difference in ORR between groups was within the prespecified margin (± 16%). Secondary endpoints included progression-free survival (PFS), CR rate, safety, immunogenicity, PK, and PD.

Results

A total of 394 subjects were randomized: PF-05280586 (n = 196) or rituximab-EU (n = 198). ORR at week 26 was 75.5% (PF-05280586) versus 70.7% (rituximab-EU), for a difference of 4.66%; 95% CI (− 4.16 to 13.47), which was entirely within the prespecified equivalence margin. Rates of CR were 29.3% (PF-05280586) versus 31.0% (rituximab-EU). Estimated 1-year PFS rates were 78.2% (95% CI 70.2–84.2) and 83.0% (95% CI 75.0–88.6) for PF-05280586 and rituximab-EU, respectively. Safety, immunogenicity, and mean serum concentrations were similar between groups.

Conclusions

The efficacy, safety, immunogenicity, PK, and PD of PF-05280586 and rituximab-EU were similar up to week 52 in subjects with previously untreated CD20-positive LTB-FL.

Clinical Trial Registration

ClinicalTrials.gov, NCT02213263 and EudraCT (2014-000132-41).

Electronic supplementary material

The online version of this article (10.1007/s40259-019-00398-7) contains supplementary material, which is available to authorized users.

A mechanistic pharmacokinetic model with drug and antidrug antibody interplay, and its application for assessing the impact of immunogenicity response on bioequivalence testing

AIMS

Single-dose pharmacokinetic (PK) studies in healthy subjects have been the design of choice for bioequivalence determination for decades. This preference has been recently extended to PK similarity studies of proposed biosimilars. However, PK similarity studies can be complicated by the effect of immunogenicity response on drug disposition. The impact is exacerbated when there is an imbalance in host-specific immunological characteristics of subjects between the test and reference groups. Such complications remain poorly understood. The purpose of this communication is to show that the impact of immunogenicity response on PK similarity determination can be critical, using adalimumab as an example.

METHODS

Data for adalimumab concentrations and immunogenicity response over 10 weeks were obtained from 133 healthy subjects receiving a 40 mg dose of Humira® in a PK similarity study. Also, a population PK model with a mechanistic construct for delineating the interplay between adalimumab disposition and antidrug antibodies response was utilized to estimate via simulation the probability that a PK similarity study would fail in typical study settings.

RESULTS

The simulations showed that the immunogenicity response can have a profound impact on the outcome of PK similarity determination. As such, the probability of failing to achieve the similarity conclusion increased to 51.9%, from 13.8% in the absence of immunogenicity response.

CONCLUSION

This study provides a model-based framework for better understanding of how a PK similarity study can be optimally designed and for interpretation of the outcome of PK similarity determination when the drug disposition is affected in the presence of immunogenicity response.

Rituximab biosimilars for lymphoma in Europe

Introduction: The approval of rituximab, a monoclonal antibody targeting CD20, revolutionized the treatment of B-cell non-Hodgkin lymphomas and became an undisputed standard of care. However, as with all biologic medicines, the complex development and manufacturing process for rituximab have meant that the medicine attracts high treatment costs. Approved rituximab biosimilars have been comprehensively demonstrated to match the reference medicine. With the potential to increase access to biologic therapy, they have a key role in helping to improve patient outcomes in lymphoma care. Areas covered: In this review, we discuss the role of rituximab in the treatment of lymphoma. We explore development and regulatory requirements for biosimilar development and the potential impact of these medicines on access and sustainability. Focusing on biosimilars of rituximab, we examine in detail the evidence for biosimilarity for the two rituximab biosimilars that are approved in Europe and provide an overview of rituximab biosimilars currently in development. Expert opinion: We foresee a wider uptake of biosimilar medicines for lymphoma treatment over the next 5 years. The associated cost savings should be invested in broadening patient access to biological therapies, enabling wider use of more expensive treatment strategies and driving innovation in cancer care.

Efficacy and safety of switching from rituximab to biosimilar CT-P10 in rheumatoid arthritis: 72-week data from a randomized Phase 3 trial

Objective

To evaluate the efficacy and safety of CT-P10, a rituximab biosimilar after a single switch, during a multinational, randomized, double-blind Phase 3 trial involving patients with RA.

Methods

Patients received 48 weeks’ treatment with CT-P10 or United States- or European Union-sourced reference rituximab (US-RTX and EU-RTX, respectively). Patients entering the extension period (weeks 48–72) remained on CT-P10 (CT-P10/CT-P10; n = 122) or US-RTX (US-RTX/US-RTX; n = 64), or switched to CT-P10 from US-RTX (US-RTX/CT-P10; n = 62) or EU-RTX (EU-RTX/CT-P10; n = 47) for an additional course. Efficacy endpoints included Disease Activity Score using 28 joints (DAS28), American College of Rheumatology (ACR) response rates, and quality of life-related parameters. Pharmacodynamics, immunogenicity and safety were also assessed.

Results

At week 72, similar improvements were observed by disease activity parameters including DAS28 and ACR response rate in the four extension period treatment groups. Quality of life improvements at week 72 vs baseline were similarly shown during the extension period in all groups. Newly developed anti-drug antibodies were detected in two patients following study drug infusion in the extension period. Similar pharmacodynamic and safety profiles were observed across groups.

Conclusion

Long-term use of CT-P10 up to 72 weeks was effective and well tolerated. Furthermore, switching from reference rituximab to CT-P10 in RA was well tolerated and did not result in any clinically meaningful differences in terms of efficacy, pharmacodynamics, immunogenicity and safety.

Trail registration

ClinicalTrials.gov, http://clinicaltrials.gov, NCT02149121.

Role of biological agents in treatment of rheumatoid arthritis

Advances in understanding of the pathophysiology of rheumatoid arthritis with concurrent advances in protein engineering led to the development of biological disease-modifying antirheumatic drugs which have dramatically revolutionized the treatment of this condition. This review article focuses on the role of biological agents currently employed in the treatment of rheumatoid arthritis, as well as novel biological agents in development.

Practical Guidance on Biosimilars, With a Focus on Latin America: What Do Rheumatologists Need to Know?

BACKGROUND/HISTORICAL PERSPECTIVE

Availability of biologic disease-modifying antirheumatic drugs (bDMARDs) has improved clinical outcomes in rheumatoid arthritis, but it also increased the cost of treatment. Biosimilars, the regulated copies of biologic products, have a potential to reduce health care costs and expand access to treatment. However, because of a complex development process, biosimilars can be considered only those noninnovator biologics with satisfactory supporting evidence (ranging from structural to clinical), as outlined in the recommendations by the World Health Organization (WHO). In Latin America, a heterogeneous regulatory landscape and nonconsistent approval practices for biosimilars create decision-making challenges for practicing rheumatologists.

SUMMARY OF LITERATURE

Most Latin American countries either have adopted or are in the process of adopting guidelines for the approval of biosimilars. However, among several marketed bDMARDs in the region, currently there are only 2 products that could be considered true biosimilars, based on the WHO criteria. The rest can be considered only intended copies, whose safety and efficacy are not fully established. One such product had to be withdrawn from the market because of safety concerns.

CONCLUSIONS AND FUTURE DIRECTIONS

Practicing rheumatologists in Latin America need to understand the regulatory situation for biosimilars in their countries. When considering bDMARDs that are not innovator products, clinicians should use only those that have been approved according to the WHO recommendations. For clarification, local health authorities or professional associations should be contacted.

Structural and functional comparability study of anti-CD20 monoclonal antibody with reference product

Background

Cell surface protein, CD20, is extensively expressed on the surface of B cells. Antibodies targeting CD20 protein are being used to treat B-cell malignancies and B-cell mediated autoimmune diseases. Considering the cost of therapy with innovator monoclonal antibodies for these diseases, development of biosimilar products for the treatment of such diseases provides affordable solution to rising healthcare costs.

Materials and Methods

Reference products of rituximab (six batches) were procured and stored as per manufacturer's instructions. Cell lines used in bioassay were procured from American Type Culture Collection and all other reagents used for analysis were of analytical grade. Primary structure was studied by intact mass analysis, peptide fingerprinting, peptide mass fingerprinting and sequence coverage analysis. Higher order structure was studied by circular dichroism, ultraviolet-visible spectroscopy, fluorescence spectroscopy, and disulfide bridge analysis. Different isoforms of reference product and SB-02 were identified using capillary isoelectric focusing and capillary zone electrophoresis. Glycosylation was studied by N-glycan mapping using LC-ESI-MS, point of glycosylation, released glycan analysis using ultra performance liquid chromatography (UPLC). Product related impurities such as oligomer content analysis and oxidized impurities were studied using size exclusion chromatography and reverse phase high performance liquid chromatography, respectively.

Results and Conclusion

Here, we report physicochemical and biological characterizations of Sun Pharma’s proposed biosimilar (SB-02) to rituximab, a monoclonal anti-CD20 antibody approved for the treatment of non-Hodgkin’s lymphoma and chronic lymphocytic leukemia. SB-02 and rituximab exhibited indistinguishable primary as well as higher-order structure upon analyzing with the array of analytical and extended characterization methods according to statistical methods. The molecule also displayed comparability to reference product in post-translational modifications and charge heterogeneity. In functional bioassays, SB-02 demonstrated comparable potency with respect to reference product. Our results indicate highly similar quality profile between SB-02 and rituximab.

Application of Pharmacometric Analysis in the Design of Clinical Pharmacology Studies for Biosimilar Development

This article provides an overview of four case studies to demonstrate the utility of pharmacometric analysis in biosimilar development to help design sensitive clinical pharmacology studies for the demonstration of biosimilarity. The two major factors that determine the sensitivity of a clinical pharmacokinetic/pharmacodynamic (PK/PD) study to demonstrate biosimilarity are the size of the potential difference to be detected (signal) and the inter-subject variability (noise), both of which can be characterized and predicted using pharmacometric approaches. To maximize the chance to detect any potential difference between the proposed biosimilar and the reference drug, the dose selected for the clinical pharmacology study should fall on the steep part of the dose-response curve. Pharmacometric analysis can be used to characterize the dose-response relationship using PD- or PK/PD-linked models. The understanding of the PD endpoints in terms of dynamic range of the response and the location of the studied dose on the dose-response curve can provide strategic advantage in the trial design. To reduce the inter-subject variability (noise), pharmacometric analysis can help avoid high variability associated with low doses, and decrease variability by controlling certain covariates in the inclusion/exclusion criteria. Pharmacometric analysis also can help select or justify margins for the equivalence test of PD endpoints. Pharmacometric analysis will assume an ever-increasing role in the clinical development of biosimilar drugs, as it helps to ensure that sufficient sensitivity is built into the study design to detect potential PK and PD differences.

Biosimilars: Implications for Clinical Practice

In 2015, the United States Food and Drug Administration (FDA) approved the first biosimilar, filgrastim-sndz, a biosimilar of the granulocyte colony-stimulating factor filgrastim. Since that time, the FDA has approved four additional biosimilar tumor necrosis factor α inhibitors, and, in May 2017, the Oncology Drug Advisory Committee voted in favor of approval of an epoetin alfa biosimilar. The patents of several widely used biologic cancer therapies (including trastuzumab, rituximab, bevacizumab, cetuximab, and pegfilgrastim) are recently expired or due to expire in the near future, so the introduction of biosimilars into the oncology treatment armamentarium is imminent. However, their arrival also will introduce challenges, including pharmacy and supply chain management and the need for education of clinicians and patients about the efficacy and safety of these agents. These considerations, along with an overview of biosimilars in the oncology pipeline, will be discussed in this review.

Biosimilars: implications for rheumatoid arthritis therapy

PURPOSE OF REVIEW

Abbreviated pathways for the approval of biosimilars have been established in the European Union (EU), the United States, and other countries. Biosimilar TNF inhibitors have been available in South Korea and the EU since 2012 and 2013, respectively, and the first biosimilar infliximab was introduced to the clinic in the United States in November 2016. Five TNF inhibitor biosimilars have now been approved, and many other biosimilars to treat rheumatoid arthritis and other inflammatory diseases are in development.

RECENT FINDINGS

Over the last 18 months, published results of randomized clinical trials (RCTs) have shown equivalent efficacy and comparable safety and immunogenicity of biosimilars with their reference products. 'Real world' experience with biosimilars in the EU continues to increase and provides evidence regarding the efficacy and safety of using biosimilars in the clinic and of switching from bio-originators to their biosimilars.

SUMMARY

Cost implications of using biosimilars and extrapolation of their use to treat diseases in which they were not tested in RCTs are of great interest. We review the results of RCTs and available experience with biosimilars in the clinic.

A randomised, double-blind trial to demonstrate bioequivalence of GP2013 and reference rituximab combined with methotrexate in patients with active rheumatoid arthritis

Objectives

The aim of this report is to demonstrate pharmacokinetic (PK) and pharmacodynamic (PD) equivalence as well as similar efficacy, safety and immunogenicity between GP2013, a biosimilar rituximab, and innovator rituximab (RTX) in patients with rheumatoid arthritis (RA) with inadequate response or intolerance to tumour necrosis factor inhibitor (TNFi) treatment.

Methods

In this multinational, randomised, double-blind, parallel-group study, 312 patients with active disease despite prior TNFi therapy were randomised to receive GP2013 or either the EU (RTX-EU) or the US (RTX-US) reference product, along with methotrexate (MTX) and folic acid. The primary endpoint was the area under the serum concentration–time curve from study drug infusion to infinity (AUC_0-inf). Additional PK and PD parameters, along with efficacy, immunogenicity and safety outcomes were also assessed up to week 24.

Results

The 90% CI of the geometric mean ratio of the AUCs were within the bioequivalence limits of 80% to 125% for all three comparisons; GP2013 versus RTX-EU: 1.106 (90% CI 1.010 to 1.210); GP2013 versus RTX-US: 1.012 (90% CI 0.925 to 1.108); and RTX-EU versus RTX-US: 1.093 (90% CI 0.989 to 1.208). Three-way PD equivalence of B cell depletion was also demonstrated. Efficacy, safety and immunogenicity profiles were similar between GP2013 and RTX.

Conclusions

Three-way PK/PD equivalence of GP2013, RTX-EU and RTX-US was demonstrated. Efficacy, safety and immunogenicity profiles were similar between GP2013 and RTX.

Trial registration number

NCT01274182; Results.

Comparative assessment of clinical response in patients with rheumatoid arthritis between PF-05280586, a proposed rituximab biosimilar, and rituximab

AIMS

To evaluate potential differences between PF-05280586 and rituximab sourced from the European Union (rituximab-EU) and USA (rituximab-US) in clinical response (Disease Activity Score in 28 Joints [DAS28] and American College of Rheumatology [ACR] criteria), as part of the overall biosimilarity assessment of PF-05280586.

METHODS

A randomised, double-blind, pharmacokinetic similarity trial was conducted in patients with active rheumatoid arthritis refractory to anti-tumour necrosis factor therapy on a background of methotrexate. Patients were treated with 1000 mg of PF-05280586, rituximab-EU or rituximab-US on days 1 and 15 and followed over 24 weeks for pharmacokinetic, clinical response and safety assessments. Key secondary end points were the areas under effect curves for DAS28 and ACR responses. Mean differences in areas under effect curves were compared against respective reference ranges established by observed rituximab-EU and rituximab-US responses using longitudinal nonlinear mixed effects models.

RESULTS

The analysis included 214 patients. Demographics were similar across groups with exceptions in some baseline disease characteristics. Baseline imbalances and group-to-group variation were accounted for by covariate effects in each model. Predictions from the DAS28 and ACR models tracked the central tendency and distribution of observations well. No point estimates of mean differences were outside the reference range for DAS28 or ACR scores. The probabilities that the predicted differences between PF-05280586 vs. rituximab-EU or rituximab-US lie outside the reference ranges were low.

CONCLUSIONS

No clinically meaningful differences were detected in DAS28 or ACR response between PF-05280586 and rituximab-EU or rituximab-US as the differences were within the pre-specified reference ranges.

TRIAL REGISTRATION NUMBER

NCT01526057.