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Results A total of 220 patients were randomized to receive study treatment as assigned. Of these, 198 met per‐protocol population criteria for inclusion in the PK data analysis. PF‐05280586, rituximab‐EU and rituximab‐US exhibited similar PK profiles following administration of assigned study drug on days 1 and 15. The 90% confidence intervals of test‐to‐reference ratios for C max, AUC T, AUC 0–∞ and AUC 2‐week were within the bioequivalence margin of 80.00–125.00% for comparisons of PF‐05280586 with rituximab‐EU, PF‐05280586 with rituximab‐US, and rituximab‐EU with rituximab‐US.

All treatments resulted in a rapid and profound reduction in CD19+ B cells and sustained profound B cell suppression up to week 25. The incidence of antidrug antibody (ADA) response ( n = 7, 10 and 9 for PF‐05280586, rituximab‐EU and rituximab‐US, respectively), time to ADA emergence and ADA titres were similar across treatments. None of the ADA‐positive samples was positive for neutralizing activity.

No clinically meaningful differences in adverse events were identified. Introduction The term ‘biosimilar’ refers to a biologic product developed to be highly similar to an existing licensed or approved biologic product,,,. Biosimilars are expected to be an essential component in enhancing patient access to these important, often lifesaving biologic products. Biologics are large, structurally complex molecules; even minor changes in the manufacturing process could produce differences that can affect the safety, immunogenicity and potency of the molecule,. Regulatory decisions for approval are based on the totality of the evidence generated from a stepwise approach that generally includes analytical, clinical pharmacokinetic (PK), and efficacy and safety studies intended to support the demonstration of biosimilarity,,,. Rituximab is a genetically engineered chimeric murine/human monoclonal immunoglobulin (Ig) G1κ antibody directed against the CD20 antigen of B cells,.

It is indicated for non‐Hodgkin's lymphoma, chronic lymphocytic leukaemia (in combination with chemotherapy), rheumatoid arthritis (RA; in combination with methotrexate) and granulomatosis with polyangiitis and microscopic polyangiitis (in combination with glucocorticoids),. The pathophysiology of RA is unknown, although it is thought to involve activation of an innate immune response, including antigen presentation and production of autoantibodies and cytokines by B cells, and involvement of other key effector cells and inflammatory modulators. Thus, B cells are an important and appropriate target for the treatment of RA, as confirmed by the efficacy of rituximab since its approval in 2006. PF‐05280586, which is under development as a potential biosimilar to rituximab, has the same primary amino acid sequence, and similar physicochemical and in vitro functional properties as rituximab,. A multicentre, multinational, randomized, double‐blind, controlled trial (REFLECTIONS B328‐01), reported herein, was designed to demonstrate the PK similarity of PF‐05280586 to rituximab sourced from the European Union (rituximab‐EU; MabThera®, F.

Hoffmann‐La Roche, Basel, Switzerland ) and United States (rituximab‐US; Rituxan®, Genentech Inc., South San Francisco, CA, USA ), and between rituximab‐EU and rituximab‐US. The present study also evaluated the pharmacodynamics (PD) and overall safety, tolerability and immunogenicity of the study drugs. Methods This study was registered ( identifier: ) and conducted in compliance with the Declaration of Helsinki and with all International Conference on Harmonisation Good Clinical Practice guidelines.

In addition, all local regulatory requirements were followed and, in particular, those affording greater protection to the safety of trial participants. The final protocol, amendments and informed consent documentation were reviewed and approved by institutional review boards and/or independent ethics committees at each investigational centre participating in the study.

A signed and dated informed consent was required from each patient before any screening procedures were conducted. Study population and design This was a phase I, double‐blind, randomized, parallel‐group, three‐arm trial (Figure ). The primary objective was to demonstrate PK similarity of PF‐05280586, rituximab‐EU and rituximab‐US in patients with active RA on a background treatment of methotrexate and who had an inadequate response to one or more tumour necrosis factor (TNF) antagonist therapies. Secondary objectives included assessing PD, safety, tolerability and immunogenicity.

Rituximab produces profound and prolonged B cell depletion,, precluding the conduct of PK studies in healthy subjects. Its use in the present clinical trial population was consistent with the labelled indication for rituximab‐EU and rituximab‐US,.

Eligible participants were adults (aged ≥18 years) with a confirmed diagnosis of RA based on 2010 American College of Rheumatology (ACR)/European League Against Rheumatism classification criteria. PD PD was evaluated using circulating CD19+ B cell counts (as a surrogate marker for CD20+ B cells) and serum IgM.

Blood samples for CD19+ B cell counts were collected predose (day 1, within 1 h prior to the start of the first infusion), and then at 72 h (day 4), 168 h (day 8), 335 h (day 15, within 1.5 h before the second infusion), 504 h (day 22), 672 h (day 29), 1344 h (day 57), 2016 h (day 85), 2688 h (day 113), 3360 h (day 141) and 4032 h (day 169). As a lowering of IgM levels has been reported in patients treated with B cell‐depleting therapies, serum samples for evaluation of IgM levels were collected at the same time points. Blood samples were analysed for CD19+ B cell counts using a laser scanning cytometry procedure (ApoCell Inc., Houston, TX, USA). CD19+ B cell count vs.time data were analysed by standard noncompartmental methods using Phoenix WinNonlin and used to calculate the mean minimum CD19+ B cell count ( C min,B cell) and median time to C min,B cell ( t min B cell).

The AUC for CD19+ B cell count vs.time (AUC T, B cell) was estimated using linear trapezoidal linear interpolation. The duration of B cell depletion ( τ B cell) was calculated as the time interval over which CD19+ B cell counts were below the quantitation limit. CD19+ B cell counts for those samples without corresponding absolute white blood cell counts could not be calculated and were not included in the data analysis. Serum samples were assayed for IgM concentrations at Covance Central Laboratory Services Inc.

(Indianapolis, IN, USA). Immunogenicity Serum samples for detecting antidrug antibodies (ADAs) and neutralizing antibodies (Nabs) were collected on days 1 (predose), 15, 29, 57, 85 and 169. Immunogenicity sample analyses followed a tiered approach of screening, confirmation and endpoint titre determination using two validated electrochemiluminescent assays – one developed to detect antibodies against PF‐05280586 and the other to detect antibodies against rituximab‐EU and rituximab‐US (QPS, LLC, Newark, DE, USA). The two ADA assays demonstrated similar performance characteristics during assay validation. The ADA samples were first analysed using the ADA assay specific for the dosed product. Samples confirmed positive for antibodies to the dosed product were then assessed for cross‐reactivity using the alternative assay. Any samples confirmed positive for ADA were further tested for Nab using one of two (one for PF‐05280586 and one for rituximab‐EU and rituximab‐US) cell‐based Nab assays.

Nab assays were based on the functionality of Nab to inhibit the complement‐dependent cytotoxicity of PF‐05280586, rituximab‐EU and rituximab‐US on CD20+ WIL2‐S cells (a human B lymphoma cell line). Safety The safety analysis was performed in all enrolled patients who received the study drug (the modified intent‐to‐treat population) and included AEs, electrocardiogram readings, vital signs and clinical laboratory data. The type, incidence and severity (mild, moderate or severe) of AEs, and the investigator's opinion of the relationship to the study treatment of any AEs, including adverse drug reactions, illnesses with onset during the study, exacerbation of previous illnesses or any clinically significant changes in physical examination or abnormal objective laboratory findings, were investigated. Treatment‐emergent AEs were defined as any AE that occurred during or after study drug administration of the first dose of the study drug or any pre‐existing events that worsened in severity after dosing. Any AEs occurring postinfusion were reviewed as potential infusion‐related reactions and verified by the reporting investigator. All serious AEs (SAEs; i.e.

Events that resulted in death, were life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in a persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect, or jeopardized the patient or required medical or surgical intervention to prevent one of these outcomes) were to be reported immediately to the sponsor, regardless of treatment or suspected relationship to study drug. If an SAE occurred, the sponsor was to be notified within 24 h of investigator awareness of the event. Statistical analysis Statistical analysis consisted of one‐way analyses of variance comparing the natural log‐transformed PK parameters ( C max, AUC 0–∞, AUC 2‐week and AUC T) for each pair‐wise comparison (PF‐05280586 vs. Rituximab‐US, PF‐05280586 vs. Rituximab‐EU, and rituximab‐EU vs. Estimates of adjusted mean differences and corresponding 90% confidence intervals (CIs) were obtained from the model and were exponentiated to provide estimates of the ratio of adjusted geometric means and 90% CIs for the ratios.

PK similarity was considered to have been demonstrated for a given test‐to‐reference comparison if the 90% CI of the ratio was within the 80.00–125.00% bioequivalence acceptance window. A sample size of 65 patients per group (195 patients total) was required to provide approximately 89% power for showing bioequivalence simultaneously for all three AUC 0–∞ comparisons, and approximately 97% power for showing bioequivalence simultaneously for all three C max comparisons. Consequently, the study was designed to have at least 86% power overall to demonstrate PK similarity of PF‐05280586 to rituximab‐EU and rituximab‐US. This estimate was based on the assumption that the true ratio of PF‐05280586 to rituximab‐EU and rituximab‐US for both AUC 0–∞ and C max was 1.00, and interpatient standard deviations (SDs) were 0.34 for log e AUC 0–∞ and 0.30 for log e C max. Approximately 210 patients were to be randomized to ensure that at least 195 patients completed PK‐related procedures per protocol. Patient demographics and disposition A total of 220 patients were randomized to treatment groups and received the study treatment as assigned (Figure ). Baseline demographics were generally similar among patients (Table ).

The majority of patients were female [ n = 170 (77.3%)] and white [ n = 171 (77.7%)], with a mean age of 54.4 years, mean weight 83.13 kg and mean body mass index 30.07 kg m –2. Of these 220 patients, 198 met per‐protocol population criteria for inclusion in the PK data analysis.

Patient disposition and ineligibility information for inclusion in the per‐protocol population is provided in Figure and Table. Baseline demographics (mITT population) A total of 18 (8.2%) patients discontinued before completing the study, including nine, three and six treated with PF‐05280586, rituximab‐EU and rituximab‐US, respectively (Figure ). No notable differences were observed across groups with regard to reason for discontinuation of the study. In the per‐protocol population, there were no significant imbalances in demographic characteristics known to affect the disposition of the study drugs among groups.

Mean ± SD body weights in the PF‐05280586, rituximab‐EU and rituximab‐US groups were 86.0 ± 22.2, 82.4 ± 20.4 and 79.9 ± 21.4 kg, respectively. PK The study drugs exhibited similar PK profiles, characterized by a rapid increase in serum drug concentration during each infusion on days 1 and 15, followed by a multiphasic decline in drug concentrations after each infusion (Figure ). Mean peak concentrations ranged from 327 μg ml –1 to 357 μg ml –1 following the first infusion and from 385 μg ml –1 to 421 μg ml –1 following the second infusion. The trough concentration ( C trough) levels immediately before the second infusion were between 78.4 μg ml –1 and 91.8 μg ml –1.

Individual and mean ± SD serum concentration–time profiles in patients with rheumatoid arthritis receiving 1000 mg intravenous doses of study drugs on day 1 and day 15 (per‐protocol population). Panels A–C: Green dashed. Mean values and interpatient variability of the PK parameters obtained from the concentration–time data of the 12‐week PK assessment period ( C max, AUC T, AUC 0–∞, AUC 2‐week, CL, V ss and t 1/2) were similar across all groups (Table; Figure ). The CV% was 26–38% for C max, 34–40% for AUC T and 37–45% for AUC 0–∞. Adjusted geometric means and 90% CIs for the ratios of C max, AUC T, AUC 0–∞ and AUC 2‐week were within the acceptance window of 80.00–125.00% for comparisons of PF‐05280586 with rituximab‐EU and rituximab‐US, and rituximab‐EU with rituximab‐US (Table ). PD Mean CD19+ B cell counts at baseline were 84–100 cells μl –1.

All treatments resulted in rapid CD19+ B cell depletion following dose administration on day 1 (Figure ). By week 2, mean CD19+ B cell count values had decreased by 98.2% to 99.8% in all groups. CD19+ B cell counts remained suppressed for the study duration (24 weeks). CD19+ B cell counts recovered to at least 50% of baseline at the end of treatment in three (4.1%) patients treated with PF‐05280586, six (8.1%) treated with rituximab EU and six (8.2%) treated with rituximab‐US. CD19+ B cell count over time in the modified intent‐to‐treat population. B, baseline In all three groups, C min,B cell values were below the quantitation limit, with a t min,B cell of 1 week. The mean (±SD) area under the CD19+ B cell count vs.

Time curve (AUC T, B cell) was 13 312 [±13 309 ( n = 68)], 14 304 [±13146 ( n = 69)] and 12 496 [±13500 ( n = 67)] cellsday ml –1 in the PF‐05280586, rituximab‐EU and rituximab‐US groups, respectively. The mean duration of B cell depletion (τ B cell) was 120–126 days. Overall, there were no observed differences among groups in the CD19+ B cell count vs. Time profile and the parameters determined. There were no major variations in circulating IgM values over time, with only small differences among the groups (data not shown). Immunogenicity Immunogenicity was evaluated in all 220 patients who received at least one dose of study drug for ADA responses (Table ).

Thirteen patients ( n = 4, n = 6 and n = 3 receiving PF‐05280586, rituximab‐EU and rituximab‐US, respectively) tested positive for low titres of ADAs in samples collected at baseline. Of these 13 patients, eight ( n = 4, n = 3 and n = 1, respectively) tested negative in all subsequent postdose samples. The other five patients who were positive for ADAs at baseline also tested positive for ADAs at one or more time points postdose.

A total of 26 patients ( n = 7, n = 10 and n = 9 receiving PF‐05280586, rituximab‐EU and rituximab‐US, respectively) tested positive for ADAs for at least one time point postdose. Of these, 22 patients did not have detectable levels of ADAs until day 85 or later ( n = 6, n = 7 and n = 9, respectively). Boyka Undisputed 4 Film Download. In two patients (one each in the PF‐05280586 and rituximab‐EU groups), ADAs first emerged on day 15 and persisted until the last sample collection on day 169. These patients also had the highest ADA titres among all patients, with peak titres of 4.24 detected on day 15 in one patient (rituximab‐EU) and 4.57 on day 169 in the other (PF‐05280586). In addition, two patients receiving rituximab‐EU had lower titres of ADAs that were first detected on days 29 and 57, and persisted until the last sampling on day 169. On day 169, ADA samples were available from 55, 58 and 52 patients from the rituximab‐US, rituximab‐EU and PF‐05280586 groups, respectively.

Among these patients, six (10.9%), eight (13.8%) and six (11.5%) patients from the rituximab‐US, rituximab‐EU and PF‐05280586 groups, respectively, tested positive for ADAs in the day 169 sample. Overall, there were no observed differences among treatment groups in the incidence of ADAs, time of ADA emergence or ADA titres.

Most (∼83%) of the 42 postdose samples that tested positive for ADAs also tested positive in the cross‐reactivity assay with similar titres. None of the samples testing positive for ADAs was positive for neutralizing activity on the cell‐based Nab assays. In general, patients who tested positive for ADAs appeared to have lower AUC 0–∞ and higher CL compared with patients who did not have any samples testing positive for ADAs (Figure ); however, the effect of ADA formation appeared to be comparable among the treatment groups as there were no apparent differences in group mean (±SD) estimates of the PK parameters. Overall, ADA development had no apparent effect on CD19+ B cell depletion/repletion profiles. For the two patients with persistent ADAs and the highest titres, one (administered rituximab‐EU) had CD19+ B cells depleted postdose for the entire study duration – up to day 169 – whereas the other patient (administered PF‐05280586) had CD19+ B cell counts postdose that became detectable again after day 85 and reached approximately 5% of the pretreatment baseline counts on day 141.

Safety Safety data from all 220 patients enrolled were evaluated. Overall, no clinically meaningful differences in the incidence or severity of AEs were found among groups (Table ).

A total of 136 (61.8%) patients experienced a treatment‐emergent AE [ n = 50 (68.5%), n = 41 (55.4%) and n = 45 (61.6%) receiving PF‐05280586, rituximab‐EU and rituximab‐US, respectively]. Across all treatments, 57 (25.9%) patients experienced a treatment‐related AE [ n = 22 (30.1%), n = 17 (23.0%) and n = 18 (24.7%), respectively). Summary of treatment‐emergent adverse events (all‐causality; mITT population) One death was reported in a 66‐year‐old female who developed a presumed bone neoplasm (no histological confirmation) 51 days after the first dose of PF‐05280586. The patient was discontinued from the study owing to this AE and subsequently died.

The AE was not considered to be related to the study drug. The overall incidence of SAEs was consistent with what might be expected in an RA population. A total of 12 treatment‐emergent SAEs occurred in 11 patients. Five PF‐05280586‐treated patients had six SAEs: cardiac failure, intentional self‐injury, presumed bone neoplasm, bacterial arthritis and, in one patient, bacterial sepsis and septic shock. In the rituximab‐EU group, two patients reported SAEs of (one each) thrombocytopenic purpura and pericarditis.

Four rituximab‐US–treated patients had SAEs (one each): cardiac failure congestive, atrial flutter, pyelonephritis and arthropathy. Two patients had SAEs that were considered to be treatment related: the thrombocytopenic purpura reported by a patient in the rituximab‐EU group and the case of atrial flutter in the rituximab‐US group. A total of four (1.8%) patients were withdrawn from treatment owing to an AE: two (2.7%) receiving PF‐05280586, one (1.4%) receiving rituximab‐EU and one (1.4%) receiving rituximab‐US.

In all, 21 (9.5%) patients experienced an AE of grade 3 or higher. The incidence of grade 3 or higher AEs was lower among patients receiving rituximab‐EU [ n = 1 (1.4%)] compared with rituximab‐US [ n = 10 (13.7%)] or PF‐05280586 [ n = 10 (13.7%)). There were no dose reductions or temporary discontinuations due to AEs during the study.

Nine patients ( n = 5, n = 2 and n = 2, receiving PF‐05280586, rituximab‐EU and rituximab‐US, respectively) had the infusion rate reduced owing to an AE. There were no AEs related to the ADA response (e.g.

Infusion related or hypersensitivity reactions), and the incidence and types of AEs observed in those patients who tested positive for ADAs were similar to those in patients testing negative for ADAs. In general, the mean changes from baseline in vital signs were small and no notable differences were observed across groups with regard to 12‐lead electrocardiogram results. Discussion The primary objective of the present study was to demonstrate the PK similarity of PF‐05280586, rituximab‐EU and rituximab‐US in patients with active RA on a background of methotrexate who had an inadequate response to one or more TNF antagonist therapies, using the standard bioequivalence acceptance range of 80.00–125.00%. The 90% CIs for test‐to‐reference ratios for the exposure parameters evaluated were within the predefined acceptance range for comparisons of PF‐05280586 with rituximab‐EU and rituximab‐US, and for rituximab‐EU compared with rituximab‐US, demonstrating PK similarity among the three products. The PK characteristics evaluated were consistent with those reported for rituximab in patients with RA.

Baseline CD19+ B cell values were comparable among the three groups and were similar to previous reports. All three treatments decreased CD19+ B cell counts, reaching a maximum reduction by week 2. These counts remained suppressed up to week 25, consistent with previous reports showing substantial and sustained depletion of CD19+ B cells following administration of the same doses of rituximab. There were no major variations in circulating IgM values over time and only small differences were noted among the groups. Taken together, these results demonstrate that PF‐05280586, rituximab‐EU and rituximab‐US had comparable CD19+ B cell depletion profiles in patients with active RA on a background of methotrexate who had an inadequate response to one or more TNF antagonist therapies. The incidence of ADA responses, time of ADA emergence and ADA titres were similar across treatments. The overall incidence of ADA responses observed was consistent with that reported (11%) in controlled and long‐term studies.

The majority of samples that tested positive for ADAs also tested positive in the cross‐reactivity assay with similar titres, suggesting that ADAs were likely to have developed against shared epitopes among the study drugs. Overall, no clinically meaningful differences in safety events were identified, although some numerical differences were observed across treatments. Although numerically more patients receiving PF‐05280586 than in the other groups discontinued the study, no differences were noted in discontinuations due to AEs.

Similarly, a numerical difference in the incidence of grade 3 or above AEs was found across groups, with a lower incidence occurring in patients receiving rituximab‐EU compared with rituximab‐US or PF‐05280586. None of the individual (preferred term) AEs of grade 3 or higher occurred in more than two patients treated with any of the three treatments.

In summary, the evidence of PK similarity of PF‐05280586 to rituximab‐EU and rituximab‐US, together with the results of safety, immunogenicity and PD assessments from the present study, support the continued development of PF‐05280586 as a potential biosimilar for rituximab. In addition, the results of PK similarity between rituximab‐EU and rituximab‐US indicated that either of the two products by itself can be used a comparator for future comparative studies with PF‐05280586. Competing Interests All authors have completed the Unified Competing Interest form at () (available on request from the corresponding author) and declare the following financial relationships with organizations that might have an interest in the submitted work in the previous 3 years: SC has been a consultant and investigator for Pfizer Inc. PE has undertaken clinical trials and provided expert advice to Abbott/Abbvie, Bristol Myers Squibb, Pfizer, UCB, MSD, Roche, Novartis, Samsung, Takeda and Lilly. MG has an ongoing clinical research grant from Pfizer Inc. DY, LAM, RL, BG, DT and XM are employees of Pfizer Inc. JCB and GSG were employees of Pfizer at the time of study conduct.

The authors would like to thank Sherry Cai from the Pfizer Clinical Assay Group for managing the analyses of drug concentration samples. This study was funded by Pfizer Inc. Editorial assistance was provided by Christina McManus, PhD, of Engage Scientific Solutions and funded by Pfizer Inc. Aletaha D, Neogi T, Silman AJ, Funovits J, Felson DT, Bingham CO 3rd, Birnbaum NS, Burmester GR, Bykerk VP, Cohen MD, Combe B, Costenbader KH, Dougados M, Emery P, Ferraccioli G, Hazes JM, Hobbs K, Huizinga TW, Kavanaugh A, Kay J, Kvien TK, Laing T, Mease P, Menard HA, Moreland LW, Naden RL, Pincus T, Smolen JS, Stanislawska‐Biernat E, Symmons D, Tak PP, Upchurch KS, Vencovsky J, Wolfe F, Hawker G. 2010 Rheumatoid arthritis classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative.

Aplikasi Penjualan Dan Stok Barang Gratis Full Version. Arthritis Rheum 2010; 62: 2569–81.