Population pharmacokinetics of Reditux™, a biosimilar Rituximab, in diffuse large B-cell lymphoma

Real-world outcomes of diffuse large B-cell lymphoma in the biosimilar era

Background

Diffuse large B-cell lymphoma (DLBCL) is an aggressive and the most common type of non-Hodgkin lymphoma (NHL). The clinical use of rituximab has improved the treatment response and survival of patients with DLBCL. The introduction of rituximab biosimilar into healthcare system has helped in providing a cost-effective treatment to B-cell lymphoid malignancies as standard of care and has improved access to patients worldwide. The aim of this study was to observe the real-world effectiveness and safety of Reditux™ and Ristova® in DLBCL patients.

Methods

Observational study in adults with DLBCL receiving Reditux™ or Ristova® across 29 centers in India (2015-2022). Effectiveness and safety were assessed up to 2 years after first dose.

Results

Out of 1,365 patients considered for analysis, 1,250 (91.6%) were treated with Reditux™ and 115 (8.42%) with Ristova®. At 2 years, progression-free survival (PFS) 69% [hazard ratio (HR), 1.16; 95% CI, 0.80-1.67], overall survival (OS) 78.7% (HR, 1.20; 95% CI, 0.78-1.86), response rates, quality of life (QoL), and overall safety in both the cohorts were comparable. The best overall response rate (BORR) at 6 months was comparable with no statistically significant differences between the Reditux™ and the Ristova® cohorts (89.2% vs. 94.3%). In multivariate analysis, BCL-2 and VAS were significant prognostic factors for PFS.

Conclusion

Reditux™ and Ristova® were comparable in real-world setting.

Clinical Trial Registration

ISRCTN registry, identifier (ISRCTN13301166).

Current evidence of rituximab in the treatment of multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disorder of the central nervous system. The immunopathology of MS involves both T and B lymphocytes. Rituximab is one of the anti-CD20 monoclonal antibody therapies which deplete B-cells. Although some anti-CD20 therapies have been approved by the Food and Drug Administration for treatment of MS, rituximab is used off-label. Several studies have shown that rituximab has a good efficacy and safety in MS, including certain specific patient conditions such as treatment-naïve patients, treatment-switching patients, and the Asian population. However, there are still questions about the optimal dose and duration of rituximab in MS due to the different dosing regimens used in each study. Moreover, many biosimilars have become available at a lower cost with comparable physicochemical properties, pharmacokinetics, pharmacodynamics, efficacy, safety, and immunogenicity. Thus, rituximab may be considered as a potential therapeutic option for patients without access to standard treatment. This narrative review summarized the evidence of both original and biosimilars of rituximab in MS treatment including pharmacokinetics, pharmacodynamics, clinical efficacy, safety, and dosing regimen.

Biosimilar Rituximab (Redditux) Added to CHOP Chemotherapy for De Novo Diffuse Large B-Cell Lymphoma Patients: Real-Life Single-Center Experience

Objective

Redditux® (RED), as a biosimilar rituximab, was approved in Turkey for all indications of the original Mabthera® (MAB) in March 2018. The aim of our study was to evaluate the efficacy and safety of RED in de novo diffuse large B-cell lymphoma.

Materials and Methods

Fifty-one patients received RED combined with the CHOP regimen. The median follow-up was 31 months. The historical control group included 219 patients treated with the MAB-CHOP regimen and the median follow-up time was 38 months. We compared the response rates and survival outcomes of these RED-CHOP and MAB-CHOP cohorts.

Results

In the RED cohort, the overall response rate (ORR) at the end of the treatment protocol was 86%, with 37 (72.5%) cases of complete response (CR) and 7 (13.5%) cases of partial response (PR). In the historical MAB cohort, the ORR was 84%, with CR and PR rates of 82% and 2%, respectively. The 24-month progression-free survival (PFS) rates were 73.76% (95% confidence interval [CI]: 0.59-0.84) and 85.2% (95% CI: 0.79-0.90) for the RED and MAB cohorts, respectively (p=0.0106). The 24-month overall survival rates were 78.4% (95% CI: 0.64-0.87) and 81.4% (95% CI: 0.75-0.86) for the RED and MAB cohorts, respectively (p=0.7461). For patients with high revised International Prognostic Index scores, 24-month PFS was 45.5% (95% CI: 0.17-0.71) and 63% (95% CI: 0.37-0.80) for the RED and MAB cohorts, respectively (p=0.0711). In the RED cohort, central nervous system (CNS) relapse was significantly increased compared to the MAB cohort (10% vs. 1.83%, p=0.004). Among the RED cohort, bone involvement at the time of diagnosis was a risk factor for CNS relapse (p=0.028). Thirteen patients died in follow-up. There were no serious adverse events causing the cessation of the drugs.

Conclusion

RED has an ORR similar to that of MAB. However, PFS rates were worse in the RED cohort. Additionally, CNS relapse ratio was a major concern for our RED cohort. Large prospective controlled studies and real-life data with longer follow-up are needed to document the non-inferiority of RED compared to MAB.

Diffuse Large B-Cell Lymphoma in Chile: The Impact of Combined CHOP Plus Rituximab in the Public Health System

PURPOSE

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma subtype. The purpose of this study was to evaluate the clinical features, prognostic factors, and results of DLBCL that was treated in the cancer centers of the public health system in Chile and compare cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) with rituximab with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP).

PATIENTS AND METHODS

Patients age > 15 years who were treated in 18 cancer centers in the country between 2001 and 2017 were included. The Kaplan-Meier method was used to calculate overall survival (OS), and Cox proportional hazard regression modeling was used to evaluate the effect of the addition of rituximab to CHOP on OS.

RESULTS

A total of 1,807 patients were evaluated. The median age at diagnosis was 62 (range, 15-95) years, with a female predominance (53%). Half of the patients were age ≥ 60 years. Serology for HIV infection was positive in 5% of cases (96 cases). International Prognostic Index scores were available for 90% of patients, of which 45% had low-risk, 25% low-intermediate-risk, 18% high-intermediate-risk, and 11% high-risk scores. CHOP was administered to 986 patients (55%; median follow-up, 13.2 years) and R-CHOP to 821 patients (45%; median follow-up, 8.4 years). R-CHOP was associated with superior OS compared with CHOP (5-year 66% v 48%, and 10-year 53% v 35%; P < .001).

CONCLUSION

Rituximab improved the survival of patients with DLBCL diagnosed and treated in Chile. The benefit was sustained over time, with curative rates of > 50%. This intervention shows that the inclusion of this biological drug justified the expenses incurred by the Ministry of Health in the National Lymphoma Protocols in Chile.

The Influence of Underlying Disease on Rituximab Pharmacokinetics May be Explained by Target-Mediated Drug Disposition

BACKGROUND AND OBJECTIVES

Rituximab is an anti-CD20 monoclonal antibody approved in several diseases, including chronic lymphocytic leukemia (CLL), diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), rheumatoid arthritis (RA), and anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV). The influence of underlying disease on rituximab pharmacokinetics has never been investigated for several cancer and non-cancer diseases simultaneously. This study aimed at assessing this influence using an integrated semi-mechanistic model accounting for target-mediated elimination of rituximab.

METHODS

Rituximab concentration-time data from five studies previously published in patients with CLL, DLBCL, FL, RA, and AAV were described using a two-compartment model with irreversible binding of rituximab to its target antigen. Both underlying disease and target antigen measurements were assessed as covariates.

RESULTS

Central volume of distribution was [95% confidence interval] 1.7-fold [1.6-1.9] higher in DLBCL than in RA, FL, and CLL, and it was 1.8-fold [1.6-2.1] higher in RA, FL, and CLL than in AAV. First-order elimination rate constants were 1.8-fold [1.7-2.0] and 1.3-fold [1.2-1.5] higher in RA, DLBCL, and FL than in CLL and AAV, respectively. Baseline latent antigen level (L₀) was 54-fold [30-94], 20-fold [11-36], and 29-fold [14-64] higher in CLL, DLBCL, and FL, respectively, than in RA and AAV. In lymphoma, L₀ increased with baseline total metabolic tumor volume (p = 6.10^-7). In CLL, the second-order target-mediated elimination rate constant (k_deg) increased with baseline CD20 count on circulating B cells (CD20_cir, p = 0.0081).

CONCLUSIONS

Our results show for the first time that rituximab pharmacokinetics is strongly influenced by underlying disease and disease activity. Notably, neoplasms are associated with higher antigen amounts that result in decreased exposure to rituximab compared to inflammatory diseases. Our model might be used to estimate unbound target amounts in upcoming studies.

Population Pharmacokinetics of Rituximab in Pediatric Patients With Frequent-Relapsing or Steroid-Dependent Nephrotic Syndrome

Objectives: Rituximab is frequently used off-label for the treatment of frequent-relapsing nephrotic syndrome (FRNS) or steroid-dependent nephrotic syndrome (SDNS), but the relapse rate remained high and the dosing regimen varied widely. The objective of this study was to characterize rituximab pharmacokinetics (PK) in pediatric patients with FRNS/SDNS, and to investigate the differences in rituximab PK between patients with FRNS/SDNS and other disease populations.

Methods: Fourteen pediatric patients received rituximab for FRNS/SDNS treatment were enrolled in a prospective, open-label, single-center PK study. A population PK model of rituximab was developed and validated, and PK parameters were derived for quantitative evaluation.

Results: A two-compartment PK model best described the data. Body surface area was the most significant covariate for both central clearance (CL) and apparent central volume of distribution (V₁). Patients with FRNS/SDNS exhibited a clinically relevant increase in rituximab CL compared to patient population with non-Hodgkin’s lymphoma (NHL).

Conclusion: This pilot study indicated that higher doses or more frequent regimens of rituximab may be required for optimal therapeutic effects in patients with FRNS/SDNS. Further clinical studies with more patients are warranted to confirm this result.

Safety and efficacy of rituximab in patients with diffuse large B-cell lymphoma in Malawi: a prospective, single-arm, non-randomised phase 1/2 clinical trial

BACKGROUND

There are no clinical trials involving patients with diffuse large B-cell lymphoma (DLBCL) in sub-Saharan Africa since antiretroviral therapy (ART) for HIV became widely available in this region. We aimed to establish the safety and efficacy of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) in patients with DLBCL in Malawi.

METHODS

This prospective, single-arm, non-randomised phase 1/2 clinical trial was done at Kamuzu Central Hospital Cancer Clinic (Lilongwe, Malawi). Eligible patients were adults (aged 18-60 years) with newly diagnosed DLBCL, an Eastern Cooperative Oncology Group performance status of 0-2, a CD4 count of 100 cells per μL or higher (if HIV-positive), measurable disease by physical examination, an absolute neutrophil count of 1000 × 109 cells per L or higher, a platelet count of 100 × 109 platelets per L or higher, a serum creatinine concentration of 132·60 μmol/L or less, a total bilirubin concentration of 34·21 μmol/L or less, a negative urine pregnancy test in women of childbearing potential, and no previous cytotoxic therapy. Pregnant or breastfeeding women, and individuals with CNS involvement from DLBCL, chronic hepatitis B infection (unless they were receiving tenofovir plus lamivudine), or any other comorbidities that would compromise the protocol objectives were excluded. Eligible patients received intravenous rituximab 375 mg/m2, cyclophosphamide 750 mg/m2, doxorubicin 50 mg/m2, and vincristine 1·4 mg/m2 (maximum 2 mg/m2), and oral prednisone 100 mg or an equivalent drug every 21 days for up to six cycles. HIV-positive patients received concurrent ART. The primary outcome was the proportion of patients with National Cancer Institute Common Terminology Criteria for Adverse Events grade 3 or 4 non-haematological toxic effects or treatment-related deaths after six cycles of treatment. Secondary efficacy outcomes included the proportion of patients with a complete response after six cycles of treatment, and progression-free survival and overall survival at 12 months and 24 months. This trial is registered with ClinicalTrials.gov, NCT02660710.

FINDINGS

Between Aug 1, 2016, and July 31, 2019, 76 patients were screened, of whom 37 were eligible for the study and received R-CHOP. The median age of patients was 44 years (IQR 39-49) and 16 (43%) were women. Of all 37 patients, 20 (54%) had stage III or IV DLBCL, and the age-adjusted international prognostic index was 2 or higher in 25 (68%) patients. 27 (73%) patients were HIV-positive, with a median CD4 count of 208 cells per μL (IQR 144-422), and 21 (78%) patients were receiving ART at enrolment. Patients completed a median of six cycles (IQR 4-6). Grade 3 or 4 non-haematological toxic effects were reported in 12 (32% [95% CI 19-49]) patients, the most common of which was infection (nine [24%] patients). Of 16 (43%) deaths, ten were due to progression of DLBCL, four were due to treatment-related complications, and two were due to other causes, yielding a treatment-related mortality of 11% (95% CI 4-26%). Grade 3 or 4 neutropenia was observed in 26 (70%) patients, and grade 3 or 4 anaemia was observed in 11 (29%) patients. A total of 22 (59%) patients had a complete response. Overall survival was 68% (95% CI 50-80) at 12 months and 55% (37-70) at 24 months, and progression-free survival was 59% (42-73) at 12 months and 53% (35-68) at 24 months.

INTERPRETATION

R-CHOP could be feasible, safe, and efficacious in patients with DLBCL in Malawi. This is the first completed clinical trial on DLBCL focused on sub-Saharan African populations. Given the paucity of data on treatment of DLBCL from this region, these results could inform emerging cancer treatment programmes in sub-Saharan Africa.

FUNDING

The University of North Carolina Lineberger Comprehensive Cancer Center.

Non-Linear Rituximab Pharmacokinetics and Complex Relationship between Rituximab Concentrations and Anti-Neutrophil Cytoplasmic Antibodies (ANCA) in ANCA-Associated Vasculitis: The RAVE Trial Revisited

BACKGROUND AND OBJECTIVES

Rituximab is approved in patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and leads to a decrease of ANCA levels. The objectives of this study were to investigate the non-linear pharmacokinetics of rituximab and the relationship between its concentrations and ANCA levels in AAV patients.

METHODS

Ninety-two AAV patients from the RAVE (Rituximab in ANCA-Associated Vasculitis) trial were assessed. Both ANCA anti-myeloperoxidase (MPO-ANCA) and anti-proteinase 3 (PR3-ANCA) levels were used as biomarkers. The pharmacokinetics of rituximab were described using a semi-mechanistic two-compartment model that included a latent target antigen turnover and allowed the estimation of specific target-mediated elimination in addition to its non-specific elimination of rituximab. The effect of rituximab on the ANCA level was described using a semi-mechanistic compartment model with a negative feedback (Friberg) model with no transit compartment. A population modeling approach was used.

RESULTS

Our pharmacokinetic and pharmacokinetic-pharmacodynamic (PK-PD) models satisfactorily described both concentration-time and concentration-effect relationship data. The mean (inter-individual standard deviation) estimated non-specific clearance was 0.15 L/day (0.30%) and the target-mediated elimination rate constant was 2.4 × 10^-5 nmol/day. The elimination half-lives for MPO-ANCA and PR3-ANCA were 24 and 18 days, respectively.

CONCLUSIONS

A non-linear target-mediated elimination of rituximab was detected in AAV patients. Our PK-PD model allowed quantification of the association between rituximab concentrations and ANCA levels. This decrease was deep but delayed, and more sustained in patients with MPO-ANCA than in those with PR3-ANCA. Our results suggest that repeating courses of rituximab might improve the clinical response to rituximab.

Efficacy and Safety of the Biosimilar IBI301 Plus Standard CHOP (I-CHOP) in Comparison With Rituximab Plus CHOP (R-CHOP) in Patients with Previously Untreated Diffuse Large B-Cell Lymphoma (DLBCL): A Randomized, Double-Blind, Parallel-Group, Phase 3 Trial

INTRODUCTION

Patients with diffuse large B-cell lymphoma (DLBCL) have limited access to rituximab. IBI301 is a recombinant chimeric murine/human anti-CD20 monoclonal antibody and is a candidate biosimilar to rituximab. This study aimed to assess the therapeutic equivalence of IBI301 and rituximab in previously untreated patients with diffuse large B-cell lymphoma (DLBCL).

METHODS

This multicenter, randomized, double-blind, parallel-group, phase 3 trial compared IBI301 and rituximab, both plus the chemotherapy of doxorubicin, cyclophosphamide, vindesine, and prednisone (CHOP), was conducted in 68 centers across China. Eligible patients with untreated CD20 positive (CD20⁺) DLBCL randomly received IBI301 (375 mg/m²) plus the standard CHOP or rituximab (375 mg/m²) plus the standard CHOP for six cycles of a 21-day cycle. The primary end point was the overall remission rate (ORR). Efficacy equivalence was defined if 95% CIs for the ORR difference between the two groups were within a ± 12.0% margin.

RESULTS

Between August 22, 2016, and September 5, 2018, 419 patients were randomly allocated into the IBI301 group (N = 209) and rituximab group (N = 210). In the full analysis set, the ORR was 89.9% and 93.8% in the IBI301 and rituximab groups, respectively, and the ORR difference was -3.9% (95% CI - 9.1%-1.3%), falling within a ± 12.0% margin. The occurrences of treatment-emergent adverse events (TEAEs) (100% vs. 99.0%) and AEs of grade ≥ 3 (87.1% vs. 83.3%) were similar in the two groups (P > 0.05).

CONCLUSIONS

IBI301 had a non-inferiority efficacy and a comparable safety compared with rituximab. IBI301 plus CHOP could be suggested as a candidate treatment regimen for untreated patients with CD20⁺ DLBCL.

TRIAL REGISTRATION

This trial is registered on ClinicalTrials.gov (NCT02867566).

Rituximab in combination with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) in diffuse large B-cell lymphoma

Background

Diffuse large B-cell lymphoma (DLBCL) is the most frequent non-Hodgkin lymphoma worldwide. The current standard of care is chemoimmunotherapy with an R-CHOP regimen. We aim to review the role of this regimen after two decades of being the standard of care.

Methods

A comprehensive literature review of DLBCL, including the epidemiology, trials defining R-CHOP as the standard of care, as well as dose intensification and dose reduction schemes. Additionally, we briefly review the development of rituximab biosimilars and the addition of targeted drugs to R-CHOP in clinical trials.

Discussion

R-CHOP cures approximately 70% of DLBCL patients. Dose-dense regimens do not show a benefit in response and increase toxicity. Dose reduction, particularly in elderly patients or with comorbidities, may be a treatment option. DLBCL constitutes a group of diseases that activate different biological pathways. Matching specific treatments to a defined genetic alteration is under development. Rituximab biosimilars have become available to a broader population, particularly in developing countries, where access to treatment is limited because of economic resources.

Conclusion

DLBCL landscape is heterogeneous. R-CHOP immunochemotherapy has been a standard of care for two decades and cures approximately 70% of cases. Molecular characterization of patients is evolving and may have critical therapeutic implications.

Comparison of Access to Novel Drugs for Lymphoma and Chronic Lymphocytic Leukemia Between India and the United States

This review will compare and contrast the costs and access to novel drugs for treating chronic lymphocytic leukemia (CLL) and lymphoma in the United States and India during the last 5 years. Clinical outcomes for patients with hematologic malignancies have improved significantly since the approval of immunotherapeutic and targeted therapies. These new treatments have had an impact on overall outcomes and have helped determine the design for translational research and future trials. Although most of these novel drugs called “innovators” are initially approved and marketed in the United States, several have also become available in countries such as India. With the expiration of patents, generic versions of innovator drugs have increased and accessibility has improved for patients. The advent of biosimilars is another route for expanding access to biologic compounds. As a result, the development costs for developing these drugs are lower, and consequently, the costs for the patient are often lower. Although the delivery of cancer care is not the same in India as it is in the United States, the introduction of biosimilars and generics has helped bridge the gap. This has made treatment of CLL and lymphoma similar in both countries and has had the same impact on patient outcomes and quality of life. Compulsory licensing for essential medications, as stipulated by the Doha Declaration, and capping of drug prices could improve global access to treatments for CLL and lymphoma.

The Influence of Different Disease States on Rituximab Pharmacokinetics

BACKGROUND

The anti-CD20 antibody rituximab, which promotes the selective depletion of CD20 positive B cells, was the first targeted therapy that was approved for the treatment of B-cell malignancies, and it is now widely prescribed in both malignant and non-malignant, immune-related diseases. However, the cause of its various clinical responses in certain diseases, have not been clearly elucidated. The variabilities in inter-individual pharmacokinetic and the emerging evidence of the relationships between pharmacokinetic and pharmacodynamic may provide a better understanding of this drug.

METHODS

We searched and summarized the latest published articles on rituximab pharmacokinetic profiles and the pharmacokinetic/pharmacodynamic models in different patient populations, including B-cell malignancies, rheumatoid arthritis, ANCA-associated vasculitis, and glomerular kidney diseases.

RESULTS

Most pharmacokinetic data are drawn from clinical studies in oncology clinical practice. Body weight, gender, and antigen-related factors are proven to be the key factors affecting rituximab pharmacokinetics. In addition, the positive exposure-response relations were reported, which provide encouraging evidence for individualized therapies. While in immune disorders, especially in the off-labeled indications, pharmacokinetic studies are quite limited. Compared with that in B-cell malignancies, the differences in the pharmacokinetic parameters may be attributed to the different pathogeneses of diseases, mechanisms of action and dosing strategies. However, the correlation between drug exposure and clinical outcomes remains unclear.

CONCLUSION

Here, we provide an overview of the complexities associated with rituximab pharmacokinetics and pharmacodynamics in different diseases. Although many influencing factors need to be verified in future studies, a better understanding of the relationships between pharmacokinetic and pharmacodynamic may assist in optimizing rituximab clinical practice.

Pharmacokinetics and safety of IBI301 versus rituximab in patients with CD20+ B-cell lymphoma: a multicenter, randomized, double-blind, parallel-controlled study

This multicenter, randomized, double-blind, parallel-controlled trial aimed to compare the pharmacokinetics (PK) of IBI301 with rituximab in patients with CD20-positive (CD20⁺) B-cell lymphoma, who achieved a complete response/unconfirmed complete response after standard treatments. Patients were randomized (1:1) to receive IBI301 or rituximab (375 mg/m², IV). Patients who continuously benefitted from the trial after the PK phase underwent the extension phase to receive up to three cycles of 3-month-cycle of rituximab/IBI301 maintenance therapy. PK was described using the area under the serum concentration–time curve from time zero to infinity (AUC_0-inf), AUC from time zero to last quantifiable concentration (AUC_0-t), and maximum serum concentration (C_max). Pharmacodynamics (PD), incidence of adverse events and immunogenicity were evaluated. PK was defined equivalent, if 90% confidence intervals (CIs) for geometric mean ratios of PK endpoints fell within the margin of 0.8–1.25. Overall, 181 patients were enrolled in IBI301 (n = 89) and rituximab (n = 92) groups. Geometric mean ratios of AUC_0-inf, AUC_0-t, and C_max were 0.91 (90% CI 0.85, 0.97), 0.91 (90% CI 0.86, 0.97), and 0.96 (90% CI 0.92, 1.01) between treatment groups, all within the bioequivalence range. Peripheral CD19⁺ and CD20⁺ B-cell counts were similar at each prespecified time point between the groups. No difference in immunogenicity was observed. The incidences of treatment-emergent adverse events (84.3% vs. 83.5%) and treatment-related AEs (56.2% vs. 61.5%) were comparable (IBI301 vs. rituximab). IBI301 was PK bioequivalent to rituximab in patients with CD20⁺ B-cell lymphoma. The PD, safety, and immunogenicity profiles of IBI301 were similar to those of rituximab.

Randomized, Double-Blind, Pharmacokinetic Equivalence Trial Comparing DRL-Rituximab With MabThera in Patients With Diffuse Large B-Cell Lymphoma

PURPOSE

We sought to compare the pharmacokinetics (PKs) of DRL-rituximab (DRL_RI; potential biosimilar) and innovator rituximab MabThera (Roche, Grenzach-Wyhlen, Germany; reference medicinal product [RMP]) in patients with diffuse large B-cell lymphoma (DLBCL). Efficacy, pharmacodynamics (PDs), safety, and immunogenicity were also compared.

PATIENTS AND METHODS

We conducted a double-blind, parallel-group study in patients with untreated DLBCL who were eligible to receive cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) therapy. Patients were randomly assigned at a one-to-one ratio to receive DRL_RI or RMP for six 21-day cycles of rituximab plus CHOP, with 18 months of follow-up after day 1, cycle 6 (C6). Primary end point was C1 PKs, measured as area under the plasma concentration–time curve from day 0 to 21 (AUC_{0-21 days}) and maximum plasma concentration (C_max). Equivalence was defined as 90% CIs for the DRL_RI/RMP geometric mean ratios (GMRs) within 80% and 125%. Secondary end points included efficacy noninferiority measured by objective response rate (ORR) at C6 and event-free survival and overall survival at 87 weeks, PK equivalence at C6 and PD equivalence (rate of B-cell depletion and repletion), safety, and immunogenicity. The trial was stopped after sufficient patients for primary end point evaluation were enrolled. Secondary end points are reported as observed.

RESULTS

A total of 151 patients were randomly assigned (DRL_RI, n = 76; RMP, n = 75). DRL_RI/RMP GMRs for AUC_{0-21 days} and C_max in C1 were 99.77 (90% CI, 87.60 to 113.63) and 96.19 (90% CI, 88.65 to 104.38), respectively. ORR at C6 for DRL_RI and RMP were 82.0% and 84.8%, respectively. Rates of B-cell depletion/repletion, immunogenicity, and adverse events were comparable in both groups.

CONCLUSION

DRL_RI and RMP had equivalent PKs, with comparable efficacy, PDs, safety, and immunogenicity.

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.

Comparison of the Efficacy of Innovator Rituximab and its Biosimilars in Diffuse Large B Cell Lymphoma Patients: A Retrospective Analysis

Diffuse large B cell lymphoma (DLBCL) is the most common form of non-Hodgkin lymphoma among adults, although it also affects the young and the elderly. DLBCL is treated with a chimeric monoclonal antibody against CD20, a B cell surface protein, named rituximab, in combination with a multidrug chemotherapeutic regimen. However, owing to its high cost, rituximab cannot be afforded by patients in developing or underdeveloped countries. In such cases, biosimilars of rituximab have been used instead of rituximab, with equivalent efficacy. In this single center, retrospective, observational study, we have compared patient outcomes such complete response (CR), partial response (PR), and overall response rate (ORR) in a cohort of 152 patients in an Indian hospital, who were treated either with innovator rituximab or Reditux, a biosimilar. We observed that the ORRs of both groups (88% in innnovator group and 82% in biosimilar group) were comparable. There was no statistically significant difference between the two groups in terms of CR (p = 0.353), PR (p = 0.42), ORR (p = 0.23), unfavorable responses, and stable or progressive disease (p = 0.42). The number of patients who died due to complications were few, and there was no significant difference between the two groups. The differences in the 3-year event-free survival and overall survival were not statistically significant. Biosimilar rituximab can suitably and safely replace the innovator rituximab for treatment of diffuse large B cell lymphoma.

Clinical Pharmacokinetic and Pharmacodynamic Considerations in Treating Non-Hodgkin Lymphoma

Non-Hodgkin lymphoma (NHL) includes a variety of closely related malignancies that originate from lymphoid precursors. The majority of NHLs are of B-cell lineage, for which traditional therapy involves chemotherapy in combination with the anti-CD20 monoclonal antibody rituximab. Ongoing research into the pathogenesis of NHL subtypes has given rise to the use of novel agents that target specific molecular pathways. While the incidence of NHL extends over a range of ages from pediatric to elderly settings, the majority of diagnoses occur over age 60 years. Increasing the use of concomitant medication coupled with declining organ function among this group of patients creates pharmacokinetic (PK) challenges in administering a number of agents involved in the treatment of NHL. In addition, since many of the new agents are administered orally, there are a number of added PK factors that must be taken into consideration with their prescribing and administration. This article will review the available literature on the PK and pharmacodynamic properties of agents commonly used in the treatment of NHL, and intends to provide information that can assist with properly using these drugs in this setting.

Sensitivity of Pegfilgrastim Pharmacokinetic and Pharmacodynamic Parameters to Product Differences in Similarity Studies

In this work, a previously developed pegfilgrastim (PG) population pharmacokinetic-pharmacodynamic (PKPD) model was used to evaluate potential factors of importance in the assessment of PG PK and PD similarity. Absolute neutrophil count (ANC) was the modelled PD variable. A two-way cross-over study was simulated where a reference PG and a potentially biosimilar test product were administered to healthy volunteers. Differences in delivered dose amounts or potency between the products were simulated. A different baseline absolute neutrophil count (ANC) was also considered. Additionally, the power to conclude PK or PD similarity based on areas under the PG concentration-time curve (AUC) and ANC-time curve (AUEC) were calculated. Delivered dose differences between the products led to a greater than dose proportional differences in AUC but not in AUEC, respectively. A 10% dose difference from a 6 mg dose resulted in 51% and 7% differences in AUC and AUEC, respectively. These differences were more pronounced with low baseline ANC. Potency differences up to 50% were not associated with large differences in either AUCs or AUECs. The power to conclude PK similarity was affected by the simulated dose difference; with a 4% dose difference from 6 mg the power was approximately 29% with 250 subjects. The power to conclude PD similarity was high for all delivered dose differences and sample sizes.

Nonlinear pharmacokinetics of rituximab in non-Hodgkin lymphomas: A pilot study

AIMS

Rituximab is an anti-CD20 monoclonal antibody approved in non-Hodgkin lymphoma (NHL). This study aimed to assess the relationship between antigen mass and nonlinear pharmacokinetics of rituximab in NHL patients.

METHODS

In a retrospective cohort of 25 NHL patients treated with rituximab, antigen mass was assessed at baseline by measuring metabolic tumour volume (MTV) by positron emission tomography. Rituximab pharmacokinetics was described using a semimechanistic 2-compartment model including a latent target antigen. Rituximab target-mediated elimination was described as irreversible binding between rituximab and it target. Histology (follicular or diffuse large B-cell lymphomas), initial MTV and body weight were tested as covariates on pharmacokinetic parameters.

RESULTS

The model allowed a satisfactory description of rituximab serum concentrations. Target-mediated elimination was maximum at the beginning of treatment and became negligible towards the end of follow-up. The second-order elimination of rituximab due to target binding and complex elimination increased with baseline MTV. Central volume of distribution increased with body weight (P = .022) and baseline MTV (P = .005).

CONCLUSIONS

This study quantified for the first time the target-mediated elimination of rituximab in NHL patients and confirmed rituximab retention by antigen mass.

Aptamers as quality control tool for production, storage and biosimilarity of the anti-CD20 biopharmaceutical rituximab

Detailed analysis of biopharmaceuticals is crucial for safety, efficacy and stability. Aptamers, which are folded, single-stranded oligonucleotides, can be used as surrogate antibodies to detect subtle conformational changes. We aimed to generate and assess DNA aptamers against the therapeutic anti-CD20 antibody rituximab. Six rituximab-specific aptamers with Kd = 354-887 nM were obtained using the magnetic bead-based systematic evolution of ligands by exponential enrichment (SELEX) technology. Aptamer folds were analysed by online prediction tools and circular dichroism spectroscopy suggesting quadruplex structures for two aptamers while others present B-DNA helices. Aptamer binding and robustness with respect to minor differences in buffer composition or aptamer folding were verified in the enzyme-linked apta-sorbent assay. Five aptamers showed exclusive specificity to the Fab-fragment of rituximab while one aptamer revealed a broader recognition pattern to other monoclonal antibodies. Structural differences upon incubation at 40 °C for 72 h or UV exposure of rituximab were uncovered by four aptamers. High similarity between rituximab originator and biosimilar lots was demonstrated. The most sensitive aptamer (RA2) detected signal changes for all lots of a copy product suggesting conformational differences. For the first time, a panel of rituximab-specific aptamers was generated allowing the assessment of conformational coherence during production, storage, and biosimilarity of different products.

The applications of anti-CD20 antibodies to treat various B cells disorders

B-lymphocyte antigen CD20 (called CD20) is known as an activated-glycosylated phosphoprotein which is expressed on the surface of all B-cells. CD20 is involved in the regulation of trans-membrane Ca²⁺ conductance and also play critical roles in cell-cycle progression during human B cell proliferation and activation. The appearance of monoclonal antibody (mAb) technology provided an effective field for targeted therapy in treatment of a variety of diseases such as cancer, and autoimmune diseases. Anti-CD20 is one of important antibodies which could be employed in treatment of several diseases. Increasing evidences revealed that efficacy of different anti-CD20 antibodies is implicated by their function. Hence, evaluation of anti-CD20 antibodies function could provide and introduce new anti-CD20 based therapies. In the present study, we summarized several applications of anti-CD20 antibodies in various immune related disorders including B-CLL (B-cell chronic lymphocytic leukemia), rheumatoid arthritis (RA), multiple sclerosis (MS) and melanoma.

Past, Present, and Future of Rituximab-The World's First Oncology Monoclonal Antibody Therapy

Rituximab is a chimeric mouse/human monoclonal antibody (mAb) therapy with binding specificity to CD20. It was the first therapeutic antibody approved for oncology patients and was the top-selling oncology drug for nearly a decade with sales reaching $8.58 billion in 2016. Since its initial approval in 1997, it has improved outcomes in all B-cell malignancies, including diffuse large B-cell lymphoma, follicular lymphoma, and chronic lymphocytic leukemia. Despite widespread use, most mechanistic data have been gathered from in vitro studies while the roles of the various response mechanisms in humans are still largely undetermined. Polymorphisms in Fc gamma receptor and complement protein genes have been implicated as potential predictors of differential response to rituximab, but have not yet shown sufficient influence to impact clinical decisions. Unlike most targeted therapies developed today, no known biomarkers to indicate target engagement/tumor response have been identified, aside from reduced tumor burden. The lack of companion biomarkers beyond CD20 itself has made it difficult to predict which patients will respond to any given anti-CD20 antibody. In the past decade, two new anti-CD20 antibodies have been approved: ofatumumab, which binds a distinct epitope of CD20, and obinutuzumab, a mAb derived from rituximab with modifications to the Fc portion and to its glycosylation. Both are fully humanized and have biological activity that is distinct from that of rituximab. In addition to these new anti-CD20 antibodies, another imminent change in targeted lymphoma treatment is the multitude of biosimilars that are becoming available as rituximab's patent expires. While the widespread use of rituximab itself will likely continue, its biosimilars will increase global access to the therapy. This review discusses current research into mechanisms and potential biomarkers of rituximab response, as well as its biosimilars and the newer CD20 binding mAb therapies. Increased ability to assess the effectiveness of rituximab in an individual patient, along with the availability of alternative anti-CD20 antibodies will likely lead to dramatic changes in how we use CD20 antibodies going forward.

How I treat Burkitt lymphoma in children, adolescents, and young adults in sub-Saharan Africa

Burkitt lymphoma (BL) is the most common pediatric cancer in sub-Saharan Africa (SSA), and also occurs frequently among adolescents and young adults (AYAs), often associated with HIV. Treating BL in SSA poses particular challenges. Although highly effective, high-intensity cytotoxic treatments used in resource-rich settings are usually not feasible, and lower-intensity continuous infusion approaches are impractical. In this article, based on evidence from the region, we review management strategies for SSA focused on diagnosis and use of prephase and definitive treatment. Additionally, potentially better approaches for risk stratification and individualized therapy are elaborated. Compared with historical very low-intensity approaches, the relative safety, feasibility, and outcomes of regimens incorporating anthracyclines and/or high-dose systemic methotrexate for this population are discussed, along with requirements to administer such regimens safely. Finally, research priorities for BL in SSA are outlined including novel therapies, to reduce the unacceptable gap in outcomes for patients in SSA vs high-income countries (HICs). Sustained commitment to incremental advances and innovation, as in cooperative pediatric oncology groups in HICs, is required to transform care and outcomes for BL in SSA through international collaboration.

Lymphoma and Pathology in Sub-Saharan Africa: Current Approaches and Future Directions

The care of patients with lymphoma relies heavily on accurate tissue diagnosis and classification. In sub-Saharan Africa, where lymphoma burden is increasing because of population growth, aging, and continued epidemic levels of human immunodeficiency virus infection, diagnostic pathology services are limited. This article summarizes lymphoma epidemiology, current diagnostic capacity, and obstacles and opportunities for improving practice in the region.

Comparative assessment of pharmacokinetics, and pharmacodynamics between RTXM83™, a rituximab biosimilar, and rituximab in diffuse large B-cell lymphoma patients: a population PK model approach

PURPOSE

The main objective was to quantify any potential differences in pharmacokinetic (PK) parameters (AUC and C_max) between RTXM83, a proposed rituximab biosimilar, and its reference product, using a population PK model approach.

METHODS

Rituximab PK and PD data were obtained from a randomized, double-blind, phase III clinical study (RTXM83-AC-01-11) in patients with diffuse large B-cell lymphoma (DLBCL) that received 375 mg/m² intravenous RTXM83 or its reference product with CHOP regimen, every 3 weeks, for six cycles. Rituximab levels were quantified by Meso Scale Discovery assay. PK analysis was performed using NONMEM 7.3.0. The effect of disease and patient covariates on RXTM83 PK was investigated. Model was evaluated using visual predictive check and non-parametric bootstrap.

RESULTS

In total, 251 DLBCL patients (127 and 124 in RXTM83-CHOP and rituximab-CHOP arms, respectively) and 5341 serum concentrations (2703 for RXTM83 and 2638 for rituximab, respectively) were available for the population PK analysis. The volume of distribution of the central compartment (V₁) and clearance of RXTM83 were estimated at 3.19 L and 12.5 mL/h, respectively. Body surface area allowed to explain the interindividual variability for V₁. A statistical analysis showed that systemic exposure (AUC and C_max) of RTXM83 was similar to rituximab. The 90% confidence intervals for all pairwise comparisons were within the predefined bioequivalence interval of 0.80-1.25. PD similarity of B-cell depletion and recovery was also observed.

CONCLUSIONS

The time course of RTXM83 was well characterized by the model developed. The systemic exposure of RTXM83 and its associated variability were similar to those for rituximab reference in DLBCL patients, demonstrating PK similarity. The PD similarity of RTXM83 and rituximab reference product was also demonstrated.

Cancer trials in sub-Saharan Africa: Aligning research and care

Satish Gopal discusses the challenges of deliverable cancer care and cancer trials in sub-Saharan Africa as well as a potential framework for overcoming these challenges.