Factors affecting toxicity, response and progression-free survival in relapsed patients with indolent B-cell lymphoma and mantle cell lymphoma treated with rituximab: a Japanese phase II study

Rituximab maintenance treatment outcomes in patients with relapsing neuromyelitis optica spectrum disorder: a monocentric retrospective analysis

Some patients with neuromyelitis optica spectrum disorder (NMOSD) experience relapse after rituximab (RTX) treatment. In this retrospective study, we analyzed the recurrence-related clinical features, laboratory investigation results, and dosing protocol of 30 female patients with relapsing NMOSD with immunoglobulin G autoantibodies against aquaporin-4 and relapses during repeated 0.5 g RTX infusions as maintenance treatment. The median follow-up period was 6.62 years. Thirty-five episodes were observed, with myelitis being the most frequent. The median expanded disability status scale change score was 0.50. The recurrence rate decreased by 44.23%/year with RTX infusion. Approximately 85.71% of the patients showed relapse without RTX infusion within 10 months. Overall, RTX may be effective for relapsing NMOSD cases.

The Efficacy of Bepotastine Besilate Compared With Hydroxyzine Pamoate for Preventing Infusion Reactions to the First Dose of Rituximab in Patients With Non-Hodgkin Lymphoma: Protocol for a Phase II, Double-Blind, Multicenter Randomized Trial

BACKGROUND

Rituximab, an anti-CD20 monoclonal antibody, can cause infusion reactions (IRs), especially during the initial rituximab infusion therapy. Generally, patients are administered a histamine H1-receptor antagonist before the rituximab infusion, along with an antipyretic analgesic, to prevent or reduce IRs. Multiple retrospective case-control studies indicate that the second generation of histamine H1-receptor antagonists might be more effective than the first generation in suppressing IRs caused by the rituximab infusion.

OBJECTIVE

This study aimed to assess the efficacy of first- and second-generation histamine H1-receptor antagonists for preventing IRs resulting from the initial infusion of rituximab in patients diagnosed with non-Hodgkin lymphoma.

METHODS

This is a phase II, double-blind, active-controlled randomized trial. It will be a multicenter study conducted across 3 facilities that aims to enroll a total of 40 patients diagnosed with non-Hodgkin lymphoma who will receive their initial rituximab infusion. Participating patients will be administered hydroxyzine pamoate or bepotastine besilate, representing first- or second-generation histamine H1-receptor antagonists, respectively. This will be combined with 400-mg acetaminophen tablets taken approximately 30 minutes before the first infusion of rituximab. The primary end point of this trial is to assess severe IRs, equivalent to grade 2 or higher as defined by the National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0, that occur within a 4-hour period after the initiation of rituximab infusion. The secondary end points include assessing the severity of the initial IR, the maximum severity of the IR, and the duration between rituximab infusion initiation and the onset of the first IR within a 4-hour period. Additionally, the trial will evaluate histamine H1-receptor antagonist-induced drowsiness using the visual analogue scale, with each patient providing their individual response.

RESULTS

This study began with patient recruitment in April 2023, with 17 participants enrolled as of November 12, 2023. The anticipated study completion is set for February 2026.

CONCLUSIONS

This study is the first randomized controlled trial comparing the effects of oral first- and second-generation histamine H1-receptor antagonists in preventing IRs induced by the initial administration of rituximab. The findings from this study hold the potential to establish the rationale for a phase III study aimed at determining the standard premedication protocol for rituximab infusion.

TRIAL REGISTRATION

Japan Registry of Clinical Trials jRCTs051220169; https://jrct.niph.go.jp/latest-detail/jRCTs051220169.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/54882.

Optimization of Rituximab Therapy in Adult Patients With PLA2R1-Associated Membranous Nephropathy With Artificial Intelligence

Introduction

Rituximab is a first-line treatment for membranous nephropathy. Nephrotic syndrome limits rituximab exposure due to urinary drug loss. Rituximab underdosing (serum level <2 μg/ml at month-3) is a risk factor for treatment failure. We developed a machine learning algorithm to predict the risk of underdosing based on patients' characteristics at rituximab infusion. We investigated the relationship between the predicted risk of underdosing and the cumulative dose of rituximab required to achieve remission.

Methods

Rituximab concentrations were measured at month-3 in 92 sera from adult patients with primary membranous nephropathy, split into a training (75%) and a testing set (25%). A forward-backward machine-learning procedure determined the best combination of variables to predict rituximab underdosing in the training data set, which was tested in the test set. The performances were evaluated for accuracy, sensitivity, and specificity in 10-fold cross-validation training and test sets.

Results

The best variables combination to predict rituximab underdosing included age, gender, body surface area (BSA), anti-phospholipase A2 receptor type 1 (anti-PLA2R1) antibody titer on day-0, serum albumin on day-0 and day-15, and serum creatinine on day-0 and day-15. The accuracy, sensitivity, and specificity were respectively 79.4%, 78.7%, and 81.0% (training data set), and 79.2%, 84.6% and 72.7% (testing data set). In both sets, the algorithm performed significantly better than chance (P < 0.05). Patients with an initial high probability of underdosing experienced a longer time to remission with higher rituximab cumulative doses required to achieved remission.

Conclusion

This algorithm could allow for early intensification of rituximab regimen in patients at high estimated risk of underdosing to increase the likelihood of remission.

Trends in non-Hodgkin lymphoma mortality rate in Japan and the United States: A population-based study

Characterizing trends in mortality rates with consideration of trends in incidence rates at the population level could help identify unmet needs in public health and provide essential indicators of cancer control. In the late 20th century, the arrival of the first molecular targeted agent, rituximab, for non-Hodgkin lymphoma (NHL) led to a paradigm shift in NHL treatment. However, the public health impact of this arrival has not been fully clarified. Here, we evaluated trends in the mortality and incidence rates of NHL in Japan and the United States. Age-standardized rates of mortality reversed after the introduction of rituximab, around 2000, beginning to decline significantly with annual percent changes (95% confidence interval) of -2.6% (-3.6% to -1.6%) in Japan and - 3.9% (-4.2% to -3.5%) in the United States. Despite an increase in incidence, the mortality in all age groups weakened the upward trends or decreased in both countries. From a long-term perspective, the trends in mortality rates differed between the countries. In the United States, the mortality rate has declined continuously since the introduction of rituximab, with a declining incidence rate. In contrast, in Japan, the mortality rate stopped declining and the incidence rate increased remarkably. The introduction of rituximab has had a substantial impact at the population level across a wide range of individuals. To reduce the disease burden in terms of mortality, elucidating risk factors that lead to a decreasing incidence rate is warranted for NHL, as well as further development of novel treatments.

A Novel Class of On-Treatment Cancer Immunotherapy Biomarker: Trough Levels of Antibody Therapeutics in Peripheral Blood

While immune checkpoint blockade has revolutionized cancer treatment, unfortunately most patients do not benefit from this treatment. Many pharmacodynamic (PD) studies have revealed essential requirements for successful cancer immunotherapy that may provide insight into how we can improve these agents. Despite enormous efforts focused on interrogating the immune system using different biospecimens (e.g. blood, primary tumor, metastatic tumor, microbiome samples), a variety of technologies (e.g. flow cytometry, bulk and single-cell RNA-sequencing, immunohistochemistry), and wide-ranging disciplines (e.g. pathology, genomics, bioinformatics, immunology, cancer biology, metabolomics, bacteriology), discovery of consistent biomarkers of response have remained elusive. Pharmacokinetics (PK) studies, however, not only provide critical information regarding safe dosing but may also reveal useful biomarkers. For example, recent studies found that trough levels of therapeutic monoclonal antibodies (mAbs) or clearance (CL) of them were associated with clinical outcome, which suggests that trough levels of mAbs may represent a new class of on-treatment cancer immunotherapy biomarker. In this review, we summarize the potential utility of trough levels of mAbs, the mechanism of varying PK, consideration for therapeutic drug monitoring, and assay attributes that will facilitate wider utilization of PK information in conjunction with PD assessments.

Epitope Mapping of an Anti-CD20 Monoclonal Antibody (C20Mab-60) Using Enzyme-Linked Immunosorbent Assay

CD20 is a glycosylated transmembrane protein and is expressed on normal B cells and B cell malignancies. Therapeutic antibodies against CD20 are developed and used in clinic. The understanding of antibody-antigen binding by revealing the epitope is essential for future application to antibody technology. Previously, we developed an anti-human CD20 monoclonal antibody, C₂₀Mab-60 (IgG_2a, kappa), using the Cell-Based Immunization and Screening (CBIS). C₂₀Mab-60 can be used for flow cytometry, Western blot, and immunohistochemical analyses. In this study, we examined the critical epitope of C₂₀Mab-60 using enzyme-linked immunosorbent assay (ELISA) with synthesized peptides. We performed ELISA with deletion mutants, and C₂₀Mab-60 reacted to the 160-179 amino acids sequence of CD20. Next, we analyzed the reaction to 20 point mutants, and C₂₀Mab-60 did not recognize the alanine-substituted peptides of N171A, P172A, S173A, and E174A. The results indicate that the binding epitope of C₂₀Mab-60, developed by CBIS, includes Asn171, Pro172, Ser173, and Glu174 of CD20.

Cross-Validation of a Multiplex LC-MS/MS Method for Assaying mAbs Plasma Levels in Patients with Cancer: A GPCO-UNICANCER Study

BACKGROUND

Different liquid chromatography tandem mass spectrometry (LC-MS/MS) methods have been published for quantification of monoclonal antibodies (mAbs) in plasma but thus far none allowed the simultaneous quantification of several mAbs, including immune checkpoint inhibitors. We developed and validated an original multiplex LC-MS/MS method using a ready-to-use kit to simultaneously assay 7 mAbs (i.e., bevacizumab, cetuximab, ipilimumab, nivolumab, pembrolizumab, rituximab and trastuzumab) in plasma. This method was next cross-validated with respective reference methods (ELISA or LC-MS/MS).

METHODS

The mAbXmise kit was used for mAb extraction and full-length stable-isotope-labeled antibodies as internal standards. The LC-MS/MS method was fully validated following current EMA guidelines. Each cross validation between reference methods and ours included 16-28 plasma samples from cancer patients.

RESULTS

The method was linear from 2 to 100 µg/mL for all mAbs. Inter- and intra-assay precision was <14.6% and accuracy was 90.1-111.1%. The mean absolute bias of measured concentrations between multiplex and reference methods was 10.6% (range 3.0-19.9%).

CONCLUSIONS

We developed and cross-validated a simple, accurate and precise method that allows the assay of up to 7 mAbs. Furthermore, the present method is the first to offer a simultaneous quantification of three immune checkpoint inhibitors likely to be associated in patients.

Relapses shortly after rituximab treatment in neuromyelitis optica spectrum disorder

OBJECTIVE

Rituximab (RTX), an anti-CD20 monoclonal antibody, has been demonstrated to be a useful maintenance therapy for neuromyelitis optica spectrum disorder (NMOSD). However, few patients may suffer from relapses shortly after RTX. In order to investigate the clinical features of RTX-related relapses and guide therapeutic strategy, 3 patients in our department were reported and literatures were reviewed.

METHODS

We reported three NMOSD patients suffered from relapses shortly after rituximab treatment in our hospital and reviewed 13 patients reported in literatures. Their demographic characteristics, clinical features and therapeutic strategy were retrospectively analyzed.

RESULTS

Sixteen patients, including three cases reported in this study, experienced 21 attacks within 1 month after RTX infusion. All of them were women with an age at onset of 34.0 ± 15.0 years. Fourteen patients were seropositive for aquaporin-4 antibody, and one was seropositive for myelin oligodendrocyte glycoprotein antibody. 57.1% (12/21) of RTX-related relapses occurred after the first use of RTX. Their clinical manifestations included optic neuritis (8/21), myelitis (11/21), and the other two relapses without detailed descriptions. Also, 62.5% (10/16) of patients had a history of prior relapses within 3 months before RTX infusions, and the location of nine relapses overlapped with previous relapses. RTX was given again after the first RTX-related relapse in eight patients, three of them with low-dosage RTX stayed stable for years, and five patients with full-dosage RTX experienced another RTX-related relapse.

CONCLUSIONS

Relapses may occur shortly after RTX treatment in NMOSD. RTX-related relapse did not necessarily mean that RTX was ineffective in low-dosage regimen. Timely and sufficient treatment of RTX is crucial to prevent a relapse. It may be more reasonable to monitor B cell repopulation so as to determine a re-treatment regimen. RTX-related relapse following full-dosage RTX may be a predictor for a second time RTX-related relapse and it may be reasonable to switch to other immunosuppressants in early stage.

A randomized phase 2/3 study of R-CHOP vs CHOP combined with dose-dense rituximab for DLBCL: the JCOG0601 trial

Rituximab plus cyclophosphamide-doxorubicin-vincristine-prednisone (R-CHOP) is the standard of care for untreated diffuse large B-cell lymphoma (DLBCL). However, the schedule for rituximab administration has not been optimized. To compare standard R-CHOP with CHOP plus dose-dense weekly rituximab (RW-CHOP) in patients with untreated DLBCL, we conducted a phase 2/3 study (JCOG0601, jRCTs031180139). Patients were randomly assigned to R-CHOP (CHOP-21 with 8 doses of rituximab once every 3 weeks [375 mg/m2]) or RW-CHOP (CHOP-21 with 8 doses of weekly rituximab [375 mg/m2]) groups. The primary end point of the phase 2 component was percent complete response (%CR) of the RW-CHOP arm, whereas that of the phase 3 component was progression-free survival (PFS). Between December 2007 and December 2014, 421 untreated patients were randomly assigned to R-CHOP (213 patients) or RW-CHOP (208 patients). The %CR in the RW-CHOP arm was 85.3% and therefore met the prespecified decision criteria for the phase 2 component. With a median follow-up of 63.4 months, the 3-year PFS and overall survival were 79.2% and 88.7% in the R-CHOP arm and 80.3% and 90.4% in the RW-CHOP arm, respectively. There was no significant difference in PFS (hazard ratio, 0.95; 90.6% confidence interval, 0.68-1.31). Although the safety profile and efficacy of RW-CHOP was comparable with R-CHOP and its tolerability was acceptable, weekly rituximab in combination with CHOP during the early treatment period did not improve PFS in untreated patients with DLBCL. This trial was registered at jrct.niph.go.jp as #jRCTs031180139.

Quantitative Clinical Pharmacology Supports the Bridging from i.v. Dosing and Approval of s.c. Rituximab in B-Cell Hematological Malignancies

A fixed-dose subcutaneous (s.c.) formulation of the anti-CD20 antibody, rituximab, has been developed to address safety, infusion time, and patient comfort concerns relating to intravenous (i.v.) dosing, and has been approved based upon a pharmacokinetic (PK)-clinical bridging strategy, which demonstrated noninferiority of s.c. vs. i.v. dosing in malignancies, including follicular lymphoma (FL) and chronic lymphocytic leukemia (CLL). A clinical development plan was undertaken to identify rituximab s.c. doses achieving noninferior exposure to rituximab i.v., and to confirm PK-clinical bridging, with the same efficacy and similar safety. This drew upon data from 1,579 patients with FL, CLL, or diffuse large B-cell lymphoma in 5 clinical studies, and showed minimum steady-state serum concentration (C_trough ) as the most appropriate exposure bridging measure. Population PK models were developed, simulations were run using covariates and PK parameters from clinical studies, and exposure-efficacy and -safety analyses performed. Population PKs showed a two-compartment model with time-dependent and -independent clearances. Clearance and volume were predominantly influenced by body surface area; disposition and elimination were similar for the s.c. and i.v. formulations. After s.c. administration, patients with FL and CLL achieved noninferior exposures to i.v. dosing. Overall, rituximab exposure and route of administration did not influence clinical responses in patients with FL or CLL, and there was no association between exposure and safety events. C_trough was shown to be an effective pharmacologic-clinical bridging parameter for rituximab in patients with FL or CLL. Clinically effective exposures are achieved with either s.c. or i.v. dosing.

Monoclonal Antibody Monitoring: Clinically Relevant Aspects, A Systematic Critical Review

Monoclonal antibody (mAb) therapy does not usually lead to a clinical response in all patients and resistance may increase over time after repeated mAb administration. This lack or loss of response to the treatment may originate from different and little-known epigenetic, biomolecular, or pathophysiological mechanisms, although an inadequate serum concentration is perhaps the most likely cause, even if not widely recognized and investigated yet. Patient factors that influence the pharmacokinetics (PK) of a mAb should be taken into account. Multiple analyses of patient-derived PK data have identified various factors influencing the clearance of mAbs. These factors include the presence of antidrug antibodies, low serum albumin, high serum levels of C-reactive protein, high body weight, and gender differences among others. The same clearance processes involved in systemic clearance after intravenous administration are also involved in local first-pass catabolism after subcutaneous administration of mAbs. Therapeutic drug monitoring has been proposed as a way to understand and respond to the variability in clinical response and remission. For both classes of mAbs with anti-inflammatory and antitumor effects, dose-guided optimization based on the measurement of serum concentrations in individual patients could be the next step for a personalized and targeted mAb therapy.

[Rituximab immunomonitoring in autoimmune diseases: a support tool in clinical practice?]

INTRODUCTION

Immune monitoring of monoclonal antibodies is a helpful tool in optimizing the management of patients treated with TNF blockers, especially in gastroenterology. In contrast, studies evaluating the interest of such monitoring are lacking for other monoclonal antibodies used in autoimmune diseases, including rituximab despite its widespread use in the field for almost 15 years. Hence, we conducted a study whose goal was to describe the clinical and biological characteristics of all patients who had a rituximab immune monitoring.

METHODS

All the clinical, biological and therapeutic data attached to the demands (from 2015 onwards) we received for immune monitoring of rituximab (measurements of rituximab serum levels and anti-rituximab antibodies using the drug-sensitive assay LISA-TRACKER Duo Rituximab®), were retrospectively reviewed. Suspected cases of hypersensitivity and secondary non-response were included.

RESULTS

Several medical specialities (nephrology, haematology, neurology, rheumatology, internal medicine) were represented among the 18 records included in the study (out of 23 demands), 10 being suspected cases of hypersensitivity and 8 secondary non-responders. All 6 patients whose symptoms were consistent with the classical presentation of serum sickness, as well as half of the secondary non-responders, were positive for antirituximab antibodies.

CONCLUSION

This detailed real world case study illustrates the potential benefits of rituximab immune monitoring (especially anti-rituximab antibodies) in autoimmune diseases, suggesting it could be helpful in suspected cases of serum sickness, as well as secondary non-response (B-cell non-depletion being an early red flag). Larger and disease-specific studies are warranted to support these findings.

Anti-CD20 monoclonal antibodies in Systemic Lupus Erythematosus

Systemic Lupus Erythematosus (SLE) is an autoimmune inflammatory condition with a wide spectrum of disease manifestations and severities, resulting in significant morbidity and mortality. The aetiopathogenesis of SLE is complex. Young women and certain ethnicities are commonly affected, suggesting a significant hormonal and genetic influence. Diverse immunological abnormalities have been described. A characteristic abnormality is the presence of autoantibodies, implicating a central role for B cells in disease pathogenesis and/or perpetuation. Whilst conventional therapies have improved outcomes, a great unmet need remains. Recently, biological therapies are being explored. B-cell depletion therapy with rituximab has been in use off-label for nearly two decades. Inconsistent results between uncontrolled and controlled studies have raised doubts about its efficacy. In this review, we will focus on B cell abnormalities and the rationale behind B-cell depletion therapy with anti-CD20 monoclonal antibody (mAb), rituximab, will be explored including an evaluation of clinical and trial experience. Finally, we will discuss the mechanistic basis for considering alternative anti-CD20 mAbs.

Prognosis of primary hepatic lymphoma: A US population-based analysis

•

Primary hepatic lymphoma (PHL) is a rare form of extranodal lymphomas, mainly invading the liver and local tissues.

•

The incidence, clinical characteristics and survival of patients with PHL in the United States.

•

An applicable PHL model can forecast the dynamic survival rate of patients with PHL.

Objective

Primary hepatic lymphoma (PHL) is a rare malignancy with lesions confined to the liver. It is characterized by a large number of monomorphic, medium-sized lymphocytic infiltrates in the hepatic sinusoid. Due to the rarity of this malignancy, our current understanding of PHL is limited.

Methods

We collected incidence, mortality, and clinical data of PHL patients diagnosed between 1975 and 2016 using the Surveillance, Epidemiology, and End Results (SEER) database. The annual percentage changes (APCs) and prognoses were analyzed using the Joinpoint and R package.

Results

Among the 1,372 patients, white males were prevalent, and the most common histological subtype was diffuse large B-cell lymphoma (DLBCL). The incidence and mortality rate of PHL was 0.075/100,000 person-years and 0.055/100,000 person-years, respectively. The annual incidence rate of PHL increased significantly, with an APC of 2.74% (P < 0.001). The 3- and 5-year overall survival (OS) rates of patients with PHL were 43.553% and 39.242%, respectively. The 3- and 5-year relative survival (RS) rates were 46.925% and 45.300%, respectively. Multivariate Cox regression analysis revealed that older age, black, DLBCL, and advanced-stage disease were independent predictors of unfavorable OS and RS. The C-index and receiver operating characteristic (ROC) analysis confirmed the prognostic value of the nomograms established in this study.

Conclusion

The nomogram established in this study is a robust tool to predict the prognosis of PHL patients.

Towards Rational Cancer Therapeutics: Optimizing Dosing, Delivery, Scheduling, and Combinations

The current trend to personalize anticancer therapies mostly relies on selecting the best drug or combination of drugs to achieve optimal efficacy in patients. In addition to the comprehensive genetic and molecular knowledge of each tumor before choosing the drugs to be given, there is probably much room left for improvement by further personalizing the very modes by which the drugs are given, once they have been carefully selected. In particular, shifting from standard dosing to tailored dosing should help in maintaining drug exposure levels in the right therapeutic window, thus ensuring that the efficacy/toxicity balance is optimal. This paper covers the current knowledge regarding pharmacokinetic/pharmacodynamic relationships of anticancer agents, from decades-old cytotoxics to the latest immune checkpoint inhibitors, the most frequent sources for long-neglected interpatient variability impacting on drug exposure levels, and what could be done to achieve real personalized medicine in oncology such as implementing therapeutic drug monitoring with adaptive dosing strategies or using model-driven modalities for personalized dosing and scheduling.

Mechanisms of Resistance to Monoclonal Antibodies (mAbs) in Lymphoid Malignancies

PURPOSE OF REVIEW

Passive immunotherapy with therapeutic monoclonal antibodies (mAbs) has revolutionized the treatment of cancer, especially hematological malignancies over the last 20 years. While use of mAbs has improved outcomes, development of resistance is inevitable in most cases, hindering the long-term survival of cancer patients. This review focuses on the available data on mechanisms of resistance to rituximab and includes some additional information for other mAbs currently in use in hematological malignancies.

RECENT FINDINGS

Mechanisms of resistance have been identified that target all described mechanisms of mAb activity including altered antigen expression or binding, impaired complement-mediated cytotoxicity (CMC) or antibody-dependent cellular cytotoxicity (ADCC), altered intracellular signaling effects, and inhibition of direct induction of cell death. Numerous approaches to circumvent identified mechanisms of resistance continue to be investigated, but a thorough understanding of which resistance mechanisms are most clinically relevant is still elusive. In recent years, a deeper understanding of the tumor microenvironment and targeting the apoptotic pathway has led to promising breakthroughs. Resistance may be driven by unique patient-, disease-, and antibody-related factors. Understanding the mechanisms of resistance to mAbs will guide the development of strategies to overcome resistance and re-sensitize cancer cells to these biological agents.

Safety and efficacy of rituximab in neuromyelitis optica spectrum disorders (RIN-1 study): a multicentre, randomised, double-blind, placebo-controlled trial

BACKGROUND

Pharmacological prevention against relapses in patients with neuromyelitis optica spectrum disorder (NMOSD) is developing rapidly. We aimed to investigate the safety and efficacy of rituximab, an anti-CD20 monoclonal antibody, against relapses in patients with NMOSD.

METHODS

We did a multicentre, randomised, double-blind, placebo-controlled clinical trial at eight hospitals in Japan. Patients aged 16-80 years with NMOSD who were seropositive for aquaporin 4 (AQP4) antibody, were taking 5-30 mg/day oral steroids, and had an Expanded Disability Status Scale (EDSS) score of 7·0 or less were eligible for the study. Individuals taking any other immunosuppressants were excluded. Participants were randomly allocated (1:1) either rituximab or placebo by a computer-aided dynamic random allocation system. The doses of concomitant steroid (converted to equivalent doses of prednisolone) and relapses in previous 2 years were set as stratification factors. Participants and those assessing outcomes were unaware of group assignments. Rituximab (375 mg/m²) was administered intravenously every week for 4 weeks, then 6-month interval dosing was done (1000 mg every 2 weeks, at 24 weeks and 48 weeks after randomisation). A matching placebo was administered intravenously. Concomitant oral prednisolone was gradually reduced to 2-5 mg/day, according to the protocol. The primary outcome was time to first relapse within 72 weeks. Relapses were defined as patient-reported symptoms or any new signs consistent with CNS lesions and attributable objective changes in MRI or visual evoked potential. The primary analysis was done in the full analysis set (all randomly assigned patients) and safety analyses were done in the safety analysis set (all patients who received at least one infusion of assigned treatment). The primary analysis was by intention-to-treat principles. This trial is registered with the UMIN clinical trial registry, UMIN000013453.

FINDINGS

Between May 10, 2014, and Aug 15, 2017, 38 participants were recruited and randomly allocated either rituximab (n=19) or placebo (n=19). Three (16%) patients assigned rituximab discontinued the study and were analysed as censored cases. Seven (37%) relapses occurred in patients allocated placebo and none were recorded in patients assigned rituximab (group difference 36·8%, 95% CI 12·3-65·5; log-rank p=0·0058). Eight serious adverse events were recorded, four events in three (16%) patients assigned rituximab (lumbar compression fracture and infection around nail of right foot [n=1], diplopia [n=1], and uterine cancer [n=1]) and four events in two (11%) people allocated to placebo (exacerbation of glaucoma and bleeding in the right eye chamber after surgery [n=1], and visual impairment and asymptomatic white matter brain lesion on MRI [n=1]); all patients recovered. No deaths were reported.

INTERPRETATION

Rituximab prevented relapses for 72 weeks in patients with NMOSD who were AQP4 antibody-positive. This study is limited by its small sample size and inclusion of participants with mild disease activity. However, our results suggest that rituximab could be useful maintenance therapy for individuals with NMOSD who are AQP4 antibody-positive.

FUNDING

Japanese Ministry of Health, Labour and Welfare, Japan Agency for Medical Research and Development, and Zenyaku Kogyo.

Treatment of mantle cell lymphoma in Asia: a consensus paper from the Asian Lymphoma Study Group

BACKGROUND

Mantle cell lymphoma (MCL) is a B cell malignancy that can be aggressive and with a poor prognosis; the clinical course is heterogeneous. The epidemiology of MCL in Asia is not well documented but appears to comprise 2-6% of all lymphoma cases based on available data, with variation observed between countries. Although international guidelines are available for the treatment of MCL, there is a lack of published data or guidance on the clinical characteristics and management of MCL in patient populations from Asia. This paper aims to review the available treatment and, where clinical gaps exist, provide expert consensus from the Asian Lymphoma Study Group (ALSG) on appropriate MCL management in Asia. BODY: Management strategies for MCL are patient- and disease stage-specific and aim to achieve balance between efficacy outcomes and toxicity. For asymptomatic patients with clearly indolent disease, observation may be an appropriate strategy. For stage I/II disease, following international guidelines is appropriate, which include either a short course of conventional chemotherapy followed by consolidated radiotherapy, less aggressive chemotherapy regimens, or a combination of these approaches. For advanced disease, the approach is based on the age and fitness of the patient. For young, fit patients, the current practice for induction therapy differs across Asia, with cytarabine having an important role in this setting. Hematopoietic stem cell transplantation (HSCT) may be justified in selected patients because of the high relapse risk. In elderly patients, specific chemoimmunotherapy regimens available in each country/region are a treatment option. For maintenance therapy after first-line treatment, the choice of approach should be individualized, with cost being an important consideration within Asia. For relapsed/refractory disease, ibrutinib should be considered as well as other follow-on compounds, if available.

CONCLUSION

Asian patient-specific data for the treatment of MCL are lacking, and the availability of treatment options differs between country/region within Asia. Therefore, there is no clear one-size-fits-all approach and further investigation on the most appropriate sequence of treatment that should be considered for this heterogeneous disease.

Optimizing drug development in oncology by clinical trial simulation: Why and how?

In therapeutic research, the safety and efficacy of pharmaceutical products are necessarily tested on humans via clinical trials after an extensive and expensive preclinical development period. Methodologies such as computer modeling and clinical trial simulation (CTS) might represent a valuable option to reduce animal and human assays. The relevance of these methods is well recognized in pharmacokinetics and pharmacodynamics from the preclinical phase to postmarketing. However, they are barely used and are poorly regarded for drug approval, despite Food and Drug Administration and European Medicines Agency recommendations. The generalization of CTS could be greatly facilitated by the availability of software for modeling biological systems, by clinical trial studies and hospital databases. Data sharing and data merging raise legal, policy and technical issues that will need to be addressed. Development of future molecules will have to use CTS for faster development and thus enable better patient management. Drug activity modeling coupled with disease modeling, optimal use of medical data and increased computing speed should allow this leap forward. The realization of CTS requires not only bioinformatics tools to allow interconnection and global integration of all clinical data but also a universal legal framework to protect the privacy of every patient. While recognizing that CTS can never replace 'real-life' trials, they should be implemented in future drug development schemes to provide quantitative support for decision-making. This in silico medicine opens the way to the P4 medicine: predictive, preventive, personalized and participatory.

Role of obinutuzumab exposure on clinical outcome of follicular lymphoma treated with first-line immunochemotherapy

AIMS

Obinutuzumab (G) is a humanized type II, Fc-glycoengineered anti-CD20 monoclonal antibody used in various indications, including patients with previously untreated front-line follicular lymphoma. We investigated sources of variability in G exposure and association of progression-free survival (PFS) with average concentration over induction (C_meanIND ) in front-line follicular lymphoma patients treated with G plus chemotherapy (bendamustine, CHOP, or CVP) in the GALLIUM trial.

METHODS

Individual exposures (C_meanIND ) were obtained from a previously established population pharmacokinetic model updated with GALLIUM data. Multivariate Cox proportional hazard models and univariate Kaplan-Meier plots investigated relationships of PFS with exposure and other potential prognostic factors.

RESULTS

Overall, G exposure was lower in high body-weight patients and in males, and slightly lower in patients with high baseline tumour burden. Analysis of clinical outcomes showed that variability in G exposure did not impact PFS in G-bendamustine-treated patients; PFS was inferior in males and patients with FCGR2a/2b T232 T low-affinity receptor variant, and superior in patients with FCGR2a/2b I232T variant. In G-CHOP/CVP arms, PFS improved with increasing C_meanIND (hazard ratio = 1.74 and 0.394 at 5^th and 95^th percentile compared to median C_meanIND ) and was inferior in patients with high baseline tumour size and B symptoms.

CONCLUSIONS

It remains unclear whether for G-CHOP/CVP patients lower G exposure is a consequence of adverse disease biology and/or resistance to chemotherapy backbone (higher clearance in nonresponder patients, as demonstrated for rituximab) rather than being the cause of poorer clinical outcome. A study with >1 dose level of G could help resolve this uncertainty.

Rituximab dosing in hematological malignancies: an old question, revisited

Rituximab is the standard of care for most B-cell malignancies. Its rapid clinical development enabled patients to receive this life-prolonging medicine sooner; however, it precluded a thorough assessment of dose selection. Extensive clinical pharmacology data collected from the recent subcutaneous development program enabled re-examination of this old question and support that the approved rituximab dosing regimens in non-Hodgkin's lymphoma and chronic lymphocytic leukemia appear to maximize the clinical benefit in the majority of patients.

Rituximab Serum Concentrations and Anti-Rituximab Antibodies During B-Cell Depletion Therapy for Myalgic Encephalopathy/Chronic Fatigue Syndrome

PURPOSE

Previous Phase II trials indicated clinical benefit from B-cell depletion using the monoclonal anti-CD20 antibody rituximab in patients with myalgic encephalopathy/chronic fatigue syndrome (ME/CFS). The association between rituximab serum concentrations and the effect and clinical relevance of antidrug antibodies (ADAs) against rituximab in ME/CFS is unknown. We retrospectively measured rituximab concentrations and ADAs in serum samples from patients included in an open-label Phase II trial with maintenance rituximab treatment (KTS-2-2010) to investigate possible associations with clinical improvement and clinical and biochemical data.

METHODS

Patients with ME/CFS fulfilling the Canadian criteria received rituximab (500 mg/m²) infusions: 2 infusions 2 weeks apart (induction), followed by maintenance treatment at 3, 6, 10, and 15 months. The measured rituximab concentrations and ADAs in serum samples included 23 of 28 patients from the trial.

FINDINGS

There were no significant differences in mean serum rituximab concentrations between 14 patients experiencing clinical improvement versus 9 patients with no improvement. Female patients had higher mean serum rituximab concentrations than male patients at 3 months (P = 0.05). There was a significant negative correlation between B-cell numbers in peripheral blood at baseline and rituximab serum concentration at 3 months (r = -0.47; P = 0.03). None of the patients had ADAs at any time point.

IMPLICATIONS

Clinical improvement of patients with ME/CFS in the KTS-2-2010 trial was not related to rituximab serum concentrations or ADAs. This finding is also in line with a recent randomized trial questioning the efficacy of rituximab in ME/CFS. Rituximab concentrations and ADAs still offer supplemental information when interpreting the results of these trials.

Influence of FCGR3A-158V/F Genotype and Baseline CD20 Antigen Count on Target-Mediated Elimination of Rituximab in Patients with Chronic Lymphocytic Leukemia: A Study of FILO Group

BACKGROUND AND OBJECTIVES

Rituximab is an anti-CD20 monoclonal antibody approved in the first-line treatment of patients with chronic lymphocytic leukemia (CLL). Rituximab pharmacokinetics shows a time dependency possibly related to changes in the target antigen amount over time. The purpose of this study was to quantify the influence of both CD20 antigenic mass and the FcγRIIIA genetic polymorphism on rituximab pharmacokinetics in CLL.

METHODS

Rituximab pharmacokinetics was described in 118 CLL patients using a semi-mechanistic model including a latent target antigen turnover, which allowed the estimation of rituximab target-mediated elimination in addition to the endogenous clearance.

RESULTS

Target-mediated elimination rate constant increased with the baseline CD20 count on circulating B cells (p = 0.00046) and in patients with the FCGR3A-158VV genotype (p = 0.0016). Physiologic elimination of antigen was lower in the Binet C disease stage (p = 0.00018). The effects of these covariates on rituximab concentrations were mainly visible at the beginning of treatment. Body surface area also increased central and peripheral volumes of distribution (p = 1.3 × 10^-5 and 0.0015, respectively).

CONCLUSIONS

A pharmacokinetic model including target-mediated elimination accurately described rituximab concentrations in CLL and showed that rituximab 'consumption' (target-mediated elimination) increases with increasing baseline antigen count on circulating B cells and in FCGR3A-158VV patients.

CLINICAL TRIAL REGISTRATION

NCT01370772.

Cardiovascular Adverse Events Complicating the Administration of Rituximab: Report of Two Cases

Rituximab is a murine/human chimeric monoclonal antibody directed against the CD20 antigen. It is widely used in combination with polychemotherapy regimens for the treatment of hematological disorders. There is no evidence of direct cardiotoxicity of the drug but a few cases of cardiovascular adverse events have been reported in the literature.

We report on two patients affected by stage IV non-Hodgkin lymphoma with bone marrow infiltration and peripheral blood involvement who experienced cardiovascular accidents temporally related to rituximab infusion. In both cases the monoclonal antibody was administered in association with a polychemotherapy regimen but administration was postponed several days later in order to avoid severe cytokine release syndrome because of the high tumor burden.

The first case concerns an episode of atrial fibrillation in a patient with a diagnosis of small B-cell lymphoma. The episode happened immediately after rituximab infusion. In the second case there was an episode of chest pain associated with fever and chills during rituximab infusion in a patient with a diagnosis of mantle cell lymphoma. In both cases we noticed an unusual correlation between symptom recurrence and the speed of rituximab infusion. Both patients presented several cardiovascular risk factors but preliminary cardiac function assessment excluded signs of heart dysfunction.

The pathogenesis of cardiovascular events during rituximab infusion remains unclear. A key role might be played by cytokine release from B cells as a consequence of rituximab activity. Moreover, pre-existing silent cardiac damage could be co-responsible for the clinical manifestations we reported.

We consider our clinical experience relevant because it raises an issue of good clinical practice: despite rituximab's good tolerability profile, patients with cardiovascular risk factors should undergo accurate cardiac assessment so that silent heart disease can be detected. If the suspicion of cardiac damage is high, more extensive cardiac assessment is recommended.

Rituximab in B-Cell Hematologic Malignancies: A Review of 20 Years of Clinical Experience

Rituximab is a human/murine, chimeric anti-CD20 monoclonal antibody with established efficacy, and a favorable and well-defined safety profile in patients with various CD20-expressing lymphoid malignancies, including indolent and aggressive forms of B-cell non-Hodgkin lymphoma. Since its first approval 20 years ago, intravenously administered rituximab has revolutionized the treatment of B-cell malignancies and has become a standard component of care for follicular lymphoma, diffuse large B-cell lymphoma, chronic lymphocytic leukemia, and mantle cell lymphoma. For all of these diseases, clinical trials have demonstrated that rituximab not only prolongs the time to disease progression but also extends overall survival. Efficacy benefits have also been shown in patients with marginal zone lymphoma and in more aggressive diseases such as Burkitt lymphoma. Although the proven clinical efficacy and success of rituximab has led to the development of other anti-CD20 monoclonal antibodies in recent years (e.g., obinutuzumab, ofatumumab, veltuzumab, and ocrelizumab), rituximab is likely to maintain a position within the therapeutic armamentarium because it is well established with a long history of successful clinical use. Furthermore, a subcutaneous formulation of the drug has been approved both in the EU and in the USA for the treatment of B-cell malignancies. Using the wealth of data published on rituximab during the last two decades, we review the preclinical development of rituximab and the clinical experience gained in the treatment of hematologic B-cell malignancies, with a focus on the well-established intravenous route of administration. This article is a companion paper to A. Davies, et al., which is also published in this issue.

FUNDING

F. Hoffmann-La Roche Ltd., Basel, Switzerland.

Bevacizumab Pharmacokinetics Influence Overall and Progression-Free Survival in Metastatic Colorectal Cancer Patients

OBJECTIVE

Clinical response to bevacizumab varies between patients treated for metastatic colorectal cancer (mCRC). The aim of this study was to quantify individual factors affecting bevacizumab pharmacokinetic variability and assess the relationship between bevacizumab concentrations and clinical outcomes.

METHODS

Bevacizumab pharmacokinetics were assessed in 130 mCRC patients using a two-compartment pharmacokinetic population model. Overall and progression-free survival (PFS) were analyzed using Cox models.

RESULTS

The bevacizumab volume of distribution increased with height (p = 10^-10) and was higher in patients with a 3/3 variable number tandem repeat of the FCGRT (Fc fragment of IgG receptor and transporter) gene (p = 0.039). The elimination rate constant increased with baseline carcinoembryonic antigen (CEA) and vascular endothelial growth factor (VEGF) concentrations, and was higher in patients with extra-hepatic metastases (p = 0.00029, 0.011, and 0.014). A bevacizumab trough concentration ≤15.5 mg/L was associated with both shorter overall survival and PFS (hazard ratio [95 % CI] 1.90 [1.20-2.99] and 1.76 [1.20-2.58], respectively).

CONCLUSION

High tumour burden is associated with low bevacizumab concentrations, and high bevacizumab concentration are associated with both decreased overall and progression-free survivals.

Phase II study of intensified rituximab induction and maintenance for low grade B cell lymphoma

Rituximab has markedly improved the outcomes of B cell lymphoma, and its maintenance has been shown to be beneficial in low grade B cell lymphoma (LGBCL). We conducted a multicenter, phase II trial of intensive rituximab induction and maintenance therapy for LGBCL to optimize the rituximab monotherapy. Patients with newly diagnosed or rituximab naïve relapsed LGBCL received 8 weekly rituximab as induction, then continued maintenance therapy with rituximab for 4 weeks at 6-month intervals. The primary endpoint was the overall response rate (ORR). Forty-five patients were enrolled from 2005 to 2009 and 36 were eligible. The ORR was 83.3% (30/36) with a complete response rate of 72.2% (26/36). The 3-year progression-free survival (PFS) was 76.7% with a median follow-up of 43.0 months. Five grade three toxicities were observed (no grade 4). Our findings suggest that this regimen demonstrates high activity with durable PFS and minimal toxicity in LGBCL patients.

Rituximab exposure is influenced by baseline metabolic tumor volume and predicts outcome of DLBCL patients: a Lymphoma Study Association report

High variability in patient outcome after rituximab-based treatment is partly explained by rituximab concentrations, and pharmacokinetic (PK) variability could be influenced by tumor burden. We aimed at quantifying the influence of baseline total metabolic tumor volume (TMTV₀) on rituximab PK and of TMTV₀ and rituximab exposure on outcome in patients with diffuse large B-cell lymphoma (DLBCL). TMTV₀ was measured by ¹⁸F-fluorodeoxyglucose-positron emission tomography-computed tomography in 108 previously untreated DLBCL patients who received four 375 mg/m² rituximab infusions every 2 weeks in combination with chemotherapy in 2 prospective trials. A 2-compartment population model allowed describing rituximab PK and calculating rituximab exposure (area under the concentration-time curve; AUC). The association of TMTV₀ and AUC with metabolic response after 4 cycles, as well as progression-free survival (PFS) and overall survival (OS), was assessed using logistic regression and Cox models, respectively. Cutoff values for patient outcome were determined using receiver operating characteristic curve analysis. Exposure to rituximab decreased as TMTV₀ increased (R² = 0.41, P < .0001). A high AUC in cycle 1 (≥9400 mg × h per liter) was associated with better response (odds ratio, 5.56; P = .0006) and longer PFS (hazard ratio [HR], 0.38; P = .011) and OS (HR, 0.17; P = .001). A nomogram for rituximab dose needed to obtain optimal AUC according to TMTV₀ was constructed, and the 375 mg/m² classical dose would be suitable for patients with TMTV₀ <281 cm³ In summary, rituximab exposure is influenced by TMTV₀ and correlates with response and outcome of DLBCL patients. Dose individualization according to TMTV₀ should be evaluated in prospective studies. These studies were registered at www.clinicaltrials.gov as #NCT00498043 and #NCT00841945.

Theranostic of biopharmaceuticals

Monoclonal antibodies (mAbs) and fusion proteins with an Fc portion of immunoglobulin G (IgG) are emblematic of the remarkable expansion of biopharmaceuticals. Despite their biological origin, these products display an interindividual variability in their efficacy and/or side effects, which must be taken into consideration. Biological monitoring allowing for adapted prescription and dose adjustments may lead to therapeutic optimization and limitation of the high costs of these drugs. Herein, we review the biological theranostic of mAbs and Fc fusion proteins, including pre-treatment analyses, monitoring of efficacy, therapeutic drug monitoring, and monitoring of side effects. Supported by concrete evidence, a specific interest is given to individualised therapeutic monitoring that combines intention to treat, biomarkers of efficacy and adaptation of serum concentrations.

Phase I study of chimeric anti-CD20 monoclonal antibody in Chinese patients with CD20-positive non-Hodgkin's lymphoma

OBJECTIVE

This study was designed to determine the safety, pharmacokinetics and biologic effects of a human-mouse chimeric anti-CD20 monoclonal antibody (SCT400) in Chinese patients with CD20-positive B-cell non-Hodgkin's lymphoma (CD20(+) B-cell NHL). SCT400 has an identical amino acid sequence as rituximab, with the exception of one amino acid in the CH1 domain of the heavy chain, which is common in Asians.

METHODS

Fifteen patients with CD20(+) B-cell NHL received dose-escalating SCT400 infusions (250 mg/m(2): n=3; 375 mg/m(2): n=9; 500 mg/m(2): n=3) once weekly for 4 consecutive weeks with a 24-week follow-up period. The data of all patients were collected for pharmacokinetics and pharmacodynamics analyses.

RESULTS

No dose-limiting toxicities were observed. Most drug-related adverse events were grade 1 or 2. Two patients had grade 3 or 4 neutropenia. Under premedication, the drug-related infusion reaction was mild. A rapid, profound and durable depletion of circulating B cells was observed in all dose groups without significant effects on T cell count, natural killer (NK) cell count or immunoglobulin levels. No patient developed anti-SCT400 antibodies during the course of the study. SCT400 serum half-life (T1/2), maximum concentration (Cmax) and area under the curve (AUC) generally increased between the first and fourth infusions (P<0.05). At the 375 mg/m(2) dose, the T1/2 was 122.5±46.7 h vs. 197.0±75.0 h, respectively, and the Cmax was 200.6±20.2 g/mL vs. 339.1±71.0 g/mL, respectively. From 250 mg/m(2) to 500 mg/m(2), the Cmax and AUC increased significantly in a dose-dependent manner (P<0.05). Patients with a high tumor burden had markedly lower serum SCT400 concentrations compared with those without or with a low tumor burden. Of the 9 assessable patients, 1 achieved complete response and 2 achieved partial responses.

CONCLUSIONS

SCT400 is well-tolerated and has encouraging preliminary efficacy in Chinese patients with CD20(+) B-cell NHL.

Rationale for optimal obinutuzumab/GA101 dosing regimen in B-cell non-Hodgkin lymphoma

Obinutuzumab (GA101) is a type II, glycoengineered anti-CD20 monoclonal antibody for the treatment of hematologic malignancies. Obinutuzumab has mechanisms of action that are distinct from those of rituximab, potentially translating into improved clinical efficacy. We present the pharmacokinetic and clinical data from the phase I/II GAUGUIN and phase I GAUDI studies that were used to identify the obinutuzumab dose and regimen undergoing phase III assessment. In phase I (GAUGUIN and GAUDI), non-Hodgkin lymphoma patients received up to a maximum 9 fixed doses (obinutuzumab 50-2000 mg). In GAUGUIN phase II, patients received obinutuzumab 400/400 mg or 1600/800 mg [first dose day (D)1, D8, cycle (C) 1; second dose D1, C2-C8]. The influence of demographic factors on pharmacokinetics and drug exposure on tumor response and toxicity were analyzed using exploratory graphical analyses. Obinutuzumab serum concentrations with 1600/800 mg were compared with a 1000 mg fixed-dose regimen (D1, D8 and D15, C1; D1, C2-C8) using pharmacokinetic modeling simulations. Factors related to CD20-antigenic mass were more influential on obinutuzumab pharmacokinetics with 400/400 versus 1600/800 mg. Higher serum concentrations were observed with 1600/800 versus 400/400 mg, irrespective of CD20-antigenic mass. Tumor shrinkage was greater with 1600/800 versus 400/400 mg; there was no significant increase in adverse events. Fixed dose 1000 mg with an additional C1 infusion resulted in similar serum concentrations to 1600/800 mg in model-based analyses. The obinutuzumab 1000 mg fixed-dose regimen identified in this exploratory analysis was confirmed in a full covariate analysis of a larger dataset, and is undergoing phase III evaluation. GAUGUIN and GAUDI are registered at www.clinicaltrials.gov (clinicaltrials.gov identifier:00517530 and 00825149, respectively).

Ibrutinib in combination with rituximab in relapsed or refractory mantle cell lymphoma: a single-centre, open-label, phase 2 trial

BACKGROUND

Ibrutinib is approved in the EU, USA, and other countries for patients with mantle cell lymphoma who received one previous therapy. In a previous phase 2 study with single-agent ibrutinib, the proportion of patients who achieved an objective response was 68%; 38 (34%) of 111 patients had transient lymphocytosis. We hypothesised that adding rituximab could target mantle cell lymphoma cells associated with redistribution lymphocytosis, leading to more potent antitumour activity.

METHODS

Patients with a confirmed mantle cell lymphoma diagnosis (based on CD20-positive and cyclin D1-positive cells in tissue biopsy specimens), no upper limit on the number of previous treatments received, and an Eastern Cooperative Oncology Group performance status score of 2 or less were enrolled in this single-centre, open-label, phase 2 study. Patients received continuous oral ibrutinib (560 mg) daily until progressive disease or unacceptable toxic effects. Rituximab 375 mg/m(2) was given intravenously once per week for 4 weeks during cycle 1, then on day 1 of cycles 3-8, and thereafter once every other cycle up to 2 years. The primary endpoint was the proportion of patients who achieved an objective response in the intention-to-treat population and safety assessed in the as-treated population. The study is registered with ClinicalTrials.gov, number NCT01880567, and is still ongoing, but no longer accruing patients.

FINDINGS

Between July 15, 2013, and June 30, 2014, 50 patients were enrolled. Median age was 67 years (range 45-86), and the median number of previous regimens was three (range 1-9). At a median follow-up of 16·5 months (IQR 12·09-19·28), 44 (88%, 95% CI 75·7-95·5) patients achieved an objective response, with 22 (44%, 30·0-58·7) patients achieving a complete response, and 22 (44%, 30·0-58·7) a partial response. The only grade 3 adverse event in >=10% of patients was atrial fibrillation, which was noted in six (12%) patients. Grade 4 diarrhoea and neutropenia occurred in one patient each. Adverse events led to discontinuation of therapy in five (10%) patients (atrial fibrillation in three [6%] patients, liver infection in one [2%], and bleeding in one [2%]). Two patients died while on-study from cardiac arrest and septic shock; the latter was deemed possibly related to treatment.

INTERPRETATION

Ibrutinib combined with rituximab is active and well tolerated in patients with relapsed or refractory mantle cell lymphoma. Our results provide preliminary evidence for the activity of this combination in clinical practice. A phase 3 trial is warranted for more definitive data.

FUNDING

Pharmacyclics LLC, an AbbVie Company.

Therapeutic drug monitoring of monoclonal antibodies in inflammatory and malignant disease: Translating TNF-α experience to oncology

Lack of response to monoclonal antibodies (mAbs) has been associated with inadequate mAb serum concentrations. Therapeutic drug monitoring (TDM) of mAbs has the potential to guide to more effective dosing in individual patients. This review discusses the mechanisms responsible for interpatient variability of mAb pharmacokinetics, summarizes exposure-response data of mAbs used in inflammatory and malignant disease, presents current evidence of mAb-TDM in inflammatory disease, and provides hurdles and required future steps for further implementing mAb-TDM.

A new frontier in haematology - combining pharmacokinetic with pharmacodynamic factors to improve choice and dose of drug

The issue of tailored dosing adjusted according to a range of patient-specific factors other than bodyweight or body surface area is of large and increasing clinical and financial concern. Even if it is known that dosing alterations are likely to be required for parameters such as body composition, gender and pharmacogenetics, the amount of dosing change is unknown. Thus, pharmacokinetically guided dosing is making a resurgence, particularly in areas of medicine where there are cost constraints or safety issues, such as in haematology medications. However, the evidence to support the behaviour is minimal, particularly when long-term outcomes are considered. In haematology, there are particular issues around efficacy, toxicity and overall cost. Newer targeted agents, such as the monoclonal antibody rituximab and the tyrosine kinase inhibitor imatinib, whilst clearly being highly effective, are dosed on a milligram per square metre (rituximab) or fixed dose basis (imatinib), regardless of body composition, tumour aspects or comorbidity. This review questions this practice and raises important clinical issues; specifically, the clinical potential for combined pharmacokinetically and pharmacodynamically guided dosing of new targeted agents in haematological malignancies. This pharmacokinetically and pharmacodynamically guided dosing is an emerging area of clinical pharmacology, driven predominantly by toxicity, efficacy and cost issues, but also because reasonable outcomes are being noted with more appropriately dosed older medications adjusted for patient-specific factors. Clinical trials to investigate the optimization of rituximab dose scheduling are required.

Development of antirituximab antibodies in children with nephrotic syndrome

BACKGROUND

Rituximab is actively used as a rescue therapy for nephrotic syndrome (NS). The development of antidrug antibodies, including antirituximab antibodies (ARA) and human antichimeric antibodies (HACA), is reported with rituximab treatment in various diseases. Here we report two pediatric patients with NS who developed ARA.

CASE DIAGNOSIS AND TREATMENT

Rituximab was given as a rescue therapy for two patients with steroid-dependent NS. Both patients had been treated orally with glucocorticosteroid, methylprednisolone, and calcineurin inhibitors but experienced frequent relapses. With rituximab treatment, the patients remained in remission for several months. After the B-cell count recovered, the patients received a second course of rituximab administration and experienced a hypersensitivity reaction during drug infusion. CD19 cell counts rose despite treatment with rituximab. ARA titers were monitored before and after rituximab treatment, and the development of ARA after the second course of rituximab administration was confirmed.

CONCLUSIONS

We report the development of HACA in two patients with NS who did not achieve B-cell depletion after repeated administration of rituximab. This report suggests that additional studies are needed to determine the incidence of ARA in patients with NS, and its clinical significance.

Subcutaneous immunoglobulin in lymphoproliferative disorders and rituximab-related secondary hypogammaglobulinemia: a single-center experience in 61 patients

Intravenous immunoglobulin replacement therapy represents the standard treatment for hypogammaglobulinemia secondary to B-cell lymphoproliferative disorders. Subcutaneous immunoglobulin infusion is an effective, safe and well-tolerated treatment approach in primary immunodeficiencies but no extensive data are available on their use in secondary hypogammaglobulinemia, a frequent phenomenon occurring after treatment with anti-CD20 monoclonal antibodies in lymphoproliferative disorders. In this retrospective study we evaluated efficacy (serum IgG trough levels, incidence of infections per year, need for antibiotics) and safety (number of adverse events) of intravenous (300 mg/kg/4 weeks) versus subcutaneous (75 mg/kg/week) immunoglobulin replacement therapy in 61 patients. In addition, the impact of the infusion methods on quality of life was compared. All patients were treated with subcutaneous immunoglobulin, and 33 out of them had been previously treated with intravenous immunoglobulin. Both treatments appeared to be effective in replacing Ig production deficiency and in reducing the incidence of infectious events and the need for antibiotics. Subcutaneous immunoglobulin obtained a superior benefit when compared to intravenous immunoglobulin achieving higher IgG trough levels, lower incidence of overall infection and need for antibiotics. The incidence of serious bacterial infections was similar with both infusion ways. As expected, a lower number of adverse events was registered with subcutaneous immunoglobulin, compared to intravenous immunoglobulin, with no serious adverse events. Finally, we observed an improvement in health-related quality of life parameters after the switch to subcutaneous immunoglobulin. Our results suggest that subcutaneous immunoglobulin is safe and effective in patients with hypogammaglobulinemia associated to lymphoproliferative disorders.

Pruritus in patients treated with targeted cancer therapies: systematic review and meta-analysis

BACKGROUND

Pruritus has been anecdotally described in association with targeted cancer therapies. The risk of pruritus has not been systematically ascertained.

OBJECTIVE

A systematic review and meta-analysis of the literature was conducted for axitinib, cetuximab, dasatinib, erlotinib, everolimus, gefitinib, imatinib, ipilimumab, lapatinib, nilotinib, panitumumab, pazopanib, rituximab, sorafenib, temsirolimus, tositumomab, vandetanib, and vemurafenib.

METHODS

Databases from PubMed, Web of Science (January 1998 through July 2012), and American Society of Clinical Oncology abstracts (2004 through 2012) were searched. Incidence and relative risk of pruritus were calculated using random- or fixed-effects model.

RESULTS

The incidences of all-grade and high-grade pruritus were 17.4% (95% confidence interval 16.0%-19.0%) and 1.4% (95% confidence interval 1.2%-1.6%), respectively. There was an increased risk of all-grade pruritus (relative risk 2.90 [95% confidence interval 1.76-4.77, P < .001]) and variation among different drugs (P < .001).

LIMITATIONS

The reporting of pruritus may vary, resulting from concomitant medications, comorbidities, and underlying malignancies. We found a higher incidence of pruritus in patients with solid tumors, concordant with those targeted therapies with the highest pruritus incidences.

CONCLUSION

There is a significant risk of developing pruritus in patients receiving targeted therapies. To prevent suboptimal dosing and decreased quality of life, patients should be counseled and treated against this untoward symptom.

Influence of FCGRT gene polymorphisms on pharmacokinetics of therapeutic antibodies

The neonatal Fc receptor (FcRn) encoded by FCGRT is known to be involved in the pharmacokinetics (PK) of therapeutic monoclonal antibodies (mAbs). Variability in the expression of FCGRT gene and consequently in the FcRn protein level could explain differences in PK observed between patients treated with mAbs. We studied whether the previously described variable number tandem repeat (VNTR) or copy number variation (CNV) of FCGRT are associated with individual variations of PK parameters of cetuximab. VNTR and CNV were assessed on genomic DNA of 198 healthy individuals and of 94 patients treated with the therapeutic mAb. VNTR and CNV were analyzed by allele-specific PCR and duplex real-time PCR with Taqman (®) technology, respectively. The relationship between FCGRT polymorphisms (VNTR and CNV) and PK parameters of patients treated with cetuximab was studied. VNTR3 homozygote patients had a lower cetuximab distribution clearance than VNTR2/VNTR3 and VNTR3/VNTR4 patients (p = 0.021). We observed no affects of VNTR genotype on elimination clearance. One healthy person (0.5%) and 1 patient (1.1%) had 3 copies of FCGRT. The PK parameters of this patient did not differ from those of patients with 2 copies. The FCGRT promoter VNTR may influence mAbs' distribution in the body. CNV of FCGRT cannot be used as a relevant pharmacogenetic marker because of its low frequency.

Rituximab biosimilars

INTRODUCTION

Rituximab is a monoclonal antibody targeting CD20, used to treat B cell malignancies and B cell-mediated autoimmune diseases. Rituximab has the largest market of any monoclonal antibody therapeutic. Its patent will expire within the next few years and several manufacturers have already produced or are developing rituximab biosimilars that aim to match the innovator rituximab as closely as possible.

AREAS COVERED

In this review, we discuss key factors that determine the efficacy of rituximab therapy, potential technical challenges in the manufacture and evaluation of biosimilars, regulatory considerations regarding the review and approval of biosimilars, and the current status of biosimilar rituximab development by various manufacturers. Due to the nature of the topic, literature searches included conference abstracts, regulatory and industry websites as well as peer reviewed literature.

EXPERT OPINION

Cost is a key limitation of current biologics usage and there is a political impetus to the licensing of biosimilars. Concerns regarding potential dissimilarities of biosimilars are legitimate, but surmountable with techniques for in vitro, in vivo and clinical testing and more clearly defined regulatory requirements. These should provide reassurance to prescribers. However, the cost of manufacturing and licensing a biosimilar remains high and the reduction in cost may be more limited than for a non-biologic small molecule drug and its generic version. This cost reduction will be critical to the impact and use of rituximab biosimilars.

Rituximab therapy in nephrotic syndrome: implications for patients' management

Rituximab offers an alternative to current immunosuppressive therapies for difficult-to-treat nephrotic syndrome. The best outcomes are seen in patients with steroid-dependent nephrotic syndrome who have failed to respond to multiple therapies. By contrast, the benefits of rituximab therapy are limited in patients with steroid-resistant nephrotic syndrome, particularly those with focal segmental glomerulosclerosis (FSGS). Therapy with plasma exchange and one or two doses of rituximab has shown success in patients with recurrent FSGS. Young patients and those with normal serum albumin at recurrence of nephrotic syndrome are most likely to respond to rituximab therapy. A substantial proportion of rituximab-treated patients with idiopathic membranous nephropathy show complete or partial remission of proteinuria, and reduced levels of phospholipase A(2) receptor autoantibodies, which are implicated in the pathogenesis of this disorder. Successful rituximab therapy induces prolonged remission and enables discontinuation of other medications without substantially increasing the risk of infections and other serious adverse events. However, the available evidence of efficacy of rituximab therapy is derived chiefly from small case series and requires confirmation in prospective, randomized, controlled studies that define the indications for use and predictors of response to this therapy.

Multicenter phase 1 trial of intraventricular immunochemotherapy in recurrent CNS lymphoma

Recurrent CNS lymphoma continues to be associated with poor outcomes in the rituximab era. Although IV rituximab mediates superior disease control of systemic non-Hodgkin lymphoma (NHL), it fails to completely eliminate the risk of meningeal recurrence, likely due to minimal CNS penetration. Given that rituximab acts synergistically with chemotherapy, we conducted the first phase 1 study of intraventricular immunochemotherapy in patients with recurrent CNS NHL. Fourteen patients received 10 mg or 25 mg intraventricular rituximab twice weekly for 4 weeks, with rituximab administered as monotherapy during the first treatment each week and rituximab administered in combination with methotrexate (MTX) during the second treatment each week. More than 150 doses were administered without serious toxicity. In a population with high-refractory CNS NHL, 75% of patients achieved complete cytologic responses and 43% achieved an overall complete response in CSF and/or brain parenchyma. Two patients achieved a first complete response of CNS NHL with intraventricular rituximab/MTX, including 1 with CNS lymphoma refractory to high-dose systemic and intrathecal MTX plus IV rituximab. We conclude that intraventricular rituximab in combination with MTX is feasible and highly active in the treatment of drug-resistant CNS NHL that is refractory or unresponsive to IV rituximab.

KEY POINTS

Phase I study showed that intraventricular rituximab plus methotrexate is feasible and active in the treatment of refractory CNS lymphoma.