A tale of two antibodies: obinutuzumabversusrituximab

The Pharmacogenetics of Rituximab: Potential Implications for Anti-CD20 Therapies in Multiple Sclerosis

There are a broad range of disease-modifying therapies (DMTs) available in relapsing-remitting multiple sclerosis (RRMS), but limited biomarkers exist to personalise DMT choice. All DMTs, including monoclonal antibodies such as rituximab and ocrelizumab, are effective in preventing relapses and preserving neurological function in MS. However, each agent harbours its own risk of therapeutic failure or adverse events. Pharmacogenetics, the study of the effects of genetic variation on therapeutic response or adverse events, could improve the precision of DMT selection. Pharmacogenetic studies of rituximab in MS patients are lacking, but pharmacogenetic markers in other rituximab-treated autoimmune conditions have been identified. This review will outline the wider implications of pharmacogenetics and the mechanisms of anti-CD20 agents in MS. We explore the non-MS rituximab literature to characterise pharmacogenetic variants that could be of prognostic relevance in those receiving rituximab, ocrelizumab or other monoclonal antibodies for MS.

Analytical comparability study of anti-CD20 monoclonal antibodies rituximab and obinutuzumab using a stability-indicating orthogonal testing protocol: Effect of structural optimization and glycoengineering

Glycoengineering and biosimilarity are the key factors for growing, promising and progressive approaches in monoclonal antibodies development. In this study, the physicochemical stability of anti-CD20 rituximab (RTX); originator and biosimilar was compared to its glycoengineered humanized version; obinutuzumab (OBZ). An orthogonal stability-indicating protocol using a set of validated bioanalytical techniques; size exclusion high performance liquid chromatography (SE-HPLC), reversed phase liquid chromatography (RP-HPLC), quantitative gel electrophoresis by TapeStation, receptor binding assay and dynamic light scattering (DLS) was used to investigate the effect of different stress factors on the pattern and kinetics of degradation. SE-HPLC results supported with spectral purity showed similar degradation extent with a different pattern of degradation between RTX and OBZ. A lower tendency to form degraded fragments and a relatively higher favorability for degradation through aggregate formation has been revealed in case of OBZ. Results were in agreement with those of DLS and receptor binding assay which showed specificity to the intact antibodies in the presence of their degradation products. Furthermore, results were additionally confirmed through denaturing quantitative gel electrophoresis which suggested reducible covalent bonds as the mechanism for aggregates formation. RP-HPLC results showed two oxidized forms via excessive oxidation of RTX and OBZ with nearly the same degradation percent. Comparability data of RTX and OBZ using the applied methodologies showed that although glycoengineering; carried out to enhance the therapeutic and biological activity of OBZ altered the pattern of degradation but did not significantly affect the overall stability. Results showed also consistent stability profile between the biosimilar and its originator RTX products.

Noninvasive Evaluation of CD20 Expression Using 64Cu-Labeled F(ab')2 Fragments of Obinutuzumab in Lymphoma

CD20-overexpressed non-Hodgkin lymphoma typically indicates progressive malignancy. Obinutuzumab is a next-generation Food and Drug Administration-approved humanized monoclonal antibody that targets CD20. Previous studies with ⁸⁹Zr-labeled obinutuzumab have successfully imaged CD20 in vivo. However, delayed tumor uptake and increased radioactive exposure caused by long blood circulation limit its clinical translation. This study aimed to develop ⁶⁴Cu-labeled F(ab')₂ fragments of obinutuzumab for imaging CD20 in lymphoma xenograft tumor models. Methods: F(ab')₂ fragments were produced from obinutuzumab using an IgG-degrading enzyme of Streptococcus pyogenes (IdeS) enzyme and purified with protein A beads. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and high-performance liquid chromatography were performed to evaluate the products and their stability. F(ab')₂ products were conjugated with p-SCN-Bn-NOTA (NOTA) for ⁶⁴Cu radiolabeling. Western blotting was performed to screen the CD20 expression levels of lymphoma cells. Enzyme-linked immunosorbent assay, flow cytometry, and confocal imaging were used to test the binding affinity in vitro. Serial PET imaging and biodistribution studies in subcutaneous lymphoma-bearing mice were performed using ⁶⁴Cu-NOTA-F(ab')₂-obinutuzumab or ⁶⁴Cu-NOTA-F(ab')₂-IgG. Results: F(ab')₂-obinutuzumab and F(ab')₂-IgG produced by the IdeS digestion system were confirmed with sodium dodecyl sulfate polyacrylamide gel electrophoresis and high-performance liquid chromatography. The radiochemical purity of ⁶⁴Cu-labeled F(ab')₂ fragments was no less than 98%, and the specific activity was 56.3 ± 7.9 MBq/mg (n = 6). Among the 5 lymphoma cell lines, Ramos showed the strongest expression of CD20, and CLL-155 showed the lowest, as confirmed by enzyme-linked immunosorbent assay, flow cytometry, and confocal imaging. PET imaging revealed rapid and sustained tumor uptake of ⁶⁴Cu-NOTA-F(ab')₂-obinutuzumab in Ramos tumor-bearing mice. The peak tumor uptake (9.08 ± 1.67 percentage injected dose per gram of tissue [%ID/g]) in the Ramos model was significantly higher than that in the CCL-155 model (2.78 ± 0.62 %ID/g) or the ⁶⁴Cu-NOTA-F(ab')₂-IgG control (1.93 ± 0.26 %ID/g, n = 4, P < 0.001). The tumor-to-blood and tumor-to-muscle ratios were 7.3 ± 1.6 and 21.9 ± 9.0, respectively, at 48 h after injection in the ⁶⁴Cu-NOTA-F(ab')₂-obinutuzumab group. Of the measured off-target organs, the kidneys showed the highest uptake. Ex vivo immunofluorescent staining verified the differential CD20 expression in the Ramos and CCL-155 tumor models. Conclusion: This study demonstrated that ⁶⁴Cu-NOTA-F(ab')₂-obinutuzumab had a rapid and sustained tumor uptake in CD20-positive lymphoma with high contrast, which could enable noninvasive evaluation of CD20 levels in the clinic.

A review of advances in the understanding of lupus nephritis pathogenesis as a basis for emerging therapies

Lupus nephritis is an important cause of both acute kidney injury and chronic kidney disease that can result in end-stage renal disease. Its pathogenic mechanisms are characterized by aberrant activation of both innate and adaptive immune responses, dysregulation of inflammatory signaling pathways, and increased cytokine production. Treatment of lupus nephritis remains a challenging issue in the management of systemic lupus erythematosus since the clinical presentation, response to treatment, and prognosis all vary considerably between patients and are influenced by ethnicity, gender, the degree of chronic kidney damage, pharmacogenomics, and non-immunological modulating factors. Elucidation of the various immunopathogenic pathways in lupus nephritis has resulted in the development of novel therapies, including biologics that target specific antigens on B lymphocytes to achieve B cell depletion, agents that modulate B cell proliferation and development, drugs that block co-stimulatory pathways, drugs that target T lymphocytes primarily, and therapies that target complement activation, signaling pathways, pro-inflammatory cytokines, and neutrophil extracellular traps. This review will discuss recent advances in the understanding of disease pathogenesis in lupus nephritis in the context of potential emerging therapies.

Novel Therapies Potentially Available for Pediatric B-Cell Non-Hodgkin Lymphoma

Burkitt lymphoma, diffuse large B-cell lymphoma (DLBCL), and primary mediastinal B-cell lymphoma are the most common aggressive pediatric mature B-cell non-Hodgkin lymphomas (B-NHLs). Despite excellent survival with current chemotherapy regimens, therapy for Burkitt lymphoma and DLBCL has a high incidence of short- and long-term toxicities. Patients who experience relapse generally have a very poor prognosis. Therefore, novel approaches using targeted therapies to reduce toxicities and improve outcomes in the relapse setting are needed. The addition of rituximab, a monoclonal antibody against CD20, to upfront therapy has improved survival outcomes for high-risk patients and may allow decreased total chemotherapy in those with low-risk disease. Antibody-drug conjugates have been combined with chemotherapy in relapsed/refractory (R/R) NHL, and multiple antibody-drug conjugates are in development. Additionally, bispecific T-cell-engaging antibody constructs and autologous CAR T-cells have been successful in the treatment of R/R acute leukemias and are now being applied to R/R B-NHL with some successes. PD-L1 and PD-L2 on tumor cells can be targeted with checkpoint inhibitors, which restore T-cell-mediated immunity and antitumor responses and can be added to conventional chemotherapy and immune-directed therapies to augment responses. Lastly, trials of small molecule inhibitors targeting cell signaling pathways in NHL subtypes are underway. This article reviews many of the targeted therapies under development that could be considered for future trials in R/R pediatric mature B-NHL.

Initial Treatment of High Tumor Burden Follicular Lymphoma

Follicular lymphoma is the most common indolent B-cell lymphoma, with most patients presenting with advanced-stage disease. Patients who are symptomatic or otherwise meet the criteria for high tumor burden merit immediate intervention with combination immunochemotherapy, although more recently, "chemotherapy-free" approaches including novel therapies have shown benefit in this treatment-naïve population. In this review, the authors critically appraise the criteria for high tumor burden, the various options available for initial therapy, and the optimal post-treatment surveillance strategies.

ImmunoPET: Concept, Design, and Applications

Immuno-positron emission tomography (immunoPET) is a paradigm-shifting molecular imaging modality combining the superior targeting specificity of monoclonal antibody (mAb) and the inherent sensitivity of PET technique. A variety of radionuclides and mAbs have been exploited to develop immunoPET probes, which has been driven by the development and optimization of radiochemistry and conjugation strategies. In addition, tumor-targeting vectors with a short circulation time (e.g., Nanobody) or with an enhanced binding affinity (e.g., bispecific antibody) are being used to design novel immunoPET probes. Accordingly, several immunoPET probes, such as 89Zr-Df-pertuzumab and 89Zr-atezolizumab, have been successfully translated for clinical use. By noninvasively and dynamically revealing the expression of heterogeneous tumor antigens, immunoPET imaging is gradually changing the theranostic landscape of several types of malignancies. ImmunoPET is the method of choice for imaging specific tumor markers, immune cells, immune checkpoints, and inflammatory processes. Furthermore, the integration of immunoPET imaging in antibody drug development is of substantial significance because it provides pivotal information regarding antibody targeting abilities and distribution profiles. Herein, we present the latest immunoPET imaging strategies and their preclinical and clinical applications. We also emphasize current conjugation strategies that can be leveraged to develop next-generation immunoPET probes. Lastly, we discuss practical considerations to tune the development and translation of immunoPET imaging strategies.

The Dual Cell Cycle Kinase Inhibitor JNJ-7706621 Reverses Resistance to CD37-Targeted Radioimmunotherapy in Activated B Cell Like Diffuse Large B Cell Lymphoma Cell Lines

The CD37 targeting radioimmunoconjugate ¹⁷⁷Lu-lilotomab satetraxetan (Betalutin) is currently being evaluated in a clinical phase 2b trial for patients with follicular lymphoma (FL) and in a phase 1 trial for patients with diffuse large B-cell lymphoma (DLBCL). Herein we have investigated the effect of ¹⁷⁷Lu-lilotomab satetraxetan in seven activated B-cell like (ABC) DLBCL cell lines. Although the radioimmunoconjugate showed anti-tumor activity, primary resistance was observed in a subset of cell lines. Thus, we set out to identify drugs able to overcome the resistance to ¹⁷⁷Lu-lilotomab satetraxetan in two resistant ABC-DLBCL cell lines. We performed a viability-based screen combining ¹⁷⁷Lu-lilotomab satetraxetan with the 384-compound Cambridge Cancer Compound Library. Drug combinations were scored using Bliss and Chou-Talalay algorithms. We identified and characterized the dual-specific CDK1/2 and AURA/B kinase inhibitor JNJ-7706621 as compound able to revert the resistance to RIT, alongside topoisomerase and histone deacetylases (HDAC) inhibitors.

The role of obinutuzumab in the management of follicular lymphoma

The outcomes for follicular lymphoma (FL) have improved significantly in recent years. This has been driven by an improved understanding of the pathobiology of FL and the development of therapeutic anti-CD20 antibodies. Combining rituximab with chemotherapy, coupled with its use as maintenance therapy, has contributed to significant improvements in disease control and progression-free survival. However, FL remains incurable and almost all patients invariably relapse. Therefore, there remains a need to develop novel therapeutic options and optimize existing regimens. Obinutuzumab (a first-in-class, glycoengineered, humanized type 2 anti-CD20 antibody) has been evaluated in a number of clinical trials. In this review, we will summarize the evaluable results of clinical trials investigating the efficacy of obinutuzumab in the treatment of FL.

The emergence of drug resistance to targeted cancer therapies: Clinical evidence

For many decades classical anti-tumor therapies included chemotherapy, radiation and surgery; however, in the last two decades, following the identification of the genomic drivers and main hallmarks of cancer, the introduction of therapies that target specific tumor-promoting oncogenic or non-oncogenic pathways, has revolutionized cancer therapeutics. Despite the significant progress in cancer therapy, clinical oncologists are often facing the primary impediment of anticancer drug resistance, as many cancer patients display either intrinsic chemoresistance from the very beginning of the therapy or after initial responses and upon repeated drug treatment cycles, acquired drug resistance develops and thus relapse emerges, resulting in increased mortality. Our attempts to understand the molecular basis underlying these drug resistance phenotypes in pre-clinical models and patient specimens revealed the extreme plasticity and adaptive pathways employed by tumor cells, being under sustained stress and extensive genomic/proteomic instability due to the applied therapeutic regimens. Subsequent efforts have yielded more effective inhibitors and combinatorial approaches (e.g. the use of specific pharmacologic inhibitors with immunotherapy) that exhibit synergistic effects against tumor cells, hence enhancing therapeutic indices. Furthermore, new advanced methodologies that allow for the early detection of genetic/epigenetic alterations that lead to drug chemoresistance and prospective validation of biomarkers which identify patients that will benefit from certain drug classes, have started to improve the clinical outcome. This review discusses emerging principles of drug resistance to cancer therapies targeting a wide array of oncogenic kinases, along with hedgehog pathway and the proteasome and apoptotic inducers, as well as epigenetic and metabolic modulators. We further discuss mechanisms of resistance to monoclonal antibodies, immunomodulators and immune checkpoint inhibitors, potential biomarkers of drug response/drug resistance, along with possible new therapeutic avenues for the clinicians to combat devastating drug resistant malignancies. It is foreseen that these topics will be major areas of focused multidisciplinary translational research in the years to come.

Helping the Released Guardian: Drug Combinations for Supporting the Anticancer Activity of HDM2 (MDM2) Antagonists

The protein p53, known as the "Guardian of the Genome", plays an important role in maintaining DNA integrity, providing protection against cancer-promoting mutations. Dysfunction of p53 is observed in almost every cancer, with 50% of cases bearing loss-of-function mutations/deletions in the TP53 gene. In the remaining 50% of cases the overexpression of HDM2 (mouse double minute 2, human homolog) protein, which is a natural inhibitor of p53, is the most common way of keeping p53 inactive. Disruption of HDM2-p53 interaction with the use of HDM2 antagonists leads to the release of p53 and expression of its target genes, engaged in the induction of cell cycle arrest, DNA repair, senescence, and apoptosis. The induction of apoptosis, however, is restricted to only a handful of p53wt cells, and, generally, cancer cells treated with HDM2 antagonists are not efficiently eliminated. For this reason, HDM2 antagonists were tested in combinations with multiple other therapeutics in a search for synergy that would enhance the cancer eradication. This manuscript aims at reviewing the recent progress in developing strategies of combined cancer treatment with the use of HDM2 antagonists.

Ontogeny, Genetics, Molecular Biology, and Classification of B- and T-Cell Non-Hodgkin Lymphoma

Mature B- and T-cell lymphomas are diverse in their biology, etiology, genetics, clinical behavior, and response to specific therapies. Here, we review the principles of diagnostic classification for non-Hodgkin lymphomas, summarize the characteristic features of major entities, and place recent biological and molecular findings in the context of principles that are applicable across the spectrum of mature lymphoid cancers.

From Biology to Therapy: The CLL Success Story

Chemoimmunotherapy has been the standard of care for patients with chronic lymphocytic leukemia (CLL) over the last decade. Advances in monoclonal antibody technology have resulted in the development of newer generations of anti-CD20 antibodies with improved therapeutic effectiveness. In parallel, our knowledge about the distinctive biological characteristics of CLL has progressively deepened and has revealed the importance of B-cell receptor (BCR) signaling and upregulated antiapoptotic proteins for survival and expansion of malignant cell clones. This knowledge provided the basis for development of novel targeted agents that revolutionized treatment of CLL. Ibrutinib and idelalisib inhibit the Bruton tyrosine kinase (BTK) and phosphoinositide 3-kinase (PI3K) delta, respectively, thus interfering with supportive signals coming from the microenvironment via the BCR. These drugs induce egress of CLL cells from secondary lymphoid organs and remarkably improve clinical outcomes, especially for patients with unmutated immunoglobulin heavy-chain genes or with p53 abnormalities that do not benefit from classical treatment schemes. Latest clinical trial results have established ibrutinib with or without anti-CD20 antibodies as the preferred first-line treatment for most CLL patients, which will reduce the use of chemoimmunotherapy in the imminent future. Further advances are achieved with venetoclax, a BH3-mimetic that specifically inhibits the antiapoptotic B-cell lymphoma 2 protein and thus causes rapid apoptosis of CLL cells, which translates into deep and prolonged clinical responses including high rates of minimal residual disease negativity. This review summarizes recent advances in the development of targeted CLL therapies, including new combination schemes, novel BTK and PI3K inhibitors, spleen tyrosine kinase inhibitors, immunomodulatory drugs, and cellular immunotherapy.

Concurrent and reactivation of hepatitis B virus infection in diffuse large B-cell lymphoma: risk factors and survival outcome

Objective

To determine the clinical features and survival difference of HBV related and Non-HBV related diffuse large B-cell lymphoma (DLBCL) and to evaluate the occurrence of HBV reactivation in DLBCL patients and related risk factors for HBV reactivation after R-CHOP therapy.

Methods

A total of 246 patients diagnosed with CD20+ DLBCL were enrolled from June 2010 to June 2015. The medical records and survival data were analysed. Multivariate logistic regression analysis was used to identify predictors of HBV reactivation. Survival curves were performed by the Kaplan-Meier method.

Results

Among patients enrolled, 80 patients were HBsAg sero-positive and 166 patients were HBsAg sero-negative. Findings showed that HBsAg sero-negative patients were significantly older than that of patients with HBsAg sero-positive (P <  0.001). Proportion of B symptom positive patients in HBsAg sero-positive were higher (p = 0.002). Higher LDH level (P = 0.019) and late Ann Arbor stage (P = 0.010) were more often observed in patients with HBsAg sero-positive. The rate of complete response, partial response, stable disease and progress disease in HBsAg sero-negative group were 63.9, 16.9, 1.1 and 18.1%, respective, which is significantly higher than that in HBsAg sero-positive group (36.2, 18.8, 1.2 and 43.8%). Kaplan-Meier analysis showed that DLBCL patients with HBsAg sero-negative had better prognosis. In total, 17 patients showed HBV reactivation among 166 patients (10.2%) with HBsAg sero-negative after R-CHOP treatment, while a significant higher HBV reactivation 18.75% (9/48) in HBsAb negative group were observed, with 8.25% (8/97) patients in HBsAb level 10-100 U/mL group, and 0% patients in HBsAb level higher than 100 U/mL group. Multivariable analysis showed that serum HBsAb and serum HBcAb were independent risk factors for HBV reactivation in DLBCL patients.

Conclusion

Our data revealed that characteristics and prognosis were significantly different between HBV related DLBCL than non-HBV related DLBCL patients. DLBCL patients with resolved hepatitis B are at a higher risk of developing HBV reactivation after R-CHOP chemotherapy compared with HBsAg-negative/HBcAb negative patients.