Clinical binding properties, internalization kinetics, and clinicopathologic activity of brentuximab vedotin: an antibody-drug conjugate for CD30-positive lymphoid neoplasms

Novel anti-CD30/CD3 bispecific antibodies activate human T cells and mediate potent anti-tumor activity

CD30 is expressed on Hodgkin lymphomas (HL), many non-Hodgkin lymphomas (NHLs), and non-lymphoid malignancies in children and adults. Tumor expression, combined with restricted expression in healthy tissues, identifies CD30 as a promising immunotherapy target. An anti-CD30 antibody-drug conjugate (ADC) has been approved by the FDA for HL. While anti-CD30 ADCs and chimeric antigen receptors (CARs) have shown promise, their shortcomings and toxicities suggest that alternative treatments are needed. We developed novel anti-CD30 x anti-CD3 bispecific antibodies (biAbs) to coat activated patient T cells (ATCs) ex vivo prior to autologous re-infusions. Our goal is to harness the dual specificity of the biAb, the power of cellular therapy, and the safety of non-genetically modified autologous T cell infusions. We present a comprehensive characterization of the CD30 binding and tumor cell killing properties of these biAbs. Five unique murine monoclonal antibodies (mAbs) were generated against the extracellular domain of human CD30. Resultant anti-CD30 mAbs were purified and screened for binding specificity, affinity, and epitope recognition. Two lead mAb candidates with unique sequences and CD30 binding clusters that differ from the ADC in clinical use were identified. These mAbs were chemically conjugated with OKT3 (an anti-CD3 mAb). ATCs were armed and evaluated in vitro for binding, cytokine production, and cytotoxicity against tumor lines and then in vivo for tumor cell killing. Our lead mAb was subcloned to make a Master Cell Bank (MCB) and screened for binding against a library of human cell surface proteins. Only huCD30 was bound. These studies support a clinical trial in development employing ex vivo-loading of autologous T cells with this novel biAb.

QuPath Analysis for CD30+ Cutaneous T-Cell Lymphoma

BACKGROUND

Mycosis fungoides is the most common subtype of cutaneous T-cell lymphoma, in which the expression of cluster of differentiation 30 (CD30)+ subtype can now be treated with the CD30 antibody conjugate brentuximab vedotin. Diagnostic methods are based on immunohistochemical (IHC) staining followed by manual assessment by pathologists, which is always a subjective calculation. QuPath, an open-source software for digital pathology image analysis, satisfies the requirements of objective approaches.

METHODS

Ten samples from mycosis fungoides patients with CD30 expression at different stages were stained for CD3 and CD30 by IHC staining, scanned, and quantitative analysis was performed using QuPath (version 2.1). Each slide was independently assessed by 3 board-certified dermatopathologists.

RESULTS

Individual estimates for CD30+/CD3+ cells varied among the individual histopathologists (mean coefficient of variation, 0.46; range, 0-0.78). QuPath analysis showed excellent separation between the positively stained cells for CD3 and CD30 IHC and other cells and tissue structures, although the results correlated strongly with the respective mean estimates of the 3 histopathologists (Pearson-R 0.93).

CONCLUSIONS

The results show a high interobserver variability evaluation of IHC markers, although quantitative image analysis offer a significant advantage for comparison. This is not only relevant for clinical routine but also especially critical in therapeutic studies addressing targeted molecules.

Highly Accurate and Robust Absolute Quantification of Target Proteins in Formalin-Fixed Paraffin-Embedded (FFPE) Tissues by LC-MS

Accurate, absolute liquid chromatography-mass spectrometry (LC-MS)-based quantification of target proteins in formalin-fixed paraffin-embedded (FFPE) tissues would greatly expand sample availability for pharmaceutical/clinical investigations but remains challenging owing to the following issues: (i) efficient/quantitative recovery of target signature peptides from FFPE tissues is essential but an optimal procedure for targeted, absolute quantification is lacking; (ii) most FFPE samples are long-term-stored; severe immunohistochemistry (IHC) signal losses of target proteins during storage were widely reported, while the effect of storage on LC-MS-based methods was unknown; and (iii) the proper strategy to prepare calibration/quality-control samples to ensure accurate targeted protein analysis in FFPE tissues remained elusive. Using targeted quantification of monoclonal antibody (mAb), antigen, and 40 tissue markers in FFPE tissues as a model system, we extensively investigate those issues and develope an LC-MS-based strategy enabling accurate and precise targeted protein quantification in FFPE samples. First, we demonstrated a surfactant cocktail-based procedure (f-SEPOD), providing high/reproducible recovery of target signature peptides from FFPE tissues. Second, a heat-accelerated degradation study within a roughly estimated 5 year storage period recapitulated the loss of protein IHC signals while LC-MS signals of all targets remained constant. This indicates that the storage of FFPE tissues mainly causes decreased immunoreactivity but unlikely chemical degradation of proteins, which strongly suggests that the storage of FFPE tissues does not cause significant quantitative bias for LC-MS-based methods. Third, while a conventional spike-and-extract approach for calibration caused substantial negative biases, a novel approach, using FFPE-treated calibration standards, enabled accurate and precise quantification. With the pipeline, we conducted the first-ever pharmacokinetics measurement of mAb and its target in FFPE tissues, where time courses by FFPE vs fresh tissues showed excellent correlation.

Drug-Induced Peripheral Neuropathy: Diagnosis and Management

Peripheral neuropathy comes in all shapes and forms and is a disorder which is found in the peripheral nervous system. It can have an acute or chronic onset depending on the multitude of pathophysiologic mechanisms involving different parts of nerve fibers. A systematic approach is highly beneficial when it comes to cost-effective diagnosis. More than 30 causes of peripheral neuropathy exist ranging from systemic and auto-immune diseases, vitamin deficiencies, viral infections, diabetes, etc. One of the major causes of peripheral neuropathy is drug induced disease, which can be split into peripheral neuropathy caused by chemotherapy or by other medications. This review deals with the latest causes of drug induced peripheral neuropathy, the population involved, the findings on physical examination and various workups needed and how to manage each case.

Marine anticancer drugs and their relevant targets: a treasure from the ocean

Marine organisms comprising animals and plants are wealthiest sources of bioactive compounds possessing various pharmacological properties specifically: free radical scavenging, antitumor, antimicrobial, analgesic, neuroprotective and immunomodulatory. Marine drugs provide an alternative source to meet the demand of effective, safe and low-cost drugs that are rising with the continuously growing world population. Cancer is one of the leading reasons of mortality in western nations in contrast to communicable diseases of developing nations. In spite of outstanding developments in cancer therapy in past three decades, there is still an insistent necessity for innovative drugs in the area of cancer biology, especially in the unexplored area of marine anticancer compounds. However, recent technological innovations in structure revelation, synthetic creation of new compounds and biological assays have made possible the isolation and clinical assessment of innumerable unique anticancer compounds from marine environment. This review provides an insight into the anticancer research so far conducted in the area of the marine natural products/synthetic derivatives, their possible molecular targets and the current challenges in the drug development. Graphical abstract.

Clinical and Radiographic Response of Extramedullary Leukemia in Patients Treated With Gemtuzumab Ozogamicin

Extramedullary leukemia (EML) is common in pediatric acute leukemia and can present at diagnosis or relapse. CD33 is detected on the surface of myeloid blasts in many patients with acute myelogenous leukemia and is the target of the antibody drug conjugate gemtuzumab ozogamicin (GO). Here we present 2 patients with CD33 EML treated with GO. They achieved significant response, with reduction of EML on both clinical and radiographic exams, specifically fluorine fluorodeoxyglucose positron emission tomography/computed tomography, demonstrating potential for targeted therapy with GO as a means of treating EML in patients with CD33 leukemia and the utility of fluorine fluorodeoxyglucose positron emission tomography/computed tomography monitoring in EML.

Antibody drug conjugates and bystander killing: is antigen-dependent internalisation required?

Antibody drug conjugates (ADCs) employ the exquisite specificity of tumour-specific monoclonal antibodies (mAb) for the targeted delivery of highly potent cytotoxic drugs to the tumour site. The chemistry of the linker, which connects the drug to the mAb, determines how and when the drug is released from the mAb. This, as well as the chemistry of the drug, can dictate whether the drug can diffuse into surrounding cells, resulting in 'bystander killing'. Initially, any bystander killing mechanism of action of an ADC was understood to involve an essential sequence of steps beginning with surface antigen targeting, internalisation, intracellular linker cleavage, drug release, and diffusion of drug away from the targeted cell. However, recent studies indicate that, depending on the linker and drug combination, this mechanism may not be essential and ADCs can be cleaved extracellularly or via other mechanisms. In this minireview, we will examine the role of bystander killing by ADCs and explore the emerging evidence of how this can occur independently of internalisation.

Brentuximab Vedotin: A Review in CD30-Positive Hodgkin Lymphoma

Intravenous brentuximab vedotin (ADCETRIS^®) is a targeted antibody-drug conjugate (ADC) active against CD30-positive cancer cells such as those associated with classical Hodgkin lymphoma (HL). In noncomparative, phase 2 trials and in the real-world setting, salvage therapy with brentuximab vedotin resulted in high objective response (complete plus partial remission) rates in patients with relapsed or refractory CD30-positive HL, including as retreatment in patients who had an objective response to previous brentuximab vedotin therapy and subsequently relapsed. These beneficial outcomes were durable during long-term follow-up. As consolidation therapy after autologous haematopoietic stem cell transplant (ASCT) in the multinational, phase 3 AETHERA trial, brentuximab vedotin prolonged progression-free-survival (PFS) compared with placebo at a median follow-up of 30 months (primary analysis), with a 43% reduction in the risk of disease progression or death. The beneficial effects of brentuximab vedotin consolidation therapy were maintained during long-term follow-up. In the clinical trial and real-world setting, brentuximab vedotin had an acceptable tolerability and safety profile, with most adverse events manageable with dose reductions and/or delays [including peripheral sensory neuropathy (PSN) and neutropenia]. With a paucity of treatments available for many patients with relapsed or refractory HL, brentuximab vedotin represents an important option for the management of patients who have failed high-dose chemotherapy/ASCT or at least two prior chemotherapy regimens and as post-ASCT consolidation therapy in patients who are at increased risk/high-risk of relapse or progression after ASCT.

Marine-Derived Pharmaceuticals - Challenges and Opportunities

Marine biosphere is the largest one of the earth and harbors an enormous number of different organisms. Living conditions differ fundamentally from those in terrestrial environment. The production of specific secondary metabolites is an important adaption mechanism of marine organisms to survive in the sea. These metabolites possess biological activities which make them interesting as possible drugs for human. The review presents sources, chemistry, production and pharmacology of FDA approved marine derived pharmaceuticals arranged according to their therapeutic indication. Four of the presently seven approved drugs are used for the treatment of cancer. Each another one is applicated for treatment of viral diseases, chronic pain and to lower triglyceride level in blood. Some other products are of interest in diagnostic and as experimental tools. Besides, this article describes challenges in drug development from marine sources, especially the supply problem.

Antibody-Drug Conjugates for Cancer Therapy

Antibody–drug conjugates (ADCs) take advantage of the specificity of a monoclonal antibody to deliver a linked cytotoxic agent directly into a tumour cell. The development of these compounds provides exciting opportunities for improvements in patient care. Here, we review the key issues impacting on the clinical success of ADCs in cancer therapy. Like many other developing therapeutic classes, there remain challenges in the design and optimisation of these compounds. As the clinical applications for ADCs continue to expand, key strategies to improve patient outcomes include better patient selection for treatment and the identification of mechanisms of therapy resistance.

Brentuximab: a major advance in treatment of CD30-positive malignancies

Antibody-directed therapies allow greater selectivity in targeting of tumor associated antigens and spare normal cells. Brentuximab vedotin is an anti-CD30 antibody–drug conjugate. It has demonstrated impressive activity in the treatment of refractory and or relapsed Hodgkin's lymphoma, anaplastic large cell lymphoma and other CD30+ lymphoid malignancies. Several ongoing trials are testing the potential use of brentuximab vedotin for treatment of various CD30+ and CD30- malignancies in the setting of high-risk untreated disease. It is being tested in combination with chemotherapy, and testing in combination with immune therapy is also planned. CD30 plays a pivotal role in immune regulation and is also an attractive new target for intervention in the setting of select auto-immune diseases, as well as graft versus host disease.

Evolving Strategies for Target Selection for Antibody-Drug Conjugates

Antibody-drug conjugates (ADCs) represent a promising modality for the treatment of cancer. The therapeutic strategy is to deliver a potent drug preferentially to the tumor and not normal tissues by attaching the drug to an antibody that recognizes a tumor antigen. The selection of antigen targets is critical to enabling a therapeutic window for the ADC and has proven to be surprisingly complex. We surveyed the tumor and normal tissue expression profiles of the targets of ADCs currently in clinical development. Our analysis demonstrates a surprisingly broad range of expression profiles and the inability to formalize any optimal parameters for an ADC target. In this context, we discuss additional considerations for ADC target selection, including interdependencies among biophysical properties of the drug, biological functions of the target and strategies for clinical development. The TPBG (5T4) oncofetal antigen and the anti-TPBG ADC A1-mcMMAF are highlighted to demonstrate the relevance of the target's biological function. Emerging platform technologies and novel biological insights are expanding ADC target space and transforming strategies for target selection.

CD30 is a potential therapeutic target in malignant mesothelioma

CD30 is a cytokine receptor belonging to the TNF superfamily (TNFRSF8) that acts as a regulator of apoptosis. The presence of CD30 antigen is important in the diagnosis of Hodgkin disease and anaplastic large cell lymphoma. There have been sporadic reports of CD30 expression in nonlymphoid tumors, including malignant mesothelioma. Given the remarkable success of brentuximab vedotin, an antibody-drug conjugate directed against CD30 antigen, in lymphoid malignancies, we undertook a study to examine the incidence of CD30 in mesothelioma and to investigate the ability to target CD30 antigen in mesothelioma. Mesothelioma tumor specimens (N = 83) were examined for CD30 expression by IHC. Positive CD30 expression was noted in 13 mesothelioma specimens, primarily those of epithelial histology. There was no significant correlation of CD30 positivity with tumor grade, stage, or survival. Examination of four mesothelioma cell lines (H28, H2052, H2452, and 211H) for CD30 expression by both FACS analysis and confocal microscopy showed that CD30 antigen localized to the cell membrane. Brentuximab vedotin treatment of cultured mesothelioma cells produced a dose-dependent decrease in cell growth and viability at clinically relevant concentrations. Our studies validate the presence of CD30 antigen in a subgroup of epithelial-type mesothelioma tumors and indicate that selected mesothelioma patients may derive benefit from brentuximab vedotin treatment.

Treatment of relapsed classical Hodgkin lymphoma in the brentuximab vedotin era

Classical Hodgkin lymphoma (HL) relapses after or is refractory to upfront multiagent chemotherapy in 20%-30% of patients. Effective salvage therapy for relapsed or refractory HL is limited, and advancements are needed. Brentuximab vedotin (BV), an anti-CD30 antibody-drug conjugate, has demonstrated significant activity and manageable toxicities in advanced HL. Currently approved as a monotherapy for patients with HL that is relapsed or refractory to multiple lines of chemotherapy or autologous stem cell transplantation, BV is now being evaluated earlier in the course of disease and in combination with other therapies. This review discusses the successful translation of BV from its conception to the clinical setting and highlights ongoing trials that may ultimately expand its role in relapsed or refractory HL and improve outcomes for patients.

Could bystander killing contribute significantly to the antitumor activity of brentuximab vedotin given with standard first-line chemotherapy for Hodgkin lymphoma?

Evaluation of: Younes A, Connors JM, Park SI et al. Brentuximab vedotin combined with ABVD or AVD for patients with newly diagnosed Hodgkin's lymphoma: a Phase 1, open-label, dose-escalation study. Lancet Oncol. 14(13), 1348–1356 (2013). With exceptionally high response rates, the CD30-directed antibody–drug conjugate brentuximab vedotin (BV) was US FDA approved for treatment of patients with relapsed/refractory Hodgkin lymphoma (HL). Now in Phase I clinical trial, it has been shown that combining BV with multiagent chemotherapy (excluding bleomycin) as first-line treatment in HL patients with high-risk disease is feasible. Complete response rates were over 90% and toxicity was manageable. Given that the malignant cell population comprises a minority of HL lesions, and that BV releases a diffusible cytotoxin via a cathepsin B-cleavable linker, we argue that a significant proportion of the antitumor activity of BV can be attributed to bystander cytotoxicity in addition to direct killing of CD30-expressing malignant cells.

CD30 targeting with brentuximab vedotin: a novel therapeutic approach to primary effusion lymphoma

Primary effusion lymphoma (PEL) is an aggressive subtype of non-Hodgkin lymphoma characterized by short survival with current therapies, emphasizing the urgent need to develop new therapeutic approaches. Brentuximab vedotin (SGN-35) is an anti-CD30 monoclonal antibody (cAC10) conjugated by a protease-cleavable linker to a microtubule-disrupting agent, monomethyl auristatin E. Brentuximab vedotin is an effective treatment of relapsed CD30-expressing Classical Hodgkin and systemic anaplastic large cell lymphomas. Herein, we demonstrated that PEL cell lines and primary tumors express CD30 and thus may serve as potential targets for brentuximab vedotin therapy. In vitro treatment with brentuximab vedotin decreased cell proliferation, induced cell cycle arrest, and triggered apoptosis of PEL cell lines. Furthermore, in vivo brentuximab vedotin promoted tumor regression and prolonged survival of mice bearing previously reported UM-PEL-1 tumors as well as UM-PEL-3 tumors derived from a newly established and characterized Kaposi's sarcoma-associated herpesvirus- and Epstein-Barr virus-positive PEL cell line. Overall, our results demonstrate for the first time that brentuximab vedotin may serve as an effective therapy for PEL and provide strong preclinical indications for evaluation of brentuximab vedotin in clinical studies of PEL patients.

Brentuximab vedotin

Brentuximab vedotin (SGN-35), an intravenously administered CD30-specific antibody-drug conjugate, has recently been approved by the U.S. Food and Drug Administration for two indications, including (i) patients with Hodgkin lymphoma relapsing after autologous stem-cell transplantation (ASCT), or after two multidrug regimens in patients with Hodgkin lymphoma who are not candidates for ASCT; and (ii) patients with systemic anaplastic large cell lymphoma (ALCL) who failed at least one prior multidrug chemotherapy regimen. Patients with Hodgkin lymphoma and ALCL treated with brentuximab vedotin showed markedly high response rates for a single agent, exceeding 70% and 80% for Hodgkin lymphoma and ALCL, respectively. The complete response rate was equally as impressive, at 34% and 57% for Hodgkin lymphoma and ALCL, respectively. Results like these and from many other upcoming clinical trials, in which brentuximab vedotin is being investigated in the frontline setting, promise to profoundly change how we manage the CD30-positive lymphoproliferative malignancies. The mechanism of action, preclinical antitumor activity, and clinical activity of brentuximab vedotin against Hodgkin lymphoma, ALCL, and other CD30-expressing lymphomas are reviewed.