Antibody Drug Conjugates (ADCs): Changing the Treatment Landscape of Lymphoma

CD25-targeted antibody-drug conjugate camidanlumab tesirine for relapsed or refractory classical Hodgkin lymphoma

Classic Hodgkin lymphoma (cHL) accounts for more than 90% of HL in developed countries. Although the current combined modality therapy make it have a high cure rate, the prognosis for heavily pretreated patients with relapsed or refractory (R/R) cHL remains poor. A novel antibody-drug conjugate (ADC), named camidanlumab tesirine (ADCT-301, Cami), is currently being evaluated for its efficacy and safety in R/R cHL. The primary objective of this review is to examine the current pharmacological properties of camidanlumab tesirine as well as its clinical antitumor activity and safety. Camidanlumab tesirine comprises a human IgG1 anti-CD25 monoclonal antibody HuMax®-TAC, conjugated to a pyrrolobenzodiazepine dimer toxin. Once it bound to CD25-expressing cells, camidanlumab tesirine is internalized by cells and delivers SG3199, then SG3199 irreversibly binds to DNA and forms DNA interstrand crosslinks, ultimately leading to cell death. In the phase 1 study, patients with R/R cHL who received camidanlumab tesirine had an overall response rate (ORR) of 71% and a complete response rate (CRR) of 42%. Additionally, the recommended doses provided in R/R cHL were determined to be 30 and 45 μg/kg. The pivotal phase 2 trial showed significant antitumor activity of camidanlumab tesirine in heavily pretreated R/R cHL patients who failed brentuximab vedotin and programmed death-1 blockade: ORR was 70.1% and CRR was 33.3%, and the median duration of response was 13.7 months. Adverse events such as fatigue, maculopapular rash, and anemia were frequently observed following administration of camidanlumab tesirine. Moreover, camidanlumab tesirine may cause Guillain-Barré syndrome or polyradiculopathy.

Polymeric nanomedicines targeting hematological malignancies

Hematological malignancies (HMs) typically persisting in the blood, lymphoma, and/or bone marrow invalidate surgery and local treatments clinically used for solid tumors. The presence and drug resistance nature of cancer stem cells (CSCs) further lends HMs hard to cure. The development of new treatments like molecular targeted drugs and antibodies has improved the clinical outcomes for HMs but only to a certain extent, due to issues of low bioavailability, moderate response, occurrence of drug resistance, and/or dose-limiting toxicities. In the past years, polymeric nanomedicines targeting HMs including refractory and relapsed lymphoma, leukemia and multiple myeloma have emerged as a promising chemotherapeutic approach that is shown capable of overcoming drug resistance, delivering drugs not only to cancer cells but also CSCs, and increasing therapeutic index by lessening drug-associated adverse effects. In addition, polymeric nanomedicines have shown to potentiate next-generation anticancer modalities such as therapeutic proteins and nucleic acids in effectively treating HMs. In this review, we highlight recent advance in targeted polymeric nanoformulations that are coated with varying ligands (e.g. cancer cell membrane proteins, antibodies, transferrin, hyaluronic acid, aptamer, peptide, and folate) and loaded with different therapeutic agents (e.g. chemotherapeutics, molecular targeted drugs, therapeutic antibodies, nucleic acid drugs, and apoptotic proteins) for directing to distinct targets (e.g. CD19, CD20, CD22, CD30, CD38, CD44, CD64, CXCR, FLT3, VLA-4, and bone marrow microenvironment) in HMs. The advantages and potential challenges of different designs are discussed.

Novel Treatments for Mantle Cell Lymphoma: From Targeted Therapies to CAR T Cells

Mantle cell lymphoma is a rare B-cell non-Hodgkin's lymphoma that retains a sobering prognosis despite an extensive research effort. Mantle cell lymphoma remains incurable even with aggressive, and at times toxic, chemoimmunotherapy with early incorporation of autologous stem cell transplantation. Given this, attention has turned to the use of targeted therapies addressing dysregulation of B-cell signaling pathways. Drugs such as immunomodulatory agents, proteasome inhibitors, and Bruton's tyrosine kinase inhibitors have shown success in the relapsed/refractory population, and there is ongoing investigation into the utilization of novel Bruton's tyrosine kinase, B-cell leukemia/lymphoma-2, and spleen tyrosine kinase inhibitors alone or in combination in both the front-line and relapsed settings. Other areas of research in novel immunotherapies include investigations of bispecific T-cell engagers and antibody-drug conjugates. Most recently, chimeric antigen receptor T-cell therapy has been granted US Food and Drug Administration approval as a result of durable remissions even in high-risk patients who have classically done poorly with traditional chemoimmunotherapy. The intent of this article is to review the literature describing these selective therapies and discuss their current and future roles in the treatment of mantle cell lymphoma.

Preliminary biological evaluation of 123I-labelled anti-CD30-LDM in CD30-positive lymphomas murine models

Overexpression of CD30 has been reported on the surface of some T-cell lymphomas, especially on Hodgkin's lymphoma (HL) and anaplastic large cell lymphoma (ALCL). CD30 targeted immunotherapy has good clinical therapy response. We have produced a novel antibody drug conjugates (ADCs)-anti-CD30-LDM, which shows attractive tumour-targeting capability and extremely potent antitumor efficacy. To further investigate biological characteristics and promote clinical translation of anti-CD30-LDM, we constructed a radiolabeled ¹²³I-anti-CD30-LDM to evaluate the biodistribution characteristics. The anti-CD30-LDM was radioiodinated by the Iodogen method. The radiochemical purity of ¹²³I-anti-CD30-LDM was more over 98%, and the specific activity of 240.5 MBq/mg. The stability and the specificity of ¹²³I-anti-CD30-LDM were evaluated in vitro. Cellular binding assays were used to evaluate the binding capabilities in CD30-positive Karpas299 cells and CD30-negative Raji cells. B-NDG mice bearing Karpas 299 and Raji xenografts were used for in vivo biodistribution studies. Our results demonstrated that anti-CD30-LDM as an ideal ADC targeted to CD30, which was labelled easily with ¹²³I and obtained the sufficient yields. The ¹²³I-anti-CD30-LDM preserved specific binding to CD30 in vitro and uptake in tumour xenografts in B-NDG mice. These results are encouraging for anti-CD30-LDM as a promising clinical translational candidate for various CD30 positive lymphomas and other diseases.

Affinity of plant viral nanoparticle potato virus X (PVX) towards malignant B cells enables cancer drug delivery

Non-Hodgkin's B cell lymphomas (NHL) include a diverse set of neoplasms that constitute ∼90% of all lymphomas and the largest subset of blood cancers. While chemotherapy is the first line of treatment, the efficacy of contemporary chemotherapies is hampered by dose-limiting toxicities. Partly due to suboptimal dosing, ∼40% of patients exhibit relapsed or refractory disease. Therefore more efficacious drug delivery systems are urgently needed to improve survival of NHL patients. In this study we demonstrate a new drug delivery platform for NHL based on the plant virus Potato virus X (PVX). We observed a binding affinity of PVX towards malignant B cells. In a metastatic mouse model of NHL, we show that systemically administered PVX home to tissues harboring malignant B cells. When loaded with the chemotherapy monomethyl auristatin (MMAE), the PVX nanocarrier enables effective delivery of MMAE to human B lymphoma cells in a NHL mouse model leading to inhibition of lymphoma growth in vivo and improved survival. Thus, PVX nanoparticle is a promising drug delivery platform for B cell malignancies.

Biological Therapy of Hematologic Malignancies: Toward a Chemotherapy- free Era

Less than 70 years ago, the vast majority of hematologic malignancies were untreatable diseases with fatal prognoses. The development of modern chemotherapy agents, which had begun after the Second World War, was markedly accelerated by the discovery of the structure of DNA and its role in cancer biology and tumor cell division. The path travelled from the first temporary remissions observed in children with acute lymphoblastic leukemia treated with single-agent antimetabolites until the first cures achieved by multi-agent chemotherapy regimens was incredibly short. Despite great successes, however, conventional genotoxic cytostatics suffered from an inherently narrow therapeutic index and extensive toxicity, which in many instances limited their clinical utilization. In the last decade of the 20th century, increasing knowledge on the biology of certain malignancies resulted in the conception and development of first molecularly targeted agents designed to inhibit specific druggable molecules involved in the survival of cancer cells. Advances in technology and genetic engineering enabled the production of structurally complex anticancer macromolecules called biologicals, including therapeutic monoclonal antibodies, antibody-drug conjugates and antibody fragments. The development of drug delivery systems (DDSs), in which conventional drugs were attached to various types of carriers including nanoparticles, liposomes or biodegradable polymers, represented an alternative approach to the development of new anticancer agents. Despite the fact that the antitumor activity of drugs attached to DDSs was not fundamentally different, the improved pharmacokinetic profiles, decreased toxic side effects and significantly increased therapeutic indexes resulted in their enhanced antitumor efficacy compared to conventional (unbound) drugs. Approval of the first immune checkpoint inhibitor for the treatment of cancer in 2011 initiated the era of cancer immunotherapy. Checkpoint inhibitors, bispecific T-cell engagers, adoptive T-cell approaches and cancer vaccines have joined the platform so far, represented mainly by recombinant cytokines, therapeutic monoclonal antibodies and immunomodulatory agents. In specific clinical indications, conventional drugs have already been supplanted by multi-agent, chemotherapy-free regimens comprising diverse immunotherapy and/or targeted agents. The very distinct mechanisms of the anticancer activity of new immunotherapy approaches not only call for novel response criteria, but might also change fundamental treatment paradigms of certain types of hematologic malignancies in the near future.

Novel targeted therapeutic agents for the treatment of childhood, adolescent and young adult non-Hodgkin lymphoma

Non-Hodgkin lymphomas (NHLs) are a heterogeneous group of malignancies. Most NHLs in children, adolescent and young adult patients are aggressive lymphomas that are generally treated with multi-agent chemotherapy or immunochemotherapy regimens. While overall survival is high, the treatment can lead to a high rate of acute and long-term toxicity. However, in the rarer instance of relapsed or refractory disease, outcomes are dismal. Novel therapeutic approaches to the treatment of both T-cell and B-cell NHLs are critical to improve outcomes while also minimising the associated toxicity of current treatment regimes. Potential therapeutic approaches in development include humoral and cellular immunotherapies, small molecule inhibitors of relevant signalling pathways and epigenetic modifying agents. In this review, we will highlight the current state of development of agents of interest with a focus on agents relevant to childhood, adolescent and young adult NHL.

A novel enediyne-integrated antibody-drug conjugate shows promising antitumor efficacy against CD30+ lymphomas

CD30 is a 120-kDa type I transmembrane glycoprotein belonging to the tumor necrosis factor receptor superfamily. Overexpression of CD30 has been reported in Hodgkin's lymphoma (HL) and anaplastic large-cell lymphoma (ALCL). CD30-targeted treatment with antibody-drug conjugates (ADCs) can lead to promising clinical benefit. Lidamycin (LDM), consisting of an apoprotein LDP and an active enediyne chromophore AE, is a member of the enediyne antibiotic family and one of the most potent antitumor agents. AE and LDP can be dissociated and reconstituted under certain conditions in vitro. LDM is an ideal payload for the preparation of ADCs. In this study, we show the generation, production, and antitumor activity of anti-CD30-LDM, a novel ADC which consists of the intact anti-CD30 antibody and LDM. First, the anti-CD30-LDP fusion protein was constructed and expressed in CHO/dhFr^- cells. Anti-CD30-LDP showed specific and high-affinity binding to CD30 and could be internalized into target cells. It also exhibited excellent tumor-targeting capability in vivo. Next, anti-CD30-LDM was prepared by assembling the enediyne molecule AE to the fusion protein anti-CD30-LDP. Anti-CD30-LDM was highly cytotoxic to HL and ALCL cell lines, with IC₅₀ values of 5-50 pm. It can also induce cell apoptosis and G2/M cell cycle arrest. In the Karpas299 xenograft model, the tumor growth was inhibited by 87.76% in mice treated with anti-CD30-LDM and with no discernible adverse effects. Taken together, anti-CD30-LDM shows attractive tumor-targeting capability and antitumor efficacy both in vitro and in vivo and could be a promising candidate for the treatment of CD30⁺ lymphomas.

Marine natural product peptides with therapeutic potential: Chemistry, biosynthesis, and pharmacology

The oceans are a uniquely rich source of bioactive metabolites, of which sponges have been shown to be among the most prolific producers of diverse bioactive secondary metabolites with valuable therapeutic potential. Much attention has been focused on marine bioactive peptides due to their novel chemistry and diverse biological properties. As summarized in this review, marine peptides are known to exhibit various biological activities such as antiviral, anti-proliferative, antioxidant, anti-coagulant, anti-hypertensive, anti-cancer, antidiabetic, antiobesity, and calcium-binding activities. This review focuses on the chemistry and biology of peptides isolated from sponges, bacteria, cyanobacteria, fungi, ascidians, and other marine sources. The role of marine invertebrate microbiomes in natural products biosynthesis is discussed in this review along with the biosynthesis of modified peptides from different marine sources. The status of peptides in various phases of clinical trials is presented, as well as the development of modified peptides including optimization of PK and bioavailability.

Antibody-targeted paclitaxel loaded nanoparticles for the treatment of CD20+ B-cell lymphoma

We developed a nano-antibody targeted chemotherapy (nATC) delivery strategy in which tumor specific and clinically relevant antibodies (rituximab, anti-CD20) are non-covalently bound to the albumin scaffold of nab-paclitaxel (ABX). We define the nanoparticle formed when the 2 drugs are bound (AR160). The newly created nATC retains the cytotoxicity of ABX and CD20 affinity of rituximab in vitro. We describe the binding characteristics of the ABX and rituximab in AR160 using peptide mapping/Biacore approach. Flow-based methods, including ImageStream and nanoparticle tracking, were used to characterize the AR160 particles in vitro. A mouse model of human B-cell lymphoma was utilized to test in vivo efficacy of AR160 therapy, which suggested improved tumor targeting (biodistribution) as the most likely mechanism of AR160 therapeutic superiority over ABX or rituximab alone. These data suggest a novel platform for nATC delivery using a slight modification of existing cancer drugs with significantly improved treatment efficacy.

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.

A new construct of antibody-drug conjugates for treatment of B-cell non-Hodgkin's lymphomas

The aim of this study was to develop a new class of antibody-drug conjugates (ADCs) with the potential to not only enhance treatment efficacy but also improve tolerability for patients with B-cell lymphomas. Classic ADCs consist of monoclonal antibodies (mAbs) linked to drugs or toxins. They selectively deliver toxic moieties to tumor cells. As such, they greatly improve the therapeutic index compared to traditional chemotherapeutic agents. However, the therapeutic efficacy and safety of ADCs are dependent on linker stability and payload toxicity. Limited payload number on a single antibody (drug-to-antibody ratio, or DAR) has been driving investigators to use extremely toxic agents; however, even very low off-target binding of these ADCs may kill patients. Herein we report a new design of ADCs that consists of rituximab (RTX) and N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-epirubicin conjugates. The latter was selectively attached to RTX via reduced disulfide bonds. Such design allows the introduction of a large payload of drug on the antibody without adding attachment sites and without compromising the antigen-targeting ability. The binding of the new conjugate, namely RTX-P-EPI, to Ramos cells (with high CD20 expression) was confirmed. The cytotoxicity of RTX-P-EPI against Raji and Ramos cells was also determined. Interestingly, two-fold inhibition of cell proliferation was observed when using RTX-P-EPI compared with their equivalent physical mixture of RTX and P-EPI. Treatment of male SCID mice bearing subcutaneous Ramos B-cell lymphoma tumors demonstrated that RTX-P-EPI possessed superior efficacy when compared to combination of RTX with chemotherapy EPI (RTX+EPI) and P-EPI (RTX+P-EPI), whereas single RTX and a non-specific conjugate IgG-P-EPI only showed marginal effect. The conjugate RTX-EPI in which EPI was directly attached to RTX demonstrated much less antitumor activity compared with RTX-P-EPI. The results suggest that this new design possesses synergistic potential of immunotherapy combined with established macromolecular therapy; moreover, a conventional chemo-agent could be utilized to generate highly effective ADCs and to achieve lower risk of off-target toxicity.

Induction of potent apoptosis by an anti-CD20 aptamer via the crosslink of membrane CD20 on non-Hodgkin's lymphoma cells

An anti-CD20 DNA aptamer was successfully generated by cell-SELEX, the crosslink of which can induce potent apoptosis in target cells.