Changing Management of Hematological Malignancies With COVID-19: Statement and Recommendations of the Lebanese Society of Hematology and Blood Transfusion

COVID-19 caused by SARS-Cov-2 is a devastating infection in patients with hematological malignancies. In 2018, the Lebanese Society of Hematology and Blood Transfusion (LSHBT) updated the guidelines for the management of hematological malignancies in Lebanon. In 2019, it was followed by a second update. Given the rapidly changing evidence and general situation for COVID-19, the LSHBT established some recommendations and suggestions for the management of the patients with hematological malignancies taking into account the Lebanese condition, economic situation, and the facts that SARS-Cov-2 infection has apparently been devastating. In this article we present recommendations and proposals to reduce or to manage SARS-Cov-2 infection in the patients with myeloid and lymphoid hematological malignancies.

Epidemiology, outcome, targeted agents and immunotherapy in adolescent and young adult non-Hodgkin and Hodgkin lymphoma

The epidemiology, outcome and targeted immunotherapy in adolescent and young adult non-Hodgkin and Hodgkin lymphoma were discussed during the 6th International Symposium on Childhood, Adolescent and Young Adult Non-Hodgkin Lymphoma September 26th-29th 2018 in Rotterdam, the Netherlands. This review summarizes some of those presentations, as well as other current and novel antibody therapy, immune check-point inhibitors, chimeric antigen receptor T cells, cancer vaccines and cytotoxic T lymphocyte therapy.

Structural Basis of Enhanced Crystallizability Induced by a Molecular Chaperone for Antibody Antigen-Binding Fragments

Monoclonal antibodies constitute one of the largest groups of drugs to treat cancers and immune disorders, and are guiding the design of vaccines against infectious diseases. Fragments antigen-binding (Fabs) have been preferred over monoclonal antibodies for the structural characterization of antibody-antigen complexes due to their relatively low flexibility. Nonetheless, Fabs often remain challenging to crystallize because of the surface characteristics of complementary determining regions and the residual flexibility in the hinge region between the variable and constant domains. Here, we used a variable heavy-chain (V_HH) domain specific for the human kappa light chain to assist in the structure determination of three therapeutic Fabs that were recalcitrant to crystallization on their own. We show that this ligand alters the surface properties of the antibody-ligand complex and lowers its aggregation temperature to favor crystallization. The V_HH crystallization chaperone also restricts the flexible hinge of Fabs to a narrow range of angles, and so independently of the variable region. Our findings contribute a valuable approach to antibody structure determination and provide biophysical insight into the principles that govern the crystallization of macromolecules.

The Antitumor Activity of IMGN529, a CD37-Targeting Antibody-Drug Conjugate, Is Potentiated by Rituximab in Non-Hodgkin Lymphoma Models

Naratuximab emtansine (IMGN529) is an investigational antibody-drug conjugate consisting of a CD37-targeting antibody conjugated to the maytansine-derived microtuble disruptor, DM1. IMGN529 has shown promising preclinical and clinical activity in non-Hodgkin lymphoma, including diffuse large B-cell lymphoma (DLBCL). Due to the aggressive nature of the disease, DLBCL is often treated with combination therapies to maximize clinical outcomes; therefore, we investigated the potential of combining IMGN529 with both standard-of-care and emerging therapies against multiple oncology-relevant targets and pathways. The strongest enhancement in potency was seen with anti-CD20 antibodies, including rituximab. The combination of IMGN529 and rituximab was more potent than either agent alone, and this combinatorial benefit was associated with increased apoptotic induction and cell death. Additional studies revealed that rituximab treatment increased the internalization and degradation of the CD37-targeting antibody moiety of IMGN529. The combination of IMGN529 and rituximab was highly efficacious in multiple xenograft models, with superior antitumor efficacy seen compared to either agent alone or treatment with R-CHOP therapy. These findings suggest a novel mechanism whereby the potency of IMGN529 can be enhanced by CD20 binding, which results in the increased internalization and degradation of IMGN529 leading to the generation of greater amounts of cytotoxic catabolite. Overall, these data provide a biological rationale for the enhanced activity of IMGN529 in combination with rituximab and support the ongoing clinical evaluation of IMGN529 in combination with rituximab in patients with relapsed and/or refractory DLBCL.

The landscape of new drugs in lymphoma

The landscape of drugs for the treatment of lymphoma has become crowded in light of the plethora of new agents, necessitating the efficient prioritization of drugs for expedited development. The number of drugs available, and the fact that many can be given for an extended period of time, has resulted in the emergence of new challenges; these include determining the optimal duration of therapy, and the need to balance costs, benefits, and the risk of late-onset toxicities. Moreover, with the increase in the number of available investigational drugs, the number of possible combinations is becoming overwhelming, which necessitates prioritization plans for the selective development of novel combination regimens. In this Review, we describe the most-promising agents in clinical development for the treatment of lymphoma, and provide expert opinion on new strategies that might enable more streamlined drug development. We also address new approaches for patient selection and for incorporating new end points into clinical trials.

Phase I Study of the Anti-CD22 Antibody-Drug Conjugate Pinatuzumab Vedotin with/without Rituximab in Patients with Relapsed/Refractory B-cell Non-Hodgkin Lymphoma

Purpose: Pinatuzumab vedotin is an antibody-drug conjugate with the potent antimicrotubule agent monomethyl auristatin E (MMAE) conjugated to an anti-CD22 antibody via a protease-cleavable linker. This phase I study determined its recommended phase II dose (RP2D) and evaluated its safety, tolerability, and antitumor activity alone and with rituximab in relapsed/refractory (r/r) non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL).Experimental Design: Patients received escalating doses of pinatuzumab vedotin every 21 days. Clinical activity at the RP2D alone or with rituximab was evaluated in r/r diffuse large B-cell lymphoma (DLBCL) and r/r indolent NHL (iNHL) patients.Results: Seventy-five patients received single-agent pinatuzumab vedotin. The RP2D was 2.4 mg/kg, based on dose-limiting toxicities (DLT) of grade 4 neutropenia >7 days in 1 of 3 patients and grade 4 neutropenia <7 days in 2 of 3 patients treated at 3.2 mg/kg (maximum assessed dose). No DLTs occurred at 2.4 mg/kg. At the RP2D, neutropenia was the most common grade ≥3 adverse event. Peripheral neuropathy-related grade ≥2 adverse events most frequently resulted in treatment discontinuation. Rituximab cotreatment did not impact safety, tolerability, or pharmacokinetics of pinatuzumab vedotin. Unconjugated MMAE exposure was much lower than antibody-conjugated MMAE exposure, without accumulation with repeat dosing. At the RP2D, objective responses were observed in DLBCL (9/25) and iNHL (7/14) patients; 2 of 8 patients treated with pinatuzumab vedotin (RP2D) and rituximab had complete responses. CLL patients showed no objective responses.Conclusions: The RP2D of pinatuzumab vedotin alone and with rituximab was 2.4 mg/kg, which was well tolerated, with encouraging clinical activity in r/r NHL. Clin Cancer Res; 23(5); 1167-76. ©2016 AACR.

Emerging drugs for diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most frequent non-Hodgkin lymphoma in western countries. Despite the addition of rituximab to chemotherapy, the prognosis is still poor and almost one-third of patients fail or relapse after first-line treatment. Gene expression profiling has identified three main signatures related to subgroups with different biological characteristics and responses to treatment. Novel agents targeting the oncogenic drivers of these subsets are currently under investigation with the aim of providing a tailored approach and avoiding unnecessary toxicity. Herein, we review the emerging therapies for DLBCL with a focus on preclinical and early clinical trials as well as future directions.