A humanized HLA-DR antibody (hu1D10, apolizumab) in combination with granulocyte colony-stimulating factor (filgrastim) for the treatment of non-Hodgkin's lymphoma: A pilot study

HLA-DR expression in melanoma: from misleading therapeutic target to potential immunotherapy biomarker

Since the advent of anti-PD1 immune checkpoint inhibitor (ICI) immunotherapy, cutaneous melanoma has undergone a true revolution with prolonged survival, as available 5-year updates for progression-free survival and overall survival demonstrate a durable clinical benefit for melanoma patients receiving ICI. However, almost half of patients fail to respond to treatment, or relapse sooner or later after the initial response to therapy. Little is known about the reasons for these failures. The identification of biomarkers seems necessary to better understand this resistance. Among these biomarkers, HLA-DR, a component of MHC II and abnormally expressed in certain tumor types including melanoma for unknown reasons, seems to be an interesting marker. The aim of this review, prepared by an interdisciplinary group of experts, is to take stock of the current literature on the potential interest of HLA-DR expression in melanoma as a predictive biomarker of ICI outcome.

A Phase I Study of Apolizumab, an Anti-HLA-DR ß-chain Monoclonal Antibody, in Patients With Solid Tumor Malignancies

BACKGROUND

Human leukocyte antigen (HLA)-DR, a member of the major histocompatibility complex class II antigen family, is a target for antibody-based therapeutics. Apolizumab (Hu1D10, Remitogen), a humanized IgG1 monoclonal anti-HLA-DR ß-chain antibody targets the antigen, 1D10, expressed on a wide variety of hematologic and solid tumor malignancies. In this Phase 1 trial, the maximum tolerated dose and dose-limiting toxicity of weekly apolizumab in patients with advanced solid tumor malignancies were determined.

PATIENTS AND METHODS

Eligible patients with refractory solid tumors were initially screened for ID10 Ag on their tumor. Patients whose tumors expressed 1D10 were administered apolizumab 0.5, 1.0, 1.5, or 3.0 mg/kg intravenously over 90 minutes weekly for 4 consecutive weeks, followed by a 4-week break, and assessment of response. Patients whose disease had not progressed were offered additional treatment.

RESULTS

Tumors from 75 patients were screened for 1D10 Ag of which 17 patients were positive and underwent treatment. The first 3 dose levels were well-tolerated. Dose-limiting toxicities of grade 3 infusion-related hypersensitivity reactions and grade 3 headache and hypertension occurred in 2 patients, respectively, at apolizumab 3.0 mg/kg. Four patients, 1 each with breast carcinoma, melanoma, renal cell carcinoma, and sarcoma had stable disease for a median of 15 weeks (range: 12 to 19 wk).

CONCLUSION

Apolizumab can be administered safely at a maximum tolerated dose of 1.5 mg/kg for 4 consecutive weeks. Adverse events and limited clinical data in both hematologic and solid tumor malignancies resulted in discontinuation of clinical development of apolizumab. HLA-DR remains an interesting immunotherapeutic target.

High-Performance Concurrent Chemo-Immuno-Radiotherapy for the Treatment of Hematologic Cancer through Selective High-Affinity Ligand Antibody Mimic-Functionalized Doxorubicin-Encapsulated Nanoparticles

Non-Hodgkin lymphoma is one of the most common types of cancer. Relapsed and refractory diseases are still common and remain significant challenges as the majority of these patients eventually succumb to the disease. Herein, we report a translatable concurrent chemo-immuno-radiotherapy (CIRT) strategy that utilizes fully synthetic antibody mimic Selective High-Affinity Ligand (SHAL)-functionalized doxorubicin-encapsulated nanoparticles (Dox NPs) for the treatment of human leukocyte antigen-D related (HLA-DR) antigen-overexpressed tumors. We demonstrated that our tailor-made antibody mimic-functionalized NPs bound selectively to different HLA-DR-overexpressed human lymphoma cells, cross-linked the cell surface HLA-DR, and triggered the internalization of NPs. In addition to the direct cytotoxic effect by Dox, the internalized NPs then released the encapsulated Dox and upregulated the HLA-DR expression of the surviving cells, which further augmented immunogenic cell death (ICD). The released Dox not only promotes ICD but also sensitizes the cancer cells to irradiation by inducing cell cycle arrest and preventing the repair of DNA damage. In vivo biodistribution and toxicity studies confirm that the targeted NPs enhanced tumor uptake and reduced systemic toxicities of Dox. Our comprehensive in vivo anticancer efficacy studies using lymphoma xenograft tumor models show that the antibody-mimic functional NPs effectively inhibit tumor growth and sensitize the cancer cells for concurrent CIRT treatment without incurring significant side effects. With an appropriate treatment schedule, the SHAL-functionalized Dox NPs enhanced the cell killing efficiency of radiotherapy by more than 100% and eradicated more than 80% of the lymphoma tumors.

IMMU-140, a Novel SN-38 Antibody-Drug Conjugate Targeting HLA-DR, Mediates Dual Cytotoxic Effects in Hematologic Cancers and Malignant Melanoma

HLA-DR is a member of the MHC class II antigen family expressed on hematologic and solid tumors. Antibodies directed against HLA-DR have demonstrated some clinical success, but toxicities limited development. IMMU-140 is an anti-HLA-DR antibody-drug conjugate composed of the active metabolite of irinotecan, SN-38, conjugated to a humanized anti-HLA-DR IgG₄ antibody (IMMU-114); the IgG₄ naked antibody is devoid of immune functions. Our aim was to determine if SN-38, the metabolite of a drug not commonly used in hematopoietic cancers, would be effective and safe when targeted to HLA-DR-expressing tumors. IMMU-140 had dual-therapeutic mechanisms, as evidenced by its retention of nonoverlapping anti-HLA-DR nonclassical apoptotic signaling and classical apoptosis mediated by its SN-38 payload. In seven human disease models [acute lymphocytic leukemia (ALL), chronic lymphocytic leukemia (CLL), multiple myeloma (MM), acute myeloid leukemia (AML), diffuse large B-cell lymphoma (DLBCL), Hodgkin lymphoma (HL), and melanoma], IMMU-140 provided significant therapeutic efficacy compared with controls, in vitro, in 3D spheroid models, and in vivo Except for MM and HL, IMMU-140 imparted significantly improved antitumor effects compared with parental IMMU-114. Even in intractable AML and ALL, where IMMU-114 only had modest antitumor effects, IMMU-140 therapy mediated >80% improvement in survival. Therapy was well tolerated, as demonstrated by no marked loss in body weight. Combined with doxorubicin, IMMU-140 produced significantly greater antitumor effects in HL than with monotherapy and without any added toxicity. The dual-therapeutic action of IMMU-140 resulted in promising therapeutic activity in a range of hematopoietic tumors and melanoma, and therefore warrants clinical development. Mol Cancer Ther; 17(1); 150-60. ©2017 AACR.

Target Therapy in Hematological Malignances: New Monoclonal Antibodies

Apart from radio- and chemotherapy, monoclonal antibodies (MoAbs) represent a new, more selective tool in the treatment of hematological malignancies. MoAbs bind with the specific antigens of the tumors. This interaction is a basis for targeted therapies which exhibit few side effects and significant antitumor activity. This review provides an overview of the functional characteristics of MoAbs, with some examples of their clinical application. The promising results in the treatment of hematological malignancies have led to the more frequent usage of MoAbs in the therapy. Development of MoAbs is a subject of extensive research. They are a promising method of cancer treatment in the future.

Immunosuppressive monoclonal antibodies: current and next generation

Monoclonal antibodies (mAbs) are well-established therapeutics, as evidenced by the large number of Food and Drug Administration-approved mAbs for the treatment of cancers, and inflammatory or autoimmune diseases, and for the prevention and treatment of solid organ transplant rejection. Although, in many cases, mAbs have improved patient survival, they are also associated with an increased incidence of opportunistic infections. We review here the current and next generation of mAbs and the risks that infectious disease specialists should be aware of.

Preclinical studies on targeted delivery of multiple IFNα2b to HLA-DR in diverse hematologic cancers

The short circulating half-life and side effects of IFNα affect its dosing schedule and efficacy. Fusion of IFNα to a tumor-targeting mAb (mAb-IFNα) can enhance potency because of increased tumor localization and improved pharmacokinetics. We used the Dock-and-Lock method to generate C2-2b-2b, a mAb-IFNα comprising tetrameric IFNα2b site-specifically linked to hL243 (humanized anti-HLA-DR). In vitro, C2-2b-2b inhibited various B-cell lymphoma leukemia and myeloma cell lines. In most cases, this immunocytokine was more effective than CD20-targeted mAb-IFNα or a mixture comprising the parental mAb and IFNα. Our findings indicate that responsiveness depends on HLA-DR expression/density and sensitivity to IFNα and hL243. C2-2b-2b induced more potent and longer-lasting IFNα signaling compared with nontargeted IFNα. Phosphorylation of STAT1 was more robust and persistent than that of STAT3, which may promote apoptosis. C2-2b-2b efficiently depleted lymphoma and myeloma cells from whole human blood but also exhibited some toxicity to B cells, monocytes, and dendritic cells. C2-2b-2b showed superior efficacy compared with nontargeting mAb-IFNα, peginterferonalfa-2a, or a combination of hL243 and IFNα, using human lymphoma and myeloma xenografts. These results suggest that C2-2b-2b should be useful in the treatment of various hematopoietic malignancies.

Evaluation of anti-human leukocyte antigen-DR monoclonal antibody therapy in spontaneous canine lymphoma

A pilot study of anti-human leukocyte antigen (HLA)-DR monoclonal antibody (mAb) in dogs with lymphoma was undertaken to verify the suitability of a canine model to address therapeutically relevant endpoints prior to a full trial in dogs, and ultimately human investigation. In vitro studies demonstrated that L243, a murine IgG1 anti-HLA-DR, binds to normal and malignant canine lymphocytes and induces apoptosis in canine lymphoma cells. Moreover, L243 was administered safely to normal dogs and dogs with lymphoma, and bound to malignant cells in nodal tissue. Preliminary evidence of transient disease stabilization was observed in a subset of dogs with advanced-stage lymphoma following L243 immunotherapy. hL243γ4P (IMMU-114), a humanized IgG4 anti-HLA-DR, currently under evaluation preclinically for human trials, was also shown to bind malignant canine lymphocytes, and safety and pharmacokinetic data from the administration of IMMU-114 to normal dogs indicate similar behavior to L243 in these assessments. These findings provide a rationale for the use of dogs with lymphoma in safety and efficacy evaluations of anti-HLA-DR mAbs for both veterinary and human applications.

A bispecific antibody-IFNalpha2b immunocytokine targeting CD20 and HLA-DR is highly toxic to human lymphoma and multiple myeloma cells

The short circulating half-life and side effects of IFNα affect its dosing schedule and efficacy. Fusion of IFNα to a tumor-targeting monoclonal antibody (MAb-IFNα) can enhance potency due to increased tumor localization and improved pharmacokinetics. We report the generation and characterization of the first bispecific MAb-IFNα, designated 20-C2-2b, which comprises two copies of IFNα2b and a stabilized F(ab)(2) of hL243 (humanized anti-HLA-DR; IMMU-114) site-specifically linked to veltuzumab (humanized anti-CD20). In vitro, 20-C2-2b inhibited each of four lymphoma and eight myeloma cell lines, and was more effective than monospecific CD20-targeted MAb-IFNα or a mixture comprising the parental antibodies and IFNα in all but one (HLA-DR(-)/CD20(-)) myeloma line, suggesting that 20-C2-2b should be useful in the treatment of various hematopoietic malignancies. 20-C2-2b displayed greater cytotoxicity against KMS12-BM (CD20(+)/HLA-DR(+) myeloma) compared with monospecific MAb-IFNα, which targets only HLA-DR or CD20, indicating that all three components in 20-C2-2b could contribute to toxicity. Our findings indicate that a given cell's responsiveness to MAb-IFNα depends on its sensitivity to IFNα and the specific antibodies, as well as the expression and density of the targeted antigens.

Therapy of B-cell malignancies by anti-HLA-DR humanized monoclonal antibody, IMMU-114, is mediated through hyperactivation of ERK and JNK MAP kinase signaling pathways

A humanized IgG4 anti-HLA-DR monoclonal antibody (IMMU-114), engineered to avoid side effects associated with complement activation, was examined for binding and cytotoxicity on leukemia, lymphoma, and multiple myeloma cell lines and chronic lymphocytic leukemia (CLL) patient specimens, followed by evaluation of the effects of IMMU-114 on extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) signaling pathways. HLA-DR was expressed on the majority of these cells at markedly higher levels than CD20, CD22, and CD74. IMMU-114 was toxic to mantle cell lymphoma, CLL, acute lymphoblastic leukemia, hairy cell leukemia, non-Hodgkin lymphoma (including rituximab-resistant), and multiple myeloma cell lines, and also patient CLL cells. IMMU-114 induced disease-free survival in tumor-bearing SCID mice with early-stage disease and in models that are relatively resistant to anti-CD20 monoclonal antibodies. Despite positive staining, acute myelogenous leukemic cells were not killed by IMMU-114. The ability of IMMU-114 to induce activation of ERK and JNK signaling correlated with cytotoxicity and differentiates the mechanism of action of IMMU-114 from monoclonal antibodies against CD20 and CD74. Thus, antigen expression is not sufficient for cytotoxicity; antibody-induced hyperactivation of ERK and JNK mitogen activated protein kinase signaling pathways are also required.

A recombinant bispecific single-chain fragment variable specific for HLA class II and Fc alpha RI (CD89) recruits polymorphonuclear neutrophils for efficient lysis of malignant B lymphoid cells

Bispecific Abs offer new perspectives for cancer immunotherapy. In this study, we describe a recombinant bispecific single-chain fragment variable (bsscFv) directed against Fc alpha RI (CD89) on polymorphonuclear neutrophils (PMNs) or monocytes/macrophages and HLA class II on lymphoma target cells. Fc alpha RI and HLA class II-directed single-chain fragment variable (scFv) fragments were isolated from phage display libraries, established from the hybridomas A77 and F3.3, respectively. The two scFv molecules were connected with a 20 aa flexible linker sequence. After expression in SF21 insect cells and chromatographic purification, the bispecific molecule showed specific binding to both Ags at K(D) values of 148 +/- 42 nM and 113 +/- 25 nM for the anti-Fc alpha RI and anti-HLA class II scFv components in the bsscFv, respectively. In Ab-dependent cytotoxicity assays with PMNs as effectors and a series of lymphoma-derived cell lines (ARH-77, RAJI, REH, NALM-6, RS4;11), the bsscFv was significantly more cytotoxic than the parental murine IgG1 and its chimeric IgG1 derivative. When targeting primary tumor cell isolates from six patients with B cell malignancies, the killing capacity of the (Fc alphaRI x HLA class II) bsscFv compared favorably to conventional HLA class II mAb. Importantly, the cell lines NALM-6 and RS411, as well as two primary tumor cell isolates, were exclusively lysed by the bsscFv. To our knowledge, this is the first report of an Fc alpha RI-directed bsscFv effectively recruiting PMNs for redirected cytotoxicity against human B cell malignancies. Our data show that an (Fc alpha RI x HLA class II) bsscFv is an interesting candidate for further engineering of small, modular immunopharmaceuticals.

Therapy of mantle cell lymphoma: current standards and future strategies

Mantle cell lymphoma is characterized clinically by an aggressive clinical course and is relatively resistant to conventional chemotherapies. When in its advanced stages, currently available immunochemotherapy regimens remain noncurative despite high initial response rates. In contrast, consolidating high-dose therapy with autologous stem cell retransfusion significantly extends progression-free survival of young patients. Currently, allogenic bone marrow transplantation represents the only therapy with the potential for a curative approach, although associated with a high rate of complications. New concepts of therapy are urgently warranted, including new molecular approaches, such as bortezomib, thalidomide, lenalidomide, and temsirolimus.

Use of antibodies and immunoconjugates for the therapy of more accessible cancers

There are currently 6 unconjugated antibodies and 3 immunoconjugates approved for use in the United States in a variety of cancers, with a considerable number of new agents in clinical testing and preclinical development. Unconjugated antibodies alone can be effective, but more often, antibodies need to be combined with chemotherapy, which enhances the efficacy of the standard treatment. Immunoconjugates tend to be more effective than their unconjugated counterparts, but their increased toxicity often restricts when and how they are used. In order to improve efficacy, a number of immunoconjugates are being examined in settings where the disease is more easily accessible, such as leukemias, or within compartments that allow easier and more direct access to the tumor, such as in the peritoneal cavity or brain, or both locally and systemically, in adjuvant situations, where the disease burden has been reduced by some other means, and with the main goal of these treatments being to kill residual disease.

Evaluation of CD20, CD22, and HLA-DR Targeting for Radioimmunotherapy of B-Cell Lymphomas

Despite the promise of radioimmunotherapy using anti-CD20 antibodies (Ab) for the treatment of relapsed patients with indolent non-Hodgkin lymphoma (NHL), most patients treated with conventional doses of (131)I-tositumomab or (90)Y-ibritumomab eventually relapse. We did comparative assessments using conventional radioimmunotherapy targeting CD20, CD22, and HLA-DR on human Ramos, Raji, and FL-18 lymphoma xenografts in athymic mice to assess the potential for improving the efficacy of radioimmunotherapy by targeting other NHL cell surface antigens. Results of biodistribution studies showed significant differences in tumor localization consistent with variable antigenic expression on the different lymphoma cell lines. Interestingly, the radioimmunoconjugate that yielded the best tumor-to-normal organ ratios differed in each tumor model. We also explored administering all three (111)In-1,4,7,10-tetra-azacylododecane N,N',N'',N'''-tetraacetic acid antibodies in combination, but discovered, surprisingly, that this approach did not augment the localization of radioactivity to tumors compared with the administration of the best single radiolabeled Ab alone. These data suggest that conventional radioimmunotherapy using anti-CD20, anti-HLA-DR, or anti-CD22 Abs is effective when used singly and provides targeted uptake of radiolabel into the tumor that is dependent on the levels of antigen expression. Improvements in tumor-to-normal organ ratios of radioactivity cannot be achieved using directly labeled Abs in combination but may be afforded by novel pretargeting methods.

Monoclonal Antibodies for B-Cell Lymphomas: Rituximab and Beyond

The year 2007 marks the 10th anniversary of approval by the U.S. Food and Drug Adminstration of the first monoclonal antibody for the treatment of cancer. Rituximab, an anti-CD20 chimeric monoclonal antibody, was approved for the treatment of patients with relapsed/refractory low-grade B-cell non-Hodgkin lymphomas. From an immunologic perspective, this therapeutic indication provided the long-elusive validation of immunotherapy as the fourth modality of treatment for patients with cancer. From a clinical perspective, it was hard to imagine then that this nonchemotherapeutic approach would dramatically impact the management of patients with almost every type of B-cell malignancy and that it would even find a place as a therapeutic option for patients with non-malignant disorders. Although thousands of patients have been treated worldwide with rituximab, there is still debate regarding its mechanism(s) of action. The demonstration that a number of patients do not benefit with this treatment and that no cures have been achieved with single-agent rituximab prompted several investigators to identify those barriers limiting the efficacy of this monoclonal antibody. Here, we summarize what we have learned in the past 10 years about rituximab efficacy and its mechanisms of action and resistance. We also discuss the new generation of monoclonal antibodies, the development of which has been spurred by the widespread success of anti-CD20 MAb therapy.