Anti-CD30-IL-12 antibody-cytokine fusion protein that induces IFN-gamma secretion of T cells and NK cell-mediated lysis of Hodgkin's lymphoma-derived tumor cells

Fusion proteins development strategies and their role as cancer therapeutic agents

Cancer continues to be leading cause of morbidity and mortality despite decades of research and advancement in chemotherapy. Most tumors can be reduced via standard oncology treatments, such as chemotherapy, radiotherapy, and surgical resection, and they frequently recur. Significant progress has been made since targeted cancer therapy inception in creation of medications that exhibit improved tumor-selective action. Particularly in preclinical and clinical investigations, fusion proteins have shown strong activity and improved treatment outcomes for a number of human cancers. Synergistically combining many proteins into one complex allows the creation of synthetic fusion proteins with enhanced characteristics or new capabilities. Signal transduction pathways are important for onset, development, and spread of cancer. As result, signaling molecules are desirable targets for cancer therapies, and significant effort has been made into developing fusion proteins that would act as inhibitors of these pathways. A wide range of biotechnological and medicinal applications are made possible by fusion of protein domains that improves bioactivities or creates new functional combinations. Such proteins may function as immune effectors cell recruiters to tumors or as decoy receptors for various ligands. In this review article, we have outlined the standard methods for creating fusion proteins and covered the applications of fusion proteins in treatment of cancer. This article also highlights the role of fusion proteins in targeting the signaling pathways involved in cancer for effective treatment.

IL12 integrated into the CAR exodomain converts CD8+ T cells to poly-functional NK-like cells with superior killing of antigen-loss tumors

Chimeric antigen receptor (CAR)-redirected T cell therapy often fails to control tumors in the long term due to selecting cancer cells that downregulated or lost CAR targeted antigen. To reprogram the functional capacities specifically of engineered CAR T cells, we inserted IL12 into the extracellular moiety of a CD28-ζ CAR; both the CAR endodomain and IL12 were functionally active, as indicated by antigen-redirected effector functions and STAT4 phosphorylation, respectively. The IL12-CAR reprogrammed CD8⁺ T cells toward a so far not recognized natural killer (NK) cell-like signature and a CD94⁺CD56⁺CD62L^high phenotype closely similar, but not identical, to NK and cytokine induced killer (CIK) cells. In contrast to conventional CAR T cells, IL12-CAR T cells acquired antigen-independent, human leukocyte antigen E (HLA-E) restricted cytotoxic capacities eliminating antigen-negative cancer cells in addition to eliminating cancer cells with CAR cognate antigen. Simultaneous signaling through both the CAR endodomain and IL12 were required for inducing maximal NK-like cytotoxicity; adding IL12 to conventional CAR T cells was not sufficient. Antigen-negative tumors were attacked by IL12-CAR T cells, but not by conventional CAR T cells. Overall, we present a prototype of a new family of CARs that augments tumor recognition and elimination through expanded functional capacities by an appropriate cytokine integrated into the CAR exodomain.

The use of supercytokines, immunocytokines, engager cytokines, and other synthetic cytokines in immunotherapy

Cytokines exert powerful immunomodulatory effects that are critical to physiology and pathology in humans. The application of natural cytokines in clinical studies has not been clearly established, and there are often problems associated with toxicity or lack of efficacy. The key reasons can be attributed to the pleiotropy of cytokine receptors and undesired activation of off-target cells. With a deeper understanding of the structural principles and functional signals of cytokine-receptor interactions, artificial modification of cytokine signaling through protein engineering and synthetic immunology has become an increasingly feasible and powerful approach. Engineered cytokines are designed to selectively target cells. Herein, the theoretical and experimental evidence of cytokine engineering is reviewed, and the "supercytokines" resulting from structural enhancement and the "immunocytokines" generated by antibody fusion are described. Finally, the "engager cytokines" formed by the crosslinking of cytokines and bispecific immune engagers and other synthetic cytokines formed by nonnatural analogs are also discussed.

Antibody-cytokine fusion proteins: A novel class of biopharmaceuticals for the therapy of cancer and of chronic inflammation

Antibody-cytokine fusion proteins represent a novel class of biopharmaceuticals, with the potential to increase the therapeutic index of cytokine 'payloads' and to promote leukocyte infiltration at the site of disease. In this review, we present a survey of immunocytokines that have been used in preclinical models of cancer and in clinical trials. In particular, we highlight how antibody format, choice of target antigen and cytokine engineering, as well as combination strategies, may have a profound impact on therapeutic performance. Moreover, by using anti-inflammatory cytokines, antibody fusion strategies can conveniently be employed for the treatment of auto-immune and chronic inflammatory conditions.

Evolution of the magic bullet: Single chain antibody fragments for the targeted delivery of immunomodulatory proteins

Immunocytokines are fusion proteins that combine the specific antigen binding capacities of an antibody or derivative thereof and the potent bioactivity of a cytokine partner. These novel biopharmaceuticals have been directed to various targets of oncological as well as non-oncological origin and a handful of promising constructs are currently advancing in the clinical trial pipeline. Several factors such as the choice of a disease specific antigen, the antibody format and the modulatory nature of the payload are crucial, not only for therapeutic efficacy and safety but also for the commercial success of such a product. In this review, we provide an overview of the basic principles and obstacles in immunocytokine design with a specific focus on single chain antibody fragment-based constructs that employ interleukins as the immunoactive component. Impact statement Selective activation of the immune system in a variety of malignancies represents an attractive approach when existing strategies have failed to provide adequate treatment options. Immunocytokines as a novel class of bifunctional protein therapeutics have emerged recently and generated promising results in preclinical and clinical studies. In order to harness their full potential, multiple different aspects have to be taken into consideration. Several key points of these fusion constructs are discussed here and should provide an outline for the development of novel products based on an overview of selected formats.

Antibody-Based Cancer Therapy: Successful Agents and Novel Approaches

Since their discovery, antibodies have been viewed as ideal candidates or "magic bullets" for use in targeted therapy in the fields of cancer, autoimmunity, and chronic inflammatory disorders. A wave of antibody-dedicated research followed, which resulted in the clinical approval of a first generation of monoclonal antibodies for cancer therapy such as rituximab (1997) and cetuximab (2004), and infliximab (2002) for the treatment of autoimmune diseases. More recently, the development of antibodies that prevent checkpoint-mediated inhibition of T cell responses invigorated the field of cancer immunotherapy. Such antibodies induced unprecedented long-term remissions in patients with advanced stage malignancies, most notably melanoma and lung cancer, that do not respond to conventional therapies. In this review, we will recapitulate the development of antibody-based therapy, and detail recent advances and new functions, particularly in the field of cancer immunotherapy. With the advent of recombinant DNA engineering, a number of rationally designed molecular formats of antibodies and antibody-derived agents have become available, and we will discuss various molecular formats including antibodies with improved effector functions, bispecific antibodies, antibody-drug conjugates, antibody-cytokine fusion proteins, and T cells genetically modified with chimeric antigen receptors. With these exciting advances, new antibody-based treatment options will likely enter clinical practice and pave the way toward more successful control of malignant diseases.

Novel immunocytokine IL12-SS1 (Fv) inhibits mesothelioma tumor growth in nude mice

Mesothelin is a glycosylphosphatidylinositol-anchored glycoprotein that is highly expressed on the cell surface of malignant mesothelioma. Monoclonal antibodies against mesothelin are being evaluated for the treatment of mesothelioma. Immunocytokines represent a novel class of armed antibodies. To provide an alternative approach to current mesothelin-targeted antibody therapies, we have developed a novel immunocytokine based on interleukin-12 (IL12) and the SS1 Fv specific for mesothelin. IL12 possesses potent anti-tumor activity in a wide variety of solid tumors. The newly-developed recombinant immunocytokine, IL12-SS1 (Fv), was produced in insect cells using a baculovirus-insect cell expression system. The SS1 single-chain Fv was fused to the C terminus of the p35 subunit of IL12 through a short linker (GSADGG). The single-chain IL12-SS1 (Fv) immunocytokine bound native mesothelin proteins on malignant mesothelioma (NCI-H226) and ovarian (OVCAR-3) cells as well as recombinant mesothelin on A431/H9 cells. The immunocytokine retained sufficient bioactivity of IL12 and significantly inhibited human malignant mesothelioma (NCI-H226) grown in the peritoneal cavity of nude mice and showed comparable anti-tumor activity to that of the SS1P immunotoxin. IL12-SS1 (Fv) is the first reported immunocytokine to mesothelin-positive tumors and may be an attractive addition to mesothelin-targeted cancer therapies.

An IL12-IL2-antibody fusion protein targeting Hodgkin's lymphoma cells potentiates activation of NK and T cells for an anti-tumor attack

Successful immunotherapy of Hodgkin's disease is so far hampered by the striking unresponsiveness of lymphoma infiltrating immune cells. To mobilize both adoptive and innate immune cells for an anti-tumor attack we fused the pro-inflammatory cytokines IL2 and IL12 to an anti-CD30 scFv antibody in a dual cytokine fusion protein to accumulate both cytokines at the malignant CD30⁺ Hodgkin/Reed-Sternberg cells in the lymphoma lesion. The tumor-targeted IL12-IL2 fusion protein was superior in activating resting T cells to amplify and secrete pro-inflammatory cytokines compared to targeted IL2 or IL12 alone. NK cells were also activated by the dual cytokine protein to secrete IFN-γ and to lyse target cells. The tumor-targeted IL12-IL2, when applied by i.v. injection to immune-competent mice with established antigen-positive tumors, accumulated at the tumor site and induced tumor regression. Data demonstrate that simultaneous targeting of two cytokines in a spatial and temporal simultaneous fashion to pre-defined tissues is feasible by a dual-cytokine antibody fusion protein. In the case of IL12 and IL2, this produced superior anti-tumor efficacy implying the strategy to muster a broader immune cell response in the combat against cancer.

Antibody-IL2 fusion proteins for tumor targeting

Increasing insight into the misbalance and poor activity of tumor infiltrating immune cells raised interest to activate and improve an antitumor immune response by accumulating IL2 in the tumor tissue. IL2 can be targeted as part of an antibody-cytokine fusion protein to the tumor tissue by a single chain fragment of variable regions (scFv) antibody recognizing a tumor-associated antigen. IL2 can moreover be combined with IL12 in a dual cytokine fusion protein, which simultaneously targets both cooperating cytokines to the tumor in order to improve the activation of both T cells and innate immune cells. We here describe in detail the construction, expression, and functional testing of antibody-IL2 fusion proteins and provide a protocol to determine the biodistribution of such proteins in animal models.

T-Cell Traffic Jam in Hodgkin's Lymphoma: Pathogenetic and Therapeutic Implications

In hematologic malignancies, the microenvironment is often characterized by nonneoplastic cells with peculiar phenotypic and functional features. This is particularly true in Hodgkin's lymphoma (HL), in which T lymphocytes surrounding Hodgkin's Reed-Sternberg cells are essentially polarized towards a memory T-helper type 2 phenotype. In this paper we will first evaluate the main processes modulating T-cell recruitment towards the lymph node microenvironment in HL, especially focusing on the role played by cytokines. We will then consider the most relevant mechanisms of immune escape exerted by neoplastic cells in order to evade antitumor immunity. The potential pathogenetic and prognostic impact of regulatory T cells in such a context will be also described. We will finally overview some of the strategies of cellular immunotherapy applied in patients with HL.

Antibody-cytokine fusion proteins: applications in cancer therapy

BACKGROUND

Antibody-cytokine fusion proteins consist of cytokines fused to an antibody to improve antibody-targeted cancer immunotherapy. These molecules have the capacity to enhance the tumoricidal activity of the antibodies and/or activate a secondary antitumor immune response.

OBJECTIVE

To review the strategies used to develop antibody-cytokine fusion proteins and their in vitro and in vivo properties, including preclinical and clinical studies focusing on IL-2, IL-12 and GM-CSF.

METHODS

Articles were found by searching databases such as PubMed and Clinical Trials of the US National Institutes of Health.

RESULTS/CONCLUSION

Multiple antibody-cytokine fusion proteins have demonstrated significant antitumor activity as direct therapeutics or as adjuvants of cancer vaccines in preclinical studies, paving the way for their clinical evaluation.

Immunotherapies for Hodgkin's lymphoma

Multiple immune evasion strategies characterize the pathobiology of Hodgkin's lymphoma. These must be considered when developing and testing immunotherapeutic approaches for this disease. The clinical experience with adoptive immunotherapy of Epstein-Barr virus positive tumors, and with monoclonal antibodies directed against CD30, CD20, and other antigens, is herein reviewed.

Interleukin-2, interleukin-12, and interferon-gamma levels and risk of young adult Hodgkin lymphoma

Young adult Hodgkin lymphoma (YAHL) is associated clinically with altered immunity, including a systemic defect in cell-mediated responses. There is strong evidence of a genetic contribution to risk, so we hypothesized that heritable alterations in cytokine production associated with Th1 function may contribute to susceptibility. We identified twin pairs in whom at least one member had YAHL and measured interleukin-2 (IL-2), interleukin-12 (IL-12), and interferon-gamma (IFN-gamma) levels in PHA-stimulated peripheral blood mononuclear cell supernatant in 90 case-twins, 84 of their disease-free twins (unaffected cotwins), and 90 matched controls. Mean difference and mean percentage difference in cytokine levels between case-twins and controls, and unaffected cotwins and controls were determined using analysis of covariance. YAHL case-twins and their unaffected cotwins had IL-12 levels that were 60.6% (P=.002) and 49% (P=.04) lower than those of their matched controls, respectively. IL-2 levels were significantly higher in case-twins (P=.049), but not unaffected cotwins (P=.57), compared with controls. Differences in IFN-gamma levels were not statistically significant in either comparison. An IL-12 polymorphism known to regulate expression was associated with a 2.8-fold (P=.03) increase in YAHL risk. Thus, both case-twins and their unaffected cotwins had a decreased ability to produce IL-12, which may contribute to YAHL susceptibility.

Simultaneous targeting of IL2 and IL12 to Hodgkin's lymphoma cells enhances activation of resting NK cells and tumor cell lysis

Hodgkin's disease (HD) is characterized by the accumulation of functionally anergic T cells in the vicinity of the malignant Hodgkin/Reed-Sternberg (H/RS) cells. To revert cellular anergy against H/RS cells, we generated an anti-CD30-antibody-interleukin-(IL)-2 and an anti-CD30-antibody-IL12 fusion protein that target IL2 and IL12, respectively, specifically to CD30+ H/RS cells. Both antibody-cytokine fusion proteins act cooperatively in the activation of resting NK cells, the induction of IFN-g gamma secretion and enhanced target cell lysis. The cooperative activity of the targeted cytokines suggests that the application of both antibody-cytokine fusion proteins may be particularly suitable for the specific immunotherapy of Hodgkin's lymphoma.

Autologous stem cell transplantation followed by consolidation chemotherapy for relapsed or refractory Hodgkin's lymphoma

Relapse remains a major cause of treatment failure after autotransplantation (auto-PBSCT) for Hodgkin's disease (HD). The administration of non-crossresistant therapies during the post-transplant period may delay or prevent relapse. We prospectively studied the role of consolidation chemotherapy (CC) after auto-PBSCT in 37 patients with relapsed or refractory HD. Patients received high-dose gemcitabine-BCNU-melphalan and auto-PBSCT followed by involved-field radiation and up to four cycles of the DCEP-G regimen, which consisted of dexamethasone, cyclophosphamide, etoposide, cisplatin, gemcitabine given at 3 and 9 months post transplant alternating with a second regimen (DPP) of dexamethasone, cisplatin, paclitaxel at 6 and 12 months post transplant. The probabilities of event-free survival (EFS) and overall survival (OS) at 2.5 years were 59% (95% CI=42-76%) and 86% (95% CI=71-99%), respectively. In all, 17 patients received 54 courses of CC and 15 were surviving event free (2.5 years, EFS=87%). There were no treatment-related deaths during or after the CC phase. Post-transplant CC is feasible and well tolerated. The impact of this approach on EFS should be evaluated in a larger, randomized study.