Antibody-based T cell-activating biologics are promising therapeutic medicines being developed for a number of indications, mainly in the oncology field. Among those, T cell bispecific antibodies are designed to bind one tumor-specific antigen and the T cell receptor at the same time, leading to a robust T cell response against the tumor. Although their unique format and the versatility of the CrossMab technology allows for the generation of safer molecules in an efficient manner, product-related variants cannot be completely avoided. Therefore, it is of extreme importance that both a manufacturing process that limits or depletes product-related impurities, as well as a thorough analytical characterization are in place, starting from the development of the manufacturing cell line until the assessment of potential toxicities. Here, we describe such an end-to-end approach to minimize, quantify and control impurities and -upon their functional characterization- derive specifications that allow for the release of clinical material.

T cell engaging bispecific antibody (TCB) is an effective immunotherapy for cancer treatment. Through co-targeting CD3 and tumor-associated antigen (TAA), TCB can redirect CD3+ T cells to eliminate tumor cells regardless of the specificity of T cell receptor. Tissue factor (TF) is a TAA that involved in tumor progression. Here, we designed and characterized a novel TCB targeting TF (TF-TCB) for the treatment of TF-positive tumors. In vitro, robust T cell activation, tumor cell lysis and T cell proliferation were induced by TF-TCB. The tumor cell lysis activity was dependent upon both CD3 and TF binding moieties of the TF-TCB, and was related to TF expression level of tumor cells. In vivo, in both tumor cell/human peripheral blood mononuclear cells (PBMC) co-grafting model and established tumor models with poor T cell infiltration, tumor growth was strongly inhibited by TF-TCB. T cell infiltration into tumors was induced during the treatment. Furthermore, efficacy of TF-TCB was further improved by combination with immune checkpoint inhibitors. For the first time, our results validated the feasibility of using TF as a target for TCB and highlighted the potential for TF-TCB to demonstrate efficacy in solid tumor treatment.

Immunotherapy strategies targeting the programmed cell death ligand 1 (PD-L1)/programmed cell death 1 (PD-1) pathway in clinical treatments have achieved remarkable success in treating multiple types of cancer. However, owing to the heterogeneity of tumors and individual immune systems, PD-L1/PD-1 blockade still shows slow response rates in controlling malignancies in many patients. Accumulating evidence has shown that an effective response to anti-PD-L1/anti-PD-1 therapy requires establishing an integrated immune cycle. Damage in any step of the immune cycle is one of the most important causes of immunotherapy failure. Impairments in the immune cycle can be restored by epigenetic modification, including reprogramming the environment of tumor-associated immunity, eliciting an immune response by increasing the presentation of tumor antigens, and by regulating T cell trafficking and reactivation. Thus, a rational combination of PD-L1/PD-1 blockade and epigenetic agents may offer great potential to retrain the immune system and to improve clinical outcomes of checkpoint blockade therapy.

UNASSIGNED: Atopics have a lower risk for malignancies, and IgE targeted to tumors is superior to IgG in fighting cancer. Whether IgE-mediated innate or adaptive immune surveillance can confer protection against tumors remains unclear.
UNASSIGNED: We aimed to investigate the effects of active and passive immunotherapy to the tumor-associated antigen HER-2 in three murine models differing in Epsilon-B-cell-receptor expression affecting the levels of expressed IgE.
UNASSIGNED: We compared the levels of several serum specific anti-HER-2 antibodies (IgE, IgG1, IgG2a, IgG2b, IgA) and the survival rates in low-IgE ΔM1M2 mice lacking the transmembrane/cytoplasmic domain of Epsilon-B-cell-receptors expressing reduced IgE levels, high-IgE KN1 mice expressing chimeric Epsilon-Gamma1-B-cell receptors with 4-6-fold elevated serum IgE levels, and wild type (WT) BALB/c. Prior engrafting mice with D2F2/E2 mammary tumors overexpressing HER-2, mice were vaccinated with HER-2 or vehicle control PBS using the Th2-adjuvant Al(OH)3 (active immunotherapy), or treated with the murine anti-HER-2 IgG1 antibody 4D5 (passive immunotherapy).
UNASSIGNED: Overall, among the three strains of mice, HER-2 vaccination induced significantly higher levels of HER-2 specific IgE and IgG1 in high-IgE KN1, while low-IgE ΔM1M2 mice had higher IgG2a levels. HER-2 vaccination and passive immunotherapy prolonged the survival in tumor-grafted WT and low-IgE ΔM1M2 strains compared with treatment controls; active vaccination provided the highest benefit. Notably, untreated high-IgE KN1 mice displayed the longest survival of all strains, which could not be further extended by active or passive immunotherapy.
UNASSIGNED: Active and passive immunotherapies prolong survival in wild type and low-IgE ΔM1M2 mice engrafted with mammary tumors. High-IgE KN1 mice have an innate survival benefit following tumor challenge.

As three decades ago, it was reported that adoptive T cell immunotherapy by infusion of autologous tumor infiltrating lymphocytes (TILs) mediated objective cancer regression in patients with metastatic melanoma. A new era of T cell immunotherapy arose since the improvement and clinical use of anti-CD19 chimeric antigen receptor T cells (CAR-T) for the treatment of refractory and relapsed B lymphocyte leukemia. However, several challenges and difficulties remain on the way to reach generic and effective T cell immunotherapy, including lacking a generic method for generating anti-leukemia-specific T cells from every patient. Here, we summarize the current methods of generating anti-leukemia-specific T cells, and the promising approaches in the future.

One type of anticancer vaccine relies on the administration of DNA constructs encoding one or multiple tumor-associated antigens (TAAs). The ultimate objective of these preparations, which can be naked or vectored by non-pathogenic viruses, bacteria or yeast cells, is to drive the synthesis of TAAs in the context of an immunostimulatory milieu, resulting in the (re-)elicitation of a tumor-targeting immune response. In spite of encouraging preclinical results, the clinical efficacy of DNA-based vaccines employed as standalone immunotherapeutic interventions in cancer patients appears to be limited. Thus, efforts are currently being devoted to the development of combinatorial regimens that allow DNA-based anticancer vaccines to elicit clinically relevant immune responses. Here, we discuss recent advances in the preclinical and clinical development of this therapeutic paradigm.

Cytotoxic T lymphocytes (CTLs) recognize the human leukocyte antigen (HLA) class I and antigenic peptide complex, and they play a crucial role in cancer immunity. Our recent study revealed that HLA class I downregulation is related to poorer prognosis and a low level of intratumoral CTLs is associated with platinum resistance, indicating the significance of immunological surveillance.

Malignant cells express antigens that can be harnessed to elicit anticancer immune responses. One approach to achieve such goal consists in the administration of tumor-associated antigens (TAAs) or peptides thereof as recombinant proteins in the presence of adequate adjuvants. Throughout the past decade, peptide vaccines have been shown to mediate antineoplastic effects in various murine tumor models, especially when administered in the context of potent immunostimulatory regimens. In spite of multiple limitations, first of all the fact that anticancer vaccines are often employed as therapeutic (rather than prophylactic) agents, this immunotherapeutic paradigm has been intensively investigated in clinical scenarios, with promising results. Currently, both experimentalists and clinicians are focusing their efforts on the identification of so-called tumor rejection antigens, i.e., TAAs that can elicit an immune response leading to disease eradication, as well as to combinatorial immunostimulatory interventions with superior adjuvant activity in patients. Here, we summarize the latest advances in the development of peptide vaccines for cancer therapy.

Immunotherapy is a promising treatment option for patients with hepatocellular carcinoma (HCC). Indeed, CD8+ T-cell responses against various tumor antigens occur in these patients. However, these antitumoral T cells show a severely impaired effector function. Several immunosuppressive mechanisms contribute to this T-cell failure, including regulatory T cells and inhibitory receptors.

The use of patient-derived dendritic cells (DCs) as a means to elicit therapeutically relevant immune responses in cancer patients has been extensively investigated throughout the past decade. In this context, DCs are generally expanded, exposed to autologous tumor cell lysates or loaded with specific tumor-associated antigens (TAAs), and then reintroduced into patients, often in combination with one or more immunostimulatory agents. As an alternative, TAAs are targeted to DCs in vivo by means of monoclonal antibodies, carbohydrate moieties or viral vectors specific for DC receptors. All these approaches have been shown to (re)activate tumor-specific immune responses in mice, often mediating robust therapeutic effects. In 2010, the first DC-based preparation (sipuleucel-T, also known as Provenge®) has been approved by the US Food and Drug Administration (FDA) for use in humans. Reflecting the central position occupied by DCs in the regulation of immunological tolerance and adaptive immunity, the interest in harnessing them for the development of novel immunotherapeutic anticancer regimens remains high. Here, we summarize recent advances in the preclinical and clinical development of DC-based anticancer therapeutics.