Abstract OT2-06-01: Highly innovative personalized RNA-immunotherapy for patients with triple negative breast cancer

Cancer Vaccines for Triple-Negative Breast Cancer: A Systematic Review

Triple-negative breast cancer (TNBC) is the subtype of breast cancer with the poorest outcomes, and is associated with a high risk of relapse and metastasis. The treatment choices for this malignancy have been confined to conventional chemotherapeutic agents, due to a lack of expression of the canonical molecular targets. Immunotherapy has been recently changing the treatment paradigm for many types of tumors, and the approach of evoking active immune responses in the milieu of breast tumors through cancer vaccines has been introduced as one of the most novel immunotherapeutic approaches. Accordingly, a number of vaccines for the treatment or prevention of recurrence have been developed and are currently being studied in TNBC patients, while none have yet received any approvals. To elucidate the efficacy and safety of these vaccines, we performed a systematic review of the available literature on the topic. After searching the PubMed, Scopus, Web of Science, Embase, Cochrane CENTRAL, and Google Scholar databases, a total of 5701 results were obtained, from which 42 clinical studies were eventually included based on the predefined criteria. The overall quality of the included studies was acceptable. However, due to a lack of reporting outcomes of survival or progression in some studies (which were presented as conference abstracts) as well as the heterogeneity of the reported outcomes and study designs, we were not able to carry out a meta-analysis. A total of 32 different vaccines have so far been evaluated in TNBC patients, with the majority belonging to the peptide-based vaccine type. The other vaccines were in the cell or nucleic acid (RNA/DNA)-based categories. Most vaccines proved to be safe with low-grade, local adverse events and could efficiently evoke cellular immune responses; however, most trials were not able to demonstrate significant improvements in clinical indices of efficacy. This is in part due to the limited number of randomized studies, as well as the limited TNBC population of each trial. However, due to the encouraging results of the currently published trials, we anticipate that this strategy could show its potential through larger, phase III randomized studies in the near future.

Nanodrugs Targeting T Cells in Tumor Therapy

In contrast to conventional anti-tumor agents, nano-carriers allow co-delivery of distinct drugs in a cell type-specific manner. So far, many nanodrug-based immunotherapeutic approaches aim to target and kill tumor cells directly or to address antigen presenting cells (APC) like dendritic cells (DC) in order to elicit tumor antigen-specific T cell responses. Regulatory T cells (Treg) constitute a major obstacle in tumor therapy by inducing a pro-tolerogenic state in APC and inhibiting T cell activation and T effector cell activity. This review aims to summarize nanodrug-based strategies that aim to address and reprogram Treg to overcome their immunomodulatory activity and to revert the exhaustive state of T effector cells. Further, we will also discuss nano-carrier-based approaches to introduce tumor antigen-specific chimeric antigen receptors (CAR) into T cells for CAR-T cell therapy which constitutes a complementary approach to DC-focused vaccination.

The paradigm shift in treatment from Covid-19 to oncology with mRNA vaccines

mRNA vaccines have gained popularity over the last decade as a versatile tool for developing novel therapeutics. The recent success of coronavirus disease (COVID-19) mRNA vaccine has unlocked the potential of mRNA technology as a powerful therapeutic platform. In this review, we apprise the literature on the various types of cancer vaccines, the novel platforms available for delivery of the vaccines, the recent progress in the RNA-based therapies and the evolving role of mRNA vaccines for various cancer indications, along with a future strategy to treat the patients. Literature reveals that despite multifaceted challenges in the development of mRNA vaccines, the promising and durable efficacy of the RNA in pre-clinical and clinical studies deserves consideration. The introduction of mRNA-transfected DC vaccine is an approach that has gained interest for cancer vaccine development due to its ability to circumvent the necessity of DC isolation, ex vivo cultivation and re-infusion. The selection of appropriate antigen of interest remains one of the major challenges for cancer vaccine development. The rapid development and large-scale production of mRNA platform has enabled for the development of both personalized vaccines (mRNA 4157, mRNA 4650 and RO7198457) and tetravalent vaccines (BNT111 and mRNA-5671). In addition, mRNA vaccines combined with checkpoint modulators and other novel medications that reverse immunosuppression show promise, however further research is needed to discover which combinations are most successful and the best dosing schedule for each component. Each delivery route (intradermal, subcutaneous, intra tumoral, intranodal, intranasal, intravenous) has its own set of challenges to overcome, and these challenges will decide the best delivery method. In other words, while developing a vaccine design, the underlying motivation should be a reasonable combination of delivery route and format. Exploring various administration routes and delivery route systems has boosted the development of mRNA vaccines.

Immunomodulating Therapies in Breast Cancer-From Prognosis to Clinical Practice

The role of the immune system in breast cancer has been debated for decades. The advent of technologies such as next generation sequencing (NGS) has elucidated the crucial interplay between somatic mutations in tumors leading to neoantigens and immune responses with increased tumor-infiltrating lymphocytes and improved prognosis of breast cancer patients. In particular, triple-negative breast cancer (TNBC) has a higher mutational burden compared to other breast cancer subtypes. In addition, higher levels of tumor-associated antigens suggest that immunotherapies are a promising treatment option, specifically for TNBC. Indeed, higher concentrations of tumor-infiltrating lymphocytes are associated with better prognosis and response to chemotherapy in TNBC. An important target within the cancer immune cell cycle is the "immune checkpoint". Immune checkpoint inhibitors (ICPis) block the interaction of certain cell surface proteins that act as "brakes" on immune responses. Recent studies have shown that ICPis improve survival in both early and advanced TNBC. However, this comes at the price of increased toxicity, particularly immune-mediated toxicity. As an alternative approach, individualized mRNA vaccination strategies against tumor-associated neoantigens represent another promising approach leading to neoantigen-specific immune responses. These novel strategies should help to improve treatment outcomes, especially for patients with triple negative breast cancer.