Immune monitoring for successfully developing frontline immunotherapies

In recent years, the development of immunotherapies for treating diseases involving the immune system, especially cancer, has rapidly grown. The marketing approval of the CTLA-4 inhibitor Yervoy® (BMS) in 2011 manifested a paradigm shift in cancer treatment and since then the still-expanding list of approvals for the PD-1 inhibitors, the 2018 Nobel Prize in Medicine to the field and the recent approvals of chimeric antigen receptor (CAR) T cells for adoptive cell therapy (ACT) have drawn a lot of attention to the field. Lastly, the advancements in next-generation sequencing (NGS) and bioinformatics have enabled the identification of tumor-specific mutation antigens (neoantigens), opening the possibility of personalized immunotherapies for cancer patients with possible enhanced clinical efficacy.

With the broadened portfolio of immune therapies and associated need for choosing between them comes also an increased need for understanding their mode-of-action and immune monitoring assays have become increasingly pivotal for successful and safe development and treatment.

In parallel, rapid development within flow cytometric reagents and instruments has on one side opened the possibility of deep immune cell profiling, and on the other side raised the bar for performing such studies due to the associated increased complexity. Biotech and pharma companies developing innovative immune therapeutic treatments need to focus on other areas such as regulatory requirements, which diseases to target, patent protection, patient inclusion, clinical trial management etcetera, and thus benefit from outsourcing such functional studies to us.

Common for all ACT strategies is the immune cell isolation, expansion and re-infusion into patients upon a pre-conditioning lymphodepleting regimen. For CAR T cell strategies, the cells are further transduced to target specific antigens on the cancer cells, and furthermore T cell receptors can be used for such transduction. Common for these strategies is an impressive potency, however, this also implies the risk of inducing severe side effects, both of which can be investigated using flow cytometric assays. Additionally, these assays can be applied for quality control of the infusion products.

Flow cytometry-based assays can be used within the following areas:

• Basic research to develop and test cellular products regarding efficacy and un-wanted side effects.
• Isolation and preparation of cellular products, e.g. CAR T cells.
  Analysis of different markers assures that enough cancer-reactive and functional T cells are used for reinfusion. It has been shown that certain cell phenotypes are advantageous regarding clinical efficacy, while also expression of the correct TCR or CAR, viability and functionality can be measured as part of the QA/QC requirements.
• Clinical immune monitoring.
  Upon re-infusion of T cells, validated flow cytometry protocols can be utilized for evaluating effectiveness of the treatment in blood samples drawn after treatment. The differentiation and exhaustion patterns of the reinfused cells can be followed at different timepoints to correlate with primary endpoints.

Personalized medicine is widely based on NGS and bioinformatics strategies and has already led to successful clinical trials, showing the enormous potential of strategies such as the neoantigen vaccines. Currently, the antigen targets included in such neoantigen vaccines are solely based on predicted T cell epitopes and thus, there is a need for validation of these by measuring if T cell responses have been induced by the vaccination.

At ImmuMap we have special expertise in using MHC multimers for staining multiple such (neo)antigen specific T cell responses. By combining the MHC multimer staining with immunophenotyping, we have developed a highly specific assay for evaluating whether the vaccines have successfully induced the targeted immune responses in patients and the quality of such cells regarding their efficacy and long-lived capabilities.

This assay is hence ideally suited for validation of the prediction and vaccination strategies and for tracking frequency and phenotype of the vaccine-induced anti-cancer T cell responses. We have successfully investigated the differentiation, maturation and exhaustion phenotypes of antigen-specific T cells to assess the immune response induced by immunotherapy in a clinical setting.

At ImmuMap we strive to advance immune monitoring efforts in the field. We apply our expertise for generating pivotal data packages needed by our clients in discovery, pre-clinical and clinical phases. We are highly appreciated for our agility and flexibility.

We develop customized assays tailored to our clients’ needs and include functional and phenotypic markers associated with therapeutic efficacy, activation, maturation, cytotoxic killing etcetera. We have several MHC multimer staining assays for detection of antigen-specific cells with high sensitivity and specificity; these are often combined with our immunophenotyping assays. Our services can be used in most therapeutic areas and have already been applied in immune oncology, autoimmunity and overall safety assessment.