Supporting the developing immune response

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Science of IRX-2

IRX-2: a human cell-derived (hd) IL-2 therapeutic

IRX-2 is an allogeneic, reproducible, primary, human cell-derived IL-2 therapeutic with multiple active cytokine components that act on various parts of the immune system, to activate the entire tumor microenvironment. In addition to IL-2, IRX-2 contains multiple human cytokines that promote or enhance an immune response. IRX-2 is administered as a subcutaneous injection around lymph node beds.

IL-2 is a powerful immune factor that plays an important role in maintaining and restoring T cell response. IL-2 has induced response in cancer patients however recombinant formulations of IL-2 have been limited by toxicity and high doses of recombinant IL-2 results in significant immune-related adverse effects.

Unlike recombinant IL-2 drugs and drug candidates, IRX-2 is derived from human blood cells (hd-IL-2 ). This difference confers several distinct advantages:

  • Multiple additional active cytokines lead to higher immune activation
  • Natural conformation leading to greater functionality
  • Physiological dosing

IRX-2 is produced under current good manufacturing procedure conditions following stimulation of human peripheral blood mononuclear cells (PBMCs) by phytohaemagglutinin (PHA)1 A peripheral blood mononuclear cell (PBMC) is any peripheral blood cell having a round nucleus. These cells consist of lymphocytes (T cells, B cells, NK cells) and monocytes. Cytokine production induced by PHA mimics that seen after brisk stimulation of human immune cells by an immunogenic pathogen or an infection. PBMCs are obtained from FDA-licensed blood banks.1

IRX-2, an hd-IL-2 therapeutic, contains multiple cytokines to support cells participating in an anticancer immune response

Early immunotherapeutic approaches to cancer tended to oversimplify the immune system, often based on the hope that a single target or receptor might restore cellular immune responses.

Today, we know that the immune system represents a complex interaction of cells. These include the cells that interact to create an immunization, antigen-presenting cells called dendritic cells (DCs), and different types of T cells required for an anticancer immune response. It is now known that defects in these cells exist in cancer and that these must be reversed in order to generate effective cellular immune responses. In addition, tumors induce immune suppression through multiple mechanisms. Thus, next-generation active immunotherapies must also effectively counteract these mechanisms of tumor-induced immune suppression. For these reasons, the multiple cytokines present in IRX-2 may be particularly effective in reversing the multiple immune deficits in cancer patients.

Preclinical data from animal and in vitro studies, as well as biologic data from patients in clinical trials, demonstrate that IRX-2 acts in multiple ways to augment the immune response.1-4


  1. Egan JE et al. J Immunother. 2007;30(6):624-633.
  2. Rogers PR, Croft M. J Immunol. 2000;164:2955-2963.
  3. Schilling B et al. Cancer Immunol Immunother. 2012;61(9):1395-1405.
  4. Wolf, G et al. OncoTargets and Therapy. 2018:11 3731–3746

How IRX-2 uses hd-IL-2 and multiple active cytokine components to enhance the immune response

Data collected to date suggest that IRX-2 reduces the immune suppression that is often seen in the cancer tumor microenvironment. This immunomodulatory activity appears to occur through the restoration of immune function and activation of a coordinated immune response against the tumor. In addition to hd-IL-2, IRX-2 contains numerous active cytokine components, which restores and activates multiple immune cell types including T cells, dendritic cells, and natural killer cells to recognize and destroy tumors.