Cytokines and growth factors can be described as small immunomodulatory proteins secreted by a wide variety of cells including fibroblasts, endothelial and stromal cells, whose role it is to regulate surrounding cells in an autocrine, paracrine, or endocrine fashion. Immunocytokines represent a promising class of activators of the immune system, with the potential to be used alone or in combination with other therapeutic modalities. Many are currently FDA approved therapy agents (e.g. IFN, IL-2 and Epo), while others are targets for approved biological blocking therapies to support treatment of a variety of diseases. Examples of cytokine blocking agents include basiliximab (IL-2R), tocilizumab and sarilumab (IL-6R), siltuximab (IL-6), ustekinumab and its biosimilars (IL-12/IL-23 p40), secukinumab (IL-17A), bevasizumab (VEGF), and denosumab (RANKL). Many more are in development and trials as biosimilars and biobetters. IL-2 and IL-15 are still clinically important cytokines as researchers look to improve potency, patient tolerance and response by developing new molecules with sustained and targeted activities. We have developed luciferase reporter bioassays which individually can be used for the quantitation of a variety of cytokines and growth factors including IL-2, IL-6, IL-12, IL-15, IL-17, IL-23, TGF-β, VEGF and RANKL using respective mechanism of action pathways. The bioassay format is based on thaw-and use cells, eliminating the need to establish and pre-culture cytokine responsive cell lines which provides the benefits of convenience, reproducibility, and transferability. We demonstrate these assays measure cytokine response and inhibition with blocking drugs or potency changes from stressed samples. In summary, these reporter-based bioassays provide valuable tools for the development, stability testing, and potency determination in the manufacture of cytokine biosimilars and biobetters.

Citation Format: Rich Moravec, Dun Li, Jennifer Wilkinson, Brad Swanson, Frank Fan, Mei Cong. Reproducible, MoA-reflecting reporter-based bioassays to enable drug development of biosimilars and biobetters [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1729.