Almirall S.A. announced the initiation of the phase I study evaluating the safety, pharmacokinetics, immunogenicity, and pharmacodynamics of ALM223, an interleukin 2 mutant fusion protein (IL-2 mu-Fc) for the potential treatment of a broad spectrum of immunological diseases. ALM223 is a modified version of the protein IL-2 designed to selectively activate Regulatory T cells (Tregs). Tregs are important regulators of the immune system activity.

Increasing their activity enables them to normalize the function of other immune cells, which could provide a therapeutic option in diseases characterized by an overactive immune system. In preclinical studies, ALM223 selectively activates Tregs without directly interfering on other types of immune cells, such as Effector T cells or Natural Killer (NK) cells. It may therefore have potential to restore immune balance and prevent the immune cells from attacking the body's own cells.

ALM223, previously referred to as SIM0278, had been developed by Simcere by utilizing their protein engineering platform. Almirall and Simcere Pharmaceutical signed an exclusive license agreement for the IL2-mu-Fc in September 2022, granting Almirall rights to develop and commercialize ALM223 for all indications outside of the Greater China region, while Simcere Pharmaceutical retained the rights within Greater China. Simcere also initiated the phase I development for the Chinese market in August 2023.