Gusacitinib is primarily utilized in the treatment of inflammatory and autoimmune diseases. It functions as a dual inhibitor of Janus kinase (JAK) and spleen tyrosine kinase (SYK), which are critical in the signaling pathways that drive immune responses. By targeting these pathways, it helps in reducing inflammation and modulating immune activity. This makes it particularly effective in conditions like rheumatoid arthritis, where excessive immune activity leads to joint inflammation and damage. Additionally, it is being explored for its potential in treating other immune-related disorders, such as psoriasis and atopic dermatitis, offering hope for patients with these chronic conditions.