INF904 is an oral medication being studied for its safety and how it behaves in the body. It is designed to block a specific receptor called C5aR1. This receptor is involved in the body’s immune response, and by blocking it, INF904 may help reduce symptoms in people with certain skin conditions. The trial is looking at how well this medication works for people with moderate to severe chronic spontaneous urticaria, which is a type of hives, or hidradenitis suppurativa, a condition that causes painful lumps under the skin.

Chronic Spontaneous Urticaria – This is a skin condition characterized by the sudden appearance of hives, which are red, itchy welts on the skin. These hives can appear anywhere on the body and may change in size and shape. The condition is termed “spontaneous” because the hives occur without an obvious trigger. It is considered chronic when the hives persist for six weeks or longer. The severity can vary, with some individuals experiencing mild symptoms and others having more severe outbreaks. The exact cause is often unknown, but it may involve the immune system.

Hidradenitis Suppurativa – This is a chronic skin condition that causes small, painful lumps to form under the skin. These lumps can break open and cause tunnels under the skin, leading to scarring. It typically occurs in areas where skin rubs together, such as the armpits, groin, and under the breasts. The condition can vary in severity, with some people experiencing mild symptoms and others having more extensive skin involvement. The exact cause is not fully understood, but it is thought to involve hair follicles and the immune system. It often starts after puberty and can persist for many years.