Lipidated interleukin-22 reduces body weight and spares lean mass in mice by a novel gut-acting mechanism additive to GLP-1 agonism.

The prevalence of metabolic diseases, including obesity and type 2 diabetes, continues to rise. Although GLP-1 receptor agonists (GLP-1RAs) now provide the first effective treatment options for patients with obesity, many still fail to reach their target weight. Interleukin (IL)-22 has emerged as a promising therapeutic due to its ability to modulate key metabolic factors. This study evaluated the potential of a novel long-acting lipidated IL-22 analog as a complementary treatment to GLP-1RAs in mouse models. Lipidated IL-22 induced up to 20% weight reduction as a monotherapy and up to 40% in combination with GLP-1RAs, demonstrating additive efficacy. Lipidated IL-22 preserved lean body mass with less than half the lean mass loss of GLP-1RAs or caloric restriction. Glycemic control was also enhanced, with lipidated IL-22 normalizing blood glucose, and improving insulin sensitivity independent of food intake. Mechanistically, lipidated IL-22 enhanced intestinal secretion of anorectic factors like PYY and doubled fecal energy loss through reduced intestinal calorie absorption. These findings demonstrate the novel intestinal mechanisms of action of lipidated IL-22 and its additive potential to GLP-1RA treatment. Therefore, lipidated IL-22 is strongly positioned as a novel anti-obesity treatment that can address critical unmet needs in the treatment of metabolic diseases.