COL-5671

COL-5671 is a selective, oral small molecule inhibitor of Salt-Inducible Kinase 3 (SIK3), currently under development for the treatment of inflammatory and autoimmune conditions. Originally part of the SIK inhibitor portfolio at Galapagos, the asset was transferred to Coultreon Biopharma in April 2025 following a $125 million Series A financing round. SIK3 is a key regulator of cytokine production; its inhibition is designed to rebalance the immune system by suppressing pro-inflammatory cytokines (such as TNF-α and IL-12) and potentially promoting anti-inflammatory pathways (such as IL-10). Coultreon plans to advance the program into Phase 2 clinical trials for psoriasis and ulcerative colitis.