Coultreon Biopharma is advancing assets that target salt-inducible kinases, proteins that drive inflammation and other immune-mediated conditions.
With $125 million in an oversubscribed series A round, Coultreon Biopharma is jumping into the immunology scene with the goal of opening up a potentially novel therapeutic mechanism.
Based in Belgium, Coultreon is building its business around a class of drugs targeting salt-inducible kinases (SIK), a family of proteins that play a central role in driving inflammation and related diseases. Coultreon has zeroed in on SIKs as a “differentiated and potentially more targeted approach” to autoimmune disease, according to the announcement.
Leading Coultreon’s SIK pipeline is COL-5671, an orally available SIK3 blocker currently in early-stage development. The biotech will use Tuesday’s haul to push COL-5671 into Phase 2 studies for psoriasis and ulcerative colitis, with an eye toward generating clinical proof-of-concept evidence by next year.
The drug, designed to be taken once-daily, works by suppressing the expression of key pro-inflammatory cytokines such as IL-23 and TNFα. COL-5671 also boosts levels of IL-10, an immunoregulatory molecule. Coultreon in its news release said this mechanism has the “potential to deliver broader and more durable disease control compared to existing therapies.”
Galapagos originally developed COL-5671 and transferred ownership to Coultreon in April 2025, according to the Tuesday release. Aside from psoriasis and ulcerative colitis, the drug has shown preclinical potential for other immune-mediated conditions, such as Crohn’s disease and rheumatoid arthritis.
Coultreon’s financing push was led by Sofinnova Investments, alongside Novo Holdings and Forbion. Regeneron Ventures participated in the fundraising, as did Gilead partner Galapagos, Samsara BioCapital and Longwood Fund.
Immunology remains a fertile field of investment for biopharma. Coultreon’s series A comes less than two weeks after Beeline Medicines debuted earlier this month, with $300 million in starting funds from Bain Capital and five assets from Bristol Myers Squibb. The startup will focus on precision therapies for autoimmune and inflammatory diseases.
Coultreon’s own backer Galapagos has been pouring money elsewhere in the space, last month reaching a cost-splitting agreement with Gilead over the pharma’s $7.8 billion acquisition of inflammatory specialist Ouro Medicines. Also with a hefty immuno takeover is Novartis, which last month swallowed Excellergy for $2 billion, gaining an investigational anti-IgE antibody for allergies.
Correction (April 28): This story has been updated to correct that Sofinnova Investments led the series A round, as opposed to Novo Holdings. BioSpace regrets the error.
