Tourmaline Bio is a pre-revenue, late-stage clinical biotech built around a single drug: pacibekitug, a fully human monoclonal antibody that blocks IL-6, a protein that drives inflammation. Tourmaline licensed pacibekitug from Pfizer in 2022 and argues the drug is differentiated within the established IL-6 inhibitor class by its long half-life, high binding affinity, and ability to be delivered as a small-volume subcutaneous injection as infrequently as once every three months. Tourmaline is pursuing two clinical programs. First, in cardiovascular inflammation, Tourmaline is running the Phase 2 TRANQUILITY trial in patients with elevated inflammatory markers and chronic kidney disease, with topline data expected in Q2 2025, and plans a Phase 2 proof-of-concept trial in abdominal aortic aneurysm, a condition with no approved pharmacological treatment. Second, in thyroid eye disease (TED), an autoimmune condition that can threaten sight, Tourmaline is running the pivotal Phase 2b spiriTED trial, with topline data expected in the second half of 2025. If approved, pacibekitug would be a specialty biologic with revenue driven by patients treated and price per treatment course. Tourmaline owes Pfizer up to $128M in development and regulatory milestones and up to $525M in sales milestones, plus low-double-digit royalties on net sales. Tourmaline has no commercial infrastructure and would need to build out or partner for commercialization.