KCL-HO-1i

**KCL-HO-1i** is an orally bioavailable small-molecule inhibitor of **heme oxygenase-1 (HO-1)**, a protein produced by perivascular tumor-associated macrophages (PvTAMs) that shields tumors from chemotherapy and immune attack. Developed by researchers at King's College London and advanced by spinout **Aethox Therapeutics**, it enhances chemotherapy efficacy by reprogramming the tumor microenvironment (TME) to promote CD8+ T-cell infiltration and effector function, converting "cold" tumors into immunologically "hot" ones responsive to treatments like 5-fluorouracil and gemcitabine. Preclinical studies in murine breast cancer (MMTV-PyMT) and sarcoma models demonstrated durable tumor control when combined with chemotherapy, with favorable pharmacokinetics (T_max 1h orally, half-life 6.3h) and minimal off-target effects.[1][2][3][4][5]