INV043

**INV043** is a next-generation photosensitizer active pharmaceutical ingredient (API) based on Invion's proprietary Photosoft™ technology for photodynamic therapy (PDT). In PDT, INV043 is activated by visible light in the presence of oxygen to generate cytotoxic reactive oxygen species that selectively kill malignant cells, induce tumor regression, and stimulate immune responses, offering a potential alternative to surgery, radiotherapy, or chemotherapy with reduced immunosuppression. Preclinical studies demonstrate ~50-fold greater phototoxicity than prior APIs like IVX-P03 and ~600-fold over talaporfin sodium, selective retention in tumors (not healthy tissue), no toxicity up to 50x therapeutic dose, and significant efficacy in models of T-cell lymphoma, triple-negative breast cancer, pancreatic cancer, and ~80% tumor control in anal squamous cell carcinoma (ASCC) when combined with immune checkpoint inhibitors (ICIs). Developed by Invion Limited in collaboration with Hudson Institute of Medical Research and others, it shows fluorescence under blue light for tumor visualization and is well-tolerated in early clinical data.[1][3][4][11]