Photoimmunotherapy Nanoliposomes Overcome Drug Delivery Barriers for Peritoneal Metastasis

Peritoneal micrometastasis is difficult to detect and treat. New approaches that combine targeted therapy, imaging, and monitoring of treatment responses are needed to address resistant micrometastasis (i.e. photoimmunotherapy; PIT). An active-loaded targeted photoactivable multi-agent liposome (TPMAL) was developed and investigated to understand safety, efficacy, tumor penetration depth, and tissue optical property changes in an in vivo mouse peritoneal model. TPMAL active-loaded formulation demonstrated batch-to-batch consistency and stability was observed for up to one year. This formulation also demonstrated enhanced photosensitizer drug delivery into peritoneal tumor nodules by 1.6X more drug delivered and up to 2900 mm penetration depth compared to antibody drug conjugates alone. TPMAL FGLD PIT combination therapy with adjuvant chemotherapy also demonstrated enhanced long-term survival. In summary, this work advances our knowledge of TPMAL for clinical translation to help manage peritoneal metastasis.