Abstract 554: The role of Mycobacterium w as a novel treatment for osteosarcoma

Abstract Osteosarcoma (OS) is the most common malignant primary tumor of bone and occurs in adolescents and young adults as well as in the elderly. Despite a number of large clinical trial efforts, metastatic sarcoma remains a lethal disease, and there have been no meaningful advances in therapy or improvements in patient outcomes for decades. Mycobacterium w (Mw, also known as Mycobacterium indicus pranii) is a non-pathogenic strain of mycobacterium which has been used as an immunomodulator against leprosy, tuberculosis and several cancers and is approved for treatment of NSCLC along with chemotherapy in India. Mw promotes a Th1 immune response and its administration in tumor bearing animals is associated with an increase in total number of tumor infiltrating immune cells (TIIC) with decrease in FOXP3 and PD-1 expressing TIIC in pancreatic cancer and melanoma. Previous studies in our lab have shown that Mw promotes mature dendritic cell and activated CD8+ T cell accumulation within the tumor microenvironment in a mouse model of pancreatic cancer. We compared the effects Mw with standard of care doxorubicin on OS tumor progression in a subcutaneous K7M2 syngeneic mouse model. Mw treatment was more effective at tumor inhibition than doxorubicin. Immunohistochemistry analyses of OS tumors revealed an increase in macrophages following Mw treatment. We aim to further analyze the tumor immune microenvironment using a panel of 28 antibodies to determine alterations due to Mw treatment. With these results we hope to show that Mw is a promising candidate for further development as a therapy for OS. Citation Format: Kirsten Stefan, Arpit Dheeraj, Dhanir Tailor, Sushil Kumar, Wenqi Li, Rajiv Modi, Manjul Joshipura, Bakulesh Khamar, Lara E. Davis, Sanjay V. Malhotra. The role of Mycobacterium w as a novel treatment for osteosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 554.