Apilimodmesylate is primarily used in biomedical research for its ability to modulate immune responses. It acts as a selective inhibitor of phosphatidylinositol 3-kinase (PI3K), particularly targeting the PIKfyve kinase pathway, which plays a key role in endosomal trafficking and cytokine production. Due to this mechanism, it shows potential in reducing the secretion of pro-inflammatory cytokines such as IL-12 and IL-23, making it a candidate for studying autoimmune and inflammatory diseases. It has also drawn interest for its antiviral properties. Studies indicate that apilimodmesylate can block the entry of certain viruses into host cells by interfering with endolysosomal pathways, showing activity against viruses like Ebola and SARS-CoV-2 in preclinical models. In oncology research, apilimodmesylate is explored for its ability to induce apoptosis in cancer cells, particularly in hematological malignancies. Its role in disrupting intracellular signaling and vesicular transport makes it a tool compound for understanding cancer cell survival and immune evasion.