Plinabulin is a VDA of novel structure in having been derived from a marine microbial source, as opposed to terrestrial sources for other VDAs. Plinabulin binds to the colchicine binding site of b-tubulin preventing polymerization and disrupting the cytoplasmic microtubule network. Plinabulin has been shown to produce anti-tumor activity in animal models as a single agent and synergistically with other chemotherapy agents including taxanes. Overall, preclinical studies indicated plinabulin had a favorable safety and activity profile leading to the initiation of clinical trials. Favorable data from early clinical studies lead to the initiation of a Phase 2 clinical trial program.