MGI Pharma is developing irofulven, a semi-synthetic compound derived from illudin S, a toxin from the Omphalotus illudens mushroom, for the potential treatment of refractory and relapsed tumors, including ovarian, prostate, hepatocellular, breast, lung and colon cancers. Phase II trials of the compound as a monotherapy or in combination therapies are ongoing for a number of these indications.