The pentyloxyterphenyl side chain derivative of echinocandin B, anidulafungin, is a 1,3-alpha-glucan synthesis inhibitor undergoing phase II clinical trials by Versicor and Eli Lilly, in various formulations, for the potential treatment of fungal and protozoal infections. Eli Lilly has retained options to the oral formulation of the compound, but development, clinical registration and marketing rights were licensed to Versicor in June 1999. The primary target of this compound is Candida, but Eli Lilly also intends to develop the drug for Aspergillus infections. No activity has been shown against Cryptococcus. The oral activity of anidulafungin is compromised by a low bioavailability, a decreased absorption when taken with food, and gastrointestinal side effects at higher doses. The development of a phosphorylated prodrug, LY-307853, which is converted in the body to anidulafungin by tissue and serum phosphatases, was discontinued in favor of an oral formulation, which uses anidulafungin directly. In February 1999, Deutsche Bank predicted sales of $100 million in 2001, rising to $300 million in 2003.