Lexicon advances cancer and bleeding disorders programs

The first, LX-1521, is a small molecule compound to be developed as a potential cancer treatment. The second, LX-5431, is a protein to be developed as a potential biotherapeutic for thrombocytopenia, a condition that results in bleeding disorders. The functions of the targets of both potential therapies were discovered in Lexicon’s Genome5000 gene knockout program, a program that has produced more than 60 drug discovery programs to date.

LX-1521 is a novel compound with potential for treating solid tumor cancers. It works by blocking the cell cycle prior to cell division, resulting in cancer cell death through apoptosis. When administered orally to mouse models of human cancer, LX-1521 demonstrates significant anti-tumor activity in vivo while exhibiting no apparent gross toxicity. In vitro, the compound inhibits growth of more than 20 human tumor cell lines derived from multiple types of cancer.

Potential uses of LX-1521 as a cancer therapy include the treatment of breast, prostate, lung, colon, ovarian, renal and pancreatic cancer, as well as melanoma.

Lexicon expects to file an investigational new drug (IND) application for LX-1521 by the end of 2005 and commence a phase I clinical trial for the compound shortly thereafter.

LX-5431 is a novel recombinant human protein with the potential for treating thrombocytopenia. It has been demonstrated in ex vivo bone marrow culture to stimulate production of platelet forming cells called megakaryocytes and may have potential for treating thrombocytopenia resulting from chemotherapy, leukemia, autoimmune disease and other conditions.

During 2005, Lexicon expects to develop scale-up methodologies to produce LX-5431 in quantities required for pre-clinical and early clinical development.