Tubulins are the proteins that form microtubules, which are key components of the cellular cytoskeleton (structural network). Microtubules are necessary for cell division (mitosis), cell structure, transport, signaling and motility. Given their primary role in mitosis, microtubules have been an important target for anticancer drugs — often referred to as antimitotic drugs, tubulin inhibitors and microtubule targeting agents. These compounds bind to tubulin in microtubules and prevent cancer cell proliferation by interfering with the microtubule formation required for cell division. This interference blocks the cell cycle sequence, leading to apoptosis.

In March 2005, the Company in-licensed Celgene’s tubulin inhibitor program. EntreMed has obtained an exclusive worldwide license to a broad grouping of these compounds for oncology and assumed responsibility for the preclinical and clinical development of the tubulin inhibitors for oncology applications. Results from in vitro and in vivo studies have shown that Celgene’s tubulin inhibitors prevent tumor cell proliferation in a dose-dependent manner and, in in vitro studies, inhibit angiogenesis.

Celgene’s tubulin inhibitors are covered by issued and pending patents.