EntreMed has initiated Phase II studies with MKC-1. The single-arm, open-label study will be conducted at approximately 15 centers in the U.S. Patients with advanced or metastatic breast cancer who have failed conventional therapies are expected to be enrolled. MKC-1 is a novel, orally active, small-molecule cell cycle inhibitor with a unique mechanism of action. Specifically, MKC-1 arrests cellular mitosis by inhibiting an intracellular target important in cellular trafficking that has been shown to be involved in cell division.

MKC-1 belongs to a novel class of antimitotics and apoptosis-inducers with in vitro efficacy against a wide range of tumor cell lines, including those exhibiting multi-drug resistance, as well as in vivo activity against a number of multidrug-resistant cell lines. MKC-1 has been shown to inhibit mitotic spindle formation, prevent chromosome segregation in the M-phase (mitosis) of the cell cycle, and induce apoptosis in multiple cell lines, consistent with a mechanism in which MKC-1 blocks the nuclear uptake of proteins essential to cell replication.