Bafetinib (formerly known as INNO-406) is an orally bioavailable, rationally designed, dual Bcr-Abl and Lyn-kinase inhibitor. According to a study published in the journal Blood (Dec. 1, 2005), bafetinib is 25 to 55 times more potent than imatinib in vitro, and at least 10 times as effective as imatinib mesylate in suppressing the growth of Bcr-Abl bearing tumors. Bafetinib has demonstrated activity in 12 of 13 imatinib-resistant cell lines.

In addition to its Bcr-Abl inhibitory properties, Bafetinib is a potent and specific inhibitor of Lyn kinase. Upregulation of Lyn kinase activity is a well recognized cause of imatinib resistance. Lyn kinase activation has also been documented in a variety of solid tumors, including prostate cancer.

CytRx plans in the first half of 2010 to initiate a Phase 2 proof-of-concept clinical trial to evaluate the efficacy and safety of bafetinib in patients with high-risk B-cell chronic lymphocytic leukemia (B-CLL).  Based on trial results, CytRx hopes to conduct a larger comparative trial to further determine efficacy of this agent.

CytRx also plans to initiate Phase 2 proof of concept clinical trials with bafetinib as a treatment for glioblastoma multiforme, a common and aggressive type of primary brain tumor, and advanced prostate cancer, in the second half of 2010.

In November 2008, CytRx announced that bafetinib demonstrated clinical responses in patients with CML in an international Phase I dose-ranging clinical trial conducted in patients with CML and other leukemias that have a certain mutation called the Philadelphia Chromosome (Ph+) and are intolerant of or resistant to Gleevec and, in some cases, second-line tyrosine kinase inhibitors such as dasatiniband nilotinib). INNO-406 has been granted Orphan Drug Status for the treatment of Philadelphia chromosome-positive (Ph+) CML by the FDA. 

CytRx holds rights to bafetinib for all territories except Japan.