Some of the more exciting efficacy data presented at this year's American Society of Hematology meeting were from Phase I trials. Two competing improved versions of Gleevec imatinib for chronic myelogenous leukemia - one from Novartis AG and the other from Bristol-Myers Squibb Co. - showed promising results in a very high percentage of late-stage CML patients, many of whom had failed Gleevec. Similarly, Genmab A/S presented Phase I data suggesting that its HuMax-CD20 human monoclonal antibody against CD20 has potential to be superior to Rituxan.
Gleevec (Glivec in the EU) became one of the first targeted therapies when it was launched in the U.S. in May 2001 by Novartis (NVS; SWX:NOVN, Basel, Switzerland) (see BioCentury, May 21, 2001). While Gleevec works and produces durable responses in the majority of patients, the drug was never perfect. A minority of patients didn't respond, and in a small percentage of responders, the cancer later developed resistance to the drug. As a result, even as Gleevec hit the market, work had begun to improve on it.
Gleevec inhibits a number of kinases, but the most important for CML is BCR-Abl, an enzyme that causes cellular