In a potential blow to Eli Lilly's (NYSE: LLY) hopes for the new blood thinner Effient, a study has tied the drug to an increased risk of cancer. The researchers analyzed data from a study that was key to FDA approval--Triton-Timi 38, which pitted Effient against its established rival Plavix--and found that the risk of new or worsened solid tumors was 60 percent higher with Effient (prasugrel).
An accompanying editorial calls for curtailed used of the drug, plus a boxed warning for Effient's label. Dr. Sanjay Kaul--an advisory panel member excluded from the Effient meeting--and Dr. George Diamond, state they "believe that to optimize the benefit-risk balance, prasugrel use should be limited to a duration of weeks rather than months," until more clinical data are available (as quoted by MedPage Today).
The researchers, Dr. James Floyd of the University of Washington and Dr. Victor Serebruany of Johns Hopkins, posit that as an antiplatelet drug, Effient may promote cancer growth by inhibiting the body's natural defenses against tumors. Lilly and Daiichi Sankyo pan that argument in a statement, maintaining that the drug isn't likely to cause cancer and that Serebruany's hypothesis has been previously presented and published and reviewed by the FDA. Furthermore, the agency "concluded that a causal link was unlikely."
They add that they continue to monitor worldwide experience in the use of prasugrel and report those findings to appropriate regulatory bodies.