Aranesp Data Dents Amgen

This is the negative survival signal against Aranesp that has investors concerned, especially since it's not the first study that's linked Aranesp to bad results for cancer patients. In February, an analysis of a Danish study of Aranesp in head and neck cancer patients also showed that use of the anemia drug led to worse outcomes for patients.

Roy Baynes, an Amgen vice president of clinical development, says it's premature to pass judgment on Aranesp's role in survival in this study because patients are still being followed. A formal statistical analysis of survival in this trial will be conducted in early 2009.

In a statement provided by Amgen in its press release, the study's principal investigator, Dr. Michael Untch, agrees: "No definitive conclusions should be drawn from the interim results of the long-term follow up until the final study report is completed," he said.

Baynes also points out that Aranesp was used in the German breast cancer study to maintain hemoglobin levels in patients at a higher level than what is considered safe today.