However, experts offer caution in interpreting these study results, which appear in the Oct. 18 issue of The Lancet. They point out several problems with the study that could have led to misleading results as well as the inability to extrapolate these findings to other cancers and clinical situations.
The researchers wanted to test whether treating cancer-related anemia in patients receiving radiation therapy would improve delivery of oxygen to the body and make treatments more effective, but it didn't, lead researcher Michael Henke, MD, tells WebMD. He is vice chairman of radiation oncology at the University of Freiburg in Germany.
Similar Drugs, Different Effects
The drug in the study -- called epoetin beta -- is similar to but not exactly the same as two other drugs used for cancer-related anemia in the U.S. Currently available treatments are Epogen and Procrit -- known generically as epoetin alfa. These drugs work by increasing production of oxygen-carrying red blood cells. Manufacturer Hoffmann-La Roche supplied the drug used in this study.
The researchers found that epoetin beta corrected cancer-related anemia in patients undergoing radiation therapy for mouth and throat cancers. However, it did not improve cancer control or survival.
In fact, Henke says, the drug appeared to worsen cancer control in these patients. Compared with the placebo group, patients receiving epoetin beta were 62% more likely to have progression of their cancer and die.
"These findings are intriguing, concerning, and surprising," Douglas Rizzo, MD, associate professor of hematology/oncology at the Medical College of Wisconsin in Milwaukee, tells WebMD.
But he has some concerns about how the researchers presented their study results. For example, even though about 350 patients were enrolled in the study, results were presented only for about 150 patients because the others were not treated according to study protocol. Rizzo notes that this makes it difficult to fully understand what the study is telling us.
Despite this and other concerns, Rizzo concludes that "I think it's likely or at least possible that these findings are true."
But why would the results of this trial differ from those of previous studies suggesting benefits of drugs for cancer-related anemia beyond its effect on anemia?
Henke cites differences in how earlier studies were done compared with this newer, more powerful study. In addition, many previous studies looked at quality of life rather than survival or cancer control, he says.
Because this study was done exclusively in patients receiving radiation therapy for cancers of the mouth and throat, Rizzo warns against extrapolating these findings to patients receiving chemotherapy or to those with other types of cancer.
Henke says that his study did not address the effect of cancer-related anemia drugs in other settings but he believes that the results would be similar.
Similarly, he says he doubts these findings are specific to the epoetin beta used in this study, referring to a study in the August issue of The Lancet showing a negative effect of epoetin alfa in women with breast cancer. "If epoetin stimulates tumor growth, it shouldn't matter which specific compound you use," Henke says.
How and when should these findings be applied to clinical practice? All experts interviewed by WebMD agreed on the need for additional well-controlled trials as well as for long-term follow-up on patients already receiving epoetin in ongoing studies.
"This alarming, well-performed study and the recent report of a prematurely terminated breast cancer study should alert and give rise to concern to all investigators working in the field of epoetin treatment for cancer-related anemia," Michael Hedenus, MD, head of hematology at County Hospital in Sundsvall, Sweden, tells WebMD.
However, he's not convinced that these findings would be the same for different cancers.
Hedenus has received unrestricted research funds from Roche and has given lectures paid for by Roche and Amgen (maker of Procrit). Roche and Amgen are WebMD sponsors.
"We have to remember that cancers consist of different entities, each with its own biology and responsiveness to different [body chemicals] and hormones," Hedenus says.
Hedenus has performed studies on the effect of epoetin on anemia related to blood cancers and says he is not aware of disease progression or deaths linked to epoetin. On the contrary, he cites his own study and two others suggesting either no effect or an improvement on survival for epoetin compared with placebo.
Studies on epoetin have shown that treatment of cancer-related anemia decreases the need for blood transfusions and improves quality of life, Tim J. Littlewood, MD, hematologist at the John Radcliffe Hospital in Oxford, England, tells WebMD. Littlewood has received consulting and lecture fees from three of the companies that make various forms of epoetin.
"There have also been some very interesting, but unproven, suggestions that [epoetin] treatment might not only have a positive impact on quality of life but also on life expectancy," he says. "There is no reason to change this practice based on this one paper in a group of patients with just one type of tumor."
With reporting by Laurie Barclay, MD.