The National Comprehensive Cancer Network estimates that 50 – 75 percent of all uses of cancer therapy are off-label. Yet the Centers for Medicare and Medicaid services limit coverage of cancer drugs for off-label indications to those indications listed in specified compendia (a comprehensive listing of drugs, their clinical properties, and recommended uses).
The authors of a new study entitled, "Reliability of Compendia Methods for Off-Label Oncology Indications" argue that the current methods for reviewing and updating evidence for compendia are seriously lacking. This study appears in the Annals of Internal Medicine.
In 2006, researchers analyzed six drug compendia's stated methods, conducted their own search of the literature related to 14 off-label indications, and measured the completeness of compendia content and citations. They found that the compendia's stated methods varied greatly from their actual practices. Of the available evidence that the authors found in their own review, very little was cited by the authors of the compendia, and what was presented was often neither the most recent nor that of highest methodological quality. According to the study, compendia also lacked consistency. They differed from each other in indications listed, evidence cited, terminology, detail, and presentation. For the 14 off-label indications studied, the compendia varied in which indications they listed and whether and how they recommended particular agents for particular types of cancer.
"Cited evidence was scanty and inconsistent across compendia, which raises questions about the process by which evidence is identified and selected to generate recommendations," said lead author, Amy P. Abernethy, M.D., Director of the Duke Cancer Care Research Program. "In addition, the evidence included in the compendia we evaluated did not seem to be updated in a timely, regular, and explicit manner."
In 2008, the researchers updated the systematic review of one of the indications in order to determine whether new information had any influence on improving the compendia's methods. Their review identified an additional 25 reports published between 2006 and 2007. In this same period, one compendium increased from three to 11 citations, whereas the others had little or no change. According to the researchers, this finding casts doubt on the compendia's adherence to other stated policies. Researchers note that it is not known if updated information would have changed recommendations.
The authors suggest that evaluation of compendia should consider not only the volume of available evidence that they encompass but also their consistency, quality, transparency, and timeliness. This study will appear online at http://www.annals.org with a perspective piece and an editorial on the same topic.
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