Doctors' resources for off-label prescribing may be incomplete, unclear

The resources doctors use to get important information about indications and reimbursement for use of cancer drugs off-label may be out-of-date and incomplete, according to a study led by researchers in the Duke Comprehensive Cancer Center.

The study, which was funded by the Agency for Healthcare Research and Quality (AHRQ), examined compendia – the online and hard copy resources that oncologists and pharmacists use when prescribing medications for diseases other than the ones for which they are FDA-approved – and found that they are sometimes unclear and do not appear to follow systematic methods to review or update evidence.

The researchers published their findings in the February 17, 2009 online issue of the journal Annals of Internal Medicine .

"Oncologists and pharmacists use the compendia to guide choice of drugs for cancer patients that are not FDA-approved for use in that patient's disease – an example would be bevacizumab – or Avastin – for brain cancer," said Amy Abernethy, M.D., an oncologist at Duke and lead investigator on the study. "Bevacizumab is approved for use in diseases such as colorectal and lung cancer; it is not FDA-approved for brain tumors, but we have evidence that suggests it could be effective in this population, including peer-reviewed studies."

When a drug is used off label, doctors and pharmacists can refer to the compendia for information on dosage; certain selected compendia can also be used as authoritative sources regarding whether the drug will be covered by Medicare, Abernethy said. Most private insurers also follow suit.

But Abernethy's study found that the compendia often did not include the most updated information on study findings, and there were significant and confusing differences between the way that common compendia presented and updated information. The researchers looked at six compendia determined to be the most commonly utilized, according to a sample of oncology pharmacists and oncologists at Duke and Tufts medical centers.

The compendia varied in many ways, including the off-label indications that were included, what was considered as evidence and the level of detail provided about the agent.

"Our study found that there are some limitations in the way the compendia are currently presented, and there are opportunities to improve the system," Abernethy said. "Determining how to improve it will be the next step for policymakers."

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