Because those early trials will eventually help regulators decide if drugs should be approved for a wider population, it's important that test patients be representative of people the medications are designed to treat, researchers said.

In addition, "There is an ethical issue of access to trials, because in general (for these patients), the standard therapeutic options have been exhausted," said James Spicer from King's College London and Guy's Hospital, who worked on the study.

By definition, there is no way to know whether an experimental drug will benefit patients.

Still, "These are life-limited people with advanced cancer and many of these patients would dearly like to have access to experimental therapies," he told Reuters Health - in part to feel like they're contributing to research that will help future patients.

Spicer's team said poorer patients may have more chronic diseases that exclude them based on trial requirements, or inequalities in education and access to care could keep them from getting into a study.

The researchers looked back at data on 430 people with cancer referred to early drug studies at Guy's Hospital in London between 2007 and early 2012. Then they compared those people to more than 10,000 Londoners with a new diagnosis of cancer in 2010.

Spicer and his colleagues rated people's socioeconomic status on a 5-point scale based on postal codes and census data on neighborhood income, education and crime.

The poorest patients, the research team found, were 47 percent less likely to be referred to the center for a cancer drug trial than the wealthiest.

"I'm not surprised, in the sense that we know there are barriers that exist for not just early phase, but for clinical trials in general," said Dr. Lillian Siu, from the drug development program at Princess Margaret Hospital in Toronto, Canada.

"In many ways, socioeconomic status is an understandable barrier because patients obviously don't get the care they probably should get because they're not able to afford, for example, travelling to the cancer center," Siu, who has studied clinical trial enrollment but wasn't involved in the new study, told Reuters Health.

LOGISTICS PLAYS A ROLE

Older cancer patients were also less likely than younger ones to be referred for clinical trials, according to the report.

Once people were referred to trial researchers, they were equally likely to be enrolled in a study - regardless of socioeconomic status and age - Spicer's team reported Monday in the Journal of Clinical Oncology.

"It does suggest that there is an issue earlier than that, of patients getting from the community to the trials clinic for consideration in the first place," Spicer said.

"It may be perfectly justified by things like comorbidities, or it may be that there's some unconscious discrimination by referrers."

Siu said making sure all advanced cancer patients are aware of clinical trial opportunities, as well as helping worse-off ones find ways to participate, should improve some of these disparities.

As an example, she said in her region there are volunteer drivers who help transport patients back and forth from their visits to the large cancer centers were trials are conducted.

"The biggest barrier to clinical trial recruitment usually isn't because the patients aren't willing, it's because first of all they aren't even offered," she said.

SOURCE: bit.ly/11NIor8 Journal of Clinical Oncology, online December 3, 2012.

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