As a treatment for relapsed follicular lymphoma (FL) and as part of a combination with rituximab for relapsed chronic lymphocytic leukemia (CLL), idelalisib shows positive results in clinical trials prior to its approval.

A recent study looked at how those clinical trial results compare to actual real-world care of patients with the two conditions.

Results of the study were published in JAMA Oncology, and showed “substantial imbalances” in several areas, including baseline comorbidities between patients who received the treatment during the trials or in the real world on Medicare.

Andrew M. Evens, DO, MSc, director of the Lymphoma Program at the Rutgers Cancer Institute called the study’s findings “interesting, but “not completely surprising.”

“The reason I say not surprising is that we know clinical trials as critically important as they are to understand the safety and efficacy of any particular treatment modality," according to Andrew M. Evens, DO, MSc. "They’re also a little more strict. I would say strict on two sides of an aisle. They’re strict on kind of study participants, and this is done for safety. The other side of the strict aisle is they’re also again for safety very strict on any study, not just this study or this drug, of how you manage adverse events and toxicities and very strict as they should be dose reductions or dose delays or dose modifications.”

The patient population for the study included 26 trial participants and 305 Medicare patients who were treated for FL and 80 trial participants and 294 Medicare patients who received the combination treatment for CLL.

Results showed a “numerically higher mortality rate” and a “significantly higher fatal infection rate” per 100 person-years for CLL. They also noted a “numerically higher” rate for FL when compared to the clinical trial rates.

The researchers wrote that “Immunosuppression-related toxic effects, including infections, may have been somewhat reduced in trials by more frequent dose reductions and exclusion of patients with ongoing infections. Selective eligibility criteria and closer monitoring of trial patients may be responsible for limited generalizability of trial data to clinical practice.”

Results showed “substantial differences” between trial participants at least 65-years-old or older and Medicare beneficiaries. The researchers concluded that their study “supports FDA initiatives to broaden trial eligibility criteria and bridge the gap between clinical studies and the intended treatment population.”

Dr. Evens said he hopes studies like this one are part of a much larger conversation involving not only doctors but also manufacturers and regulators, all with the goal of providing the best possible care of patients.

By Adam Hochron