Conflict of interest disclosure in off-label oncology clinical trials.

Abstract

6041 Background: Off-label prescribing of anti-cancer targeted therapies is increasingly prevalent. Post-regulatory evidence and reporting requirements for reimbursement for off-label oncologic indications are less stringent than the threshold for United States Food and Drug Administration registration. What are the prevalence, reliability, and predictors of conflict of interest (COI) and funding disclosure statements in published reports of studies of cancer targeted therapies conducted in the post-regulatory setting? Methods: As a part of a federally-funded systematic review, manuscripts were included in the analysis if they were used to support one of 19 indications for cancer targeted therapies that were off-label but reimbursable according to authoritative compendia in 2006 or before. Studies were categorized according to trial design, trial results, average impact factor of journals, and the presence of COI and funding disclosure statements. Results: Sixty-nine studies were included in the systematic review. Prevalence of COI and funding disclosures was low, at 33% and 58%, respectively; time trends showed some improvement between 2002 to 2007, but only 60% of studies had disclosures by 2007. Predictors of COI disclosure were publication in high impact factor journals (p<0.001), large study sample size (p=0.001), enrollment exclusively in the US (p=0.04), and study of the targeted therapy in combination with other agents as opposed to the study drug alone (p=0.03). Studies with multiple sites were more likely to include a funding disclosure statement (p=0.01). Conclusions: There is need for more consistent disclosure of potential sources of bias in COI and funding statements in studies of off-label indications for anti-cancer targeted therapies.