Clinical trial results for cancer drugs often not published

(HealthDay)—Although the U.S. Food and Drug Administration Amendments Act requires publication of the results of completed trials of cancer drugs conducted in the United States, results for almost half of the studies have not been made publicly available three years later, according to research published online July 22 in the Journal of Clinical Oncology.

Thi-Anh-Hoa Nguyen, of the Assistance Publique-Hôpitaux de Paris, and colleagues searched an online registry for phase II, III, and IV trials of cancer drugs conducted in the United States that had a primary completion date between Dec. 26, 2007, and May 31, 2010. ClinicalTrials.gov and PubMed were searched to identify published results of these clinical trials.

The researchers found 646 clinical trials of cancer drugs, including 209 randomized controlled trials (RCTs). At one year following completion, the results for 9 percent of the clinical trials were posted online at ClinicalTrials.gov, 12 percent were published in journals, and 20 percent were available via both sources. For RCTs, at one year following completion, the results for 12 percent of the clinical trials were posted online at ClinicalTrials.gov, 5 percent were published in journals, and 17 percent were available via both sources. At three years, for all clinical trials and RCTs, respectively, the results for 31 and 38 percent were posted online at ClinicalTrials.gov, 35 and 32 percent were published in journals, and 55 and 56 percent were available via both sources. For phase III trials, the results were publicly available for 15 percent of the studies at 12 months, 39 percent at 24 months, and 64 percent at 36 months.

"The article describe[s] an incomplete picture of cancer drug reporting that has potentially profound effects on patient management and counseling, as timely and complete dissemination of results can refine patient treatments, outcomes, and safety," write the authors of an accompanying editorial.