Outcome of phase II oncology clinical trial abstracts presented at annual meeting of the American Society of Clinical Oncology (ASCO)

Abstract

6010 Background: Translation of evidence-based medicine into clinical practice depends on timely and full publication of clinical trials. Previous studies have shown that a substantial number of phase I and III trials presented at the annual meetings of ASCO remain unpublished more than 5 years after presentation. We investigated the outcome of phase II trials presented at ASCO. Methods: We searched for phase II trials using the 1997 ASCO Annual Meeting Proceedings. We excluded trials reporting only preliminary data or interim analyses. The following information were extracted from each study: type of presentation, country of origin, sample size, sponsor, treatment modality, novelty of treatment, and efficacy. A literature search was performed using the Medline and EMBASE databases up until January 2006 for full publications in peer-reviewed journals. If a trial was not found, the authors were contacted by E-mail. Results: We identified 124 phase II trials with 13.7%, 30.6%, and 55.6% presented orally, in poster, and in print, respectively. Most trials were either submitted from countries in North America (50.8%) or Europe (34.7%). Funding came from the pharmaceutical companies (24.2%), governments (20.2%), study institutions (15.3%), private foundations (9.7%), or was not specified (30.6%). The top 5 cancers studied were lung, breast, ovarian, gastric, and sarcoma. Treatment included mostly chemotherapy, either alone (87.1%) or in combination with other modalities (3.2%). To date only 70.2% of the trials have been published. The median time to publication for all abstracts was 23 months. The cumulative rates of publication were 12.9%, 34.7%, 51.6%, 64.5%, and 68.5% at 1, 2, 3, 5, and 7 years, respectively. None of the factors we analyzed, including type of presentation, country of origin, sample size, sponsor, novelty of treatment, and efficacy, influenced the likelihood of or time to publication. Conclusions: About a third of phase II oncology clinical trials initially presented as abstracts at the 1997 ASCO annual meeting have not been published almost a decade later. Similar to phase I and III trials, underreporting of phase II trials is an important problem with serious implications for clinical practice that needs to be addressed. No significant financial relationships to disclose.