Characteristics and outcomes of breast cancer patients enrolled in the National Cancer Institute Cancer Therapy Evaluation Program sponsored phase I clinical trials.

Abstract

Breast cancer (BC) is the most commonly diagnosed cancer and the second leading cause of cancer-related death among women. Given the availability of approved therapies and abundance of phase II and III clinical trials, historically few BC patients have been referred for consideration of participation on a phase I trial. We were interested in determining whether clinical benefit rates differed in patients with BC from other patients enrolled in phase I trials. We performed a retrospective analysis of all Cancer Therapy Evaluation Program (CTEP) sponsored phase I trials from 1993 to 2012. We report an analysis of demographic variables, rates of response to treatment, grade 4 toxicities, and treatment-related deaths. De-identified data from 8087 patients were analyzed, with 1,376 having a diagnosis of BC. The median time from initial cancer diagnosis to enrollment in a CTEP-sponsored phase I clinical trial was 614days for all patients. Breast cancer patients were enrolled on average 790days after initial diagnosis, while non-BC patients had a median enrollment time of 582days (p<0.001). Breast cancer patients had more clinical responses than non-BC patients (18.3% vs. 4.3%, respectively). Along with the higher rate of response, BC patients remained on phase I trials longer than non-BC patients with a median of 70days while the latter were on trial for a median of 57days. The overall rate of death related to the treatment drugs was 0.47%. Our data confirm our hypothesis that when compared to a general population of patients with cancer enrolled on phase I clinical trials, BC patients tend to derive clinical benefit from these therapies with similar toxicity profile. This evidence further supports enrollment of BC patients on phase I trials.