Researchers report initial feasibility of identifying patients who are exceptional responders to cancer therapy
A pilot study evaluating identification of cancer patients who respond to treatment that is ineffective in at least 90 percent of patients found that it was indeed able to confirm a majority of proposed patients as exceptional responders based on clinical data submitted for consideration. Being able to identify which patients are actual exceptional responders is an important step in determining why these patients respond so uniquely and will hopefully provide new information about genetic or other molecular factors that could help identify means to predict benefit for patients with similar disease characteristics. The study was designed to see if clinicians nationwide could identify exceptional responder patients who also had available tumor tissue removed before an exceptional response to treatment. Exceptional responder patients are those who achieved a complete response to a treatment that would be expected to occur in 10 percent or less of patients; a partial response to therapy of greater than 6 months that would be expected in 10 percent or less of patients; or a response at least three times the duration expected at the beginning of therapy. Any tumor type or any systemic treatment in adults or children would be eligible for consideration in this study if it met these criteria.
Since September 2014 the study has reviewed over 80 cases based on clinical information and is collecting tissue for analysis. If a clinician believes their patient qualifies as an exceptional responder, they can submit clinical information about the case, without identifiers, to a dedicated email box. If provisionally accepted, tissue from the tumor is then sent to a central tissue repository which determines if the sample meets the trial criteria and where DNA and RNA is extracted and sent for molecular characterization. This initial feasibility assessment included cases identified as of December 2, 2014. Updated information to the end of March 2015 will be presented at the annual meeting of the American Association for Cancer Research (AACR) in Philadelphia on Sunday, April 19, 2015 (‘The NCI exceptional responders initiative: Initial feasibility result’. Barbara A. Conley et al. NCI. Abstract #612). Of the over 80 cases submitted, 46 were provisionally approved and 26 cases were found not to meet the criteria for exceptional responders or were withdrawn; the others were under evaluation. Of those cases that did appear to meet the study criteria, the biopsy specimens came from 41 solid tumors and 5 blood-borne cancers. Approximately three-quarters of the patients had been treated with conventional therapy and about one-quarter had received newer, targeted drugs or combinations of targeted and conventional therapy. Ultimately, the investigators in this pilot study hope to examine samples from over three hundred verified exceptional responders.