POSB269 the Use of External Data to Inform Survival Extrapolation in Oncology Technology Appraisals: A Comprehensive Review

As stated in the NICE DSU 21, the use of external data to inform survival extrapolation in health technology assessments (HTA) needs future research. This study provides a review of the use of external data sources to quantitatively inform survival extrapolation in technology appraisals (TAs) and its acceptance by the Evidence Review Group (ERG). A systematic literature review was conducted including all NICE TAs that were published from December 2001 onwards. TA committee papers were screened and considered for full-text review when they (a) related to an oncology treatment and (b) included external data to quantitatively inform survival extrapolation. TAs were excluded when using external data to validate survival extrapolation. The full-text review entailed a comprehensive analysis of the NICE committee papers, specifically the company submission and ERG report. The following information was extracted: type of external data source (clinical trial data, registry data, general population mortality), utilization of external data in the company submission, and criticism and alternative scenarios proposed by the ERG. 529 TAs were screened, of which 28 reported the use of external data to quantitatively inform survival extrapolation. These TAs were in seven disease areas, mostly in melanoma (n=9) and breast cancer (n=7). Twenty-two TAs used historical clinical trial data and fourteen used registry data. Key criticism by the ERG were: external data not representative of trial population, poor adjustment to trial population, non-transparent implementation/execution, utilization of incorrect methods, and clinically implausible extrapolation. Only rarely was external data used to inform survival extrapolation beyond clinical trial observations. Meanwhile, TAs that did use external data to inform survival extrapolation were heavily criticized. It is therefore good practice to ensure that external data is representative of current standard of care and that the approach described in the company submission is transparent and coherent.