Trifluridine/tipiracil (FTD/TPI) in extensively pre-treated metastatic colorectal cancer (mCRC) patients: Evaluation of prognostic subgroups of the TALLISUR study

3556 Background: Compared to placebo, FTD/TPI significantly improved overall survival (OS) in patients (pts) with pre-treated mCRC in the pivotal phase III RECOURSE trial. Subgroup analyses indicated that all subgroups benefitted from FTD/TPI. Of note, FTD/TPI prolonged survival even more in pts ≥ 65 years old. To evaluate these observations with data from daily clinical practice, we performed a subgroup analysis of the TALLISUR study. Methods: In this prospective, multi-center, German, open-label, phase IV study, pts with extensively pre-treated mCRC chose between best supportive care (BSC) or oral FTD/TPI (35 mg/m 2 bid on days 1 – 5 and 8 – 12 of each 28-day cycle). Duration of treatment and OS were analyzed for various subgroups. Based on a post-hoc analysis of the RECOURSE trial, 3 subgroups were defined according to: best, good and poor prognostic characteristics (BPC, GPC, PPC). Pts with < 3 metastatic sites at inclusion and ≥ 18 months from diagnosis to inclusion were considered to have GPC. GPC pts without liver metastasis at inclusion were considered to have BPC. All remaining pts were considered to have PPC. Results: Of 195 eligible pts, 186 pts chose treatment with FTD/TPI, while 9 pts decided to receive BSC only. Median OS was 6.9 (95% CI 6.1 – 8.3) months. Mean duration of treatment with FTD/TPI was 14.6 (range 0.1 – 102.7) weeks. Results of the subgroup analysis are summarized in the table. Pts ≥ 65 years old presented a longer median OS (7.2 vs 6.2 months). Conclusions: When given the choice between treatment and BSC in late-stage CRC, the vast majority of pts opted for treatment. Low metastatic burden and indolent disease were factors of good prognosis for FTD/TPI therapy regarding OS. Independent of baseline characteristics such as age, sidedness, and time of onset of metastases, virtually all pts benefitted from therapy with FTD/TPI. Albeit not statistically significant, elderly pts tend to have improved survival with FTD/TPI, consistent with results from RECOURSE. Clinical trial registration number: EudraCT No 2017-000292-83 . [Table: see text]