Impact of primary tumour side on 3-year survival outcomes of first-line (1L) FOLFOX-4 ± cetuximab in patients with RAS wild-type (wt) metastatic colorectal cancer (mCRC) in the phase III TAILOR trial

Abstract Background The TAILOR trial demonstrated a significant survival advantage with the addition of cetuximab to 1L FOLFOX-4 in patients from China with RAS wt mCRC and met all of its endpoints. We report the impact of primary tumor side on 3-year overall survival (OS) in TAILOR. Methods TAILOR was a randomized, open-label, multicenter, phase 3 trial that evaluated 1L cetuximab + FOLFOX-4 vs FOLFOX-4 in patients from China with RAS wt mCRC. The primary endpoint was progression-free survival time, as determined by independent review committee; secondary endpoints included OS time, ORR, and safety/tolerability. Tumors were categorized in evaluable patients as left (L)-sided (splenic flexure, descending colon, sigmoid colon, and rectum) or right (R)-sided (appendix, cecum, ascending colon, hepatic flexure, and transverse colon). Results Of the 393 treated patients with RAS wt mCRC, median follow-up time was 57.0 months (range, 1.5–75.5), and 391 patients were evaluable for tumor side. Median OS and 3-year OS rates by primary tumor side are summarized in the table. Table . 591P Primary tumor side: L Primary tumor side: R Cetuximab + FOLFOX-4 (n = 146) FOLFOX-4 (n = 162) Cetuximab + FOLFOX-4 (n = 45) FOLFOX-4 (n = 38) Median OS (95% CI), months 22.0 (18.7–25.5) 18.3 (15.2–20.2) 11.5 (7.5–20.4) 9.4 (7.5–18.8) 3-year OS rate (95% CI), % 32 (25–40) 16 (11–22) 23 (11–38) 14 (5–28) Conclusions This updated analysis at > 4.5 years’ median follow-up is consistent with previous results from the TAILOR study, which showed improved OS with the addition of cetuximab to FOLFOX-4. Indeed, the 3-year OS rate was doubled in patients with L-sided mCRC and > 1.5 times higher in those with R-sided disease, showing that patients with mCRC might benefit from treatment with cetuximab irrespective of primary tumor side. Overall, these results confirm cetuximab in combination with FOLFOX-4 as an effective standard-of-care 1L therapy for patients with RAS wt mCRC. Clinical trial identification NCT01228734; EMR62202-057. Editorial acknowledgement Medical writing assistance (funded by Merck Healthcare KGaA, Darmstadt, Germany) was provided by Marjorie Rummelt, PhD, of ClinicalThinking, Inc, Hamilton, NJ, USA. Legal entity responsible for the study Merck Healthcare KGaA. Funding Merck Healthcare KGaA. Disclosure J. Nippgen: Full / Part-time employment: Merck Serono. W. Chen: Full / Part-time employment: Merck Serono. J. Li: Research grant / Funding (institution): Merck; Research grant / Funding (institution): Roche. All other authors have declared no conflicts of interest.