The FOxTROT platform: Clinical trials and exploratory research for personalization of neoadjuvant (NA) therapy in locally advanced colon cancer (LACC)—ISRCTN83842641.

Abstract

TPS3636 Background: The FOxTROT1 trial demonstrated a significant reduction in 2-year (yr) recurrence with 6 weeks (wks) of oxaliplatin and fluoropyrimidine (OxFp) NA chemotherapy (NAC) in patients (pts) with LACC, establishing NAC as a new therapeutic option. The ongoing FOxTROT platform will refine and personalize NA therapy in LACC. FOxTROT2 is testing NAC in older pts and those with frailty, who are poorly represented in clinical trials. FOxTROT3 is assessing intensified NAC with modified FOLFOXIRI (mFOLFOXIRI; 5-fluorouracil, oxaliplatin, irinotecan) in fit pts. The FOxTROT platform will also test targeted treatments with established safety and efficacy in defined molecular subgroups. FOxTROT4 is investigating the efficacy and safety of NA encorafenib and cetuximab in BRAF-mutant pMMR LACC. Other arms in setup are shown in Table. Methods: FOxTROT platform trials are international, multicenter, open-label, phase II/III RCTs. Pts with resectable, cT3-4 N0-2 M0, biopsy-proven colon adenocarcinoma are eligible for recruitment. Pts whose age or frailty precludes mFOLFOXIRI can be considered for FOxTROT2. Pts suitable for mFOLFOXIRI can be considered for FOxTROT3. BRAF-mutant pMMR pts can be considered for FOxTROT4. Pts are randomized 2:1 between intervention and control arms. FOxTROT2 randomizes between 6 wks OxFp NAC (choice of 100% or 80% dose) vs proceeding straight to surgery. Adjuvant chemotherapy (AC) is per physician choice. Primary outcome is 3-yr DFS. 759 pts will be recruited over 5 yrs. FOxTROT3: 6 wks mFOLFOXIRI NAC vs 6 wks OxFp NAC. All pts receive AC but physicians may de-escalate mFOLFOXIRI to OxFp. Hierarchical co-primary endpoints: tumor regression grade (TRG) (blinded central assessment) and 3-yr DFS. 873 pts over 5 yrs. FOxTROT4: 6 wks NA encorafenib and cetuximab vs 6 wks OxFp NAC. AC is per physician choice. Primary outcome: TRG. 45 pts over 3 yrs. Secondary outcomes include: histopathological endpoints, downstaging, minimal residual disease by ctDNA, safety, toxicity, OS, surgical outcomes and patient-reported outcomes; and DFS in FOxTROT4. The FOxTROT platform opened 7th Feb 2022, funded by Yorkshire Cancer Research. At submission, 50 pts had been randomized at 23 centers. Trial design and management is conducted in partnership with patient representatives. A program of translational and radiomics research is running in parallel. International recruitment in France and India will commence in 2023 with additional international partners joining from 2024. Clinical trial information: ISRCTN83842641 . [Table: see text]