LBA36Randomized phase II study of CAPTEM versus FOLFIRI in RAS mutated, MGMT methylated metastatic colorectal cancer (mCRC): Final analysis, tumour biomarkers and methylated ctDNA

Abstract Background In non-randomized trials, temozolomide (TMZ) has shown activity in about 10% of pts with chemorefractory mCRC bearing MGMT methylation. Methods This multicenter, randomized phase II trial investigated PFS superiority of second-line CAPTEM (Arm A) vs FOLFIRI (arm B) in RAS mutated mCRC pts with MGMT methylation centrally confirmed by MSP. Eligible pts had ECOG PS 0-1, measurable disease, and failed prior oxaliplatin-based therapy. Randomization to arm A (capecitabine 750 mg/sqm b.i.d. days 1-14 plus TMZ 75 mg/sqm b.i.d. days 10-14 q28) or B was stratified according to time elapsed from the start of oxaliplatin-based therapy and PD ( Results A total of 86 pts were randomized (43 per arm). After a median follow-up of 30.5 months (IQR 12.2-36.3), 79 disease PFS events occurred. PFS and OS were 3.5 (2.0-5.0) and 9.5 (8.2-25.8) months in arm A vs 3.5 (2.3-6.1) and 10.6 (8.5-20.8) in arm B (HR = 1.86 [0.82-1.72] and HR = 0.97 [0.58-1.61]), respectively. ORR and DCR were 11.6% and 53.5% in both arms. Grade ≥3 treatment-related adverse events had higher incidence in arm B versus A (47.6% vs 16.3%), and quality of life was significantly worse in arm B. In the subgroup with negative MGMT IHC expression, there were no significant differences between the two arms in terms of activity and efficacy endpoints, whereas in pts with positive MGMT IHC expression CAPTEM regimen was associated with significantly inferior outcomes in terms of PFS (2.0 vs 3.5 mos; HR = 2.08 [1.02-4.21]), OS (5.7 vs 10.6 mos; OR = 1.07 [0.39-2.93]) and DCR (15.4 vs 56.5%; OR = 0.23 [0.04-0.99]), interaction test p = 0.125, 0.732, 0.028. Predicting outcomes with MB was more accurate when using ctDNA vs tumor DNA. Conclusions TMZ-based treatment should be investigated by a phase III trial, ideally conducted in patients with MGMT methylated/MGMT IHC negative tumors. Clinical trial identification NCT02414009. Legal entity responsible for the study Fondazione IRCCS Istituto Nazionale Tumori di Milano. Funding Fondazione IRCCS Istituto Nazionale Tumori di Milano. Disclosure F. Pietrantonio: Honoraria (self), Advisory / Consultancy: Sanofi; Honoraria (self), Advisory / Consultancy: Amgen; Honoraria (self), Advisory / Consultancy: Bayer; Honoraria (self), Advisory / Consultancy: Merck-Serono; Honoraria (self), Advisory / Consultancy: Roche; Honoraria (self), Advisory / Consultancy: Servier. F. Morano: Honoraria (self): Servier Italia SpA . S. Lonardi: Honoraria (self), Advisory / Consultancy: Amgen; Honoraria (self), Advisory / Consultancy: Bayer; Honoraria (self), Advisory / Consultancy: Merk-Serono; Honoraria (self), Advisory / Consultancy: Roche; Honoraria (self), Advisory / Consultancy: Servier; Honoraria (self), Advisory / Consultancy: Bristol-Mayers-Squibb. L. Rimassa: Honoraria (self), Advisory / Consultancy: AstraZeneca; Honoraria (self), Advisory / Consultancy: AbbVie; Honoraria (self), Advisory / Consultancy: Gilead; Honoraria (self), Advisory / Consultancy: Roche; Honoraria (self), Advisory / Consultancy: Lilly; Honoraria (self), Advisory / Consultancy: Bayer; Honoraria (self), Advisory / Consultancy: Sirtex Medical; Honoraria (self), Advisory / Consultancy: Italfarmaco; Honoraria (self), Advisory / Consultancy: Sanofi; Honoraria (self), Advisory / Consultancy: Baxter; Honoraria (self), Advisory / Consultancy: Ipsen; Honoraria (self), Advisory / Consultancy: ArQule; Honoraria (self), Advisory / Consultancy: Xelixis; Honoraria (self), Advisory / Consultancy: Amgen; Honoraria (self), Advisory / Consultancy: Incyte; Honoraria (self), Advisory / Consultancy: Celgene; Honoraria (self), Advisory / Consultancy: Eisai. A. Sartore-Bianchi: Honoraria (self), Advisory / Consultancy: Sanofi; Honoraria (self), Advisory / Consultancy: Amgen; Honoraria (self), Advisory / Consultancy: Bayer; Honoraria (self), Advisory / Consultancy: Merk-Serono; Honoraria (self), Advisory / Consultancy: Roche. M. Di Bartolomeo: Advisory / Consultancy: Lilly; Advisory / Consultancy: Servier; Travel / Accommodation / Expenses: Roche. F.G.M. De Braud: Honoraria (self), Advisory / Consultancy: TizianaLife Sciences; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony: BMS; Honoraria (self), Advisory / Consultancy: Celgene; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony: Novartis; Honoraria (self), Advisory / Consultancy: Servier; Honoraria (self), Advisory / Consultancy: Pharm Research Associated; Honoraria (self), Advisory / Consultancy: Daiichi Sankyo; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony: Ignyta; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony: Amgen; Honoraria (self), Advisory / Consultancy: Pfizer; Honoraria (self), Advisory / Consultancy: Octimet Oncology; Honoraria (self), Advisory / Consultancy: Incyte; Honoraria (self), Advisory / Consultancy: Teofarma; Honoraria (self), Advisory / Consultancy: Pierre Fabre; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony: Roche; Honoraria (self), Advisory / Consultancy: EMD Serono; Speaker Bureau / Expert testimony: Eli Lilly; Speaker Bureau / Expert testimony: AstraZeneca; Speaker Bureau / Expert testimony: Gentili; Speaker Bureau / Expert testimony: Fondazione Menarini. All other authors have declared no conflicts of interest.