Kaitlyn K.H. Goey

Maintenance treatment with capecitabine and bevacizumab versus observation in metastatic colorectal cancer: updated results and molecular subgroup analyses of the phase 3 CAIRO3 study

Background The phase 3 CAIRO3 study showed that capecitabine plus bevacizumab (CAP-B) maintenance treatment after six cycles capecitabine, oxaliplatin, and bevacizumab (CAPOX-B) in metastatic colorectal cancer (mCRC) patients is effective, without compromising quality of life. In this post hoc analysis with updated follow-up and data regarding sidedness, we defined subgroups according to RAS/BRAF mutation status and mismatch repair (MMR) status, and investigated their influence on treatment efficacy. Patients and methods A total of 558 patients with previously untreated mCRC and stable disease or better after six cycles CAPOX-B induction treatment were randomised to either CAP-B maintenance treatment (n = 279) or observation (n = 279). Upon first progression, patients were to receive CAPOX-B reintroduction until second progression (PFS2, primary end point). We centrally assessed RAS/BRAF mutation status and MMR status, or used local results if central assessment was not possible. Intention-to-treat stratified Cox models adjusted for baseline covariables were used to examine whether treatment efficacy was modified by RAS/BRAF mutation status. Results RAS, BRAF mutations, and MMR deficiency were detected in 240/420 (58%), 36/381 (9%), and 4/279 (1%) patients, respectively. At a median follow-up of 87 months (IQR 69-97), all mutational subgroups showed significant improvement from maintenance treatment for the primary end point PFS2 [RAS/BRAF wild-type: hazard ratio (HR) 0.57 (95% CI 0.39-0.84); RAS-mutant: HR 0.74 (0.55-0.98); V600EBRAF-mutant: HR 0.28 (0.12-0.64)] and secondary end points, except for the RAS-mutant subgroup regarding overall survival. Adjustment for sidedness instead of primary tumour location yielded comparable results. Although right-sided tumours were associated with inferior prognosis, both patients with right- and left-sided tumours showed significant benefit from maintenance treatment. Conclusions CAP-B maintenance treatment after six cycles CAPOX-B is effective in first-line treatment of mCRC across all mutational subgroups. The benefit of maintenance treatment was most pronounced in patients with RAS/BRAF wild-type and V600EBRAF-mutant tumours. ClinicalTrials.gov number NCT00442637.

Clinicopathological factors influencing outcome in metastatic colorectal cancer patients treated with fluoropyrimidine and bevacizumab maintenance treatment vs observation: an individual patient data meta-analysis of two phase 3 trials

Background:The CAIRO3 and AIO 0207 trials demonstrated the efficacy of fluoropyrimidine plus bevacizumab (FP+Bev) maintenance treatment in metastatic colorectal cancer (mCRC) patients. In this individual patient data meta-analysis with updated follow-up, we aim to provide more precise estimates of treatment effects and to identify subgroups that benefit most from maintenance treatment or observation.Methods:In 871 patients, randomised to FP+Bev maintenance treatment or observation, we investigated whether treatment effect was modified by sex, age, performance status, response to induction treatment, primary tumour location, number of metastatic sites, disease stage and primary tumour resection, serum LDH, platelet count, CEA, and RAS/BRAF mutation status. Primary end point was time to second progression after reintroduction of the induction regimen (PFS2). Secondary end points were first progression-free survival (PFS1) and overall survival (OS).Results:At a median follow-up of 68.5 months (IQR 54.6–87.0 months), maintenance treatment was more effective compared with observation in PFS1 (HR 0.40(95% CI 0.34–0.47)) and PFS2 (HR 0.70(0.60–0.81)). No subgroups were identified that did not benefit from maintenance treatment in PFS1 and PFS2; no clinically relevant subgroup effects were observed. Regarding OS, pooled results were not significant (HR 0.91(0.78–1.05)), and the trials showed marked heterogeneity in overall treatment effect and subgroup effects.Conclusions:FP+Bev maintenance treatment is effective in all patients, regardless of the investigated subgroups.

Prognostic value of primary tumor resection in synchronous metastatic colorectal cancer (mCRC): Individual patient data (IPD) analysis of first-line randomized trials from the ARCAD database.

658 Background: In patients (pts) with mCRC with an asymptomatic primary tumor, there is limited evidence regarding the indication for primary tumor resection. The primary objective was to evaluate the prognostic value of primary tumor resection in synchronous mCRC pts. Methods: In this IPD analysis, a total of 3,423 pts from 8 first-line randomized trials (RCTs) with systemic therapy in the ARCAD (Aide et Recherche en Cancerologie Digestive) database were analyzed. Five RCTs included targeted (anti-VEGF and/or anti-EGFR) agents. Synchronous mCRC was defined as distant metastases occurring ≤ 6 months of the initial CRC diagnosis. Overall survival (OS) and progression-free survival (PFS) were compared by stratified multivariate Cox models. Results: There were 710 (21%), 1,705 (50%) and 1,008 (29%) pts with non-resected and resected synchronous mCRC and metachronous mCRC, respectively. Compared to the non-resection group, pts in the synchronous resection group were associated with female gender, colon tumor...