Efficacy and safety of FOLFIRI/Aflibercept (FA) in an elderly population with metastatic colorectal cancer (mCRC) after the failure of an oxaliplatin-based regimen

Abstract

Introduction: Aflibercept (ziv-aflibercept) significantly improves progression-free (PFS) and overall survival (OS) when added to FOLFIRI, compared with FOLFIRI alone, in the overall population of patients pretreated with oxaliplatin-based therapy. A subset analysis of elderly patients included in the registration VELOUR trial suggested that elderly (> 65 years) patients have a consistent, albeit small benefit in OS in PFS and a higher percentage of grade 3-4 toxicity. Our hypothesis was that selected patients with good PS could benefit from FOLFIRI-aflibercept (FA), provided they underwent careful monitoring of toxicity, and rapid intervention.

Methods: We conducted a retrospective, multicentre, observational study of elderly patients (> 70 years) with mCRC treated with FOLFIRI-aflibercept after progression on an oxaliplatin-based regimen as part of routine clinical practice at seven hospitals from the Galician Research Group on Digestive Tumours (GITuD).

Results: Of 315 patients treated with FA between June 2013 to November 2018, 71 elderly patients were recorded in this study. Median age was 72.7 years (range 70-84 years) and 33.4% were over 75 years (compared with only 14% in the VELOUR study subanalysis), 66.2 % were male, 83.1 % ECOG PS0-1, 43.7 % left-sided location, 76.1 % low grade, 63.4% RASmt and 2.8% BRAFmt, 66.2 % synchronous presentation and 77.5 % primary tumor resection. Prior therapy included bevacizumab (57.7%) and anti-EGFR agents (22.5%). Median of FA cycles was 9 (range 1-35 cycles). Overall Response Rate (ORR) and disease control rate (DCR) were 31.0 % and 63.4 %, respectively. With a median follow up of 27.1 months, median PFS was 6.6 months (95% CI, 5.0-8.3 months) and median OS was 15.1 months (95% CI, 12.1-18.1 months). The most common grade 3-4 toxicities were asthenia (18.3%), neutropenia (15.5%), diarrhoea (11.3%) and mucositis (9.9%). Aflibercept most common grade 3-4 related toxicities were hypertension (5.6%), dysphonia (5.6%), proteinuria (2.8%). Two patients experienced grade 5 toxicity (1 cerebrovascular event and 1 bowel perforation). This toxicity was managed with dose reduction of aflibercept in 39.4 % of cases, dose reduction of FOLFIRI on 57.7% and led to the discontinuation of aflibercept in 39.4%.

Conclusion: Older patients with mCRC are underrepresented in clinical trials. The VELOUR study included only 6.4% patients over 65 years of age and only 14% of those over 65 were 75 years or older. Elderly patients treated with FA in the VELOUR trial experienced a higher rate of G3-4 adverse events (89.3% versus 80.5%) but this increase in toxicity was even more evident in the control arm (67.4% versus 59.4%). Our series confirms that with careful dose adjustment based on toxicity, including dose interruption if necessary elderly patients can be treated with FA with a 49.3% of grade 3-4 toxicity a PFS of 6.6 months and OS of 15.1 months, results that are comparable to those of younger patients.