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Real-life experience with maintenance chemotherapy plus biologics after the first-line treatment of RAS wild-type metastatic colon cancer (mCRC): A multicenter Onco-Colon Turkey study
Background
Randomized clinical trials showed that maintenance chemotherapy plus biologics in patients with mCRC could increase the progression free survival (PFS) without any advantage for overall survival (OS). Our aim was to study the real-life experience (onco-colon registry Turkey) of maintenance chemotherapy with antiEGFR or antiVEGF mAbs after the standart firstline doublet chemotherapy backbone in RAS wild-type mCRC patients.
Methods
This multicenter, retrospective study aimed to evaluate clinicians' attitude and post-induction therapies in patients with RAS wild-type mCRC treated with doublet chemotherapy as a first-line regimen plus anti-EGFR or anti-VEGF who did not experience disease progression within the first 6 months during the first series of therapy. The safety and effectiveness of these strategies were evaluated at 28 centers. Progression-free survival (PFS), overall survival (OS), adverse events, and objective response rate (ORR) were compared in groups receiving anti-EGFR and anti-VEGF-based therapy as first-line therapy.
Results
Among 1065 patients with RAS wild-type mCRC treated with doublet plus anti-EGFR or anti-VEGF as a first-line regimen from January 2016 to March 2019, 665 eligible patients with no progression within the first 6 months were included in the current analysis. The median follow-up was 25 months (6-59) and the median age was 60 (17-85), and 35% of the patients were female. The rate of maintenance therapy was 37.7% in those who received anti-VEGF-based therapy as initial therapy, and 29.2% in patients who received anti-EGFR-based therapy (p=0.036). There was no significant difference between the groups receiving panitumumab and cetuximab in terms of transition to maintenance therapy in the group receiving anti-EGFR treatment, 28.3%, 30.1%, respectively (p=0.685). Of these patients, 151 (22.7%) patients were fluoropyrimidine (5FU/LV /capecitabine) + biologic combination, 42 (6.3%) patients were anti-EGFR or anti-VEGF (single agent), and 18 (2.7%) patients were single-agent fluoropyrimidine (5FU) /LV /capecitabine), and 454 (68.3%) patients continued induction therapy without switching to maintenance therapy until disease progression, unacceptable toxicity, patient judgment, or completion of planned therapy. The median PFS values of the cohorts who continued to receive 5FU/LV + anti-EGFR / VEGF, anti-EGFR/VEGF single agent, 5FU/LV single agent, and combination therapy without maintenance therapy were found as 16.8, 14.3, 15.8, and 11.8 months, respectively (p < 0.001). The median overall survival values of the cohorts were determined as 35.5, 44.5, 38.9 and 28.3 months, respectively (p < 0.001). There was no difference between groups in ORR (p=0.057).
Conclusions
In a “real life” setting, among the treatment strategies following the anti-EGFR/VEGF-based doublet first-line induction regimen in RAS wild-type mCRC patients, the combination of 5FU/LV + biologic as maintenance therapy emerges as the most widely adopted and effective regimen with survival advantage.
Legal entity responsible for the study
The author.
Funding
Amgen.
Disclosures
M. Artac: Honoraria (self): Amgen; Travel / Accommodation / Expenses: Amgen. N. Karadurmus: Honoraria (Institution): Novartis, Roche, MSD. D. Çevik: Full / Part-time employment: Amgen. All other authors have declared no conflicts of interest.
