Purpose:
Double inhibition of epidermal growth factor receptor (EGFR) using a tyrosine kinase inhibitor plus a monoclonal antibody may be a novel treatment strategy for non–small cell lung cancer (NSCLC). We assessed the efficacy and toxicity of afatinib + cetuximab versus afatinib alone in the first-line treatment of advanced EGFR-mutant NSCLC.
Patients and Methods:
In this phase II, randomized, open-label study, patients with stage III/IV EGFR-positive NSCLC were randomly assigned (1:1) to receive afatinib (group A) or afatinib + cetuximab (group A + C). Oral afatinib 40 mg was given once daily; cetuximab 250 mg/m² was administered intravenously on day 15 of cycle 1, then every 2 weeks at 500 mg/m² for 6 months. The primary endpoint was time to treatment failure (TTF) rate at 9 months. Exploratory analysis of EGFR circulating tumor DNA in plasma was performed.
Results:
Between June 2016 and November 2018, 59 patients were included in group A and 58 in group A + C. The study was ended early after a futility analysis was performed. The percentage of patients without treatment failure at 9 months was similar for both groups (59.3% for group A vs. 64.9% for group A + C), and median TTF was 11.1 (95% CI, 8.5–14.1) and 12.9 (9.2–14.5) months, respectively. Other endpoints, including progression-free survival and overall survival, also showed no improvement with the combination versus afatinib alone. There was a slight numerical increase in grade ≥3 adverse events in group A + C. Allele frequency of the EGFR gene mutation in circulating tumor DNA at baseline was associated with shorter PFS, regardless of the treatment received.
Conclusions:
These results suggest that addition of cetuximab to afatinib does not warrant further investigation in treatment-naïve advanced EGFR-mutant NSCLC.
9079 Background: First-line treatment of metastatic EGFR-mutated NSCLC relies on EGFR-TKIs. However, all patients (pts) eventually develop progression. Dual inhibition of EGFR with afatinib (A), an irreversible pan-erbB TKI, and cetuximab (C), an EGFR monoclonal antibody, has shown activity in EGFR-mutated pts with acquired resistance to TKIs, regardless of the T790M status. Methods: We conducted a phase II randomized trial in advanced NSCLC pts harboring an activating EGFR mutation, who had not received prior therapy. Pts were treated with A (40 mg/d) until progression alone or with C 500 mg/m² every 2 weeks during 6 months (mos) (beginning at D15 at 250 mg/m²). Primary endpoint was time-to-treatment failure (TTF) at 9 mos for pts with del19 and L858R mutations. Secondary endpoints include safety, progression-free survival (PFS), overall survival (OS). Prospective monitoring of the T790M mutation was performed on circulating tumoral DNA (ctDNA) by digital PCR. Results: Trial was stopped early due to futility analysis after 118 pts were enrolled (59 in each arm). Baseline characteristics were balanced between the 2 arms, and especially for the types of EGFR mutation (del19, 55.9 vs 50.8%; L858R, 39 vs 40.7%; others, 5.1 vs 8.5% in AC and A arms, respectively). Treatment-related AEs of any grades were similar, although there was an excess of grade 3 AEs in the AC arm (50 vs 37.3%), but no of grade 5. The excess in grade 3-5 AEs was essentially due to cutaneous (96.6 vs 81.4%), eyes (32.8 vs 27.1%), hematological (22.4 vs 15.3%) but not to digestive toxicities (89.7 vs 98.3%). Among the 117 pts included in the efficacy analysis, 9-months TTF was 63.3% (47.5-75.6) in arm A and 65.8% (50.1-77.66) in arm AC. Median TTF was 11.1 mos (8.3-not reached [NR]) and 10.8 mos (9.2-13.7) in arms A and AC, respectively. Median PFS was 11.1 mos (8.3-NR) and 12.8 mos (9.2-13.7), respectively. Median OS was 20.8 mos (17.5-NR) and NR (17-NR), respectively. Conclusions: Efficacy of AC was similar to that of A alone. These results don’t support further evaluation of this combination in this setting. Results of ctDNA monitoring will be reported during the meeting. Clinical trial information: NCT02716311.
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