Efficacy and Tolerance of First-Line Afatinib in Elderly NSCLC Patients with EGFR Mutations in Vietnam: A Multicenter Real-World Study

Background: Afatinib, a second-generation epidermal growth factor receptor(EGFR) tyrosine kinase, has proven effective for non-small-cell lung cancer (NSCLC) patients with EGFR mutations through randomized controlled trials and real-world studies. Elderly patients exhibit unique characteristics in terms of physical condition and comorbidities, leading to differences in clinical practice for selecting the initial dosage and making dose adjustments compared to younger patients. This study aims to evaluate the effectiveness and adverse effects of first-line Afatinib treatment in elderly patients with NSCLC harboring EGFR mutations in Vietnam in a real-world context.

Methods: We conducted a retrospective analysis of 135 patients, aged 65 years and older, across nine cancer centers in Vietnam. These patients, who harbored drug-sensitive EGFR mutations (excluding de novo T790M), received first-line Afatinib treatment between April 2018 and June 2022. The primary endpoints, time to treatment failure (TTF), and overall survival (OS) were assessed using the Kaplan-Meier method, and comparisons were conducted using the log-rank test. Secondary endpoints included the overall response rate (ORR) according to RECIST 1.1 and adverse effects as classified by CTCAE 4.0.

Results: The median age was 71.2 years (SD ± 5.3). Comorbidities included cardiovascular disease (20.7%), diabetes (5.2%), chronic obstructive pulmonary disease (2.2%), and hepatitis B (0.7%). Common mutations constituted 71.9% of cases, with uncommon mutations representing 28.1%. Brain metastases were observed in 24.4% of patients. Initial treatment doses were 40 mg for 35.6% of patients and 30 mg for 62.2%. With a median follow-up of 34.3 months, the median TTF was 16.3 months (95% CI: 15.4-19.5), and the median OS was 32.9 months (95% CI: 28.9-37.5). Factors associated with decreased OS included poor performance status, current smoking, and the presence of uncommon mutations. The ORR was 77.8%, with a complete response of 11.1% and a disease control rate of 94.1%. The most common toxicities were dermatologic and mucosal, including diarrhea (55.6%), rash (48.9%), and stomatitis (40.7%), predominantly in grades 1 and 2. Initiating treatment at doses below 40 mg significantly reduced most toxicities compared to the 40 mg dose. The presence of brain metastases did not significantly affect ORR, TTF, or OS. Starting treatment at doses below 40 mg significantly lowered the response rate but did not impact TTF or OS.

Conclusion: First-line treatment with Afatinib in elderly patients with NSCLC and EGFR mutations demonstrates significant efficacy and manageable toxicity in a Vietnamese multicenter real-life setting. The effectiveness of Afatinib was confirmed, with known and well-controlled adverse effects, supporting its use in this patient population.