Effect of early dose reduction of osimertinib on efficacy in the first-line treatment for EGFR-mutated non-small cell lung cancer.

Osimertinib is used as the first-line therapy for patients with epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC). However, early dose reduction is often required due to adverse events (AEs). This study aimed to evaluate the effect of early dose reduction of osimertinib on efficacy and safety. This was a retrospective study including patients with EGFR-mutated NSCLC who were started on osimertinib as the first-line therapy between August 2018 and December 2021. Patients whose doses were reduced to less than 80 mg/day within 6 months of osimertinib initiation or started at 40 mg/day were defined as the dose reduction group. The primary endpoint was progression-free survival (PFS). Factors affecting PFS were explored using the Cox proportional hazards model. A total of 85 patients were included in this study. No significant differences in patient characteristics were observed between the dose reduction (n = 25) and standard dose groups (n = 60). The median PFS in the dose reduction group was significantly prolonged compared with that in the standard dose group (26.0 months vs. 12.0 months, p = 0.03). Multivariable analysis of 84 patients, excluding a patient with unknown brain metastasis, revealed that EGFR exon 21 L858R mutation, malignant pleural effusion or pleural metastasis, liver metastasis, and dose reduction within 6 months were independent factors affecting PFS. Early dose reduction of osimertinib is an effective therapeutic strategy for prolonging PFS in patients with EGFR-mutated NSCLC.

Upfront Use of First-/Second-Generation EGFR-TKI Followed by Osimertinib Shows Better Prognosis than Upfront Osimertinib Therapy in Japanese Patients with Non-small-cell Lung Cancer with Exon 19 Deletion: A Single-Center Retrospective Study.

Clinical evidence on the increased efficacy of sequential epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) therapy in patients with EGFR-mutated non-small-cell lung cancer (NSCLC) is limited. This study aimed to compare the efficacy of upfront use of first-/second-generation TKI followed by osimertinib with upfront osimertinib therapy for each representative EGFR mutation in Japanese patients with NSCLC. Patients with EGFR-mutated NSCLC were classified into two groups: first-/second-generation TKI followed by osimertinib (sequential TKI group) and upfront osimertinib groups. The total time to treatment failure (TTF) of TKI therapies, progression-free survival (PFS), and overall survival (OS) were retrospectively evaluated. Of the 74 patients included in the analysis, 38 and 34 patients had exon 19 deletion and L858R, respectively, and other two patients had minor mutations. The sequential TKI group had a significantly longer TTF than the upfront osimertinib group in overall patients (33.2 vs. 11.2 months; p = 0.007) and in the subgroup of exon 19 deletion (36.7 vs. 10.0 months; p = 0.004), but not in the subgroup of L858R (22.6 vs. 15.6 months; p = 0.37). The similar tendency was observed in PFS. OS of the sequential TKI group was significantly longer compared with the upfront osimertinib group in overall patients, the subgroup of exon 19 deletion, and the subgroup of L858R. The upfront use of first-/second-generation TKI followed by osimertinib is one of the feasible and effective strategies in Japanese patients with EGFR-mutated NSCLC, especially in patients with exon 19 deletion.

Association of STAT3, CYP3A5, and ABCG2 Polymorphisms With Osimertinib-induced Adverse Events in NSCLC Patients.

BACKGROUND/AIM: Osimertinib is a key drug for treating epidermal growth factor receptor (EGFR) mutation-positive non-small cell lung cancer (NSCLC). Genetic differences may be associated to adverse events (AEs) induced by osimertinib. This retrospective observational multicenter study evaluated the association of genotypes, including STAT3 -1697C>G, CYP3A5 6986A>G, and ABCG2 421C>A, with the incidence of osimertinib-induced AEs in patients with EGFR mutation-positive NSCLC. PATIENTS AND METHODS: A total of 85 patients treated with osimertinib (Institution A: 33 patients, Institution B: 52 patients) were enrolled in the study. Single nucleotide polymorphisms were determined by real-time PCR, and the incidence of AEs was compared for each genotype. RESULTS: Paronychia incidence was 59% for the CC genotype, 19% for the CG genotype, and 19% for the GG genotype at STAT3 -1697C>G. A genotype-related trend was observed (Cochran-Armitage test, p=0.009). Multivariate analysis showed that the CC genotype at STAT3 -1697C>G and female sex were significant independent factors associated with paronychia [odds ratio (OR)=6.41, 95% confidence interval (CI)=1.94-21.20 and OR=3.40, 95%CI=1.03-11.22, respectively]. The incidence of diarrhea was 53% for the CC genotype, 30% for the AC genotype, and 29% for the AA genotype at ABCG2 421C>A, and a genotype-related trend was observed (p=0.048). However, the CC genotype at ABCG2 421C>A was not a significant independent factor associated with diarrhea in multivariate analysis. No significant associations were detected between other polymorphisms and the incidence of AEs. CONCLUSION: STAT3 -1697C>G may be a novel risk factor for osimertinib-induced paronychia in patients with NSCLC.