Osimertinib therapy as first-line treatment before acquiring T790M mutation: from AURA1 trial

Liquid biopsy for breast cancer and other solid tumors: a review of recent advances

Liquid biopsy using circulating tumor DNA (ctDNA) has been reported to be less invasive and effective for comprehensive genetic analysis of heterogeneous solid tumors, including decision-making for therapeutic strategies, predicting recurrence, and detecting genetic factors related to treatment resistance in various types of cancers. Breast cancer, colorectal cancer, and lung cancer are among the most prevalent malignancies worldwide, and clinical studies of liquid biopsy for these cancers are ongoing. Liquid biopsy has been used as a companion diagnostic tool in clinical settings, and research findings have accumulated, especially in cases of colorectal cancer after curative resection and non-small cell lung cancer (NSCLC) after curative chemoradiotherapy, in which ctDNA detection helps predict eligibility for adjuvant chemotherapy. Liquid biopsy using ctDNA shows promise across a wide range of cancer types, including breast cancer, and its clinical applications are expected to expand further through ongoing research. In this article, studies on liquid biopsy in breast cancer, colorectal cancer, and NSCLC are compared focusing on ctDNA.

Early dose reduction of osimertinib in advanced EGFR -mutated non-small cell lung cancer

Osimertinib has become the standard of care for epidermal growth factor receptor ( EGFR )-mutated non-small cell lung cancer (NSCLC). In order to prevent or treat toxicity, the osimertinib dose may be reduced. However, data regarding the impact of dose reduction during treatment are limited. We aimed to compare the efficacy of osimertinib early dose reduction during the first 3 months of treatment with late dose reduction in EGFR -mutated advanced NSCLC. This retrospective study included patients with EGFR -mutated advanced NSCLC who received osimertinib. We constituted two groups: 'early dose reduction' (early) with patients receiving a reduced dose of osimertinib from 80 to 40 mg within the 3 months of osimertinib initiation and 'late dose reduction' (late) with patients receiving a reduced dose after 3 months of full-dose treatment. Thirty-five patients were included, with 17 and 18 patients in the early and late groups, respectively, and a higher median age in the early group (76 vs. 67 years). The real-world progression-free survival (rwPFS) at 1 year was 70.5% in the early group and 88.9% in the late group ( P  = 0.31). Median rwPFS was 32.7 and 24.6 months ( P  = 0.98), and the median overall survival was 46.9 versus not reached in early and late groups, respectively ( P  = 0.17). Central nervous system rwPFS was not different between the early and late groups: 29.8 and 35.8 months, respectively ( P  = 0.39). We showed that a reduced dose of osimertinib within the first 3 months of treatment, compared to a later reduced dose, could influence treatment response or patient survival.

Real-world efficacy of low dose osimertinib as second-line treatment in patients with epidermal growth factor receptor-mutated advanced non-small cell lung cancer

Background

Response rates of epidermal growth factor receptor (EGFR)-mutated advanced non-small cell lung cancer (NSCLC) to lower doses of osimertinib [20 mg once daily (OD) and 40 mg OD] are similar to those of the recommended dose of 80 mg OD, but there is a lack of real-world evidence on the effect of the lower doses of osimertinib on survival outcomes. We conducted this study to assess the efficacy and safety of lower osimertinib doses for patients with EGFR-mutated advanced NSCLC whose disease had progressed on earlier generation EGFR tyrosine kinase inhibitors (TKIs) in a real-world clinical practice.

Methods

This multicenter, retrospective study included patients with EGFR-mutated advanced NSCLC treated with low doses of osimertinib after failing first- or second-generation EGFR TKIs due to acquired T790M mutation. Data on demographics, staging, treatment history, best overall response rate (ORR) based on RECIST 1.1, and adverse events (AEs) were collected from the patients' case notes. Descriptive data were described in percentages and medians. Progression-free survival (PFS) and overall survival (OS) were calculated using the Kaplan-Meier method.

Results

Of the 22 patients studied [males =8 and females =14; Eastern Cooperative Oncology Group (ECOG) 1 or 2 =7 and ECOG 3 or 4 =15], 45.5% were on 40 mg OD, 31.8% were on 80 mg every other day (EOD), and 22.7% on 40 mg EOD. First-line EGFR TKIs used included afatinib, erlotinib, and gefitinib. The ORR with lower doses of second-line osimertinib was 77.3%. Overall, the median PFS was 10.0 months [95% confidence interval (CI): 8.6-11.4] and median OS was 13.0 months (95% CI: 9.4-16.6). In patients with ECOG 1 or 2, the median PFS was 18.0 months (95% CI: 5.8-30.2) and the median OS was not reached at the time of analysis. In patients with poor ECOG performance status of 3 and 4, good survival outcomes were also seen with a median PFS of 7.0 months (95% CI: 4.7-9.3) and median OS of 10.0 months (95% CI: 7.5-12.5). All AEs except one case of paronychia were Grade 1. There were no Grade 3 or 4 AEs.

Conclusions

Treatment with low dose osimertinib demonstrated good efficacy and tolerability in EGFR-mutated advanced NSCLC patients who failed first-line treatment with first- or second-generation EGFR TKIs due to T790M mutation.

Osimertinib 80 mg EOD? Does this work?

Osimertinib is a third-generation thyroxine kinase inhibitor (TKI) used in treating advanced non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutation. Osimertinib is used as a second line treatment for patients who develop EGFR T790 M resistance mutation rather than first line due to financial constraints. We present a case of a 60-year-old Chinese gentleman who diagnosed as stage 4 adenocarcinoma with EGFR Exon 19 deletion. His disease progressed after a year of treatment with afatinib. His plasma T790 M was negative and due to delay in tissue biopsy, he was empirically started on osimertinib. However, in view of financial concerns, he opted a dose reduction of 80 mg every alternate day rather than the conventional dose of 80 mg daily. Serial CT Thorax showed partial response based on RECIST 1.1 criteria and he has 9 months of progression free survival. This case report shows that Osimertinib in reduced dose may achieve good partial response and progression free survival in patients.