Regarding the efficacy of anti-EGFR therapy, the patient with an I326V mutation had progressive disease (+115%) despite no genetic alterations detected in the EGFR pathway that could drive resistance, suggesting an alternate resistance mechanism.
Osimertinib was approved by the US Food & Drug Administration in November 2015 for patients whose tumors exhibited T790M mutation and for those with progressive disease on other EGFR TKIs.
NSCLC patients harboring EGFR T790 M mutations who experienced progressive disease after first EGFR-TKI treatment and started osimertinib treatment between April 2016 and August 2018 were retrospectively screened.
In a subset of patients, we further showed that reappearance of EGFR mutations could be detected in plasma up to 5 months ahead of progressive disease (PD), suggesting an early detection of drug resistance.
Adult patients (age > or = 18 years), with non squamous EGFR mutation, treated with first line palliative therapy, with non progressive disease post 4-6 cycles of pemetrexed-carboplatin were randomized.
Patients received the second epidermal growth factor receptor-tyrosine kinase inhibitor after experiencing an adverse event or progressive disease on the first epidermal growth factor receptor-tyrosine kinase inhibitor.
We compared amphiregulin expression using immunohistochemistry in EGFR wild-type NSCLC patients (n=24) that developed either stable or progressive disease following erlotinib or gefitinib treatment.
However, the levels of the EGFR exon 19 deletion driver mutation and the T790M resistance mutation in the circulating tumor DNA continued to rise and the patient died from progressive disease 6 weeks after commencement of combination therapy.
Eight patients received an EGFR TKI: three cases with G719X plus another mutation had partial responses (PRs) to erlotinib; of three cases with L858R plus another mutation, two displayed PRs and one (with EGFR-L858R+A871G) progressive disease (PD) to erlotinib; one NSCLC with EGFR-L861Q+E709A and one with delL747_T751+R776S had PRs to EGFR TKIs.
In this study, we investigated the efficacy of continuous epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) administration in lung adenocarcinoma patients harboring favorable mutations regarding the progressive disease (PD) status with appearance of indolent new lesions.
EGFRT790M was identified from plasma DNA in 54% (15 of 28) of patients with prior clinical response to gefitinib/erlotinib, 29% (4 of 14) with prior stable disease, and in 0% (0 of 12) that had primary progressive disease or were untreated with gefitinib/erlotinib.
Five of the 13 patients with <i>EGFR</i> mutations were treated with EGFR-TKIs, two of whom manifested a partial response, two stable disease, and one progressive disease.
Patients with EGFR-activating mutations (del19 and L858R) that progressed using first-line gefitinib treatment were enrolled and treated with gefitinib beyond PD plus pemetrexed 500 mg/m<sup>2</sup> q3w.
The EGFR mutations were seen significantly more frequently in patients with a partial response than in patients with stable disease or progressive disease (P = 0.046, Fisher's exact test).
TAM counts were significantly higher in patients with progressive disease than in those without (p < 0.0001), a trend that remained in patients with known EGFR mutation status (n = 59) and those with wild-type EGFR (n = 20).
Awareness of this phenomenon with epidermal growth factor receptor tyrosine kinase inhibitors is important for physicians treating patients with NSCLC, so that it is not misinterpreted as progressive disease resulting in premature cessation of effective therapy.
Actionable EGFR mutations were detected in 24 tissue and 19 ctDNA samples, yielding concordance of 79%, with a shorter time interval between tissue and blood collection associated with increased concordance (P = 0.038). ctDNA sequencing identified eight patients harboring a resistance mutation who developed progressive disease while on targeted therapy, and for whom tissue sequencing was not possible.
We here determined the frequency of T790M acquisition at diagnosis of progressive disease in patients with <i>EGFR</i>-mutated non-small cell lung cancer (NSCLC) treated with afatinib as first-line EGFR-TKI.
Among the 35 patients who were plasma EGFR mutation positive and treated with first generation of EGFR-tyrosine kinase inhibitors (TKIs), 23 (65.7%) achieved partial response, 11 (31.4%) sustained disease, and 1 (2.9%) progressive disease.