Moreover, early adaptive responses limit the initial efficacy of BRAF inhibition, leading mostly to incomplete responses that may favor the selection of a sub-population of resistant clones and the acquisition of alterations that cause tumor regrowth and progressive disease.
In patients with clinical benefit (progressive disease after 8 weeks), ctDNA testing revealed previously undetected mutations in RAS/BRAF (71%) and EGFR (47%), which often emerged polyclonally.
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.
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.
<b>Methods:</b> Patients with advanced NSCLC, known <i>EGFR</i> mutation and progressive disease on an EGFR TKI immediately prior to enrollment without intervening therapy were enrolled.
This study aimed to analyze the characteristics and outcomes of patients suffering from non-small-cell lung cancer (NSCLC) with epidermal growth factor receptor mutations (EGFRm+) receiving gefitinib who remained clinically stable following confirmation of progressive disease (PD) using Response Evaluation Criteria in Solid Tumors (RECIST) (R-PD) and identify those who benefited from tyrosine kinase inhibitor therapy beyond PD.
The results of this study indicate that in CLL the expression of the p53 protein, analyzed by a simple and reliable immunocytochemical method, is strongly associated with p53 gene mutations, a morphological variant (CLL with >10% prolymphocytes), advanced clinical stage, progressive disease, poor response to therapy, and short survival.
He developed progressive disease in liver 4 months later, and the biopsy of liver metastases showed neuroendocrine carcinoma maintained the same EGFR mutation.
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).
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.
Tumours from 31 patients with metastatic colorectal cancer who had either an objective response (n=10) or stable disease or progressive disease (n=21) after treatment with cetuximab or panitumumab were screened for genetic changes in EGFR or its immediate intracellular effectors.
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).
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.
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.
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.
Traditional RECIST criteria are not suited for proper assessment of response to PD-(L)1 inhibitors; and more tailored criteria (e.g. immune-related response criteria) should be employed for patients treated with PD-(L)1 inhibitors; moreover in patients with an evidence of disease progression on initial disease evaluation, treatment should not be stopped except after confirmation of progressive disease with a second evaluation at least 4 weeks later.
Of 24 patients with actionable mutations, five were given genotype-matched drugs corresponding to actionable mutations: everolimus to PIK3CA mutation in parotid carcinosarcoma (partial response) and tracheal squamous cell carcinoma (stable disease; 21% reduction), sorafenib to PDGFRA mutation in auditory canal adenocarcinoma (partial response), sorafenib to BRAF mutation in microcytic adnexal carcinoma (progressive disease), and afatinib to ERBB2 mutation in esophageal adenocarcinoma (progressive disease).
In two patients with K-RAS mutations pretreatment, posttreatment plasmas were evaluated: a patient with clinical progressive disease retained the mutant DNA, while in a patient with a complete response (CR), the K-RAS mutation was no longer detectable.