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.
A 61-year-old woman with EGFR mutation positive stage IV lung adenocarcinoma was administered 1<sup>st</sup> generation EGFR-TKI for 8 months as the first line therapy, then chemotherapy and 2<sup>nd</sup> generation EGFR-TKI after progressive disease (PD).
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.
Although no melanomas had high-level amplification of BRAF, the two patients with progressive disease as their best response had BRAF copy gain in their tumors.
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.
Plasma beta-arrestin-1 levels were considerably higher in lung cancer patients than in healthy donors and were higher in patients who later experienced a progressive disease than in patients showing complete/partial response following EGFR inhibitor therapy.
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.
Patients with advanced or recurrent HER2-positive gastric adenocarcinoma who were diagnosed with progressive disease after the first-line trastuzumab-based therapy and developed pathologically confirmed adenocarcinoma within 3 months after completion of trastuzumab-based therapy were enrolled in this study.
Exome analysis of patients with progressive disease (PD) revealed 1 CRC with high-level microsatellite instability and 1 instance of HER2 oncogene amplification; 3 of 4 remaining patients with PD had allergic reactions to cetuximab, while none of the subjects with PR or SD had this complication.
The clinical response to EGFR TKIs was reassessed for all patients as follows: 16 of 73 patients had a partial response (21.9%), 12 patients had stable disease (16.5%), and 45 patients had progressive disease (61.6%).
Patients who screened positive for HER1/2 and who did not have progressive disease during chemotherapy (four to eight cycles) were randomly assigned one to one to lapatinib or placebo after completion of first-line/initial chemotherapy for metastatic disease.
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).