Patients with p53 gene mutations showed chemoresistance (progressive disease of 42.9%, P = .0339) and a relatively poor prognosis after chemotherapy (P = .1391).
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.
Additionally, the presence of BRAFV600E was tested in peripheral mononuclear blood cells (PBMCs) as well as brain biopsies from LCH-ND patients, and the response to BRAF-V600E inhibitor was evaluated in 4 patients with progressive disease.
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.
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.
TP53 mutations were associated with chemoresistance, defined as progressive disease on therapy (p = 0.0358; p = 0.0136 for mutations affecting p53 loop domains L2/L3).
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.
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 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.
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.
The absence of statistically significant correlations between p53 gene mutation and progressive disease, however, does not deny its putative relevance in early phases of tumor development.
Patients with complete or partial remission were compared with those with stable or progressive disease with respect to TP53 genotype and overall survival.
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.
Six had V600E-positive tumours (n=4 had PD; n=1 had SD; n=1 unevaluable for response), and 11 had tumours containing wild-type BRAF (n=9 PD; n=1 SD; n=1 unevaluable for response).
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).
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.