Overcoming Osimertinib Resistance in Advanced Non-small Cell Lung Cancer

Exploring the structural activity relationship of the Osimertinib: A covalent inhibitor of double mutant EGFRL858R/T790M tyrosine kinase for the treatment of Non-Small Cell Lung Cancer (NSCLC)

The USFDA granted regular approval to Osimertinib (AZD9291) on March 2017, for treating individuals with metastatic Non-Small Cell Lung Cancer having EGFR T790M mutation. Clinically, Osimertinib stands at the forefront for the treatment of patients with Non-Small Cell Lung Cancer. Osimertinib forms a covalent bond with the Cys797 residue and predominantly spares binding to WT-EGFR, thereby reducing toxicity and enabling the administration of doses that effectively inhibit T790M. However, a high percentage of patients treated with Osimertinib (AZD9291) developed a tertiary cysteine797 to serine797 (C797S) mutation in the EGFR kinase domain, rendering resistance to it. This comprehensive review sheds light on the chemistry, computational aspects, structural features, and expansive spectrum of biological activities of Osimertinib and its analogues. The in-depth exploration of these facets serves as a valuable resource for medicinal chemists, empowering them to design better Osimertinib analogues. This exhaustive study not only provides insights into improving potency but also emphasizes considerations for mutant selectivity and optimizing pharmacokinetic properties. This review acts as a guiding beacon for the strategic design and development of next-generation Osimertinib analogues.

Real-world study of lazertinib as second-line or greater treatment in advanced non-small cell lung cancer

BACKGROUND

Lazertinib is an oral, third-generation EGFR-TKI, which specifically targets the EGFR T790M mutation along with activating mutations Ex19del and L858R. More real-world data are needed to evaluate its efficacy and safety in treating locally advanced and metastatic non-small cell lung cancer (NSCLC) following prior EGFR TKI treatment.

METHODS

This multicenter retrospective study was conducted at seven university hospitals affiliated to the Catholic Medical Center (CMC) in Korea. A clinical data warehouse (CDW) platform was used to access and extract information.

RESULTS

A total of 48 patients were assessed. The majority were female (75%) and diagnosed with adenocarcinoma (95.8%). All patients had the EGFR mutation at diagnosis, 27 (56.3%) had the exon 19 deletion, 20 (41.7%) had the L858R mutation, and one (2.0%) had the exon 18 mutation. The median progression-free survival (PFS) was 15.4 months. At 6, 12, and 18 months, PFS rates were 79.1%, 53.6%, and 27.3%, respectively. When PFS was analyzed by prior TKI duration (<18 months vs. >18 months), significant differences were noted at the 6 and 9-month mark (p = 0.013 and p = 0.010, respectively). In multivariate analysis for PFS, only prior TKI duration and ECOG score showed statistical significance (p = 0.026 and p = 0.049, respectively). In the multivariate analysis for OS, ECOG score showed statistical significance (p = 0.006). Among 48 patients, 34 (70.8%) experienced adverse events (AEs) related to lazertinib. The most frequent AEs were skin reaction (29.8%), diarrhea (21.3%), and peripheral neuropathy (20.8%).

CONCLUSIONS

The results suggest that lazertinib is effective in second or more line settings, with tolerable safety profile. More patient data are necessary to find possible prognostic markers associated with patient outcome.

The potential therapeutic regimen for overcoming resistance to osimertinib due to rare mutations in NSCLC

The mechanisms of osimertinib resistance have not been well characterized. We conducted next-generation sequencing to recognize novel resistance mechanism and used cell line-derived xenograft (CDX) and patient-derived xenograft (PDX) models to evaluate the anti-proliferative effects of aspirin in vivo and in vitro. We observed that PIK3CG mutations led to acquired resistance to osimertinib in a patient and further confirmed that both PIK3CG and PIK3CA mutations caused osimertinib resistance. Mechanistically, the expression of PI3Kγ or PI3Kα was up-regulated after PIK3CG or PIK3CA lentivirus transfection, respectively, and which can be effectively suppressed by aspirin. Lastly, our results from in vivo studies indicate that aspirin can reverse osimertinib resistance caused by PIK3CG or PIK3CA mutations in both CDX and PDX models. Herein, we first confirmed that mutations in PIK3CG can lead to resistance to osimertinib, and the combined therapy may be a strategy to reverse PIK3CG/PIK3CA mutation-induced osimertinib resistance.

Integration of rapid PCR testing as an adjunct to NGS in diagnostic pathology services within the UK: evidence from a case series of non-squamous, non-small cell lung cancer (NSCLC) patients with follow-up

AIMS

Somatic genetic testing in non-squamous, non-small cell lung carcinoma (NSCLC) patients is required to highlight subgroups eligible for a number of novel oncological therapies. This study aims to determine whether turnaround times for reporting epidermal growth factor receptors (EGFR) by next-generation sequencing (NGS) alone is sufficient to meet the needs of lung cancer patients.

METHODS

We performed a retrospective case series with follow-up. Outcomes of EGFR testing (102 tests) in 96 patients by NGS were compared with a rapid, fully automated PCR-based platform (Idylla) in local histopathology laboratories.

RESULTS

Turnaround time for reporting NGS was 17 calendar days. Reporting using the Idylla EGFR Mutation Test, by contrast, gave a potential turnaround time of 3.8 days from request to authorisation. Three-quarters of patients presenting with stage IV disease had a performance status of 0, 1, or 2 but 18% experienced rapid clinical deterioration (p<0.05). A third of these patients were deceased by the time NGS reports were available.

CONCLUSIONS

We discuss issues around integrating rapid PCR testing alongside NGS in multidisciplinary care pathways and strategies for mitigating against foreseeable difficulties. Dual testing for stage IV non-squamous, NSCLC patients has the potential to improve care and survival outcomes by providing access to the right test at the right time.