Real-world use of osimertinib in non-small cell lung cancer: ASTRIS study Korean subgroup analysis

Objective: ASTRIS is a large real-world, open-label, multinational clinical study of osimertinib in patients with epidermal growth factor receptor (EGFR) T790M mutation-positive advanced non-small cell lung cancer (NSCLC) who have previously received a tyrosine kinase inhibitor (TKI). We report data from the Korean ASTRIS subgroup.Methods: Adult patients with locally advanced or metastatic NSCLC with a confirmed T790M mutation, WHO performance status of 0-2 and prior EGFR-TKI therapy, received osimertinib 80 mg once daily. Efficacy outcomes were overall survival (OS), investigator-assessed response rate (RR) and progression-free survival (PFS), and time to treatment discontinuation (TTD).Results: At data cut-off (20 October 2017), 466 Korean patients were enrolled. Baseline EGFR molecular testing was mainly performed on biopsied tissue (75.1%). Baseline mutations co-occurring with T790M included exon 19 deletions (60.7%) and L858R (32.8%). 1-year OS was 82.7% (OS data not matured at data cut-off). Overall, RR was 71.0%, median PFS was 12.4 months and median TTD was 15.0 months. In patients with/without CNS metastases, RR was 68.0% and 79.6%, respectively; median PFS, 10.8 and 11.0 months, respectively; and median TTD, 11.2 and 14.7 months, respectively. Overall, 31.1% of patients experienced ≥1 adverse event (AE), leading to dose modification (12.0%), discontinuation (5.2%) or death (2.8%). Serious AEs (24.9%) included pulmonary embolism (1.7%), pleural effusion (1.7%), and pneumonia (1.5%).Conclusion: In this real-world subgroup analysis of Korean patients in the ASTRIS study, osimertinib demonstrated comparable clinical efficacy to that attained in the global ASTRIS study and other clinical trials, with no new safety concerns.

Integrating Osimertinib in Clinical Practice for Non-Small Cell Lung Cancer Treatment

Treatment of non-small cell lung cancer (NSCLC) is evolving with the use of precision medicine for patients with sensitizing epidermal growth factor receptor (EGFR) mutation. First- and second-generation EGFR tyrosine kinase inhibitors (TKIs) remained the standard of care for patients with EGFR-mutated advanced NSCLC for about a decade. However, treatment resistance eventually develops for most patients who experience initial response to these agents. The most commonly acquired resistance mechanism is the T790M gatekeeper mutation. Poor drug penetration leading to central nervous system (CNS) relapse and dose-limiting toxicities are other concerns. The third-generation EGFR-TKI osimertinib, initially approved as the second-line treatment for patients with T790-mutant NSCLC, demonstrated survival benefits in TKI-naïve EGFR-mutated patients, especially in patients with CNS metastasis. The FLAURA study has shown statistically significant progression-free survival benefit and prolongation of all post-progression outcome endpoints, time to first subsequent therapy, second subsequent therapy, and second progression on subsequent treatment, along with acceptable toxicity and better quality of life outcomes. These data favor osimertinib in the first-line setting for EGFR-mutated NSCLC. This is an important milestone since sequencing the TKI therapy based on accurate prediction of T790M is clinically challenging. In countries like India, T790M testing is not routinely conducted and two-thirds of patients with NSCLC do not receive any second-line therapy. Osimertinib can be administered pragmatically as a first-line therapy. Mature overall survival data from the FLAURA study will be important and could help define the optimal personalized treatment for patients with advanced NSCLC.Funding: AstraZeneca Pharma India Ltd.

Making the first move in EGFR-driven or ALK-driven NSCLC: first-generation or next-generation TKI?

The traditional approach to the treatment of patients with advanced-stage non-small-cell lung carcinoma (NSCLC) harbouring ALK rearrangements or EGFR mutations has been the sequential administration of therapies (sequential treatment approach), in which patients first receive first-generation tyrosine-kinase inhibitors (TKIs), which are eventually replaced by next-generation TKIs and/or chemotherapy upon disease progression, in a decision optionally guided by tumour molecular profiling. In the past few years, this strategy has been challenged by clinical evidence showing improved progression-free survival, improved intracranial disease control and a generally favourable toxicity profile when next-generation EGFR and ALK TKIs are used in the first-line setting. In this Review, we describe the existing preclinical and clinical evidence supporting both treatment strategies - the 'historical' sequential treatment strategy and the use of next-generation TKIs - as frontline therapies and discuss the suitability of both strategies for patients with EGFR-driven or ALK-driven NSCLC.

Efficacy and safety of osimertinib in treating EGFR-mutated advanced NSCLC: A meta-analysis

Osimertinib is the only Food and Drug Administration-approved third-generation epidermal growth factor receptor (EGFR) tyrosine-kinase inhibitor (TKI). A meta-analysis was performed to aggregate the mixed results of published clinical trials to assess the efficacy and safety of osimertinib. A systematic search of the PubMed, Web of Science, and Cochrane Library electronic databases was performed to identify eligible literature. The primary endpoints were overall response rate (ORR), disease control rate (DCR), progression-free survival (PFS), and adverse events (AEs). A total of 3,086 advanced nonsmall cell lung cancer (NSCLC) patients from 11 studies have been identified. The aggregate efficacy parameters for treatment-naïve patients with EGFR-TKI-sensitizing mutations are as follows: ORR 79% (95% CI 75-84%), DCR 97% (95% CI 95-99%), 6-month PFS 83% (95% CI 80-87%), and 12-month PFS 64% (95% CI 59-69%). The aggregate efficacy parameters for advanced NSCLC harboring T790M mutations after earlier-generation EGFR-TKI therapy are as follows: ORR 58% (95% CI 46-71%), DCR 80% (95% CI 63-98%), 6-month PFS 63% (95% CI 58-69%), and 12-month PFS 32% (95% CI 17-47%). EGFR-TKI-naïve patients with EGFR-positive mutations tend to have longer median PFS than EGFR-TKI-pretreated counterparts (19.17 vs. 10.58 months). The most common AEs were diarrhea and rash, of which the pooled incidences were 44 and 42%, respectively. Generally, osimertinib is a favorable treatment option for previously treated T790M mutation-positive advanced NSCLC as well as a preferable therapy for untreated EGFR mutation-positive advanced NSCLC. Additionally, osimertinib is well tolerated by most patients.

Safety of osimertinib in EGFR-mutated non-small cell lung cancer

INTRODUCTION

Osimertinib is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), specifically designed to inhibit EGFR sensitizing and T790M acquired mutations, minimizing exposure in EGFR-wild-type tissues. Areas covered: Osimertinib use in EGFR-mutated non-small cell lung cancer patients is described, focusing on safety and tolerability from studies supporting its approval. Expert opinion: Osimertinib demonstrated greater efficacy, including CNS activity, compared to chemotherapy, with a manageable safety profile in pretreated T790M+ EGFR-mutated patients, leading to FDA approval in 2015 within record time in the oncology field. However, the therapeutic strategy in the EGFR-mutated population is changing, following the FLAURA study in untreated EGFR-mutated patients, in which osimertinib improved progression-free survival compared to other TKIs, with a similar toxicity profile but a lower serious adverse event rate. In April 2018, the FDA and EMA approved osimertinib as first-line therapy for EGFR-mutated patients. Long-term survival data will ultimately establish the true benefit of upfront versus sequential strategies guided by T790M status. These studies favor osimertinib for tolerability and safety, except for the slightly higher rate of interstitial lung disease, but which was nonetheless manageable. In the coming years, osimertinib will be consolidated as standard therapy in the EGFR population and in naïve and pretreated patients, based on mature survival data and the toxicity profile.

Oncogene addicted non-small-cell lung cancer: current standard and hot topics

Lung cancer is the leading cause of cancer mortality worldwide. Activating mutations in the EGFR and rearrangements in the anaplastic lymphoma kinase (ALK) or ROS proto-oncogene 1 receptor tyrosine kinase (ROS1) genes have been identified as oncogenic drivers in non-small-cell lung cancer. Development of specific small-molecule tyrosine kinase inhibitors, able to interfere with tumor growth and metastatic spread, dramatically changed the natural history of oncogene-addicted non-small-cell lung cancer. However, despite advances in targeted therapies, all patients inevitably develop acquired resistance to tyrosine kinase inhibitors. Novel promising and effective treatments are under investigations.

Osimertinib

Epidermal growth factor receptor (EGFR)-mutated (exons 18-21) advanced non-small cell lung cancers (NSCLCs) are generally characterized by exquisite sensitivity to treatment with an EGFR-tyrosine kinase inhibitor (-TKI). First-generation or reversible EGFR-TKIs include gefitinib and erlotinib, while, more recently, second-generation or irreversible EGFR-TKIs have been developed, namely afatinib and dacomitinib, with the aim of overcoming/delaying acquired resistance to treatment. Nevertheless, clinical trials have shown that resistance eventually emerges after a median time of slightly less than one year, regardless of whether first- or second-generation EGFR-TKIs are used. In this context, a secondary EGFR mutation in exon 20, namely T790M, has been found to be responsible for approximately 60% of cases of acquired resistance. Alternatively, T790M resistance mutation can be found de novo, in which case it limits the antitumor activity of both first- or second-generation EGFR-TKIs. Osimertinb is an orally bioavailable, third-generation EGFR-TKI that acts by irreversibly binding both EGFR activating mutations and T790M, while sparing wild-type EGFR. On this basis, osimertinib has proven more efficacious than platinum-based chemotherapy in the setting of EGFR T790M-positive NSCLCs pretreated with a first- or second-generation EGFR-TKI. More recently, in another phase 3 trial, osimertinib outperformed gefitinib or erlotinib as first-line treatment of EGFR-mutated (ex19del or L858R) advanced NSCLCs, thus emerging as a new standard of care in this setting. In the present review, we will discuss the preclinical and clinical development of osimertinib, briefly touching upon its activity in special populations and biomarkers of sensitivity to treatment.

Second-Line Treatment Options in Non-Small-Cell Lung Cancer: Report From an International Experts Panel Meeting of the Italian Association of Thoracic Oncology

Non-small-cell lung cancer (NSCLC) patients inevitably progress to first-line therapy and further active treatments are warranted. In the past few years, new second-line therapies, beyond chemotherapy agents, have become available in clinical practice. To date, several options for the second-line treatment of non-oncogene-addicted NSCLC patients ranging from chemotherapy in combination with antivascular endothelial growth factor receptor to immunotherapeutics are available. In oncogene-driven tumors, the better knowledge of mechanisms of acquired resistance to earlier tyrosine kinase inhibitors is leading to novel active inhibitors now available/in development. The second-line algorithm treatment of NSCLC becomes very intricate and the selection of proper patients with one of the new available therapeutic options is of paramount importance to personalize and optimize the treatment. In this review we discuss the second-line treatment opportunities of addicted as well as not-addicted NSCLC.

Patients with NSCLC may display a low ratio of p.T790M vs. activating EGFR mutations in plasma at disease progression: implications for personalised treatment

Introduction

NSCLC harboring activating mutations of EGFR is highly sensitive to first-line EGFR-tyrosine kinase inhibitors (TKIs), but drug resistance depending on the EGFR mutation p.T790M will occur in about 50-60% of patients. Detailed information on the amount of p.T790M plasmatic level associated with resistance to EGFR-TKIs and guidance to treatment with p.T790M-effective TKI depending on these levels, is lacking.

Methods

This study enrolled p.T790M-positive patients (n=49) affected by EGFR-mutated NSCLC at progression to first-line EGFR-TKIs and, in selected cases (n=5), after second-line treatment with osimertinib. Cell-free circulating tumor DNA (cftDNA) was extracted from plasma and the quantitative analysis of EGFR ex19del, p.L858R and p.T790M was performed by digital droplet PCR.

Results

The mean amount of mutated alleles at progression to first-line EGFR-TKIs was 108,492 copies/ml for ex19del, 97,336 copies/ml for p.L858R, but only 8,754 copies/ml for p.T790M. There was no significant correlation between progression-free survival and the ratio of p.T790M over EGFR activating mutations. The analysis of cftDNA in 5 patients treated with osimertinib revealed a marked decrease of all EGFR mutant alleles.

Conclusions

The amount of p.T790M in plasma can be much lower than activating EGFR mutations. Despite this finding, osimertinib is effective in p.T790M-positive patients. These results indicate that clones driving resistance to EGFR-TKIs represent a minority among cells bearing activating EGFR-mutations. In addition, the identification of a threshold level of p.T790M is not a strict requirement for the selection of patients to be treated with osimertinib, since treatment showed a decrease in all EGFR mutated cells.