Pharmacokinetic drug evaluation of osimertinib for the treatment of non-small cell lung cancer

Introduction: First- and second-generation epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib, erlotinib, icotinib, and afatinib are the standard-of-care for first-line therapy of non-small-cell lung cancer (NSCLC) harboring activating EGFR mutations. Unfortunately, after initial activity of an average 9–13 months, disease progression has been reported in the majority of patients. In about 50% of cases the progression is due to the onset of the T790M mutation in exon 20 of the EGFR gene. Third-generation EGFR-TKIs targeting this mutation were investigated, with osimertinib the only reaching clinical practice.

Areas covered: A structured search of bibliographic databases for peer-reviewed research literature and of main meetings using a focused review question addressing osimertinib, was undertaken.

Expert opinion: Osimertinib is the standard-of-care for EGFR-mutated patients progressing to first-line EGFR-TKIs due to the acquired EGFR T790M mutation. Results from the head-to-head first-line trial comparing osimertinib versus gefitinib or erlotinib in activating EGFR mutations might change the front-line approach. Osimertinib in combination regimens, such as immunotherapy, and in adjuvant setting are ongoing. Thus, the strategic approach for the management of EGFR-mutated NSCLC patients will change further in the next few years.     

Osimertinib for EGFR T790M mutation-positive non-small cell lung cancer

Introduction: Significant advances have been made since the development of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) targeting EGFR mutations in non-small-cell lung cancer (NSCLC), however, lung cancer cells eventually acquire resistance to those agents. Osimertinib (AZD9291) has been developed as 3^rd generation EGFR-TKI with activities against sensitizing mutations and T790 M resistance mutation, which account for about 50% of the mechanisms of acquired resistance to 1^st or 2^nd generation EGFR-TKIs. A recent phase I/II clinical trial with osimertinib for advanced NSCLC patients with known sensitizing EGFR mutations and documented disease progression on prior EGFR-TKIs revealed promising effect with acceptable toxicities.

Areas covered: This article summarizes current understanding and available preclinical and clinical data on osimertinib and also discusses future directions. The literature search included PubMed and the latest articles from international conferences.

Expert commentary: The development of osimertinib has provided new therapeutic options for NSCLC patients harboring T790 M. Compared with other EGFR-TKIs including rociletinib, osimertinib seems to possess an advantage with respect to the effect and safety profile among existing EGFR-TKIs. However, tumor progression still occurs even when treating with osimertinib. A further understanding of the mechanisms of resistance is eagerly anticipated in order to develop next generation EGFR-TKIs.     

The next generation of epidermal growth factor receptor tyrosine kinase inhibitors in the treatment of lung cancer

The discovery of “driver” genomic alterations in patients with non‐small cell lung cancer (NSCLC) has dramatically changed the field of thoracic oncology in recent years. The best understood of these molecular drivers are those involving the epidermal growth factor receptor (EGFR), which when aberrantly activated are integral to the development of a subset of NSCLC tumors. First‐generation and second‐generation tyrosine kinase inhibitors (TKIs) specific to the activated EGFR have shown significant efficacy and have brought about the era of targeted therapy for NSCLC. The most common resistance mechanism is a threonine‐to‐methionine substitution (T790M) in exon 20 of the EGFR gene. Although the previous standard of care in patients with EGFR‐mutated NSCLC that progressed on initial TKI therapy was chemotherapy, third‐generation EGFR TKIs have now been developed and have yielded promising results for this population of patients with NSCLC. This article reviews the emerging data regarding third‐generation agents in the treatment of patients with advanced NSCLC. Cancer 2015;121:E1–E6. © 2014 American Cancer Society.