Adjuvant treatment of non-small cell lung cancer: focus on targeted therapy

Integrating immune checkpoint inhibitors and targeted therapies in the treatment of early stage non-small cell lung cancer: a narrative review

Prognosis of early stage non-small cell lung cancer (eNSCLC) is poor even when treated radically with surgery and (neo)adjuvant chemotherapy (Cht). The discovery of tyrosine kinase inhibitors (TKIs) for oncogene addicted NSCLC and immune checkpoint inhibitors (ICIs) have revolutionised the therapeutic paradigm and improved survival of advanced NSCLC. The unprecedented impact of these drugs has shifted the focus of investigation to early stage disease aiming at improving cure. In this context, several single arm phase II studies evaluating neoadjuvant ICI alone or in combination with platinum-based Cht have shown encouraging rates of pathological response which have spurred several ongoing randomized trials with (neo)adjuvant ICI. More recently, ADAURA study evaluating adjuvant osimertinib demonstrated a profound reduction of the risk of recurrence in patients with stage I (>4 cm)-IIIA eNSCLC harbouring EGFR sensitizing mutations. ICIs and TKIs represent a true revolution in the treatment of eNSCLC call to challenge the current standard of care. However, questions regarding drug resistance, recurrence patterns, biomarker identification, optimal treatment duration and sequencing need be answered to effectively integrate new drugs in the rapidly evolving therapeutic landscape of NSCLC. In this review we critically review new developments and future perspectives of TKIs and ICI as (neo)adjuvant strategies for eNSCLC.

EGFR first- and second-generation TKIs-there is still place for them in EGFR-mutant NSCLC patients

Identification of epidermal growth factor receptor (EGFR) as a molecular target has radically changed the treatment of metastatic non-small cell lung cancer (NSCLC) from standard chemotherapy to personalized, targeted therapy. First-, second- and third-generation EGFR tyrosine kinase inhibitors (TKIs) are now available for the treatment of EGFR-mutant NSCLC patients. This review will focus on the clinical development of first- and second-generation EGFR TKIs. We will emphasize on essential points like the head-to-head comparison among EGFR TKIs, their activity on brain metastases, mechanisms of resistance, as well as their combination with anti-angiogenic compounds, other targeted therapies, or immunotherapy. The efficacy of first- and second-generation EGFR TKIs in early-stage EGFR-mutant NSCLC will be also finally reviewed.

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.