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.     

LS‐106, a novel EGFR inhibitor targeting C797S,exhibits antitumor activities both in vitro and in vivo

With the wide clinical use of the third‐generation epidermal growth factor receptor (EGFR) inhibitor osimertinib for the treatment of EGFR‐mutated non–small cell lung cancer (NSCLC), acquired resistance caused by EGFR C797S tertiary mutation has become a concern. Therefore, fourth‐generation EGFR inhibitors that could overcome this mutation have gained increasing attention in recent years. Here, we identified LS‐106 as a novel EGFR inhibitor against C797S mutation and evaluated its antitumor activity both in vitro and in vivo. In cell‐free assay, LS‐106 potently inhibited the kinase activities of EGFR^{19del/T790M/C797S} and EGFR^{L858R/T790M/C797S} with IC₅₀ values of 2.4 nmol/L and 3.1 nmol/L, respectively, which was more potent than osimertinib. Meanwhile, LS‐106 exhibited comparable kinase inhibitory effect to osimertinib on EGFR^L858R/T790M and wild‐type EGFR. Results from cellular experiments demonstrated that LS‐106 potently blocked the phosphorylation of EGFR C797S triple mutations in the constructed BaF3 cells that highly expressed EGFR^{19del/T790M/C797S} or EGFR^{L858R/T790M/C797S}, and thus inhibited the proliferation of these cells. We also constructed tumor cells harboring EGFR^{19del/T790M/C797S} (named PC‐9‐OR cells) using the CRISPR/Cas9 system and found that LS‐106 markedly suppressed the activation of EGFR^{19del/T790M/C797S} and the proliferation of PC‐9‐OR cells. Moreover, cells harboring EGFR^{19del/T790M/C797S} underwent remarkable apoptosis upon LS‐106 treatment. In vivo experiments further demonstrated that oral administration of LS‐106 caused significant tumor regression in a PC‐9‐OR xenograft model, with a tumor growth inhibition rate (TGI) of 83.5% and 136.6% at doses of 30 and 60 mg/kg, respectively. Taken together, we identified LS‐106 as a novel fourth‐generation EGFR inhibitor against C797S mutation and confirmed its preclinical antitumor effects in C797S–triple‐mutant tumor models.     

Modeling the Cost-Effectiveness of Adjuvant Osimertinib for Patients with Resected EGFR-mutant Non-Small Cell Lung Cancer

IntroductionThe epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor osimertinib was recently approved for resected EGFR-mutant stages IB-IIIA non-small cell lung cancer due to improved disease-free survival (DFS) in this population compared with placebo. This study aimed to evaluate the cost-effectiveness (CE) of this strategy.Materials and MethodsWe constructed a Markov model using post-resection health state transitions with digitized DFS data from the ADAURA trial to compare cost and quality-adjusted life years (QALYs) of 3 years of adjuvant osimertinib versus placebo over a 10-year time horizon. An overall survival (OS) benefit of 5% was assumed. Costs and utility values were derived from Medicare reimbursement data and literature. A CE threshold of 3 times the gross domestic product per capita was used. Sensitivity analyses were performed.ResultsThe incremental cost-effectiveness ratio for adjuvant osimertinib was $317 119 per QALY-gained versus placebo. Initial costs of osimertinib are higher in years 1-3. Costs due to progressive disease (PD) are higher in the placebo group through the first 6.5 years. Average pre-PD, post-PD, and total costs were $2388, $379 047, and $502 937, respectively, in the placebo group, and $505 775, $255 638, and $800 697, respectively, in the osimertinib group. Sensitivity analysis of OS gains reaches CE with an hazard ratio (HR) of 0.70-0.75 benefit of osimertinib over placebo. A 50% discount to osimertinib drug cost yielded an ICER of $115 419.ConclusionsThree-years of adjuvant osimertinib is CE if one is willing to pay $317 119 more per QALY-gained. Considerable OS benefit over placebo or other economic interventions will be needed to reach CE.     

奥希替尼治疗晚期肺腺癌1例并文献复习

分析1例晚期肺腺癌患者应用第1代表皮生长因子受体酪氨酸激酶抑制剂(epidermal growth factor receptor tyrosine kinase inhibitors,EGFR-TKIs)(吉非替尼)治疗耐药后的应用奥希替尼治疗的临床疗效及不良反应。患者应用吉非替尼治疗11个月出现耐药,后给予奥希替尼治疗28个月病情进展,期间未出现严重不良反应。奥希替尼治疗第1代EGFR-TKIs耐药后的晚期肺腺癌患者,临床疗效较好,不良反应少。     

奥希替尼治疗获得性表皮生长因子受体-酪氨酸激酶抑制剂耐药T790M突变肺腺癌晚期1例

报告1例使用奥西替尼治疗表皮生长因子受体(epithelial growth factor receptor,EGFR)基因19外显子缺失突变耐药后T790M突变肺腺癌晚期患者。患者,女,72岁,无明显诱因出现左侧胸闷、气喘5 d于当地医院治疗,查胸部CT示双侧胸腔积液,右肺中叶占位,并纵隔淋巴结肿大。为求进一步治疗遂来郑州大学第一附属医院,入院完善相关检查,PET-CT示右肺中叶软组织肿块代谢较活跃,考虑肺癌,建议结合病理诊断;双侧锁骨上区、纵隔及右肺门多发淋巴结肿大,代谢活跃,考虑转移。不符合手术指征,未进行手术治疗,第1次CT引导下经皮肺穿刺活检确诊肺腺癌,基因检测示EGFR基因第19外显子缺失突变,于2017年11月29日开始服用吉非替尼,至2018年12月4日停止服用。期间复查CT发现右上肺结节较前增大,第2次CT引导下经皮肺穿刺活检结果示肺腺癌,基因检测示EGFR基因18外显子缺失突变,合并EGFR基因第20外显子T790M突变,于2018年12月4日开始服用奥希替尼至今,复查未见异常。