Background: Epidermal growth factor receptor (EGFR) mutations are frequently found in non-small cell lung cancer (NSCLC) patients. Various EGFR mutations respond differently to EGFR tyrosine kinase inhibitors (TKIs), and several TKIs have been approved for use on common mutations but none have been approved for EGFR exon 20 insertions, indicating a need for targeted therapy for this subpopulation. A systematic literature review (SLR) and meta-analysis were conducted to synthesize epidemiological and outcome data for the uncommon EGFR exon 20 insertion mutation. Methods: An SLR was performed on August 7, 2018 following the Preferred Reporting Item for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, using the Population, Intervention Comparators, Outcomes and Study Design (PICOS) criteria. Studies were identified based on a systematic search using key biomedical literature databases: EMBASE, MEDLINE, and Cochrane. Relevant congress abstracts published between 2015–2018 were also identified. Two independent reviewers screened all citations and full-text articles using PICOS-based criteria; any discrepancies were resolved by a third independent reviewer. Data were extracted into a predefined template for meta-analysis and summarized using the PRISMA flow diagram. Results: A total of 61 studies reporting the number of EGFR mutation−positive patients and/or NSCLC patients were identified. A meta-analysis found that 3.7% of EGFR mutation−positive patients and 0.8% of NSCLC patients harbored the EGFR exon 20 insertion, with geographic variations in epidemiology. There were 12, 10, and 12 studies, respectively, that reported overall survival, progression-free survival, and overall response rates in 2 cohorts, patients with EGFR exon 20 insertions and patients without EGFR exon 20 mutations. A Most patient populations in these studies included a mixture of treatment at various lines. A meta-analysis of outcomes across these studies showed that patients with EGFR exon 20 insertions experienced worse outcomes compared with those without the mutation (Table 1). Meta-analyses were weighted based on each study’s relevant population. No economic or quality of life studies were identified. Conclusions: Exon 20 insertion mutations represent an important subgroup of EGFR mutations in patients with NSCLC, and current therapies have limited efficacy. These relatively poor outcomes indicate a need for novel treatment strategies.
Victoria Crossland, Aaron Galaznik, Huamao M. Lin, Dimitrios Tomaras, Shan Ashton Garib, Shuanglian Li, Hui Huang and Anna Forsythe
Maral DerSarkissian, Shuanglian Li, Aaron Galaznik, Rachel Bhak, Iryna Bocharova, Thomas Kulalert, Huamao M. Lin, Hui Huang and Mei Sheng Duh
Background: Mutations in the epidermal growth factor receptor (EGFR) gene have been identified in 10%–50% of patients with non-small cell lung cancer (NSCLC). Exon 20 insertion mutations represent about 2%–10% of this group. Reports of real world experience of NSCLC patients with EGFR exon 20 insertion mutations are limited. This study describes patient characteristics, treatment patterns, and survival outcomes of NSCLC patients with EGFR exon 20 insertions based on real world data. Methods: Flatiron Health electronic health record data, largely from community oncology practices, from January 2011–April 2018 were used for this retrospective observational study. Treatment-naïve (TN) and relapsed/refractory (RR) second-line patients diagnosed with NSCLC with EGFR exon 20 insertion mutation aged ≥18 years at treatment initiation were included. Patient characteristics were described, and Kaplan-Meier analyses were used to assess real world overall survival (rwOS) separately for TN (starting at first-line therapy) and RR (starting at second-line therapy) patients. Results: There were 128 TN and 71 RR patients identified. Median age was 66.5 and 65.0 years for TN and RR patients, respectively, and over half were female (TN: 59.4%, RR: 53.5%). Among 83 TN and 47 RR patients with known ECOG score at advanced diagnosis, most had score 0–1 (TN: 56.3%; RR: 62.0%). Central nervous system metastases were observed in 35.2% of TN and 33.8% of RR patients. While 45.3% of TN patients received any chemotherapy, approximately 20% of both TN and RR patient groups had exposure to various EGFR TKIs. Overall, median rwOS was low at 14.6 months for TN patients, and 10.1 months for RR patients. Conclusion: Real world survival of patients with EGFR exon 20 NSCLC remains poor. Treatment with any chemotherapy regimen was most commonly used followed by EGFR TKIs in TN patients, while the proportion treated with chemotherapy and EGFR TKIs was similar in RR patients. Despite limited evidence in this population, over a fifth of TN and RR patients received EGFR TKI monotherapy. This study demonstrated unmet need for improved therapeutic options in TN and RR patients with NSCLC with EGFR exon 20 insertion mutation.