Integrating comprehensive genomic sequencing of non-small cell lung cancer into a public healthcare system.

OBJECTIVES: Standard molecular testing for patients with stage IV non-small cell lung cancer (NSCLC) in the Canadian publicly funded health system includes single gene testing for EGFR, ALK, and ROS-1. Comprehensive genomic profiling (CGP) may broaden treatment options for patients. This study examined the impact of CGP in a publicly funded health system. METHODS: Consenting patients with stage IV NSCLC without known targetable alterations underwent CGP on diagnostic samples. Patients that had progressed on targeted therapy were also eligible. The CGP assay was a hybrid capture next generation sequencing (NGS) panel (Oncomine Comprehensive Assay Version 3, ThermoFisher). The number of actionable alterations, changes in treatment, clinical trial eligibility and costs as a result of CGP were evaluated and patient willingness-to-pay. RESULTS: Of 182 screened patients,134 (74%) had successful CGP testing. Twenty percent had received prior targeted therapy. Incremental actionable alterations were identified in 31% of patients. The most common novel targets identified were mutations in ERBB2 (exon 20 insertions), MET (exon 14 skipping) and KRAS (G12C). At data cut off (31/12/2020), 16% of patients had a change in treatment as a result of CGP. Additional clinical trial options were identified for 75% of patients. The incremental direct laboratory cost for CGP beyond public reimbursement for single gene tests was $747 CAD/case. CONCLUSION: CGP identifies additional actionable targets beyond single gene tests with a direct impact on patient treatment and increased clinical trial eligibility. These benefits highlight the value of CGP in patients with NSCLC in public health systems.

The presence and variant allele fraction of EGFR mutations in ctDNA and development of resistance.

BACKGROUND: Peripheral blood sampling for detection of EGFR T790M in cell-free circulating tumour (ct) DNA in TKI-resistant EGFR mutant (EGFRm) lung cancer is now standard. The value of more comprehensive sequencing is unknown. METHODS: Prospective ctDNA analysis in patients with EGFRm NSCLC was performed using a next generation sequencing (NGS) panel of regions of 11 genes detecting single nucleotide variants and small insertions/deletions at ≥0.1% variant allele frequency (VAF) was performed. Patients were grouped according to treatment phase, including: (A) pre EGFR-TKI, (B) stable or responding to EGFR-TKI, (C) radiographic progression during EGFR-TKI, and (D) during chemotherapy treatment. RESULTS: Seventy-two patients with stage IV EGFRm NSCLC were enrolled and first blood samples were analysed. Primary sensitizing mutations in del19 or L858R were present in 66 (92%) and uncommon EGFRm in 6 (8%). Mutations in ctDNA were found in 53 samples (74%). T790M was detected in 3 of 4 patients with T790M-negative tissue. Other co-occurring EGFRm were found in 10 patients (7%) including K745R during first-line osimertinib. TP53 (n = 10), KRAS (n = 1), PI3KCA (n = 1) and ALK (n = 3) gene mutations also were detected. The presence of an EGFRm (excluding T790M) was associated with untreated or progressive disease, p = 0.04. In TKI-treated patients without radiologic progression, median progression free survival (PFS) was 10 months versus 2.1 months (HR 2.22, 95% CI: 0.89-5.54, p = 0.08) if an EGFRm in ctDNA was detected. If T790M was present in ctDNA, median PFS was 3.0 months versus 9.7 months (HR 4.59, 95% CI: 1.43-14.73, p = 0.005). High % VAF of both EGFRm and T790M correlated with inferior PFS (p = 0.01 and p = 0.03 respectively). CONCLUSION: In addition to the emergence of resistance mutations, the presence of the primary or co-occurring EGFRm in patients receiving EGFR-TKIs may associate with shorter PFS and may be useful in longitudinal analyses of ctDNA to direct therapy.