Patients with advanced non-small cell lung cancer who harbor targetable mutations achieve substantially better outcomes when treated with matched targeted therapies compared to standard chemotherapy. Between 2020 and 2022 alone, the FDA approved 24 therapies targeting NSCLC-specific genetic variants, creating a rapidly evolving treatment landscape that demands timely and accurate biomarker testing.
Comprehensive genomic profiling using next-generation sequencing detects alterations in hundreds of genes simultaneously from a single tissue sample. Unlike single-gene tests, CGP panels can identify multiple actionable biomarkers at once and can be used retrospectively when new therapies receive guideline endorsement after the original sequencing was performed.
Published adherence rates to guideline-recommended targeted therapy in advanced NSCLC range widely, from 43 to 85.7 percent across different studies, with well-known biomarkers like EGFR and ALK showing higher adherence than newer, more recently approved targets. This variability reflects inconsistency in reporting definitions and unfamiliarity with emerging biomarker data among clinicians.
CGP testing faces a key barrier in commercial insurance payers, who often refuse coverage citing insufficient evidence of clinical utility over smaller gene panels or concern about treatment variability. Yet smaller panels miss a significant proportion of actionable variants, with CGP detecting actionable alterations in 32 percent of patients compared to only 14 percent for smaller panels.
This retrospective cohort study analyzed deidentified records from 1,407 stage IV NSCLC patients who underwent tissue-based sequencing with the Tempus xT CGP assay between 2018 and 2022. The Tempus multimodal database includes data from geographically diverse oncology practices across the United States, including academic institutions, integrated delivery networks, and community practices.
The Tempus xT assay detects single-nucleotide variants, insertions and deletions, copy number variants in 596 to 648 genes, and chromosomal rearrangements in 22 genes. This broad panel allowed the study to capture 15 NCCN-recommended actionable variants paired with 25 matched targeted therapies.
Patients were classified as having targetable variants if they had an NCCN-defined actionable variant and a matched targeted therapy was recommended at the time of their first medication after sequencing. Adherence was defined as receiving that matched targeted therapy. The evolution of NCCN guidelines from 2017 to 2023 was carefully mapped to account for which biomarker-therapy pairs were recommended at each point in time.
Variants for which matched therapy is only recommended in second-line settings, specifically EGFR exon 20 insertions, KRAS G12C, and ERBB2, were classified as targetable only if the patient received medication in second-line or beyond. Patients who had already received targeted therapy before the CGP test were excluded to avoid confounding the adherence measurement.
Among 233 patients with targetable variants who were evaluable for adherence analysis, 201 patients received guideline-recommended matched targeted therapy, yielding an overall adherence rate of 86.3 percent. The median time from CGP sequencing to start of matched targeted therapy was 23 days, reflecting an efficient clinical workflow in this cohort.
Adherent patients had longer real-world overall survival than nonadherent patients among those receiving first-line therapy after sequencing, with a hazard ratio of 0.70 in favor of adherent patients. Median real-world overall survival was not reached within two years of sequencing in adherent patients, while nonadherent patients had a median of 17.2 months.
Importantly, 27 adherent patients had been sequenced before their matched therapy was included in NCCN guidelines. For these patients, the median time from sequencing to therapy start was 304 days, but the median time from NCCN guideline inclusion to start of therapy was only 96 days. This demonstrates that retrospective CGP results can be rapidly leveraged once new guideline recommendations are issued.
Among patients without targetable variants, only 4.9 percent received targeted therapy, a rate significantly lower than in adherent patients, confirming that targeted therapies were being prescribed appropriately based on genomic findings rather than empirically.
Adherence rates varied significantly by specific variant, with 100 percent adherence for EGFR exon 19 deletions and only 47 percent for BRAF V600E mutations. All other variants with at least 10 evaluable patients showed adherence rates of 70 percent or higher, including EGFR L858R at 97 percent, ALK fusions at 85 percent, and KRAS G12C at 80 percent.
A statistically significant negative correlation was found between adherence rate and the recency of NCCN guideline inclusion of matched therapy (Pearson r of -0.65, p=0.02, excluding BRAF V600E as an outlier). This means that biomarkers with newer guideline recommendations had lower adherence rates, reflecting a lag time needed for clinical familiarity to build after new recommendations are issued.
The contrast between EGFR L858R and KRAS G12C illustrates this pattern clearly. EGFR L858R was recommended in guidelines prior to 2018, and patients with this variant received matched therapy in a median of 17 days regardless of when they were sequenced. KRAS G12C was only added to guidelines in June 2021, and patients sequenced before that date received matched therapy within a median of 95 days after guideline inclusion.
BRAF V600E had the lowest adherence despite being in guidelines since 2017, which the authors attribute to the complexity of managing the required combination of dabrafenib plus trametinib, a unique adverse event profile for BRAF-targeting regimens, and guideline allowance of nontargeted systemic therapy as an alternative.
The 86.3 percent adherence rate is among the highest reported in the literature for NSCLC biomarker-matched therapy. The study authors attribute this in part to the use of CGP, which simultaneously identifies all actionable variants from a single sample, compared to sequential single-gene testing that may miss biomarkers or introduce delays.
Guideline timing alone does not explain all adherence variation. Clinical genomic literacy, the ease of interpreting a next-generation sequencing report, the strength of clinical evidence for each matched therapy, and access to testing all influence whether oncologists actually prescribe the recommended treatment once an actionable variant is identified.
The finding that less than 5 percent of patients without targetable variants received targeted therapies addresses a concern raised by some commercial payers: that broad CGP panels would lead to excessive off-guideline prescribing. In this cohort, the data shows that targeted therapies were being prescribed primarily when genomic evidence supported it.
The retrospective real-world design means the reasons for nonadherence were not captured, and confounders including insurance coverage, prior authorization delays, clinical workflow variability, and different electronic medical record environments across diverse oncology practices could not be fully controlled. These factors likely contribute to the 13.7 percent nonadherence rate that remains unexplained.
This is the first real-world study to demonstrate that patients who received CGP results before NCCN guideline inclusion of their matched targeted therapy were able to rapidly access those therapies once the guideline recommendation was issued. This finding underscores the forward-looking value of broad panel testing, which captures biomarkers before their full clinical significance is recognized.
As more targeted therapies receive NCCN endorsement each year, CGP will become increasingly essential not only for initial treatment selection but also for understanding how co-occurring resistance and prognostic variants affect treatment efficacy at both diagnosis and disease progression.
The high adherence rate and fast treatment initiation observed in this study demonstrate that CGP testing is a viable and clinically effective component of precision oncology for advanced NSCLC. Expanding access to CGP, particularly by addressing commercial payer coverage barriers, would allow more patients to benefit from timely matched targeted therapy as the biomarker and drug landscape continues to evolve.