Tumor mutational burden (TMB) in circulating tumor DNA (ctDNA) has shown promise in predicting benefit from PD-L1/PD-1 inhibitors in retrospective studies. Aiming to assess blood TMB (bTMB) prospectively, we conducted B-F1RST (NCT02848651), an open-label, phase 2 trial that evaluated bTMB as a predictive biomarker for first-line atezolizumab monotherapy in locally advanced or metastatic stage IIIB–IVB non-small cell lung cancer (n = 152). The co-primary endpoints were investigator-assessed objective response rate (ORR) per RECIST version 1.1 and investigator-assessed progression-free survival (PFS) between high and low bTMB subgroups at the pre-defined bTMB ≥ 16 (14.5 mutations per megabase) cutoff. Secondary endpoints included investigator-assessed PFS, overall survival (OS) and duration of response at various bTMB cutoffs, as well as safety. Investigator-assessed PFS in the bTMB ≥ 16 versus bTMB < 16 groups was not statistically significant. However, bTMB ≥ 16 was associated with higher ORR, and ORR improved as bTMB cutoffs increased. No new safety signals were seen. In exploratory analyses, patients with maximum somatic allele frequency (MSAF) < 1% had higher ORR than patients with MSAF ≥ 1%. However, further analysis showed that this effect was driven by better baseline prognostics rather than by MSAF itself. At 36.5-month follow-up, an exploratory analysis of OS found that bTMB ≥ 16 was associated with longer OS than bTMB < 16. Further study and assay optimization will be required to develop bTMB as a predictive, standalone biomarker of immunotherapy or for use in conjunction with other biomarkers.

Purpose: Patients with KRAS-mutant non–small cell lung cancer (NSCLC) with brain metastases (BM) have a poor prognosis. Adagrasib (MRTX849), a potent oral small-molecule KRASG12C inhibitor, irreversibly and selectively binds KRASG12C, locking it in its inactive state. Adagrasib has been optimized for favorable pharmacokinetic properties, including long half-life (∼24 hours), extensive tissue distribution, dose-dependent pharmacokinetics, and central nervous system penetration; however, BM-specific antitumor activity of KRASG12C inhibitors remains to be fully characterized. Experimental Design: A retrospective database query identified patients with KRAS-mutant NSCLC to understand their propensity to develop BM. Preclinical studies assessed physiochemical and pharmacokinetic properties of adagrasib. Mice bearing intracranial KRASG12C-mutant NSCLC xenografts (LU99-Luc/H23-Luc/LU65-Luc) were treated with clinically relevant adagrasib doses, and levels of adagrasib in plasma, cerebrospinal fluid (CSF), and brain were determined along with antitumor activity. Preliminary clinical data were collected from 2 patients with NSCLC with untreated BM who had received adagrasib 600 mg twice daily in the phase Ib cohort of the KRYSTAL-1 trial; CSF was collected, adagrasib concentrations measured, and antitumor activity in BM evaluated. Results: Patients with KRAS-mutant NSCLC demonstrated high propensity to develop BM (≥40%). Adagrasib penetrated into CSF and demonstrated tumor regression and extended survival in multiple preclinical BM models. In 2 patients with NSCLC and untreated BM, CSF concentrations of adagrasib measured above the target cellular IC50. Both patients demonstrated corresponding BM regression, supporting potential clinical activity of adagrasib in the brain. Conclusions: These data support further development of adagrasib in patients with KRASG12C-mutant NSCLC with untreated BM. See related commentary by Kommalapati and Mansfield, p. 3179

Non–small lung cancers (NSCLC) frequently (∼30%) harbor KRAS driver mutations, half of which are KRASG12C. KRAS-mutant NSCLC with comutated STK11 and/or KEAP1 is particularly refractory to conventional, targeted, and immune therapy. Development of KRASG12C inhibitors (G12Ci) provided a major therapeutic advance, but resistance still limits their efficacy. To identify genes whose deletion augments efficacy of the G12Cis adagrasib (MRTX-849) or adagrasib plus TNO155 (SHP2i), we performed genome-wide CRISPR/Cas9 screens on KRAS/STK11-mutant NSCLC lines. Recurrent, potentially targetable, synthetic lethal (SL) genes were identified, including serine–threonine kinases, tRNA-modifying and proteoglycan synthesis enzymes, and YAP/TAZ/TEAD pathway components. Several SL genes were confirmed by siRNA/shRNA experiments, and the YAP/TAZ/TEAD pathway was extensively validated in vitro and in mice. Mechanistic studies showed that G12Ci treatment induced gene expression of RHO paralogs and activators, increased RHOA activation, and evoked ROCK-dependent nuclear translocation of YAP. Mice and patients with acquired G12Ci- or G12Ci/SHP2i-resistant tumors showed strong overlap with SL pathways, arguing for the relevance of the screen results. These findings provide a landscape of potential targets for future combination strategies, some of which can be tested rapidly in the clinic. Significance: Identification of synthetic lethal genes with KRASG12C using genome-wide CRISPR/Cas9 screening and credentialing of the ability of TEAD inhibition to enhance KRASG12C efficacy provides a roadmap for combination strategies. See related commentary by Johnson and Haigis, p. 4005

Effective therapy for non–small-cell lung cancer (NSCLC) depends on morphological and genomic classification, with comprehensive screening for guideline-recommended biomarkers critical to guide treatment. Companion diagnostics, which provide robust genotyping results, represent an important component of personalized oncology. We evaluated the clinical validity of Guardant360 CDx as a companion diagnostic for sotorasib for detection of KRAS p.G12C, an important oncogenic NSCLC driver mutation. KRAS p.G12C was tested in NSCLC patients from CodeBreaK100 (NCT03600833) in pretreatment plasma samples using Guardant360 CDx liquid biopsy and archival tissue samples using therascreen^® KRAS RGQ polymerase chain reaction (PCR) kit tissue testing. Matched tissue and plasma samples were procured from other clinical trials or commercial vendors, and results were compared. Demographics and clinical characteristics and objective response rate (ORR) were evaluated. Of 126 CodeBreaK patients, 112 (88.9%) were tested for KRAS p.G12C mutations with Guardant360 CDx. Among 189 patients in the extended analysis cohort, the positive and negative percent agreement (95% CI) for Guardant360 CDx plasma testing relative to therascreen^® KRAS RGQ PCR kit tissue testing were 0.71 (0.62, 0.79) and 1.00 (0.95, 1.00), respectively; overall percent agreement (95% CI) was 0.82 (0.76, 0.87). TP53 co-mutations were the most common regardless of KRAS p.G12C status (KRAS p.G12C–positive, 53.4%; KRAS p. G12C–negative, 45.5%). STK11 was co-mutated in 26.1% of KRAS p.G12C–positive samples. The ORR was similar among patients selected by plasma and tissue testing. Comprehensive genotyping for all therapeutic targets including KRAS p.G12C is critical for management of NSCLC. Liquid biopsy using Guardant360 CDx has clinical validity for identification of patients with KRAS p.G12C–mutant NSCLC and, augmented by tissue testing methodologies as outlined on the approved product label, will identify patients for treatment with sotorasib.

Aim: To determine real-world outcomes with first-line pembrolizumab monotherapy for metastatic non-small-cell lung cancer with PD-L1 tumor expression ≥50%. Methods: This retrospective study include... Lay abstract This study analyzed electronic health record data to determine outcomes for patients who received first-line pembrolizumab monotherapy for metastatic non-small-cell lung cancer. These ...

Purpose: The tumor-associated vasculature (TAV) differs from healthy blood vessels by its convolutedness, leakiness, and chaotic architecture, and these attributes facilitate the creation of a treatment-resistant tumor microenvironment. Measurable differences in these attributes might also help stratify patients by likely benefit of systemic therapy (e.g., chemotherapy). In this work, we present a new category of computational image-based biomarkers called quantitative tumor-associated vasculature (QuanTAV) features, and demonstrate their ability to predict response and survival across multiple cancer types, imaging modalities, and treatment regimens involving chemotherapy. Experimental Design: We isolated tumor vasculature and extracted mathematical measurements of twistedness and organization from routine pretreatment radiology (CT or contrast-enhanced MRI) of a total of 558 patients, who received one of four first-line chemotherapy-based therapeutic intervention strategies for breast (n = 371) or non–small cell lung cancer (NSCLC, n = 187). Results: Across four chemotherapy-based treatment strategies, classifiers of QuanTAV measurements significantly (P < 0.05) predicted response in held out testing cohorts alone (AUC = 0.63–0.71) and increased AUC by 0.06–0.12 when added to models of significant clinical variables alone. Similarly, we derived QuanTAV risk scores that were prognostic of recurrence-free survival in treatment cohorts who received surgery following chemotherapy for breast cancer [P = 0.0022; HR = 1.25; 95% confidence interval (CI), 1.08–1.44; concordance index (C-index) = 0.66] and chemoradiation for NSCLC (P = 0.039; HR = 1.28; 95% CI, 1.01–1.62; C-index = 0.66). From vessel-based risk scores, we further derived categorical QuanTAV high/low risk groups that were independently prognostic among all treatment groups, including patients with NSCLC who received chemotherapy only (P = 0.034; HR = 2.29; 95% CI, 1.07–4.94; C-index = 0.62). QuanTAV response and risk scores were independent of clinicopathologic risk factors and matched or exceeded models of clinical variables including posttreatment response. Conclusions: Across these domains, we observed an association of vascular morphology on CT and MRI—as captured by metrics of vessel curvature, torsion, and organizational heterogeneity—and treatment outcome. Our findings suggest the potential of shape and structure of the TAV in developing prognostic and predictive biomarkers for multiple cancers and different treatment strategies.