Effects of Concurrent Administration of Spironolactone in Veterans with Metastatic Prostate Cancer Receiving Abiraterone: A Real-World Retrospective Study.

INTRODUCTION: Prostate cancer is the most common cancer in men in the United States with low survival rates once metastasized. Abiraterone is approved for use in castrate-sensitive and castrate-resistant prostate cancer and is used extensively in the Veterans Affairs (VA) healthcare system. Spironolactone, a diuretic used to treat heart failure, edema, ascites, and hypertension, may increase androgen levels and reduce effectiveness of abiraterone when used concurrently to treat prostate cancer patients. While previous case studies support this, no large epidemiology studies have been conducted. The current study utilizes the large, VA prostate cancer data core and evaluates the effect of concomitant spironolactone on efficacy of abiraterone treatment in metastatic prostate cancer patients. PATIENTS AND METHODS: The study selected 18,943 veterans with metastatic prostate cancer on abiraterone treatment. Of these, 581 patients (3.1%) were also on concomitant spironolactone. The concomitant treatment group, abiraterone + spironolactone, significantly differed from the abiraterone-only group in body mass index, prevalence rates of heart failure and liver disease, and being previously treated with docetaxel. A 1:1 propensity score matching method was used to balance sample sizes and baseline traits between the two treatment groups, abiraterone versus abiraterone + spironolactone. Kaplan-Meier curves and Cox proportional hazard model were used to compare 5-year overall survival and all-cause mortality outcomes, respectively, between the two groups. RESULTS: After propensity score matched, the abiraterone + spironolactone group was treated with abiraterone significantly longer than the abiraterone-only group (mean ± standard deviation days 549.0 ± 552.3 vs. 435.5 ± 474.1; p = 0.0002) and had a higher 5-year overall survival rate (44% vs. 37%; p = 0.0116). Veterans with metastatic prostate cancer treated with abiraterone + spironolactone also had a lower 5-year all-cause mortality compared to those only on abiraterone (hazard ratio 0.80, 95% confidence intervals 0.61-0.96; p = 0.012). CONCLUSION: This large VA observational study suggests that concomitant use of spironolactone does not compromise cancer control or survival of metastatic prostate cancer patients treated with abiraterone.

Concerning Safety and Efficacy of Concurrent and Consolidative Durvalumab With Thoracic Radiation Therapy in PDL1-Unselected Stage III Non-Small Cell Lung Cancer: Brief Report.

PURPOSE: Consolidative durvalumab, an anti-programmed death ligand 1 (PDL1) immune checkpoint inhibitor, administered after concurrent chemoradiation improves outcomes of patients with locally advanced non-small cell lung cancer (NSCLC) without substantially increasing toxicities. We studied a chemotherapy-free regimen of thoracic radiation therapy (RT) with concurrent and consolidative durvalumab. METHODS AND MATERIALS: This single-arm phase 2 trial enrolled patients with stage III NSCLC (regardless of tumor PDL1 expression), Eastern Cooperative Oncology Group (ECOG) performance status 0-1, adequate pulmonary function, and RT fields meeting standard organ constraints. Participants received 2 cycles of durvalumab (1500 mg every 4 weeks) concurrently with thoracic RT (60 Gy in 30 fractions), followed by up to 13 cycles of consolidative durvalumab. RESULTS: After 10 patients were enrolled, the trial was closed because of poor clinical outcomes. With a median follow-up of 12 months, 5 patients had disease progression and 8 patients died. Six patients experienced 15 treatment-related, grade ≥3 events, including 1 grade 4 acute kidney injury during consolidation and 2 fatal pulmonary events. One fatal pulmonary event occurred during the concurrent phase in an active smoker; the other occurred after the first cycle of consolidative durvalumab. The primary endpoint of progression-free survival at 12 months was 20% (50% for PDL1≥1% vs 0% for PDL1 unavailable or <1%). Median overall survival was not reached, 10.5 months, and 7 months, for PDL1 ≥1%, <1%, and unavailable, respectively. CONCLUSIONS: In PDL1 unselected stage III NSCLC, thoracic RT plus concurrent and consolidative durvalumab is associated with high-grade toxicity and early disease progression.

Characteristics of Long-Term Survivors With EGFR-Mutant Metastatic NSCLC.

Introduction: Characteristics of long-term survivors in EGFR-mutant (EGFRm) NSCLC are not fully understood. This retrospective analysis evaluated a multi-institution cohort of patients with EGFRm NSCLC treated in the pre-osimertinib era and sought to describe characteristics of long-term survivors. Methods: Clinical characteristics and outcomes were abstracted from the electronic medical records of patients with EGFRm metastatic NSCLC who started first-line therapy before 2015. Demographics and comutations were compared between greater than or equal to 5-year survivors and less than 5-year survivors. Multivariable Cox proportional hazard and logistic regression models were used to evaluate factors associated with survival and the odds of death within 5 years, respectively. Results: Overall, 133 patients were greater than or equal to 5-year survivors; 127 were less than 5-year survivors. Burden of pathogenic comutations including TP53 and PIK3CA was similar between greater than or equal to 5-year survivors and less than 5-year survivors. Receipt of first-line chemotherapy rather than EGFR tyrosine kinase inhibitor was similar between the groups (22% of <5-y versus 31% of ≥5-y). Baseline brain metastasis and history of smoking were associated with higher odds of death within 5 years (odds ratio = 2.16, p = 0.029 and odds ratio = 1.90, p = 0.046, respectively). Among patients without baseline brain metastases, cumulative incidence of brain metastases at 5 years was 42.3%. Both baseline and post-baseline brain metastasis were associated with worse overall survival compared with no brain metastasis (hazard ratio = 3.26, p < 0.001 and hazard ratio = 4.99, p < 0.001, respectively). Conclusions: Within patients treated for EGFRm metastatic NSCLC before 2015, absence of brain metastasis and nonsmoking status were predictive of 5-year survival. Our findings help to define a subset of patients with EGFRm NSCLC with excellent survival outcomes who may not require intensification of initial therapy.

Cmai: Predicting Antigen-Antibody Interactions from Massive Sequencing Data.

The interaction between antigens and antibodies (B cell receptors, BCRs) is the key step underlying the function of the humoral immune system in various biological contexts. The capability to profile the landscape of antigen-binding affinity of a vast number of BCRs will provide a powerful tool to reveal novel insights at unprecedented levels and will yield powerful tools for translational development. However, current experimental approaches for profiling antibody-antigen interactions are costly and time-consuming, and can only achieve low-to-mid throughput. On the other hand, bioinformatics tools in the field of antibody informatics mostly focus on optimization of antibodies given known binding antigens, which is a very different research question and of limited scope. In this work, we developed an innovative Artificial Intelligence tool, Cmai, to address the prediction of the binding between antibodies and antigens that can be scaled to high-throughput sequencing data. Cmai achieved an AUROC of 0.91 in our validation cohort. We devised a biomarker metric based on the output from Cmai applied to high-throughput BCR sequencing data. We found that, during immune-related adverse events (irAEs) caused by immune-checkpoint inhibitor (ICI) treatment, the humoral immunity is preferentially responsive to intracellular antigens from the organs affected by the irAEs. In contrast, extracellular antigens on malignant tumor cells are inducing B cell infiltrations, and the infiltrating B cells have a greater tendency to co-localize with tumor cells expressing these antigens. We further found that the abundance of tumor antigen-targeting antibodies is predictive of ICI treatment response. Overall, Cmai and our biomarker approach filled in a gap that is not addressed by current antibody optimization works nor works such as AlphaFold3 that predict the structures of complexes of proteins that are known to bind.

Effects of gestational hypothyroidism on mouse brain development: Gabaergic systems and oxidative stress.

Hormonal imbalance during pregnancy is a risk factor for neuropsychiatric impairment in the offspring. It has been suggested that hypothyroidism leads to dysfunction of cortical GABAergic interneurons and inhibitory system development that in turn underlies impairment of the central nervous system. Here we investigated how gestational hypothyroidism affected offspring GABAergic system development as well as redox regulation parameters, because of previous links identified between the two. Experimental Gestational Hypothyroidism (EGH) was induced in CD-1 mice with 0.02% methimazole (MMI) in drinking water from embryonic day 9 (E9) until tissue collection at embryonic day 14 (E14) or E18. We examined GABAergic cell distribution and inhibitory system development gene expression as well as redox relevant gene expression and direct measures across all embryos regardless of sex. Intrauterine restriction of maternal thyroid hormones significantly impacted both of these outcomes in brain, as well as altering redox regulation in the placenta. GAD67+ neuronal migration was reduced, accompanied by a disruption in gene expression influencing GABAergic cell migration and cortical inhibitory neural system development. EGH also altered embryonic brain gene expression of Gpx1, Nfe2l2, Cat levels in the dorsal E14 brains. Additionally, EGH resulted in elevated TBARS, Gpx1 and Nfe2l2 in the ventral E18 brains. Furthermore, EGH downregulated placental Gpx1 gene expression at E14 and increased protein oxidation at E18. These findings support the hypothesis that sufficient maternal thyroid hormone supply to the fetus influences central nervous system development, including processes of GABAergic system development and redox equilibrium.

Corneal Transplant Rejection Following Durvalumab Therapy in a Patient With NSCLC: A Case Report.

We report the case of corneal transplant rejection in a 77-year-old male receiving durvalumab as consolidative therapy for stage IIIB non-small cell lung cancer (NSCLC). Following successful chemoradiation and initiation of durvalumab, the patient underwent a right corneal transplant for corneal dystrophy. Six months after an initially stable post-transplant course, he developed progressive visual decline culminating in graft failure 1 year later despite treatment with prednisone eye drops. This case adds to the limited evidence implicating immune checkpoint inhibitors (ICIs) in corneal graft rejection, emphasizing the need for multidisciplinary evaluation and close monitoring of corneal transplant recipients undergoing ICI therapy.

Non-Small Cell Lung Cancer, Version 4.2024, NCCN Clinical Practice Guidelines in Oncology

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Non-Small Cell Lung Cancer (NSCLC) provide recommendations for the treatment of patients with NSCLC, including diagnosis, primary disease management, surveillance for relapse, and subsequent treatment. The panel has updated the list of recommended targeted therapies based on recent FDA approvals and clinical data. This selection from the NCCN Guidelines for NSCLC focuses on treatment recommendations for advanced or metastatic NSCLC with actionable molecular biomarkers.

Highly variable timing renders immunotherapy efficacy and toxicity impractical biomarkers of one another in clinical practice.

Background: A useful clinical biomarker requires not only association but also a consistent temporal relationship. For instance, chemotherapy-induced neutropenia and epidermal growth-factor inhibitor-related acneiform rash both occur within weeks of treatment initiation, thereby providing information prior to efficacy assessment. Although immune checkpoint inhibitor (ICI)-associated immune-related adverse events (irAE) have been associated with therapeutic benefit, irAE may have delayed and highly variable onset. To determine whether ICI efficacy and irAE could serve as clinically useful biomarkers for predicting each other, we determined the temporal relationship between initial efficacy assessment and irAE onset in a diverse population treated with ICI. Methods: Using two-sided Fisher exact and Cochran-Armitage tests, we determined the relative timing of initial efficacy assessment and irAE occurrence in a cohort of 155 ICI-treated patients (median age 68 years, 40% women). Results: Initial efficacy assessment was performed a median of 50 days [interquartile range (IQR) 39-59 days] after ICI initiation; median time to any irAE was 77 days (IQR 28-145 days) after ICI initiation. Median time to first irAE was 42 days (IQR 20-88 days). Overall, 58% of any irAE and 47% of first irAE occurred after initial efficacy assessment. For clinically significant (grade ≥2) irAE, 60% of any and 53% of first occurred after initial efficacy assessment. The likelihood of any future irAE did not differ according to response (45% for complete or partial response vs. 47% for other cases; P=1). In landmark analyses controlling for clinical and toxicity follow-up, patients demonstrating greater tumor shrinkage at initial efficacy assessment were more likely to develop future grade ≥2 (P=0.05) and multi-organ (P=0.02) irAE. Conclusions: In contrast to that seen with chemotherapy and molecularly targeted therapies, the temporal relationship between ICI efficacy and toxicity is complex and bidirectional. In practice, neither parameter can be routinely relied on as a clinical biomarker to predict the other.

Brief Report: Real-World Efficacy and Safety of Sotorasib in U.S. Veterans with KRAS G12C-Mutated NSCLC.

Introduction: The KRAS G12C inhibitor sotorasib was approved for treating advanced NSCLC in the second line or later on the basis of the CodeBreaK100 trial. Nevertheless, data on the real-world efficacy and safety of sotorasib, and to its optimal dose, remain limited. Methods: Patients treated with sotorasib for NSCLC through the Veterans Health Administration were retrospectively identified from the Corporate Data Warehouse. Survival, response, and toxicity data were obtained from chart review. Results: Among the 128 patients treated with sotorasib through the Veterans Health Administration, objective response rate was 34%, progression-free survival (PFS) six months, and overall survival 12 months. Similar PFS was observed among the 16 patients who received frontline sotorasib without any prior systemic therapy for NSCLC. Toxicity leading to sotorasib interruption or dose reduction occurred in 37% of patients, whereas sotorasib discontinuation for toxicity occurred in 25%. Notably, sotorasib dose reduction was associated with substantially improved PFS and OS. Conclusions: In this real-world study, the observed efficacy of sotorasib was similar to the results of CodeBreaK100. Patients who received frontline sotorasib had similar PFS to our overall cohort, suggesting that first-line sotorasib monotherapy may benefit patients who are not eligible for chemotherapy. Toxicities leading to sotorasib interruption, dose reduction, or discontinuation were common. Sotorasib dose reduction was associated with improved survival, suggesting that sotorasib dose reduction may not compromise efficacy.

NCCN Guidelines® Insights: Mesothelioma: Pleural, Version 1.2024.

Mesothelioma is a rare cancer that originates from the mesothelial surfaces of the pleura and other sites, and is estimated to occur in approximately 3,500 people in the United States annually. Pleural mesothelioma is the most common type and represents approximately 85% of these cases. The NCCN Guidelines for Mesothelioma: Pleural provide recommendations for the diagnosis, evaluation, treatment, and follow-up for patients with pleural mesothelioma. These NCCN Guidelines Insights highlight significant updates to the NCCN Guidelines for Mesothelioma: Pleural, including revised guidance on disease classification and systemic therapy options.

pan-MHC and cross-Species Prediction of T Cell Receptor-Antigen Binding.

Profiling the binding of T cell receptors (TCRs) of T cells to antigenic peptides presented by MHC proteins is one of the most important unsolved problems in modern immunology. Experimental methods to probe TCR-antigen interactions are slow, labor-intensive, costly, and yield moderate throughput. To address this problem, we developed pMTnet-omni, an Artificial Intelligence (AI) system based on hybrid protein sequence and structure information, to predict the pairing of TCRs of αß T cells with peptide-MHC complexes (pMHCs). pMTnet-omni is capable of handling peptides presented by both class I and II pMHCs, and capable of handling both human and mouse TCR-pMHC pairs, through information sharing enabled this hybrid design. pMTnet-omni achieves a high overall Area Under the Curve of Receiver Operator Characteristics (AUROC) of 0.888, which surpasses competing tools by a large margin. We showed that pMTnet-omni can distinguish binding affinity of TCRs with similar sequences. Across a range of datasets from various biological contexts, pMTnet-omni characterized the longitudinal evolution and spatial heterogeneity of TCR-pMHC interactions and their functional impact. We successfully developed a biomarker based on pMTnet-omni for predicting immune-related adverse events of immune checkpoint inhibitor (ICI) treatment in a cohort of 57 ICI-treated patients. pMTnet-omni represents a major advance towards developing a clinically usable AI system for TCR-pMHC pairing prediction that can aid the design and implementation of TCR-based immunotherapeutics.

Mesothelioma: Peritoneal, Version 2.2023, NCCN Clinical Practice Guidelines in Oncology.

Mesothelioma is a rare cancer originating in mesothelial surfaces of the peritoneum, pleura, and other sites. These NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) focus on peritoneal mesothelioma (PeM). The NCCN Guidelines for PeM provide recommendations for workup, diagnosis, and treatment of primary as well as previously treated PeM. The diagnosis of PeM may be delayed because PeM mimics other diseases and conditions and because the disease is so rare. The pathology section was recently updated to include new information about markers used to identify mesothelioma, which is difficult to diagnose. The term "malignant" is no longer used to classify mesotheliomas, because all mesotheliomas are now defined as malignant.

Phase II Randomized Trial of Carboplatin, Pemetrexed, and Bevacizumab With and Without Atezolizumab in Stage IV Nonsquamous Non-Small-Cell Lung Cancer Patients Who Harbor a Sensitizing EGFR Mutation or Have Never Smoked.

INTRODUCTION: Patients with non-small-cell lung cancer (NSCLC) who have never smoked or have tumors with mutations in EGFR generally derive minimal benefit from single-agent PD-1/PD-L1 checkpoint inhibitors. Prior data indicate that adding PD-L1 inhibition to anti-VEGF and cytotoxic chemotherapy may be a promising approach to overcoming immunotherapy resistance in these patients, however prospective validation is needed. This trial in progress (NCT03786692) is evaluating patients with stage IV NSCLC who have never smoked or who have tumors with sensitizing EGFR alterations to determine if a 4-drug combination of atezolizumab, carboplatin, pemetrexed, and bevacizumab can improve outcomes compared to carboplatin, pemetrexed and bevacizumab without atezolizumab. METHODS: This is a randomized, phase II, multicenter study evaluating carboplatin, pemetrexed, bevacizumab with and without atezolizumab in 117 patients with stage IV nonsquamous NSCLC. Randomization is 2 to 1 favoring the atezolizumab containing arm. Eligible patients include: 1) those with tumors with sensitizing EGFR alterations in exons 19 or 21 or 2) patients who have never smoked and have wild-type tumors (ie, no EGFR, ALK or ROS1 alterations). Patients are defined as having never smoked if they have smoked less than 100 cigarettes in a lifetime. Patients with EGFR-mutated tumors must have disease progression or intolerance to prior tyrosine kinase inhibitor (TKI) therapy. The primary endpoint is progression-free survival (PFS). Secondary endpoints include overall survival (OS), response rate, duration of response, and time to response. CONCLUSION: This phase II trial is accruing patients at U.S. sites through the National Comprehensive Cancer Network (NCCN). The trial opened in August 2019 and accrual is expected to be completed in the Fall of 2024.

Phase 1 trial of bemcentinib (BGB324), a first-in-class, selective AXL inhibitor, with docetaxel in patients with previously treated advanced non-small cell lung cancer.

OBJECTIVES: AXL, a transmembrane receptor tyrosine kinase, is highly expressed and associated with poor prognosis in non-small cell lung cancer (NSCLC). Bemcentinib (BGB324), a selective orally bioavailable small molecule AXL inhibitor, synergizes with docetaxel in preclinical models. We performed a phase I trial of bemcentinib plus docetaxel in previously treated advanced NSCLC. MATERIALS AND METHODS: Escalation of two dose levels of bemcentinib (200 mg load × 3 days then 100 mg daily, or 400 mg load × 3 days then 200 mg daily) in combination with docetaxel (60 or 75 mg/m2 every 3 weeks) followed a 3+3 study design. Due to hematologic toxicity, prophylactic G-CSF was added. Bemcentinib monotherapy was administered for one week prior to docetaxel initiation to assess pharmacodynamic and pharmacokinetic effects alone and in combination. Plasma protein biomarker levels were measured. RESULTS: 21 patients were enrolled (median age 62 years, 67% male). Median treatment duration was 2.8 months (range 0.7-10.9 months). The main treatment-related adverse events were neutropenia (86%, 76% ≥G3), diarrhea (57%, 0% ≥G3), fatigue (57%, 5% ≥G3), and nausea (52%, 0% ≥G3). Neutropenic fever occurred in 8 (38%) patients. The maximum tolerated dose was docetaxel 60 mg/m2 with prophylactic G-CSF support plus bemcentinib 400 mg load × 3 days followed by 200 mg daily thereafter. Bemcentinib and docetaxel pharmacokinetics resembled prior monotherapy data. Among 17 patients evaluable for radiographic response, 6 (35%) patients had partial response and 8 (47%) patients had stable disease as best response. Bemcentinib administration was associated with modulation of proteins involved in protein kinase B signaling, reactive oxygen species metabolism, and other processes. CONCLUSION: Bemcentinib plus docetaxel with G-CSF support demonstrates anti-tumor activity in previously treated, advanced NSCLC. The role of AXL inhibition in the treatment of NSCLC remains under investigation.

Systemic immune parameters after prior radiation therapy in patients receiving immune checkpoint inhibitors.

INTRODUCTION: Preclinical studies have demonstrated the ability of radiation therapy (RT) to augment immune response and tumor control by immune checkpoint inhibitors (ICI). However, numerous clinical trials combining RT and ICI have yielded relatively disappointing results. To improve understanding of optimal use of these therapies, we assessed systemic immune effects of prior RT in patients receiving ICI. METHODS AND MATERIALS: Pre- and post-ICI blood samples were collected from patients enrolled in a prospective immunotherapy biospecimen protocol. Mutiplex panels of 40 cytokines and 120 autoantibodies (Ab) were analyzed. We identified differences in these parameters according to receipt, timing, and type of prior RT. We calculated P values using the Pearson product-moment correlation coefficient and false discovery rate (FDR) using the Benjamini-Hochberg Procedure. RESULTS: Among 277 total patients, 69 (25%) received RT in the 6 months prior to ICI initiation. Among RT-treated patients, 23 (33%) received stereotactic RT, and 33 (48%) received curative intent RT. There was no significant difference in demographics or type of immunotherapy between patients according to prior RT exposure. Baseline complement C8 Ab and MIP-1d/CCL15 were significantly higher among patients with prior RT. For MIP-1d/CCL15, only prior stereotactic RT was associated with significant differences. CONCLUSIONS: Prior RT is associated with few changes in systemic immune parameters in patients receiving ICI. The underlying mechanisms and optimal approach to harnessing the potential synergy of RT and ICI require further prospective clinical investigation.

NCCN Guidelines® Insights: Non-Small Cell Lung Cancer, Version 2.2023.

The NCCN Guidelines for Non-Small Cell Lung Cancer (NSCLC) provide recommendations for management of disease in patients with NSCLC. These NCCN Guidelines Insights focus on neoadjuvant and adjuvant (also known as perioperative) systemic therapy options for eligible patients with resectable NSCLC.

A phase II clinical trial evaluating the safety and efficacy of durvalumab as first line therapy in advanced and metastatic non-small cell lung cancer patients with Eastern Cooperative Oncology Group performance status of 2.

Background: Approximately 30-40% of patients with advanced and metastatic non-small cell lung cancer (NSCLC) present with an impaired performance status (PS). There are limited prospective data on the safety and efficacy of durvalumab in these patients. Methods: In this single-arm phase II clinical trial (NCT02879617), patients with previously untreated Stage IIIB/IV NSCLC and ECOG PS of 2 received durvalumab 1500 mg every 28 days until progression or unacceptable toxicity. The primary endpoints were overall survival (OS) and safety determined by grade ≥3 treatment-related adverse events (TRAEs). Findings: Between April 2017 and March 2021, 50 patients were enrolled, of whom 47 received durvalumab. With a median follow-up of 28 months, median OS was 6 months (95% CI 4-10). TRAEs grade 3 occurred in nine of 47 patients (19%, 95% CI 9%-33%). OS in patients with a PD-L1 TPS of 0, 1-49%, and ≥50% was six months (95% CI 3-15), 11 months (95% CI 4-16), and 11 months (95% CI 0-not reached (NR)), respectively. Health related quality of life (HQRL) assessed at baseline and during therapy demonstrated no statistically significant change over the course of treatment. Interpretation: This study demonstrates that single agent durvalumab is safe and well tolerated in the 1st line treatment of patients with advanced NSCLC and ECOG PS of 2, with an encouraging OS benefit in patients with PD-L1 positive tumors. This trial is amongst the largest prospective studies evaluating durvalumab in the 1st line treatment of advanced stage NSCLC and a PS of 2. Funding: AstraZeneca, NCI P30CA047904.

Non-Small Cell Lung Cancer, Version 3.2022, NCCN Clinical Practice Guidelines in Oncology.

NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Non-Small Cell Lung Cancer (NSCLC) provide recommended management for patients with NSCLC, including diagnosis, primary treatment, surveillance for relapse, and subsequent treatment. Patients with metastatic lung cancer who are eligible for targeted therapies or immunotherapies are now surviving longer. This selection from the NCCN Guidelines for NSCLC focuses on targeted therapies for patients with metastatic NSCLC and actionable mutations.

Blood-based tumor mutational burden as a biomarker for atezolizumab in non-small cell lung cancer: the phase 2 B-F1RST trial.

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.