Unusual Adverse Events in a Patient With BRAF-Mutated Non-Small Cell Lung Cancer Treated With BRAF/MEK Inhibition.

BRAF/MEK inhibition remains standard of care for treatment of BRAF-mutated non-small cell lung cancer (NSCLC). Although common adverse events (AEs) have been reported through clinical trials and ongoing clinical practice, only a handful of reports have detailed unusual adverse events associated with these medications. This report presents a patient with BRAF-mutated NSCLC treated with dabrafenib and trametinib who experienced 2 unusual AEs-Sweet syndrome and MEK-associated retinopathy-that responded to steroid treatment. The patient was able to continue BRAF/MEK inhibition through a coordinated multidisciplinary approach. This case highlights the importance for all clinicians to recognize unusual AEs associated with BRAF/MEK inhibition, particularly in the setting of expanded use for all BRAF V600E-mutated solid tumors.

A plain language summary of the results from the group of patients in the CHRYSALIS study with EGFR exon 20 insertion-mutated non-small-cell lung cancer who received amivantamab.

WHAT IS THIS SUMMARY ABOUT?: This is a plain language summary of an article published in the Journal of Clinical Oncology in 2021. It describes the first results from 1 group of patients in the phase 1 CHRYSALIS study with epidermal growth factor receptor (EGFR) exon 20 insertion (ex20ins) mutations. This part of the CHRYSALIS study (called cohort D) investigated the bispecific antibody amivantamab (brand name RYBREVANT®) in patients with non-small-cell lung cancer (NSCLC) with an EGFR ex20ins mutation. EGFR mutations are one of the most common causes of NSCLC tumors, with EGFR ex20ins mutations being more common among people of Asian descent. Patients who took part in this study had cancer that could not be removed by surgery, and whose cancer had worsened after receiving other forms of treatment, such as chemotherapy. Typically, patients with this type of mutation are difficult to treat or do not experience treatment response with commonly used therapies that target EGFR. WHAT WERE THE RESULTS?: The CHRYSALIS study took place between May 27, 2016, and June 8, 2020, in select hospitals in the USA, Japan and South Korea. In cohort D, amivantamab showed promising results, with an overall response rate of 40%. This means that 4 of every 10 patients in CHRYSALIS cohort D had tumors that shrank or were no longer measurable. Clinical Trial Registration: NCT02609776 (the CHRYSALIS Phase I Study) (ClinicalTrials.gov).

Neoadjuvant atezolizumab and chemotherapy in patients with resectable non-small-cell lung cancer: an open-label, multicentre, single-arm, phase 2 trial.

BACKGROUND: Approximately 25% of all patients with non-small-cell lung cancer present with resectable stage IB-IIIA disease, and although perioperative chemotherapy is the standard of care, this treatment strategy provides only modest survival benefits. On the basis of the activity of immune checkpoint inhibitors in metastatic non-small-cell lung cancer, we designed a trial to test the activity of the PD-L1 inhibitor, atezolizumab, with carboplatin and nab-paclitaxel given as neoadjuvant treatment before surgical resection. METHODS: This open-label, multicentre, single-arm, phase 2 trial was done at three hospitals in the USA. Eligible patients were aged 18 years or older and had resectable American Joint Committee on Cancer-defined stage IB-IIIA non-small-cell lung cancer, an Eastern Cooperative Oncology Group performance status of 0-1, and a history of smoking exposure. Patients received neoadjuvant treatment with intravenous atezolizumab (1200 mg) on day 1, nab-paclitaxel (100 mg/m2) on days 1, 8, and 15, and carboplatin (area under the curve 5; 5 mg/mL per min) on day 1, of each 21-day cycle. Patients without disease progression after two cycles proceeded to receive two further cycles, which were then followed by surgical resection. The primary endpoint was major pathological response, defined as the presence of 10% or less residual viable tumour at the time of surgery. All analyses were intention to treat. This study is registered with ClinicalTrials.gov, NCT02716038, and is ongoing but no longer recruiting participants. FINDINGS: Between May 26, 2016, and March 1, 2019, we assessed 39 patients for eligibility, of whom 30 patients were enrolled. 23 (77%) of these patients had stage IIIA disease. 29 (97%) patients were taken into the operating theatre, and 26 (87%) underwent successful R0 resection. At the data cutoff (Aug 7, 2019), the median follow-up period was 12·9 months (IQR 6·2-22·9). 17 (57%; 95% CI 37-75) of 30 patients had a major pathological response. The most common treatment-related grade 3-4 adverse events were neutropenia (15 [50%] of 30 patients), increased alanine aminotransferase concentrations (two [7%] patients), increased aspartate aminotransferase concentration (two [7%] patients), and thrombocytopenia (two [7%] patients). Serious treatment-related adverse events included one (3%) patient with grade 3 febrile neutropenia, one (3%) patient with grade 4 hyperglycaemia, and one (3%) patient with grade 2 bronchopulmonary haemorrhage. There were no treatment-related deaths. INTERPRETATION: Atezolizumab plus carboplatin and nab-paclitaxel could be a potential neoadjuvant regimen for resectable non-small-cell lung cancer, with a high proportion of patients achieving a major pathological response, and manageable treatment-related toxic effects, which did not compromise surgical resection. FUNDING: Genentech and Celgene.

Ovarian clear cell carcinoma, outcomes by stage: the MSK experience.

OBJECTIVE: Ovarian clear cell carcinomas (OCCCs) are rare, and uncertainty exists as to the optimal treatment paradigm and validity of the FIGO staging system, especially in early-stage disease. METHODS: We performed a retrospective cohort study of all OCCC patients diagnosed and treated at Memorial Sloan Kettering Cancer Center between January 1996 and December 2013. Progression-free survival (PFS) and overall survival (OS) were calculated by stage and race, and comparisons were made using the log-rank test. Statistical significance was set at p<0.05. Type and duration of treatment were also recorded. RESULTS: There were 177 evaluable patients. The majority of patients were stage I at diagnosis (110/177, 62.2%). Of these, 60/110 (54.6%) were stage IA, 31/110 (28.2%) were stage IC on the basis of rupture-only, and 19/110 (17.3%) were stage IC on the basis of surface involvement and/or positive cytology of ascites or washings. Patients with stage IA and IC based on rupture-only had similar PFS/OS outcomes. Patients with stage IC based on surface involvement and/or positive cytology had a statistically significant decrement in PFS/OS. Stage was an important indicator of PFS/OS, while race was not. CONCLUSIONS: OCCC often presents in early stage. Women with stage IA OCCC have excellent prognosis, and future studies should explore whether they benefit from adjuvant chemotherapy. Women with IC OCCC need further staging clarification, as surgical rupture alone affords better prognosis than surface involvement and/or positive cytology. Women with advanced OCCC have poor survival and are often chemotherapy resistant/refractory. New treatment paradigms are needed.

Real-World Efficacy and Safety of Amivantamab for EGFR-Mutant NSCLC.

INTRODUCTION: Amivantamab-vmjw (amivantamab) is a bispecific EGFR/MET antibody approved for patients with advanced NSCLC with EGFR exon 20 insertion mutations, after prior therapy. Nevertheless, the benefits and safety of amivantamab in other EGFR-mutant lung cancer, with or without osimertinib, and with concurrent radiation therapy, are less known. METHODS: We queried the MD Anderson Lung Cancer GEMINI, Fred Hutchinson Cancer Research Center, University of California Davis Comprehensive Cancer Center, and Stanford Cancer Center's database for patients with EGFR-mutant NSCLC treated with amivantamab, not on a clinical trial. The data analyzed included initial response, duration of treatment, and concomitant radiation safety in overall population and prespecified subgroups. RESULTS: A total of 61 patients received amivantamab. Median age was 65 (31-81) years old; 72.1% were female; and 77% were patients with never smoking history. Median number of prior lines of therapies was four. On the basis of tumor's EGFR mutation, 39 patients were in the classical mutation cohort, 15 patients in the exon 20 cohort, and seven patients in the atypical cohort. There were 37 patients (58.7%) who received amivantamab concomitantly with osimertinib and 25 patients (39.1%) who received concomitant radiation. Furthermore, 54 patients were assessable for response in the overall population; 19 patients (45.2%) had clinical response and disease control rate (DCR) was 64.3%. In the classical mutation cohort of the 33 assessable patients, 12 (36.4%) had clinical response and DCR was 48.5%. In the atypical mutation cohort, six of the seven patients (85.7%) had clinical response and DCR was 100%. Of the 13 assessable patients in the exon 20 cohort, five patients (35.7%) had clinical response and DCR was 64.3%. Adverse events reported with amivantamab use were similar as previously described in product labeling. No additional toxicities were noted when amivantamab was given with radiation with or without osimertinib. CONCLUSIONS: Our real-world multicenter analysis revealed that amivantamab is a potentially effective treatment option for patients with EGFR mutations outside of exon 20 insertion mutations. The combination of osimertinib with amivantamab is safe and feasible. Radiation therapy also seems safe when administered sequentially or concurrently with amivantamab.

Tyrosine Kinase Inhibitors With and Without Up-Front Stereotactic Radiosurgery for Brain Metastases From EGFR and ALK Oncogene-Driven Non-Small Cell Lung Cancer (TURBO-NSCLC).

PURPOSE: Newer-generation tyrosine kinase inhibitors (TKIs) for non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) rearrangements have demonstrated high CNS activity. The optimal use of up-front stereotactic radiosurgery (SRS) for brain metastases (BM) in patients eligible for CNS-penetrant TKIs is controversial, and data to guide patient management are limited. MATERIALS AND METHODS: Data on TKI-naïve patients with EGFR- and ALK-driven NSCLC with BM treated with CNS-penetrant TKIs with and without up-front SRS were retrospectively collected from seven academic centers in the United States. Time-to-CNS progression and overall survival (OS) were analyzed, with multivariable adjustment in Fine & Gray and Cox proportional hazards models for clinically relevant factors. RESULTS: From 2013 to 2022, 317 patients were identified (200 TKI-only and 117 TKI + SRS). Two hundred fifty (79%) and 61 (19%) patients received osimertinib and alectinib, respectively. Patients receiving TKI + SRS were more likely to have BM ≥1 cm (P < .001) and neurologic symptoms (P < .001) at presentation. Median OS was similar between the TKI and TKI + SRS groups (median 41 v 40 months, respectively; P = .5). On multivariable analysis, TKI + SRS was associated with a significant improvement in time-to-CNS progression (hazard ratio [HR], 0.63 [95% CI, 0.42 to 0.96]; P = .033). Local CNS control was significantly improved with TKI + SRS (HR, 0.30 [95% CI, 0.16 to 0.55]; P < .001), whereas no significant differences were observed in distant CNS control. Subgroup analyses demonstrated a greater benefit from TKI + SRS in patients with BM ≥1 cm in diameter for time-to-CNS progression and CNS progression-free survival. CONCLUSION: The addition of up-front SRS to CNS-penetrant TKI improved time-to-CNS progression and local CNS control, but not OS, in patients with BM from EGFR- and ALK-driven NSCLC. Patients with larger BM (≥1 cm) may benefit the most from up-front SRS.

Thymidylate synthase expression and molecular alterations in adenosquamous carcinoma of the lung.

Thymidylate synthase expression is known to be higher in squamous cell carcinoma than in adenocarcinoma of the lung. It is thought that this is the reason for the poor efficacy of pemetrexed in squamous cell carcinoma. However, there is limited data on thymidylate synthase expression in adenosquamous carcinoma, a distinct subtype of lung cancer containing both squamous and glandular differentiation. Furthermore, molecular alterations like epidermal growth factor receptor and Kirsten rat sarcoma 2 viral oncogene homolog mutations, which are seen in adenocarcinomas, are not well understood in mixed histology tumors such as adenosquamous carcinoma. In our study, we sought to better characterize adenosquamous tumors of the lung. Using immunohistochemistry to evaluate thymidylate synthase protein levels, we found that the expression of thymidylate synthase in these mixed tumors roughly parallel that of squamous cell carcinoma, instead of falling in between squamous cell and adenocarcinoma. Of note, in adenosquamous samples, the expression of thymidylate synthase was more closely correlated within the two components than would be expected by random chance alone. Also, we had a relatively high rate of epidermal growth factor receptor (11%) and Kirsten rat sarcoma 2 viral oncogene homolog (33%) mutations in these specimens, with the mutations showing convergence in both the glandular and squamous components upon microdissection. Our results indicate that adenosquamous carcinomas are not simple mixtures of their two histological components; they rather behave as their own entity, and it is important to further understand their behavior. Given the similarity of thymidylate synthase expression between squamous cell and adenosquamous carcinoma, and that thymidylate synthase is the main target of pemetrexed, we extrapolate that pemetrexed may also have inferior clinical activity in adenosquamous carcinoma.

Neoadjuvant immunotherapy in resectable non-small-cell lung cancer.

The advent of immune checkpoint inhibition has pushed the treatment paradigm for resectable non-small-cell lung cancer (NSCLC) toward neoadjuvant therapy. A growing number of promising trials have examined the utility of neoadjuvant immunotherapy, both alone and in combination with other modalities such as radiation therapy (RT) and chemotherapy. The phase II LCMC3 and NEOSTAR trials demonstrated a role for neoadjuvant immunotherapy in inducing meaningful pathologic responses, and another phase II trial established the feasibility of combining neoadjuvant durvalumab with RT. Significant interest in neoadjuvant chemoimmunotherapy resulted in the conduct of multiple successful phase II trials including the Columbia trial, NADIM, SAKK 16/14, and NADIM II. Across these trials, neoadjuvant chemoimmunotherapy led to high rates of pathologic response and improved surgical outcomes without compromising surgical timing or feasibility. CheckMate-816, which was a randomized phase III trial studying neoadjuvant nivolumab in addition to chemotherapy, definitively established a benefit for neoadjuvant chemoimmunotherapy compared to chemotherapy alone for resectable NSCLC. Despite the growing literature and success of these trials, several outstanding questions remain, including the relationship between pathologic response and patient survival, the role of biomarkers such as programmed death ligand 1 and circulating tumor DNA in determining patient selection and treatment course, and the utility of additional adjuvant therapies. Longer follow-up of CheckMate-816 and other ongoing phase III trials may help address these questions. Ultimately, the complexity of managing resectable NSCLC highlights the importance of a multidisciplinary approach to patient care.

Self-Renewing CD8+ T-cell Abundance in Blood Associates with Response to Immunotherapy.

Treatment with immune checkpoint blockade (ICB) often fails to elicit durable antitumor immunity. Recent studies suggest that ICB does not restore potency to terminally dysfunctional T cells, but instead drives proliferation and differentiation of self-renewing progenitor T cells into fresh, effector-like T cells. Antitumor immunity catalyzed by ICB is characterized by mobilization of antitumor T cells in systemic circulation and tumor. To address whether abundance of self-renewing T cells in blood is associated with immunotherapy response, we used flow cytometry of peripheral blood from a cohort of patients with metastatic non-small cell lung cancer (NSCLC) treated with ICB. At baseline, expression of T-cell factor 1 (TCF1), a marker of self-renewing T cells, was detected at higher frequency in effector-memory (CCR7-) CD8+ T cells from patients who experienced durable clinical benefit compared to those with primary resistance to ICB. On-treatment blood samples from patients benefiting from ICB also exhibited a greater frequency of TCF1+CCR7-CD8+ T cells and higher proportions of TCF1 expression in treatment-expanded PD-1+CCR7-CD8+ T cells. The observed correlation of TCF1 frequency in CCR7-CD8+ T cells and response to ICB suggests that broader examination of self-renewing T-cell abundance in blood will determine its potential as a noninvasive, predictive biomarker of response and resistance to immunotherapy.

The American Association for Thoracic Surgery (AATS) 2023 Expert Consensus Document: Staging and multidisciplinary management of patients with early-stage non-small cell lung cancer.

Novel targeted therapy and immunotherapy drugs have recently been approved for use in patients with surgically resectable lung cancer. Accurate staging, early molecular testing, and knowledge of recent trials are critical to optimize oncologic outcomes in these patients.

Management of infusion-related reactions (IRRs) in patients receiving amivantamab in the CHRYSALIS study.

BACKGROUND: Amivantamab, a fully humanized EGFR-MET bispecific antibody, has antitumor activity in diverse EGFR- and MET-driven non-small cell lung cancer (NSCLC) and a safety profile consistent with associated on-target activities. Infusion-related reaction(s) (IRR[s]) are reported commonly with amivantamab. We review IRR and subsequent management in amivantamab-treated patients. METHODS: Patients treated with the approved dose of intravenous amivantamab (1050 mg, <80 kg; 1400 mg, ≥80 kg) in CHRYSALIS-an ongoing, phase 1 study in advanced EGFR-mutated NSCLC-were included in this analysis. IRR mitigations included split first dose (350 mg, day 1 [D1]; remainder, D2), reduced initial infusion rates with proactive infusion interruption, and steroid premedication before initial dose. For all doses, pre-infusion antihistamines and antipyretics were required. Steroids were optional after the initial dose. RESULTS: As of 3/30/2021, 380 patients received amivantamab. IRRs were reported in 256 (67%) patients. Signs/symptoms of IRR included chills, dyspnea, flushing, nausea, chest discomfort, and vomiting. Most of the 279 IRRs were grade 1 or 2; grade 3 and 4 IRR occurred in 7 and 1 patients, respectively. Most (90%) IRRs occurred on cycle 1, D1 (C1D1); median time-to-first-IRR onset during C1D1 was 60 min; and first-infusion IRRs did not compromise subsequent infusions. Per protocol, IRR was mitigated on C1D1 with holding of infusion (56% [214/380]), reinitiating at reduced rate (53% [202/380]), and aborting infusion (14% [53/380]). C1D2 infusions were completed in 85% (45/53) of patients who had C1D1 infusions aborted. Four patients (1% [4/380]) discontinued treatment due to IRR. In studies aimed at elucidating the underlying mechanism(s) of IRR, no pattern was observed between patients with versus without IRR. CONCLUSION: IRRs with amivantamab were predominantly low grade and limited to first infusion, and rarely occurred with subsequent dosing. Close monitoring for IRR with the initial amivantamab dose and early intervention at first IRR signs/symptoms should be part of routine amivantamab administration.

CD73 Inhibitor Oleclumab Plus Osimertinib in Previously Treated Patients With Advanced T790M-Negative EGFR-Mutated NSCLC: A Brief Report.

INTRODUCTION: CD73 is overexpressed in EGFR-mutated NSCLC and may promote immune evasion, suggesting potential for combining CD73 blockers with EGFR tyrosine kinase inhibitors (TKIs). This phase 1b-2 study (NCT03381274) evaluated the anti-CD73 antibody oleclumab plus the third-generation EGFR TKI osimertinib in advanced EGFR-mutated NSCLC. METHODS: Patients had tissue T790M-negative NSCLC with TKI-sensitive EGFR mutations after progression on a first- or second-generation EGFR TKI and were osimertinib naive. They received osimertinib 80 mg orally once daily plus oleclumab 1500 mg (dose level 1 [DL1]) or 3000 mg (DL2) intravenously every 2 weeks. Primary end points included safety and objective response rate by Response Evaluation Criteria in Solid Tumors version 1.1. RESULTS: By July 9, 2021, five patients received DL1 and 21 received DL2. Of these patients, 60.0% and 85.7% had any-grade treatment-related adverse events (TRAEs) and 20.0% and 14.3% had grade 3 TRAEs, respectively. No dose-limiting toxicities, serious TRAEs, or deaths occurred. Four patients were T790M positive on retrospective circulating tumor DNA (ctDNA) testing; three had objective partial responses. In patients who were T790M negative in tumor and ctDNA, objective response rate was 25.0% at DL1 and 11.8% at DL2 (all partial responses); response durations at DL2 were 14.8 and 16.6 months. In patients receiving DL2, excluding those who were T790M positive by ctDNA, median progression-free survival was 7.4 months, and median overall survival was 24.8 months. DL2 was the recommended phase 2 dose. CONCLUSIONS: Oleclumab plus osimertinib was found to have moderate activity with acceptable tolerability in previously treated patients with advanced EGFR-mutated NSCLC.

Comutations and KRASG12C Inhibitor Efficacy in Advanced NSCLC.

Molecular modifiers of KRASG12C inhibitor (KRASG12Ci) efficacy in advanced KRASG12C-mutant NSCLC are poorly defined. In a large unbiased clinicogenomic analysis of 424 patients with non-small cell lung cancer (NSCLC), we identified and validated coalterations in KEAP1, SMARCA4, and CDKN2A as major independent determinants of inferior clinical outcomes with KRASG12Ci monotherapy. Collectively, comutations in these three tumor suppressor genes segregated patients into distinct prognostic subgroups and captured ∼50% of those with early disease progression (progression-free survival ≤3 months) with KRASG12Ci. Pathway-level integration of less prevalent coalterations in functionally related genes nominated PI3K/AKT/MTOR pathway and additional baseline RAS gene alterations, including amplifications, as candidate drivers of inferior outcomes with KRASG12Ci, and revealed a possible association between defective DNA damage response/repair and improved KRASG12Ci efficacy. Our findings propose a framework for patient stratification and clinical outcome prediction in KRASG12C-mutant NSCLC that can inform rational selection and appropriate tailoring of emerging combination therapies. SIGNIFICANCE: In this work, we identify co-occurring genomic alterations in KEAP1, SMARCA4, and CDKN2A as independent determinants of poor clinical outcomes with KRASG12Ci monotherapy in advanced NSCLC, and we propose a framework for patient stratification and treatment personalization based on the comutational status of individual tumors. See related commentary by Heng et al., p. 1513. This article is highlighted in the In This Issue feature, p. 1501.

A Transcriptome-Based Precision Oncology Platform for Patient-Therapy Alignment in a Diverse Set of Treatment-Resistant Malignancies.

Predicting in vivo response to antineoplastics remains an elusive challenge. We performed a first-of-kind evaluation of two transcriptome-based precision cancer medicine methodologies to predict tumor sensitivity to a comprehensive repertoire of clinically relevant oncology drugs, whose mechanism of action we experimentally assessed in cognate cell lines. We enrolled patients with histologically distinct, poor-prognosis malignancies who had progressed on multiple therapies, and developed low-passage, patient-derived xenograft models that were used to validate 35 patient-specific drug predictions. Both OncoTarget, which identifies high-affinity inhibitors of individual master regulator (MR) proteins, and OncoTreat, which identifies drugs that invert the transcriptional activity of hyperconnected MR modules, produced highly significant 30-day disease control rates (68% and 91%, respectively). Moreover, of 18 OncoTreat-predicted drugs, 15 induced the predicted MR-module activity inversion in vivo. Predicted drugs significantly outperformed antineoplastic drugs selected as unpredicted controls, suggesting these methods may substantively complement existing precision cancer medicine approaches, as also illustrated by a case study. SIGNIFICANCE: Complementary precision cancer medicine paradigms are needed to broaden the clinical benefit realized through genetic profiling and immunotherapy. In this first-in-class application, we introduce two transcriptome-based tumor-agnostic systems biology tools to predict drug response in vivo. OncoTarget and OncoTreat are scalable for the design of basket and umbrella clinical trials. This article is highlighted in the In This Issue feature, p. 1275.

International Association for the Study of Lung Cancer Study of Reproducibility in Assessment of Pathologic Response in Resected Lung Cancers After Neoadjuvant Therapy.

INTRODUCTION: Pathologic response has been proposed as an early clinical trial end point of survival after neoadjuvant treatment in clinical trials of NSCLC. The International Association for the Study of Lung Cancer (IASLC) published recommendations for pathologic evaluation of resected lung cancers after neoadjuvant therapy. The aim of this study was to assess pathologic response interobserver reproducibility using IASLC criteria. METHODS: An international panel of 11 pulmonary pathologists reviewed hematoxylin and eosin-stained slides from the lung tumors of resected NSCLC from 84 patients who received neoadjuvant immune checkpoint inhibitors in six clinical trials. Pathologic response was assessed for percent viable tumor, necrosis, and stroma. For each slide, tumor bed area was measured microscopically, and pre-embedded formulas calculated unweighted and weighted major pathologic response (MPR) averages to reflect variable tumor bed proportion. RESULTS: Unanimous agreement among pathologists for MPR was observed in 68 patients (81%), and inter-rater agreement (IRA) was 0.84 (95% confidence interval [CI]: 0.76-0.92) and 0.86 (95% CI: 0.79-0.93) for unweighted and weighted averages, respectively. Overall, unweighted and weighted methods did not reveal significant differences in the classification of MPR. The highest concordance by both methods was observed for cases with more than 95% viable tumor (IRA = 0.98, 95% CI: 0.96-1) and 0% viable tumor (IRA = 0.94, 95% CI: 0.89-0.98). The most common reasons for discrepancies included interpretations of tumor bed, presence of prominent stromal inflammation, distinction between reactive and neoplastic pneumocytes, and assessment of invasive mucinous adenocarcinoma. CONCLUSIONS: Our study revealed excellent reliability in cases with no residual viable tumor and good reliability for MPR with the IASLC recommended less than or equal to 10% cutoff for viable tumor after neoadjuvant therapy.

Assessing Pathologic Response in Resected Lung Cancers: Current Standards, Proposal for a Novel Pathologic Response Calculator Tool, and Challenges in Practice.

The efficacy of neoadjuvant treatment for NSCLC can be pathologically assessed in resected tissue. Major pathologic response (MPR) and pathologic complete response (pCR), defined as less than or equal to 10% and 0% viable tumor cells, respectively, are increasingly being used in NSCLC clinical trials to establish them as surrogate end points for efficacy to shorten time to outcome. Nevertheless, sampling and MPR calculation methods vary between studies. The International Association for the Study of Lung Cancer recently published detailed recommendations for pathologic assessment of NSCLC after neoadjuvant treatment, with methodology being critical. To increase methodological rigor further, we developed a novel MPR calculator tool (MPRCT) for standardized, comprehensive collection of percentages of viable tumor, necrosis, and stroma in the tumor bed. In addition, tumor width and length in the tumor bed are measured and unweighted and weighted MPR averages are calculated, the latter to account for the varying proportions of tumor beds on slides. We propose sampling the entire visible tumor bed for tumors having pCR regardless of size, 100% of tumors less than or equal to 3 cm in diameter, and at least 50% of tumors more than 3 cm. We describe the uses of this tool, including potential formal analyses of MPRCT data to determine the optimum sampling strategy that balances sensitivity against excessive use of resources. Solutions to challenging scenarios in pathologic assessment are proposed. This MPRCT will facilitate standardized, systematic, comprehensive collection of pathologic response data with a standardized methodology to validate studies designed to establish MPR and pCR as surrogate end points of neoadjuvant treatment efficacy.

Targeting S100A9-ALDH1A1-Retinoic Acid Signaling to Suppress Brain Relapse in EGFR-Mutant Lung Cancer.

The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) osimertinib has significantly prolonged progression-free survival (PFS) in patients with EGFR-mutant lung cancer, including those with brain metastases. However, despite striking initial responses, osimertinib-treated patients eventually develop lethal metastatic relapse, often to the brain. Although osimertinib-refractory brain relapse is a major clinical challenge, its underlying mechanisms remain poorly understood. Using metastatic models of EGFR-mutant lung cancer, we show that cancer cells expressing high intracellular S100A9 escape osimertinib and initiate brain relapses. Mechanistically, S100A9 upregulates ALDH1A1 expression and activates the retinoic acid (RA) signaling pathway in osimertinib-refractory cancer cells. We demonstrate that the genetic repression of S100A9, ALDH1A1, or RA receptors (RAR) in cancer cells, or treatment with a pan-RAR antagonist, dramatically reduces brain metastasis. Importantly, S100A9 expression in cancer cells correlates with poor PFS in osimertinib-treated patients. Our study, therefore, identifies a novel, therapeutically targetable S100A9-ALDH1A1-RA axis that drives brain relapse. SIGNIFICANCE: Treatment with the EGFR TKI osimertinib prolongs the survival of patients with EGFR-mutant lung cancer; however, patients develop metastatic relapses, often to the brain. We identified a novel intracellular S100A9-ALDH1A1-RA signaling pathway that drives lethal brain relapse and can be targeted by pan-RAR antagonists to prevent cancer progression and prolong patient survival. This article is highlighted in the In This Issue feature, p. 873.

Hepatoid Adenocarcinoma of the Lung Responsive to Frontline Combination Chemotherapy With Immunotherapy: Case Report.

Hepatoid adenocarcinoma of the lung (HAL) is a rare extrahepatic tumor characterized by histologic features of hepatocellular carcinoma. The standard treatment for nonresectable HAL has not been established, though traditionally, these tumors have been treated with platinum-based chemotherapy. Here, we report the use of combination chemotherapy and immunotherapy in a patient presenting with metastatic HAL and an elevated alpha-fetoprotein. The patient had an excellent clinical, radiographic, and biomarker response. This case supports the use of chemoimmunotherapy, which is now the standard of care first-line treatment in NSCLC, for HAL.