Long-term survival with first-line nivolumab plus ipilimumab in patients with advanced non-small-cell lung cancer: a pooled analysis

BACKGROUND

First-line nivolumab plus ipilimumab prolongs survival versus chemotherapy in advanced non-small-cell lung cancer (NSCLC). We further characterized clinical benefit with this regimen in a large pooled patient population and assessed the effect of response on survival.

PATIENTS AND METHODS

Data were pooled from four studies of first-line nivolumab plus ipilimumab in advanced NSCLC (CheckMate 227 Part 1, 817 cohort A, 568 Part 1, and 012). Overall survival (OS), progression-free survival (PFS), objective response rate, duration of response, and safety were assessed. Landmark analyses of OS by response status at 6 months and by tumor burden reduction in responders to nivolumab plus ipilimumab were also assessed.

RESULTS

In the pooled population (N = 1332) with a minimum follow-up of 29.1-58.9 months, median OS was 18.6 months, with a 3-year OS rate of 35%; median PFS was 5.4 months (3-year PFS rate, 17%). Objective response rate was 36%; median duration of response was 23.7 months, with 38% of responders having an ongoing response at 3 years. In patients with tumor programmed death-ligand 1 (PD-L1) <1%, ≥1%, 1%-49%, or ≥50%, 3-year OS rates were 30%, 38%, 30%, and 48%. Three-year OS rates were 30% and 38% in patients with squamous or non-squamous histology. Efficacy outcomes in patients aged ≥75 years were similar to the overall pooled population (median OS, 20.1 months; 3-year OS rate, 34%). In the pooled population, responders to nivolumab plus ipilimumab at 6 months had longer post-landmark OS than those with stable or progressive disease; 3-year OS rates were 66%, 22%, and 14%, respectively. Greater depth of response was associated with prolonged survival; in patients with tumor burden reduction ≥80%, 50% to <80%, or 30% to <50%, 3-year OS rates were 85%, 72%, and 44%, respectively. No new safety signals were identified in the pooled population.

CONCLUSION

Long-term survival benefit and durable response with nivolumab plus ipilimumab in this large patient population further support this first-line treatment option for advanced NSCLC.

Deciphering radiological stable disease to immune checkpoint inhibitors

BACKGROUND

'Stable disease (SD)' as per RECIST is a common but ambiguous outcome in patients receiving immune checkpoint inhibitors (ICIs). This study aimed to characterize SD and identify the subset of patients with SD who are benefiting from treatment. Understanding SD would facilitate drug development and improve precision in correlative research.

PATIENTS AND METHODS

A systematic review was carried out to characterize SD in ICI trials. SD and objective response were compared to proliferation index using The Cancer Genome Atlas gene expression data. To identify a subgroup of SD with outcomes mirroring responders, we examined a discovery cohort of non-small-cell lung cancer (NSCLC). Serial cutpoints of two variables, % best overall response and progression-free survival (PFS), were tested to define a subgroup of patients with SD with similar survival as responders. Results were then tested in external validation cohorts.

RESULTS

Among trials of ICIs (59 studies, 14 280 patients), SD ranged from 16% to 42% in different tumor types and was associated with disease-specific proliferation index (ρ = -0.75, P = 0.03), a proxy of tumor kinetics, rather than relative response to ICIs. In a discovery cohort of NSCLC [1220 patients, 313 (26%) with SD to ICIs], PFS ranged widely in SD (0.2-49 months, median 4.9 months). The subset with PFS >6 months and no tumor growth mirrored partial response (PR) minor (overall survival hazard ratio 1.0) and was proposed as the definition of SD responder. This definition was confirmed in two validation cohorts from trials of NSCLC treated with durvalumab and found to apply in tumor types treated with immunotherapy in which depth and duration of benefit were correlated.

CONCLUSIONS

RECIST-defined SD to immunotherapy is common, heterogeneous, and may largely reflect tumor growth rate rather than ICI response. In patients with NSCLC and SD to ICIs, PFS >6 months and no tumor growth may be considered 'SD responders'. This definition may improve the efficiency of and insight derivable from clinical and translational research.

Clinical characteristics and molecular features of non-small cell lung cancers (NSCLCs) following disease progression on immune checkpoint inhibitors (ICIs)

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Background: ICIs are cornerstones of therapy for advanced NSCLC. Despite dramatic and sometimes durable responses to therapy, most patients (pts) either (i) do not respond to therapy (intrinsic resistance), or (ii) subsequently progress after initial clinical benefit (acquired resistance). Currently, insights into the molecular mechanisms of resistance to ICIs in NSCLC are lacking. Methods: To investigate clinical and molecular features of pts progressing on ICIs, we identified pts who underwent repeat tumor biopsies on and/or after disease progression on ICIs and were included in the Stand Up 2 Cancer (SU2C)/Mark Foundation multi-institutional cohort. Biopsy specimens underwent whole-exome sequencing (WES) and/or whole transcriptome sequencing (RNAseq). Results: We identified 37 pts who underwent a total of 47 repeat biopsies on or after ICIs. Six pts underwent multiple post-ICI biopsies (range 2-4). Twenty-five pts (68%) received PD-(L)1 inhibitor monotherapy, 6 (16%) received PD-(L)1 plus CTLA-4 inhibitors, and 6 (16%) received other PD-1 inhibitor-based combinations. Overall, the objective response rate was 46% among pts undergoing repeat biopsies (complete response 2 [5%], partial response 15 [41%], stable disease 14 [38%], progressive disease 5 [14%] and not evaluable 1 [3%]). Median progression-free survival (PFS) was 8.1 months. In total, pre-ICI biopsy specimens were available in 20 pts. WES and RNAseq were performed on 67 and 44 specimens, respectively. Median tumor mutation burden (TMB) in pre-ICI specimens was 5.0 mutations/Mb versus 4.9 mutations/Mb in post-ICI specimens ( p= 0.3, Mann-Whitney U test). Among 20 paired pre/post-ICI specimens, there was no significant difference in TMB (pre-treatment median 3.9 mutations/Mb; post-treatment median 4.3 mutations/Mb; p= 0.7, Wilcoxon signed-rank test). One pt with a complete response acquired a nonsense mutation in B2M, and one pt with a partial response acquired a nonsense mutation in JAK1. Among 10 paired pre/post-ICI specimens that underwent RNAseq, we observed significant decreases in granzyme B and perforin in post-ICI specimens ( p= 4×10-5 and p= 2×10-3, respectively, limma-voom analysis). Conclusions: Genomic alterations impairing antigen presentation (e.g., B2M) or immune activation (e.g., JAK1) may enable resistance to ICIs in a small subset of cases. However, the majority of repeat biopsies obtained from pts progressing on ICIs lacked clear genetic mediators of resistance, suggesting the presence of additional tumor-intrinsic and/or tumor-extrinsic factors underlying resistance to ICIs in NSCLC.

Multimodal integration of radiology, pathology, and genomics for prediction of response to PD-1 blockade in patients with non–small cell lung cancer

9064

Background: Immunotherapy is now given to almost all patients with advanced non-small cell lung cancer (NSCLC). However, developing robust biomarkers to predict benefit remains challenging. We set out to evaluate the predictive capacity of integrating medical imaging, histopathologic, and genomic features to develop a multimodal biomarker for immunotherapy response. Methods: We used baseline data that is routinely obtained during diagnostic clinical workup at a single center in patients with NSCLC and known outcomes following immunotherapy. The multimodal dataset included DNA alterations from NGS, CT scan images, and digitized PD-L1 immunohistochemistry (IHC) slides. Guided by experts in each field, we developed a workflow to extract data for each patient and used an attention-gated machine learning approach to integrate the features into a risk prediction model. Results: Our cohort included 247 patients with advanced NSCLC who received immunotherapy and had complete radiology, pathology, genomic, and clinical data. The patient cohort was 54% female, had a median age of 68 years (range 38-93), and 88% patients had a smoking history. Responders (CR/PR) vs non-responders (SD/PD) showed a median PFS and OS of 2.7 months (95% CI 2.5-3.0) and 11.4 months (95% CI 10.3-12.8), respectively. Of all patients, 187 (76%) had segmentable disease on chest CT scans. We used a radiomics approach and aggregated the average individual lesion predictions to construct patient-level response predictions which resulted in an overall AUC = 0.65, 95% CI 0.57-0.73. We next studied digitized FFPE slides of pre-treatment PD-L1 IHC staining of tumor specimens. Overall, 52% of slides showed PD-L1 tumor proportion score (TPS) ≥ 1% and were used to extract IHC-texture, a novel spatial characterization of PD-L1 staining. Logistic regression modeling on IHC-texture resulted in prediction accuracy of AUC = 0.62 (95% CI 0.51-0.73) which was inferior to the pathologist-assessed PD-L1 TPS (AUC = 0.73, 95% CI 0.65-0.81). We next implemented a dynamic deep attention-based multiple instance learning model with masking to evaluate the impact of combining features from all modalities. Our multimodal model (AUC = 0.80, 95% CI 0.74-0.86) outperformed unimodal measures, including tumor mutational burden (AUC = 0.61, 95% CI 0.52-0.70) and PD-L1 TPS (AUC = 0.73, 95% CI 0.65-0.81). Conclusions: Our study is a proof of concept for using multimodal features to improve prediction of immunotherapy response over standard-of-care approaches in patients with NSCLC using expert-guided machine learning.

Clinical definition of acquired resistance to immunotherapy in patients with metastatic non-small-cell lung cancer

Acquired resistance (AR) to programmed cell death protein 1/programmed death-ligand 1 [PD-(L)1] blockade is frequent in non-small-cell lung cancer (NSCLC), occurring in a majority of initial responders. Patients with AR may have unique properties of persistent antitumor immunity that could be re-harnessed by investigational immunotherapies. The absence of a consistent clinical definition of AR to PD-(L)1 blockade and lack of uniform criteria for ensuing enrollment in clinical trials remains a major barrier to progress; such clinical definitions have advanced biologic and therapeutic discovery. We examine the considerations and potential controversies in developing a patient-level definition of AR in NSCLC treated with PD-(L)1 blockade. Taking into account the specifics of NSCLC biology and corresponding treatment strategies, we propose a practical, clinical definition of AR to PD-(L)1 blockade for use in clinical reports and prospective clinical trials. Patients should meet the following criteria: received treatment that includes PD-(L)1 blockade; experienced objective response on PD-(L)1 blockade (inclusion of a subset of stable disease will require future investigation); have progressive disease occurring within 6 months of last anti-PD-(L)1 antibody treatment or rechallenge with anti-PD-(L)1 antibody in patients not exposed to anti-PD-(L)1 in 6 months.

Aligning tumor mutational burden (TMB) quantification across diagnostic platforms: phase II of the Friends of Cancer Research TMB Harmonization Project

BACKGROUND

Tumor mutational burden (TMB) measurements aid in identifying patients who are likely to benefit from immunotherapy; however, there is empirical variability across panel assays and factors contributing to this variability have not been comprehensively investigated. Identifying sources of variability can help facilitate comparability across different panel assays, which may aid in broader adoption of panel assays and development of clinical applications.

MATERIALS AND METHODS

Twenty-nine tumor samples and 10 human-derived cell lines were processed and distributed to 16 laboratories; each used their own bioinformatics pipelines to calculate TMB and compare to whole exome results. Additionally, theoretical positive percent agreement (PPA) and negative percent agreement (NPA) of TMB were estimated. The impact of filtering pathogenic and germline variants on TMB estimates was assessed. Calibration curves specific to each panel assay were developed to facilitate translation of panel TMB values to whole exome sequencing (WES) TMB values.

RESULTS

Panel sizes >667 Kb are necessary to maintain adequate PPA and NPA for calling TMB high versus TMB low across the range of cut-offs used in practice. Failure to filter out pathogenic variants when estimating panel TMB resulted in overestimating TMB relative to WES for all assays. Filtering out potential germline variants at >0% population minor allele frequency resulted in the strongest correlation to WES TMB. Application of a calibration approach derived from The Cancer Genome Atlas data, tailored to each panel assay, reduced the spread of panel TMB values around the WES TMB as reflected in lower root mean squared error (RMSE) for 26/29 (90%) of the clinical samples.

CONCLUSIONS

Estimation of TMB varies across different panels, with panel size, gene content, and bioinformatics pipelines contributing to empirical variability. Statistical calibration can achieve more consistent results across panels and allows for comparison of TMB values across various panel assays. To promote reproducibility and comparability across assays, a software tool was developed and made publicly available.

Lesion-level heterogeneity of radiologic progression in patients treated with pembrolizumab

BACKGROUND

Disease progression is often considered a binary state reflecting presence or absence of response. Meaningful heterogeneity between metastatic sites of a given patient may exist, however, and may impact therapeutic outcomes. To characterize the heterogeneity of progression with immunotherapy, we evaluated lesion-level dynamics of pembrolizumab-treated patients across three tumor types.

PATIENTS AND METHODS

Individual metastatic lesion dynamics were analyzed retrospectively in patients with advanced melanoma, non-small-cell lung cancer (NSCLC), and gastric or gastroesophageal junction (G/GEJ) cancer who received pembrolizumab in KEYNOTE-001 or KEYNOTE-059. Primary progression was defined as radiologic progression as per RECIST v1.1 occurring at the first on-treatment study scan (∼9-12 weeks, +2-week window) and secondary progression as progression occurring beyond the first scan (∼14 weeks and beyond). The change in sum of target lesions and of individual lesions was examined, as were patterns and timing of progression.

RESULTS

9239 individual lesions from 1194 patients were analyzed. Among patients with primary progression [39% (200/511) of patients with melanoma, 41% (179/432) with NSCLC, 61% (154/251) with G/GEJ cancer], most patients (51%-63%) had a mixture of growing, stable, and shrinking lesions. Despite overall primary progression, a minority of patients (19%-25%) had tumor growth at every metastatic site and 17%-32% had ≥1 shrinking lesion. Among patients with secondary progression [22% (113/511) of patients with melanoma, 27% (117/432) with NSCLC, 18% (44/251) with G/GEJ cancer], few patients had rebound growth (>20% increase in diameter from nadir) in all lesions whereas the majority (74%-84%) had sustained regression in ≥1 lesion.

CONCLUSIONS

Lesion-level heterogeneity at the time of disease progression was common in pembrolizumab-treated patients, with many patients demonstrating ongoing disease control in a subset of tumor sites. These results may inform clinical decision-making, trial design, and tumor sampling in the future.

IgE blockade with omalizumab reduces pruritus related to immune checkpoint inhibitors and anti-HER2 therapies

Background:

Immunoglobulin E (IgE) blockade with omalizumab has demonstrated clinical benefit in pruritus-associated dermatoses (e.g. atopic dermatitis, bullous pemphigoid, urticaria). In oncology, pruritus-associated cutaneous adverse events (paCAEs) are frequent with immune checkpoint inhibitors (CPIs) and targeted anti-human epidermal growth factor receptor 2 (HER2) therapies. Thus, we sought to evaluate the efficacy and safety of IgE blockade with omalizumab in cancer patients with refractory paCAEs related to CPIs and anti-HER2 agents.

Patients and methods:

Patients included in this multicenter retrospective analysis received monthly subcutaneous injections of omalizumab for CPI or anti-HER2 therapy-related grade 2/3 pruritus that was refractory to topical corticosteroids plus at least one additional systemic intervention. To assess clinical response to omalizumab, we used the Common Terminology Criteria for Adverse Events version 5.0. The primary endpoint was defined as reduction in the severity of paCAEs to grade 1/0.

Results:

A total of 34 patients (50% female, median age 67.5 years) received omalizumab for cancer therapy-related paCAEs (71% CPIs; 29% anti-HER2). All had solid tumors (29% breast, 29% genitourinary, 15% lung, 26% other), and most (n = 18, 64%) presented with an urticarial phenotype. In total, 28 of 34 (82%) patients responded to omalizumab. The proportion of patients receiving oral corticosteroids as supportive treatment for management of paCAEs decreased with IgE blockade, from 50% to 9% (P < 0.001). Ten of 32 (31%) patients had interruption of oncologic therapy due to skin toxicity; four of six (67%) were successfully rechallenged following omalizumab. There were no reports of anaphylaxis or hypersensitivity reactions related to omalizumab.

Conclusions:

IgE blockade with omalizumab demonstrated clinical efficacy and was well tolerated in cancer patients with pruritus related to CPIs and anti-HER2 therapies.

Safety of thoracic radiotherapy in patients with prior immune-related adverse events from immune checkpoint inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICIs) and thoracic radiotherapy are increasingly used to treat advanced cancers. Despite data indicating exaggerated radiation toxicities in patients with autoimmune disease, the safety of thoracic radiotherapy in patients with prior ICI-associated immune-related adverse events (irAEs) is undefined.

PATIENTS AND METHODS

Patients treated from 2014 to 2020 with ICIs were queried for receipt of corticosteroids and radiotherapy. Patients who received thoracic radiation after symptomatic irAEs were assessed for ≥grade 2 radiation pneumonitis (RP). Characteristics predictive of RP were assessed using logistic regression and response relationships were modeled.

RESULTS

Among 496 assessed patients, 41 with irAE history subsequently treated with thoracic radiotherapy were analyzed. Most irAEs were grade 2 (n = 21) and 3 (n = 19). Median time from irAE onset to radiotherapy was 8.1 months. Most patients received stereotactic body radiation therapy (n = 20) or hypofractionated radiotherapy (n = 18). In total, 25 patients (61%) developed ≥grade 2 RP at a median of 4 months from radiotherapy and 11 months from onset of irAEs. Three months from RP onset, 16 of 24 (67%) assessable patients had persistent symptoms. Among patients with prior ICI pneumonitis (n = 6), five patients (83%) developed ≥grade 2 RP (grade 2, n = 3; grade ≥3, n = 2). The mean lung radiation dose (MLD) predicted for RP (odds ratio: 1.60, P = 0.00002). The relationship between MLD and RP was strong (area under the receiver-operating characteristic curve: 0.85) and showed an exaggerated dose-response. Among patients with an MLD >5 Gy (n = 26), 21 patients (81%) developed ≥grade 2 RP.

CONCLUSION

This is the first study assessing the toxicity of radiotherapy among patients with prior irAEs from ICIs. Patients with prior irAEs were found to be at very high risk for clinically significant and persistent RP from thoracic radiotherapy. Careful consideration should be given to the possibility of an increased risk of RP, and close monitoring is recommended in these patients.

How to make the best use of immunotherapy as first-line treatment of advanced/metastatic non-small-cell lung cancer

Antibodies that target programmed death 1 (PD-1) or its ligand [programmed death ligand 1 (PD-L1)] have become a mainstay of first-line treatment of advanced/metastatic non-small-cell lung cancer (NSCLC) without targetable genetic alterations. In this review, we summarize results from recent clinical trials that have evaluated the anti-PD-1 antibodies pembrolizumab and nivolumab and the anti-PD-L1 antibodies atezolizumab and durvalumab as first-line treatment as monotherapy and in combination with chemotherapy, other immunotherapies, and antiangiogenesis agents. We discuss factors that may influence treatment selection, including patient baseline clinical and demographic characteristics, tumor histology, and biomarkers such as PD-L1 expression and tumor mutation burden. While immunotherapy has become a central component of first-line treatment of most patients with advanced NSCLC, important questions remain about how treatment should be managed for individual patients.

COVID-19 in patients with lung cancer

BACKGROUND

Patients with lung cancers may have disproportionately severe coronavirus disease 2019 (COVID-19) outcomes. Understanding the patient-specific and cancer-specific features that impact the severity of COVID-19 may inform optimal cancer care during this pandemic.

PATIENTS AND METHODS

We examined consecutive patients with lung cancer and confirmed diagnosis of COVID-19 (n = 102) at a single center from 12 March 2020 to 6 May 2020. Thresholds of severity were defined a priori as hospitalization, intensive care unit/intubation/do not intubate ([ICU/intubation/DNI] a composite metric of severe disease), or death. Recovery was defined as >14 days from COVID-19 test and >3 days since symptom resolution. Human leukocyte antigen (HLA) alleles were inferred from MSK-IMPACT (n = 46) and compared with controls with lung cancer and no known non-COVID-19 (n = 5166).

RESULTS

COVID-19 was severe in patients with lung cancer (62% hospitalized, 25% died). Although severe, COVID-19 accounted for a minority of overall lung cancer deaths during the pandemic (11% overall). Determinants of COVID-19 severity were largely patient-specific features, including smoking status and chronic obstructive pulmonary disease [odds ratio for severe COVID-19 2.9, 95% confidence interval 1.07-9.44 comparing the median (23.5 pack-years) to never-smoker and 3.87, 95% confidence interval 1.35-9.68, respectively]. Cancer-specific features, including prior thoracic surgery/radiation and recent systemic therapies did not impact severity. Human leukocyte antigen supertypes were generally similar in mild or severe cases of COVID-19 compared with non-COVID-19 controls. Most patients recovered from COVID-19, including 25% patients initially requiring intubation. Among hospitalized patients, hydroxychloroquine did not improve COVID-19 outcomes.

CONCLUSION

COVID-19 is associated with high burden of severity in patients with lung cancer. Patient-specific features, rather than cancer-specific features or treatments, are the greatest determinants of severity.

Locoregional control, failure patterns and clinical outcomes in patients with stage III non-small cell lung cancers treated with chemoradiation and durvalumab

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Background: Definitive concurrent chemoradiation (cCRT) and durvalumab is a standard therapy for patients with unresectable stage III non-small cell lung cancers (NSCLC). Data is limited on outcomes with this regimen outside of clinical trials. Local-regional control rates to date remain undefined. Methods: We reviewed patients with stage III unresectable NSCLC treated between November 2017 and February 2019 with cCRT. Patients that received at least one cycle of durvalumab were further assessed for 12-month progression free survival (PFS), overall survival (OS), and the incidence and pattern of local-regional and metastatic failures. Disease-relapse was characterized to determine patients potentially eligible for metastasis-directed ablative therapies. Toxicities leading to durvalumab discontinuation were evaluated using CTCAE v.5.0. Results: Of the 83 patients with stage III NSCLC treated with cCRT (median 60Gy), 62 received durvalumab and were evaluable (median follow-up: 12 months). Patients (n = 21, 25%) did not receive durvalumab largely related to metastatic progression (n = 9) or persistent cCRT toxicity (n = 10). In the 62 durvalumab treated patients the median age was 66 (range: 49 - 86), 73% had stage IIIB (n = 33) or IIIC (n = 12) disease, and 58% (n = 36) had adenocarcinoma. The median time from cCRT end to durvalumab start was 1.5 months. Patients received a median of 8 months of durvalumab; 35% (n = 22) of patients completed 12 months of therapy. Common reasons for discontinuing durvalumab included disease progression (32%, 20/62) and toxicity (24%, 15/62). The estimated 12-month PFS and OS were 65% (95% CI: 51 - 79%) and 85% (95% CI: 75 - 95%), respectively. High TMB (≥ 8.8 mt/Mb) or PD-L1 (≥ 1% or PD-L1 ≥ 50%) did not predict improved PFS. Patients who discontinued durvalumab due to toxicity did not have inferior PFS. The cumulative 12-month incidence of local-regional and distant metastatic failures were 18% (95% CI: 5.9 - 30%) and 30% (95% CI: 16.3 - 44.5%), respectively. Of the 17 patients with distant metastases, 9 had oligometastases and would have been potential candidates for comprehensive ablative therapies. Conclusions: Outcomes and toxicities outcomes with cCRT and durvalumab in clinical practice align with the PACIFIC trial. Analysis of disease-relapse suggests a substantial minority of patients with disease progression may be potential candidates for metastasis-directed therapies. Local regional outcomes appear improved to historical data of cCRT alone.

Long-term responders to PD-1 blockade in patients with advanced non-small cell lung cancer (NSCLC)

9549

Background: Long-term response – the plateau of the survival curve – is the transcendent benefit from PD-1 blockade. However, only a subset of responses achieve substantial durability. The frequency, characteristics, and predictors of long-term responders (LTR) to PD-1 blockade are not well known and may differ from short-term responders (STR). Methods: Patients with advanced NSCLC treated with anti-PD-1/PD-L1 therapy from two institutions (MSK and DFCI) were examined. Responses were assessed by RECIST. LTR was defined as PR/CR lasting ≥ 24 months. STR was defined as PR/CR lasting < 12 months. Comparisons were also made to patients with progressive disease (PD). PD-L1 expression was assessed by IHC. TMB was assessed by targeted NGS; high TMB was defined as ≥ median of the cohort. A subset had detailed molecular profiling by MSK-IMPACT. Fisher’s exact and Mann-Whitney U tests were used to compare features, and the log-rank test was used to compare survival. Results: Of 2318 patients (MSK n = 1536, DFCI n = 782), 126 (5.4%, 95% CI 4.6-6.4%) achieved LTR, with similar rates in both cohorts. STR occurred in 139 (6%). Overall survival was longer in LTR compared to STR (median NR vs 19.6 months, HR 0.07, p < 0.001). LTR had deeper responses compared to STR (median best overall response -69% vs -46%, p < 0.001). Patients with LTR were younger ( < 65 years old) and had increased TMB (≥ median mut/Mb) compared to both STR and PD (p = 0.006, p = 0.03; p < 0.001, p < 0.001). The rate of LTR was enriched among patients with both high TMB/high PD-L1 compared to those with low TMB/low PD-L1 (9% vs 1%, OR 9.2, p < 0.001), while STR was similar in both groups (7% vs 6%). 2% of patients with sensitizing EGFR mutations (n = 243) achieved LTR. Loss of function variants in ARID1A (14% vs 2%), PTEN (8% vs 0%), and KEAP1 (12% vs 2%) were enriched in LTR compared to STR (p < 0.05 for each). Among patients with KRAS mutations, the rate of LTR was higher in those with co-mutation with TP53 compared to STK11 (11% vs 2%, p = 0.01). Conclusions: Long-term response (LTR, ongoing response ≥ 24 months) to PD-1 blockade is an uncommon but profound clinical outcome in metastatic lung cancers. Younger age and high TMB correlate with LTR; the combination of high TMB/high PD-L1 enriches for LTR but not STR. Features predicting long term response may be distinct from those predicting initial response.

CT and PET radiomic features associated with major pathologic response to neoadjuvant immunotherapy in early-stage non-small cell lung cancer (NSCLC)

9031

Background: An early biomarker of response to immunotherapy (IO) is needed urgently to identify the patients (pts) who will derive benefit. We reported the first clinical trial of neoadjuvant IO (nIO) in resectable non-small cell lung cancer (NSCLC) (NCT02259621). In this study, we investigated whether there was an association between MPR and radiomic features (RF) in [18F]-fluorodeoxyglucose ([18F]-FDG) PET and standard CT images obtained at baseline and after nIO in early stage NSCLC tumors. Methods: Prior to receiving neoadjuvant nivolumab or nivolumab/ipilimumab, patients with Stage I-IIIA NSCLC underwent two [18F]-FDG PET-CTs and/or plain CTs: a baseline scan at enrollment (PRE), and after nIO (POST). After neoadjuvant treatment, tumors were resected and evaluated for MPR. Volumes of interest (VOIs) were drawn around primary tumors on the scans. Using our novel radiomic software, Imager-4D, VOIs were evaluated for 20 RFs assessing [18F]-FDG standard uptake value (SUV) or Hounsfield unit (HU) heterogeneity and spatial distribution in PET and CT images respectively. The baseline, post-treatment, and percent change in RFs before and after nIO were compared between tumors with and without MPR. Wilcoxon test was used for the comparisons. Results: The PRE and POST scans of 24 pts were analyzed. All pts had PRE and POST CTs performed, and 17 pts had PRE and POST [18F]-FDG PET-CT scans. 7 of 24 (29%) had MPR. In the CT scan analysis, HU-based RFs of voxel count, total volume, energy, entropy, homogeneity, contrast, and dissimilarity in POST CT scans each significantly association with MPR. In the PET scan analysis, SUV mean and voxel count RFs in the POST scans, and the percent change in the cluster shade RF between PRE and POST scans were significantly associated with MPR. Conclusions: Collectively, we identified a significant increase in heterogeneity in the POST CT images of NSCLC tumors that had MPR. This association may reflect increased T cell infiltration or tumor necrosis. In contrast, most [18F]-FDG-based RFs did not distinguish MPR vs non-MPR tumors, although the sample size was limited. We will further investigate these HU-based RFs as non-invasive markers of response to IO in conjunction with pathologic markers of IO response and in a larger patient cohort.

Nivolumab + ipilimumab versus platinum-doublet chemotherapy as first-line treatment for advanced non-small cell lung cancer: Three-year update from CheckMate 227 Part 1

9500

Background: In the phase 3 CheckMate 227 Part 1 (NCT02477826; minimum follow-up, 29.3 mo), 1L NIVO + IPI significantly improved overall survival (OS) vs chemo in treatment-naive patients (pts) with aNSCLC and tumor PD-L1 expression ≥ 1% (primary analysis) or < 1% (pre-specified descriptive analysis). Here we report data with 3-y minimum follow-up. Methods: Pts with stage IV / recurrent NSCLC and PD-L1 ≥ 1% (n = 1189) were randomized 1:1:1 to NIVO (3 mg/kg Q2W) + IPI (1 mg/kg Q6W), NIVO (240 mg Q2W) alone, or chemo. Pts with PD-L1 < 1% (n = 550) were randomized to NIVO + IPI, NIVO (360 mg Q3W) + chemo, or chemo. Primary endpoint was OS with NIVO + IPI vs chemo in pts with PD-L1 ≥ 1%. An exploratory analysis of OS in pts by response status (CR/PR, SD, progressive disease [PD]) at 6 mo was conducted. Results: After a median follow-up of 43.1 mo (database lock, 28 Feb 2020), pts with PD-L1 ≥ 1% continued to derive OS benefit from NIVO + IPI vs chemo (HR: 0.79; 95% CI, 0.67–0.93); 3-y OS rates were 33% (NIVO + IPI), 29% (NIVO), and 22% (chemo). At 3 y, 18% of pts with PD-L1 ≥ 1% treated with NIVO + IPI remained progression-free vs 12% with NIVO and 4% with chemo; 38% of confirmed responders remained in response in the NIVO + IPI arm at 3 y vs 32% in the NIVO arm and 4% in the chemo arm. In pts with PD-L1 < 1%, OS HR for NIVO + IPI vs chemo was 0.64 (95% CI, 0.51–0.81); 3-y OS rates were 34% (NIVO + IPI), 20% (NIVO + chemo), and 15% (chemo); 13%, 8%, and 2% of pts remained progression-free; and 34%, 15%, and 0% of confirmed responders remained in response, respectively. Pts with PD-L1 ≥ 1% with either CR/PR at 6 mo had longer subsequent OS with NIVO + IPI vs chemo; pts with SD or PD at 6 mo had generally similar subsequent OS between treatments (Table); results in PD-L1 < 1% pts will be presented. Any-grade / grade 3–4 treatment-related AEs were observed in 77% / 33% of all pts treated with NIVO + IPI, and 82% / 36% with chemo. Conclusions: With 3 y minimum follow-up, NIVO + IPI continued to provide durable and long-term OS benefits vs chemo for pts in 1L aNSCLC. Pts with PD-L1 ≥ 1% who achieved CR/PR at 6 mo had marked OS benefit with NIVO + IPI vs chemo. No new safety signals were identified for NIVO + IPI. Clinical trial information: NCT02477826. [Table: see text]

Early ctDNA response assessment for prediction of platinum sensitivity in small cell lung cancer

9067

Background: Small cell lung cancer (SCLC) is an aggressive disease, characterized by inevitable chemotherapy resistance and rapid progression. We hypothesized that circulating tumor DNA (ctDNA) analysis can rapidly identify sensitivity to platinum-based therapy. Methods: Patients with SCLC at Memorial Sloan Kettering Cancer Center underwent serial plasma collections, including prior to the start of treatment and prior to Cycle 2 Day 1 of therapy (C2D1). Tumor mutations were identified from pre-treatment biopsies by MSK-IMPACT and/or pre-treatment plasma by CAncer Personalized Profiling by deep Sequencing (CAPP-Seq). Median variant allele fraction (VAF) of all mutations was monitored on subsequent blood draws using CAPP-Seq. Progression free survival (PFS) was measured from the time of first pre-treatment blood draw. Results: Plasma was collected from 19 patients treated with carboplatin and etoposide, including three who received concurrent atezolizumab. Seven were female, and mean age was 64.5 years. ctDNA was detected in 17 patients (89%), including in the two patients in our series with limited stage disease. The most common mutations were in TP53 and RB1 in 14 and 6 patients, respectively. Fourteen patients had available plasma at C2D1. At baseline prior to treatment, median VAF did not differ significantly between radiologic responders and non-responders (9.4% versus 30.3%, p = 0.35). After one cycle of chemotherapy, the VAF percent decrease was significantly more in responders versus non-responders (-96.9% versus -10.3%, p < 0.001). Median VAF was therefore significantly lower by C2D1 in patients who responded compared to non-responders (0.51% versus 27.2%, p = 0.02). Those who ultimately responded to therapy all had a > 2 fold decrease in VAF by C2D1. With a median follow-up of 180 days, PFS was significantly longer in patients with > 2 fold decrease in VAF by C2D1 (6.4 versus 1.9 months, log rank p < 0.001). Conclusions: A 2-fold decrease in plasma VAF by C2D1 predicted platinum-sensitivity in SCLC and was associated with longer PFS. ctDNA may permit early assessment of benefit and expedite alternative treatment options for those without significant decrease in median VAF after one cycle of therapy.

Molecular subtypes and clinical outcomes to initial systemic treatment in patients with small cell lung cancer

9018

Background: Investigators have proposed that differential expression of the transcription regulators ASCL1 and NeuroD1 can be used to define molecular subtypes of small cell lung cancers (SCLCs). Here we evaluate SCLC subtypes based on ASCL1 and NeuroD1 expression in patients (pts) treated with first-line (1L) chemotherapy profiled with targeted next-generation sequencing (NGS). Methods: We used NGS (MSK-IMPACT) to profile tumors from pts with SCLCs. We performed IHC to assess ASCL1 (A) or NeuroD1 (N). Objective response rate (ORR) to therapy was determined using RECIST. PFS and OS were analyzed using Kaplan-Meier. Results: 281 pts with SCLCs were profiled with NGS (102 LS-SCLC; 179 ES-SCLC). Most frequently mutated genes were TP53 (90%), RB1 (68%), KMT2D (22%), NOTCH1 (15%), FAT1 (14%), PTPRD (12%). Mutations in BIRC3, FOXL2, TENT5C, TET1, NRAS, KIT, TSHR, ESR1 were enriched in ASCL1-/NeuroD1+ (A-/N+), and mutations in KMT2D and EP300 were enriched in A-/N- (p<0.05). Copy number alterations in WWTR1, ATR, IKZF1, PALB2, PIK3CB were enriched in A-/N+ (p<0.05). IHC for ASCL1 and NeuroD1 was performed on 78 samples: 11 A-/N-, 32 A+/N-, 4 A-/N+, 31 A+/N+. Overall survival at 1 year based on subtype was 25% in A-/N- (2/9), 60% in A-/N+ or A+/N- (13/32), and 55% in A+/N+ (10/25). For the 10 pts who survived 2 years, 5 were A+/N- and 5 were A+/N+. 146 pts treated with 1L platinum had RECIST-evaluable disease. ORR was 75% (110/146; 95% CI 68-82%). Median PFS was 7 months with CR/PR and 3.5 months with SD/PD (HR 0.32; 95% CI 0.18-0.56). Median OS was 17 months with CR/PR and 11 months with SD/PD (HR 0.55; 95% CI 0.34-0.9). Mutations in RUNX1, EPHA7, CDKN2A, FLT1 and copy number alterations in FGFR1, CCND1 were enriched in patients with SD/PD (p<0.05). PFS rate at 6 months was 25% in A-N- (1/4), 60% in A-/N+ or A+/N- (9/15), and 55% in A+/N+ (6/11). For the 7 pts who survived 2 years, 3 were A+/N- and 4 were A+/N+. Conclusions: Molecular subtypes defined by ASCL1 and NeuroD1 encompass molecular characteristics that may predict patient outcomes. Further investigation is needed to delineate the underlying biological differences among the various subtypes to help define therapeutic vulnerabilities of each subtype of SCLC. Completion of IHC for ASCL1, NeuroD1 and additional key transcription factors POU2F3 and YAP1 are in progress for the entire cohort. WES and RNA sequencing are occurring in parallel and will be correlated with IHC results and clinical outcomes.

Acquired resistance to PD-1 blockade in NSCLC

9621

Background: Although durability is the trademark characteristic of response to PD-1 blockade, acquired resistance can occur. The frequency, patterns, and survival outcomes of patients with acquired resistance to PD-1 blockade are unknown. Methods: All patients with NSCLC treated with PD-1 blockade at MSKCC were examined. Acquired resistance was defined as initial CR/PR (by RECIST) followed by progression/death. Oligo vs systemic patterns of acquired resistance were defined as progression in ≤ 2 sites of disease or ≥ 3 sites of disease, respectively. Results: Of 1201 patients treated with PD-1 blockade, 243 (20%) achieved initial response and 189 (78%, 95% CI 72-83%) eventually developed acquired resistance (AR). Onset of AR was variable and decreased with longer duration of response (53% within 1 year, 37% 1-2 years, 10% > 2 years). Patients with PD-L1 expression < 50% and TMB < 8mut/Mb were more likely to develop resistance compared those with PD-L1 expression ≥50% and TMB ≥8mut/Mb (OR 5.5, p = 0.02). Unlike organ sites of primary refractory disease, AR commonly occurred in lymph nodes (41%) and infrequently in the liver (6%). Patterns of AR were most commonly oligo rather than systemic (79/141 [56%], 39/141 [28%]); some patients died without radiographic progression (23/141 [16%]). Oligo-AR occurred later (median onset 13 vs 5.6 mo) and associated with improved post-progression survival (median OS 55.2 vs 9.2 mo, HR 6.0, p < 0.001) compared to systemic-AR. Post-progression survival was highest in patients with AR compared to those with initial SD or PD to PD-1 blockade (median 18.9 vs 12.5 vs 4.4, p < 0.001). Of 49 patients treated initially with locally-directed therapy for AR, 28 (57%) remain alive and systemic therapy-free. Conclusions: Acquired resistance to PD-1 blockade is common in NSCLC. Risk of acquired resistance is lower in biomarker-enriched patients and with increased duration of response. Patterns of acquired resistance is commonly oligo in nature, which is amenable to locally-directed therapy and can be associated with improved survival. Differences in organ-site distribution and post-progression survival suggest distinct biology associated with acquired resistance vs primary refractory disease.

Success and failure of additional immunosuppressants in steroid-refractory pneumonitis related to immune checkpoint blockade

3078

Background: Severe immune related adverse events (irAEs) with immune checkpoint blockade are uncommon but can be fatal. Steroids are the most common initial treatment for most non-endocrine irAEs, but some patients are or become refractory to steroids. When steroids are not effective, there is limited data to guide management strategies, particularly in the context of pneumonitis. Methods: All patients at MSK treated with immune checkpoint blockade from 2013-2020 were queried for receipt of an immunosuppressant (e.g. TNF antagonists, mycophenolate mofetil, cyclophosphamide) beyond steroids. Patient records were then manually reviewed to identify patients who received such therapy for management of immunotherapy-related pneumonitis. Results: Among 5363 patients treated with immune checkpoint blockade, 364 (6.8%) received an additional immunosuppressant for an irAE, including 28 (0.5% of all patients treated) patients treated for pneumonitis. Most of these pneumonitis events (19/28, 68%) were grade 3 or higher. Agents used included mycophenolate mofetil (7/28; 25%), TNF antagonists (23/28; 82%), and cyclophosphamide (1/28; 3.5%); more than one medication was used in 3 patients (11%). The indications were primary non-response to steroids (n = 16, 57%) and recrudescence after initial response to steroids (n = 12, 43%). At 90 days from initiation of the additional immunosuppressant, 13/28 (46%) patients were alive with improvement or resolution of pneumonitis while 15/28 (54%) had died. Survival with resolution/improvement was more common in patients treated for recrudescence vs primary non-response (67% vs 25%, p = 0.05). Conclusions: Outcomes with additional immunosuppressants in the setting of steroid-refractory immune-related pneumonitis are poor, but resolution can occur in some cases. A deeper understanding of the mechanistic underpinnings of irAEs is needed to more effectively tailor immunosuppressant therapies, particularly in severe pneumonitis events.

Nivolumab (NIVO) plus ipilimumab (IPI) with two cycles of chemotherapy (chemo) in first-line metastatic non-small cell lung cancer (NSCLC): CheckMate 568 Part 2

9560

Background: In Part 1 of the phase II CheckMate 568 study (NCT02659059), NIVO + IPI was active and tolerable in patients (pts) with advanced NSCLC. The addition of chemo to dual immune checkpoint inhibitor therapy may further improve initial disease control. We report results from Part 2 of CheckMate 568, which evaluates NIVO + IPI combined with 2 cycles of chemo in pts with advanced treatment-naive NSCLC. Methods: Adult pts with untreated stage IV NSCLC received NIVO 360 mg Q3W + IPI 1 mg/kg Q6W combined with 2 cycles of histology-based platinum-doublet chemo, followed by NIVO + IPI without chemo until disease progression/unacceptable toxicity for ≤ 2 years. The primary endpoints were dose-limiting toxicity (DLT) within the first 9 weeks and safety/tolerability. Treatment was considered safe if ≤ 25% of at least 22 evaluable pts had a DLT. DLTs included but were not limited to: uncontrolled grade 3 non-skin treatment-related adverse events (TRAEs), grade 4 TRAEs, grade 2 treatment-related pneumonitis not resolved within 14 days, and treatment-related hepatic function abnormalities. Results: In total, 36 pts received treatment; 97% of pts completed 2 cycles of chemo combined with NIVO + IPI. Three pts discontinued IPI while continuing NIVO. Minimum follow-up was 14.9 months. Only 1 (3%) pt experienced a DLT (transient, asymptomatic grade 3 AST and ALT elevation) within the first 9 weeks. The elevation occurred on cycle 1, day 21 and resolved 2 weeks later with discontinuation of IPI, delay of NIVO, and treatment with prednisone; chemo was continued throughout and NIVO was restarted thereafter without recurrent toxicity. Grade 3–4 TRAEs occurred in 21 (58%) pts. Eight (22%) pts experienced a TRAE leading to discontinuation, most commonly colitis, encephalopathy, pneumonitis, and arthralgia (each in 2 [6%] pts); these events occurred outside of the 9-week window for DLT assessment. The most common select TRAEs (defined as AEs of potential immunologic causes) were skin related (18 [50%] pts); the most common grade 3–4 select TRAEs were endocrine (3 [8%] pts), skin related, gastrointestinal, and pulmonary (each in 2 [6%] pts). No treatment-related deaths occurred. Updated safety in addition to efficacy data will be presented. Conclusions: In pts with untreated advanced NSCLC, the addition of 2 cycles of platinum-doublet chemo to NIVO + tumor-optimized IPI was tolerable. No unexpected safety signals were observed. Clinical trial information: NCT02659059 .

Effect of STK11 mutations on efficacy of PD-1 inhibition in non-small cell lung cancer (NSCLC) and dependence on KRAS mutation status

e15113

Background: STK11 mutations ( STK11m) have been associated with resistance to ICI in KRAS-mutant ( KRASm) NSCLC. Whether STK11m status also impacts clinical outcomes to ICI in KRAS wild-type (wt) NSCLC is unknown. Methods: We analyzed clinical outcomes of patients (pts) with NSCLC treated with ICI according to KRAS and STK11 mutation status in independent discovery (DFCI+MGH) and validation (MSKCC) cohorts. TCGA and xCell data were interrogated to identify differences in tumor gene expression and tumor immune cell subsets, respectively, according to KRAS/ STK11 co-mutation status. Results: Of 1195 pts with advanced nonsquamous NSCLC treated with ICI, 447 (37.4%) had a KRASm, 252 (21.1%) had pathogenic STK11 mutations, and 128 (10.7%) had concurrent KRASm and STK11m. ICI outcomes for the discovery and validation cohorts in KRASm and KRASwt cases by STK11 mutation status are shown in Table. In the combined cohort (discovery+validation), STK11m was associated with significantly worse outcomes to ICI among KRASm cases: ORR 10.2% vs 30.7%, P < 0.001; median progression-free survival (mPFS): 2.0 vs 4.8 months (mo), HR:0.49 [95%CI:0.39-0.61], P < 0.0001; median overall survival (mOS): 6.1 vs 16.9 mo, HR:0.50 [95%CI:0.39-0.63], P < 0.0001. In multivariable analysis, STK11m was associated with significantly shorter PFS (HR:0.56, P = 0.002) and OS (HR:0.57, P = 0.006). By contrast, STK11m had no impact on ICI outcomes among KRASwt cases: ORR 24.2% vs 19.2%, P = 0.21; mPFS: 2.5 vs 2.8 mo, HR:0.98 [95%CI:0.79-1.21], P = 0.89; mOS: 12.0 vs 11.5 mo, HR:1.06 [95%CI:0.85-1.33], P = 0.57. Among KRASwt cases, STK11m had no impact on ICI outcomes among both smokers and never smokers, when analyzed separately. Gene ontology analysis from TCGA revealed that among KRASm but not KRASwt NSCLC, STK11m was associated with the downregulation of MHC class II-related genes (P = 0.02). Cell subset transcriptome analysis showed significantly lower proportions of M1 macrophages among KRASm/ STK11m but not among KRASwt/ STK11m NSCLCs (P < 0.01). Conclusions: STK11m are associated with resistance to ICI in KRASm but not KRASwt NSCLC. STK11m/ KRASm vs STK11m/ KRASwt NSCLC have distinct immunophenotypes. [Table: see text]

Outcomes to first-line pembrolizumab in patients with PD-L1-high (≥50%) non-small-cell lung cancer and a poor performance status

9568

Background: Patients with non-small cell lung cancer (NSCLC) and a poor Eastern Cooperative Oncology Group performance status (ECOG PS) have been excluded from immunotherapy clinical trials. We sought to evaluate clinical outcomes to first-line pembrolizumab in patients with advanced NSCLC, a PD-L1 tumor proportion score (TPS) of ≥50%, and an ECOG PS of 2. Methods: We performed a multicenter retrospective analysis of patients with metastatic NSCLC and a PD-L1 tumor proportion score (TPS) of ≥50% (negative for genomic alterations in EGFR and ALK) who received treatment with first-line commercial pembrolizumab. Clinical outcomes were compared in patients based on ECOG PS. Results: Among 234 patients, 83.3% (N = 195) had an ECOG PS of 0 or 1, and 16.7% (N = 39) had an ECOG PS of 2. The baseline clinicopathological characteristics were balanced between the ECOG PS 0-1 vs 2 groups in terms of age, sex, tobacco use, histology, KRAS mutation status, presence of other potentially targetable driver mutations ( BRAF, MET, HER2, RET), history of central nervous system (CNS) disease, and PD-L1 TPS distribution. Compared to patients with an ECOG PS of 0-1, patients with an ECOG PS of 2 had a significantly lower objective response rate (ORR 43.1% vs 25.6%; P = 0.04), a numerically shorter median progression free survival (mPFS 6.6 months vs 4.0 months; P = 0.09), and a significantly shorter median overall survival (mOS 20.3 months vs 7.4 months; P < 0.001). Upon disease progression, patients with an ECOG PS of 2 were significantly less likely to receive second-line systemic therapy compared to patients with an ECOG PS of 0-1 (55.5% vs 14.3%, P < 0.001). Conclusions: Although a subset of patients with an ECOG PS of 2 can respond first-line pembrolizumab, clinical outcomes in this population are poor, and use of second-line systemic therapy is infrequent.

Clinical characteristics and anti-PD-(L)1 treatment outcomes of KRAS-G12C mutant lung cancer compared to other molecular subtypes of KRAS-mutant lung cancer

9596

Background: KRAS mutations are identified in approximately 30% of NSCLC. There are no FDA approved targeted therapies for patients with KRAS-mutant non-small cell lung cancer (NSCLC) but novel direct inhibitors of KRAS G12C have shown some activity in early phase clinical trials. We hypothesized that patients with KRAS-G12C mutations may have distinct clinical characteristics and responses to systemic therapies compared to patients with non-G12C subtypes. Methods: We identified patients with KRAS-mutant lung cancers who underwent next-generation sequencing with MSK-IMPACT, between January 2014 and December 2018. Baseline characteristics were compared with the Chi-square and Fisher’s exact test for categorical data and Wilcoxon rank-rum test for continuous data. Overall survival was calculated from time of diagnosis of metastatic/recurrent disease to date of death or last follow up, with left truncation to account for time of MSK-IMPACT. Overall survival was compared between groups using the Cox proportional-hazards model. Response evaluations where performed by independent thoracic radiologists according to RECIST 1. and compared between group with the Fisher’s exact test. Results: We identified 1194 patients with KRAS -mutant NSCLC, 772 with recurrent or metastatic disease. Of patients with advanced disease, 46% (352/772) had mutations in KRAS-G12C and 54% harbored non-G12C mutations (15% G12D, 16% G12V, 8% G12A, 4% G13D). Co-mutation patterns were similar with respect to KEAP1 (p=0.9) and STK11 (p=1.0). Patients with non-G12C mutations had a higher proportion of never smokers (10% vs 1.4% p<0.001). The median OS from diagnosis was 13 months for G12C and non-G12C patients (p=0.99). 45% (347/772) received 1L or 2L line treatment with PD-(L)1 inhibitor. RECIST measurements were available for 290/347 cases (84%). ORR with anti-PD-(L)1 treatment was 24% vs 28% in G12C vs non-G12C patients (p=0.5). In patients with PD-L1 50% (n=103), ORR was 39% for G12C vs 58% non-G12C patients (p=0.06). Conclusions: KRAS G12C mutations are present in 12% of patients with NSCLC and represent a relevant subtype of NSCLC given KRAS G12C inhibitors now in clinical development. Baseline characteristics including co-mutation patterns are similar between patients with G12C and non-G12C, except for smoking history. The efficacy of KRAS G12C direct inhibitors will need to be compared to other available therapies for KRAS mutant NSCLC (chemotherapy and PD-(L)1 inhibitors) to identify most effective therapeutic strategy.

Pathologic features of response to neoadjuvant anti-PD-1 in resected non-small-cell lung carcinoma: a proposal for quantitative immune-related pathologic response criteria (irPRC)

Background

Neoadjuvant anti-PD-1 may improve outcomes for patients with resectable NSCLC and provides a critical window for examining pathologic features associated with response. Resections showing major pathologic response to neoadjuvant therapy, defined as ≤10% residual viable tumor (RVT), may predict improved long-term patient outcome. However, %RVT calculations were developed in the context of chemotherapy (%cRVT). An immune-related %RVT (%irRVT) has yet to be developed.

Patients and methods

The first trial of neoadjuvant anti-PD-1 (nivolumab, NCT02259621) was just reported. We analyzed hematoxylin and eosin-stained slides from the post-treatment resection specimens of the 20 patients with non-small-cell lung carcinoma who underwent definitive surgery. Pretreatment tumor biopsies and preresection radiographic 'tumor' measurements were also assessed.

Results

We found that the regression bed (the area of immune-mediated tumor clearance) accounts for the previously noted discrepancy between CT imaging and pathologic assessment of residual tumor. The regression bed is characterized by (i) immune activation-dense tumor infiltrating lymphocytes with macrophages and tertiary lymphoid structures; (ii) massive tumor cell death-cholesterol clefts; and (iii) tissue repair-neovascularization and proliferative fibrosis (each feature enriched in major pathologic responders versus nonresponders, P < 0.05). This distinct constellation of histologic findings was not identified in any pretreatment specimens. Histopathologic features of the regression bed were used to develop 'Immune-Related Pathologic Response Criteria' (irPRC), and these criteria were shown to be reproducible amongst pathologists. Specifically, %irRVT had improved interobserver consistency compared with %cRVT [median per-case %RVT variability 5% (0%-29%) versus 10% (0%-58%), P = 0.007] and a twofold decrease in median standard deviation across pathologists within a sample (4.6 versus 2.2, P = 0.002).

Conclusions

irPRC may be used to standardize pathologic assessment of immunotherapeutic efficacy. Long-term follow-up is needed to determine irPRC reliability as a surrogate for recurrence-free and overall survival.

Clinical activity of programmed cell death 1 (PD-1) blockade in never, light, and heavy smokers with non-small-cell lung cancer and PD-L1 expression ≥50

Background:

Immune checkpoint inhibitors (ICIs) are standard therapies for patients with advanced non-small-cell lung cancer (NSCLC) and a programmed death-ligand 1 (PD-L1) tumor proportion score (TPS) ≥50%. Tumor mutation burden (TMB) also predicts response to ICIs but is often not available in real time for decision making in the first-line setting. Smoking exposure can be a proxy for TMB in NSCLC. The impact of smoking status on efficacy of PD-1 blockade in NSCLC patients with PD-L1 TPS ≥50% has not been well defined.

Patients and methods:

To investigate the relationship between smoking and activity of ICIs in NSCLC, we retrospectively studied 315 patients with NSCLC and PD-L1 TPS ≥50% at five USA academic medical centers. Objective response rates (ORRs), progression-free survival (PFS), and duration of response (DOR) were compared between never (<100 lifetime cigarettes), light (≤10 pack-years), and heavy (>10 pack-years) smokers. A subset of patients underwent next-generation sequencing to estimate TMB.

Results:

We identified 36 (11%) never, 42 (13%) light, and 237 (75%) heavy smokers with NSCLC and PD-L1 TPS ≥50% treated with ICIs. Objective responses were observed in 27%, 40%, and 40% of never, light, and heavy smokers, respectively (P = 0.180 never versus heavy; P = 1.000 light versus heavy). Median PFS and median DOR were numerically shorter in never and light smokers compared with heavy smokers (PFS 3.0 versus 4.0 versus 5.4 months; median DOR 6.9 versus 10.8 versus 17.8 months), but were not statistically different [PFS: hazard ratio (HR) 1.37, P = 0.135 and HR 1.24, P = 0.272; DOR: HR 1.92, P = 0.217 and HR 1.79, P = 0.141].

Conclusions:

PD-(L)1 inhibitors are associated with antitumor activity in NSCLC with PD-L1 TPS ≥50% regardless of smoking status. Nevertheless, there is a signal of potentially decreased durability among never and light smokers that should be further evaluated. Distinct immunobiologic features may affect initial response versus durability of antitumor immunity to programmed cell death 1 (PD-1) blockade.

PD-L1 expression, tumor mutational burden, and response to immunotherapy in patients with MET exon 14 altered lung cancers

Background

MET exon 14 alterations are actionable oncogenic drivers. Durable responses to MET inhibitors are observed in patients with advanced MET exon 14-altered lung cancers in prospective trials. In contrast, the activity of immunotherapy, PD-L1 expression and tumor mutational burden (TMB) of these tumors and are not well characterized.

Patients and methods

Patients with MET exon 14-altered lung cancers of any stage treated at two academic institutions were identified. A review of clinicopathologic and molecular features, and an analysis of response to single-agent or combination immune checkpoint inhibition were conducted. PD-L1 immunohistochemistry was carried out and TMB was calculated by estimation from targeted next-generation sequencing panels.

Results

We identified 147 patients with MET exon 14-altered lung cancers. PD-L1 expression of 0%, 1%-49%, and ≥50% were 37%, 22%, and 41%, respectively, in 111 evaluable tumor samples. The median TMB of MET exon 14-altered lung cancers was lower than that of unselected non-small-cell lung cancers (NSCLCs) in both independently evaluated cohorts: 3.8 versus 5.7 mutations/megabase (P < 0.001, n = 78 versus 1769, cohort A), and 7.3 versus 11.8 mutations/megabase (P < 0.001, n = 62 versus 1100, cohort B). There was no association between PD-L1 expression and TMB (Spearman's rho=0.18, P = 0.069). In response-evaluable patients (n = 24), the objective response rate was 17% (95% CI 6% to 36%) and the median progression-free survival was 1.9 months (95% CI 1.7-2.7). Responses were not enriched in tumors with PD-L1 expression ≥50% nor high TMB.

Conclusion

A substantial proportion of MET exon 14-altered lung cancers express PD-L1, but the median TMB is lower compared with unselected NSCLCs. Occasional responses to PD-1 blockade can be achieved, but overall clinical efficacy is modest.

Outcomes to first-line pembrolizumab in patients with non-small-cell lung cancer and very high PD-L1 expression

BACKGROUND

In non-small-cell lung cancers with programmed death-ligand 1 (PD-L1) expression on ≥50% of tumor cells, first-line treatment with the PD-1 inhibitor pembrolizumab improves survival compared with platinum-doublet chemotherapy. Whether higher PD-L1 levels within the expression range of 50%-100% predict for even greater benefit to pembrolizumab is currently unknown.

PATIENTS AND METHODS

In this multicenter retrospective analysis, we analyzed the impact of PD-L1 expression levels on the overall response rate (ORR), median progression-free survival (mPFS), and median overall survival (mOS) in patients who received commercial pembrolizumab as first-line treatment of non-small-cell lung cancer (NSCLC) with a PD-L1 expression of ≥50% and negative for genomic alterations in the EGFR and ALK genes .

RESULTS

Among 187 patients included in this analysis, the ORR was 44.4% [95% confidence interval (CI) 37.1% to 51.8%], the mPFS was 6.5 months (95% CI 4.5-8.5), and the mOS was not reached. The median PD-L1 expression level among patients who experienced a response to pembrolizumab was significantly higher than among patients with stable or progressive disease (90% versus 75%, P < 0.001). Compared with patients with PD-L1 expression of 50%-89% (N = 107), patients with an expression level of 90%-100% (N = 80) had a significantly higher ORR (60.0% versus 32.7%, P < 0.001), a significantly longer mPFS [14.5 versus 4.1 months, hazard ratio (HR) 0.50 (95% CI 0.33-0.74), P < 0.01], and a significantly longer mOS [not reached versus 15.9 months, HR 0.39 (95% CI 0.21-0.70), P = 0.002].

CONCLUSION

Among patients with NSCLC and PD-L1 expression of ≥50% treated with first-line pembrolizumab, clinical outcomes are significantly improved in NSCLCs with a PD-L1 expression of ≥90%. These findings have implications for treatment selection as well as for clinical trial interpretation and design.

EGFR mutation subtypes and response to immune checkpoint blockade treatment in non-small-cell lung cancer

BACKGROUND

Although EGFR mutant tumors exhibit low response rates to immune checkpoint blockade overall, some EGFR mutant tumors do respond to these therapies; however, there is a lack of understanding of the characteristics of EGFR mutant lung tumors responsive to immune checkpoint blockade.

PATIENTS AND METHODS

We retrospectively analyzed de-identified clinical and molecular data on 171 cases of EGFR mutant lung tumors treated with immune checkpoint inhibitors from the Yale Cancer Center, Memorial Sloan Kettering Cancer Center, University of California Los Angeles, and Dana Farber Cancer Institute. A separate cohort of 383 EGFR mutant lung cancer cases with sequencing data available from the Yale Cancer Center, Memorial Sloan Kettering Cancer Center, and The Cancer Genome Atlas was compiled to assess the relationship between tumor mutation burden and specific EGFR alterations.

RESULTS

Compared with 212 EGFR wild-type lung cancers, outcomes with programmed cell death 1 or programmed death-ligand 1 (PD-(L)1) blockade were worse in patients with lung tumors harboring alterations in exon 19 of EGFR (EGFRΔ19) but similar for EGFRL858R lung tumors. EGFRT790M status and PD-L1 expression did not impact response or survival outcomes to immune checkpoint blockade. PD-L1 expression was similar across EGFR alleles. Lung tumors with EGFRΔ19 alterations harbored a lower tumor mutation burden compared with EGFRL858R lung tumors despite similar smoking history.

CONCLUSIONS

EGFR mutant tumors have generally low response to immune checkpoint inhibitors, but outcomes vary by allele. Understanding the heterogeneity of EGFR mutant tumors may be informative for establishing the benefits and uses of PD-(L)1 therapies for patients with this disease.

Phase Ib study of atezolizumab combined with cobimetinib in patients with solid tumors

BACKGROUND

Preclinical evidence suggests that MEK inhibition promotes accumulation and survival of intratumoral tumor-specific T cells and can synergize with immune checkpoint inhibition. We investigated the safety and clinical activity of combining a MEK inhibitor, cobimetinib, and a programmed cell death 1 ligand 1 (PD-L1) inhibitor, atezolizumab, in patients with solid tumors.

PATIENTS AND METHODS

This phase I/Ib study treated PD-L1/PD-1-naive patients with solid tumors in a dose-escalation stage and then in multiple, indication-specific dose-expansion cohorts. In most patients, cobimetinib was dosed once daily orally for 21 days on, 7 days off. Atezolizumab was dosed at 800 mg intravenously every 2 weeks. The primary objectives were safety and tolerability. Secondary end points included objective response rate, progression-free survival, and overall survival.

RESULTS

Between 27 December 2013 and 9 May 2016, 152 patients were enrolled. As of 4 September 2017, 150 patients received ≥1 dose of atezolizumab, including 14 in the dose-escalation cohorts and 136 in the dose-expansion cohorts. Patients had metastatic colorectal cancer (mCRC; n = 84), melanoma (n = 22), non-small-cell lung cancer (NSCLC; n = 28), and other solid tumors (n = 16). The most common all-grade treatment-related adverse events (AEs) were diarrhea (67%), rash (48%), and fatigue (40%), similar to those with single-agent cobimetinib and atezolizumab. One (<1%) treatment-related grade 5 AE occurred (sepsis). Forty-five (30%) and 23 patients (15%) had AEs that led to discontinuation of cobimetinib and atezolizumab, respectively. Confirmed responses were observed in 7 of 84 patients (8%) with mCRC (6 responders were microsatellite low/stable, 1 was microsatellite instable), 9 of 22 patients (41%) with melanoma, and 5 of 28 patients (18%) with NSCLC. Clinical activity was independent of KRAS/BRAF status across diseases.

CONCLUSIONS

Atezolizumab plus cobimetinib had manageable safety and clinical activity irrespective of KRAS/BRAF status. Although potential synergistic activity was seen in mCRC, this was not confirmed in a subsequent phase III study.

CLINICALTRIALS.GOV IDENTIFIER

NCT01988896 (the investigators in the NCT01988896 study are listed in the supplementary Appendix, available at Annals of Oncology online).

Five-year long-term overall survival for patients with advanced NSCLC treated with pembrolizumab: Results from KEYNOTE-001

LBA9015

Background: Pembrolizumab (pembro) monotherapy has demonstrated durable antitumor activity in advanced PD-L1–expressing NSCLC. We present 5-y OS for patients (pts) enrolled in the phase 1b KEYNOTE-001 study (NCT01295827), the first trial evaluating pembro in advanced NSCLC. These data provide the longest efficacy/safety follow-up for NSCLC pts treated with pembro. Methods: Pts had confirmed locally advanced/metastatic NSCLC and provided a contemporaneous tumor sample for PD-L1 evaluation by IHC using the 22C3 antibody. Pts received pembro 2 mg/kg Q3W or 10 mg/kg Q2W or Q3W. The primary efficacy endpoint was ORR. OS was a secondary endpoint. Results: 550 pts were enrolled (treatment-naive, n=101; previously treated, n=449). As of November 5, 2018 (data cutoff), median (range) follow-up was 60.6 (51.8–77.9) mo; 82% (n=450/550) had died. Estimated 5-y OS rates were 23.2% for treatment-naive pts and 15.5% for previously treated pts (Table). ORR (by investigator per irRC) was 42% (95% CI, 32–52) for treatment-naive pts and 23% (95% CI, 19–27) for previously treated pts. Median (range) DOR was 16.8 (2.1+ to 55.7+) mo and 38.9 (1.0+ to 71.8+) mo, respectively. Immune-mediated AEs had occurred in 17% of pts at 5 y, similar to the incidence reported at 3-y follow-up. Additional results, including outcomes in key subgroups and detailed safety follow-up data, will be presented. Conclusions: In KEYNOTE-001, 5-y OS rate was 23.2% in treatment-naive pts and 15.5% in previously treated pts with advanced NSCLC treated with pembro, compared to a historical rate of ~5% (per SEER 2008–2014), prior to the introduction of anti–PD-1 therapy. 5-y OS rate was at least 25% in pts with PD-L1 TPS ≥50% in both pt populations in KEYNOTE-001. Clinical trial information: NCT01295827. [Table: see text]

Association of STK11/LKB1 genomic alterations with lack of benefit from the addition of pembrolizumab to platinum doublet chemotherapy in non-squamous non-small cell lung cancer

102

Background: Addition of pembrolizumab (P) to platinum-doublet chemotherapy [carboplatin (or cisplatin) and pemetrexed (CP)] prolongs overall survival and is a standard of care (SOC) for the 1st line treatment of metastatic EGFR/ALK wild-type (wt) non-squamous non-small cell lung cancer (mnsNSCLC). Despite widespread adoption of the CPP regimen, molecular determinants of clinical benefit from the addition of P to CP remain poorly defined. We previously identified genomic alterations in STK11/LKB1 as a major driver of primary resistance to PD-1/PD-L1 blockade in mnsNSCLC. Here, we examine the impact of STK11/LKB1 alterations on clinical outcomes with CPP chemo-immunotherapy. Methods: 497 pts with mnsNSCLC and tumor genomic profiling encompassing STK11/LKB1 from 17 academic institutions in the US and Europe were included in this study. Clinical outcomes were collected for two distinct patient cohorts: a) 377 pts treated with first-line CPP (or > 1st line following FDA-approved TKIs) that were alive for 14 days thereafter and b) 120 STK11/LKB1-mt pts that received CP prior to regulatory approval of CPP. Results: Among 377 CPP-treated pts, STK11/LKB1 genomic alterations (N = 102) were associated with significantly shorter PFS (mPFS 4.8m vs 7.2m, HR 1.5, 95% CI 1.1 to 2.0; P = 0.0063) and shorter OS (mOS 10.6m vs 16.7m, HR 1.58, 95% CI 1.09 to 2.27; P = 0.0083) compared with STK11/LKB1-wt tumors (N = 275). ORR also differed significantly between the two groups (32.6% vs 44.7%, P = 0.049). Similar results were obtained when limiting the analysis to EGFR and ALK-wt tumors (N = 333). Importantly, in pts with STK11/LKB1-mt mnsNSCLC, addition of pembrolizumab to CP did not improve PFS (mPFS 4.8m vs 4.3m, HR 1.13, 95% CI 0.83 to 1.54, P = 0.75) or OS (mOS 10.6m vs 10.3m, HR 1.03, 95% CI 0.71 to 1.49, P = 0.79) compared to CP alone. Conclusions: In mnsNSCLC, STK11/LKB1 alterations define a subgroup of pts with inferior clinical outcomes with CPP and lack of benefit from the addition of pembrolizumab to CP chemotherapy. Novel therapeutic strategies are required to establish effective antitumor immunity in STK11/LKB1-mutant NSCLC.

ml-RECIST: Machine learning to estimate RECIST in patients with NSCLC treated with PD-(L)1 blockade

9052

Background: Real-world evidence (RWE) is increasingly important for discovery and may be an opportunity for regulatory approval. Effective use of RWE relies on determining treatment-specific outcomes, such as overall response rate (ORR) and progression-free survival (PFS), which are challenging to accurately evaluate retrospectively and at scale. We hypothesized the use of machine learning of text radiology reports from patients with NSCLC treated with PD-1 blockade could be used to train a model that estimates RECIST-defined outcomes. Methods: 2753 imaging reports from 453 patients with advanced NSCLC treated with PD-1 blockade were collected and separated into independent training (80%, n = 362) and validation (20%, n = 92) cohorts. Reports were limited to interval of PD-1 blockade. RECIST reads performed by thoracic radiologists on all patients served as “gold standard” to determine ORR, occurrence of, and date of progression. Baseline reports were compared to all follow up reports to determine machine-learning RECIST (ml-RECIST). A four layers neural-network model for classification was proposed to solve the three above tasks. Results: In the training cohort, ml-RECIST best estimated ORR by RECIST (accuracy CR/PR 84%, SD 82%, POD 91%). ml-RECIST estimated PFS by RECIST accurately predicting progression occurred at any time (86%) and exact progression date (65%). Date of progression was closely correlated (Pearson’s r coefficient = 0.91, 95% CI:0.89-0.94, p < 0.001) in patients determined to have progressed by both methods. Similar accuracy of ml-RECIST was observed in the validation cohort (accuracy CR/PR 84%, SD 80%, POD 90%; progression occurred 86%, progression date 72%). Accuracy was consistent when RECIST reads were performed prospectively as part of clinical trials vs retrospectively for standard of care treatment (e.g. CR/PR 82% vs 88%, respectively). ml-RECIST-defined response similarly determined improvement in overall survival compared to RECIST (HR = 0.19, p < 0.001 vs HR = 0.26, p < 0.001 respectively). Conclusions: Machine learning-RECIST ("ml-RECIST") accurately estimates outcomes using imaging text reports. ml-RECIST may be tool to determine outcomes expeditiously and at scale for use in RWE studies, enabling more useful and reliable applications of large clinical databases.

TMB standardization by alignment to reference standards: Phase II of the Friends of Cancer Research TMB Harmonization Project

2624

Background: Tumor mutational burden (TMB) is a predictive biomarker of response to immune checkpoint inhibitors across multiple cancers. In Phase 1 of the Friends of Cancer Research Harmonization Project, we demonstrated a robust correlation between TMB estimated using targeted next-generation sequencing (NGS) gene panels and whole exome sequencing (WES) applied to MC3-TCGA data. These findings demonstrated variability in TMB estimates across different panels. Phase 2 evaluates sustainable TMB reference standard materials for TMB alignment to assess this variability. The goal of this effort is to establish best practices for estimating TMB in order to improve consistency across panels, for the sake of optimizing clinical application and facilitating integration of datasets generated from multiple assays. Methods: Fifteen laboratories with targeted panels at different stages of development participated. We identified a set of reference standards consisting of 10 well-characterized human-derived lung and breast tumor-normal matched cell lines. WES was performed using a uniform bioinformatics pipeline agreed upon by all team members (WES-TMB). Each laboratory used their own sequencing and bioinformatics pipelines (tumor-only and tumor-normal) to estimate TMB according to genes represented in their respective panels (panel-TMB). The association between WES-TMB and each panel-TMB was investigated using regression analyses. Bias (relative to WES-TMB) and variability in TMB estimates across panels were rigorously assessed. All analyses were blinded. Results: The set of reference standards spanned a clinically meaningful TMB range (4.3 to 31.4 mut/Mb). Preliminary data from 12 laboratories shows a good correlation between panel-TMB and WES-TMB in this empirical analysis. Across panels, regression R2 values range 0.77-0.96 with slopes ranging 0.60-1.26. Calibration analyses that seek to minimize variability of TMB estimates across panels using the established set of reference standards are ongoing, as well as investigating cancer type dependence on the relationship between panel-TMB vs. WES-TMB, which will be available at the time of presentation. Conclusions: Preliminary findings demonstrate feasibility of using sustainable reference control cell lines to standardize and align estimation of TMB across different targeted NGS assays. Future studies aim to validate reference standard material as a reliable alignment tool by using formalin-fixed paraffin-embedded human tumor samples.

Molecular correlates of PD-L1 expression in patients with non-small cell lung cancer

9018

Background: PD-L1 expression is the only FDA-approved predictive biomarker for patients with NSCLC treated with immune checkpoint inhibitors. The impact of tumor molecular profiling on tumor PD-L1 expression is not known. We hypothesized that somatic mutations and copy number alterations may be associated with distinct patterns of PD-L1 expression in patients with NSCLC. Methods: We examined patients with NSCLC in whom PD-L1 testing and targeted next-generation sequencing (MSK-IMPACT) were performed on the same tissue sample. PD-L1 expression was determined by IHC using the E1L3N antibody clone and categorized as PD-L1 high (≥ 50%), intermediate (1-49%), or negative ( < 1%) expression. The association of PD-L1 with individual genes, pathways, tumor mutation burden, whole genome duplication (WGD), and aneuploidy (fraction of genome altered (FGA)) were evaluated. P-values < 0.05 and q-values < 0.15 were considered significant for individual genes. Results: 1023 patients with NSCLC had PD-L1 testing and MSK-IMPACT performed on the same tissue sample, 18% (n = 180) had high, 21% (n = 218) had intermediate, and 61% (n = 625) had negative PD-L1 expression. High PD-L1 expression was significantly enriched in metastatic vs primary lesions (p < 0.001). There was a minor correlation between PD-L1 and TMB (spearman rho = 0.195) and PD-L1 and FGA (spearman rho = 0.11). Similar rates of WGD were found among patients with high, intermediate, and negative PD-L1 expression (p = 0.38). Mutations in KRAS and TERT were significantly enriched in PD-L1 high compared to other groups (p = 0.001, q = 0.14; p < 0.001, q = 0.003). By contrast, mutations in EGFR and STK11 were associated with PD-L1 negativity (p < 0.001, q = 0.001; p = 0.001, q = 0.14). Pathway analysis showed DNA repair (p < 0.001), TP53 (p < 0.001), and SWI/SNF (p = 0.04) pathways significantly associated with PD-L1 high compared to PD-L1 negative expression. Conclusions: The genetic features of NSCLC are associated with distinct patterns of PD-L1 expression. This data may provide insight to how the molecular phenotype can interact with the immunologic phenotype of tumors.

Biomarker-directed precision oncology of pembrolizumab-based combination therapy for non-small cell lung cancer: Phase II KEYNOTE-495/KeyImPaCT study

TPS9117

Background: Pembrolizumab-based combination immunotherapy aims to improve clinical outcomes over pembrolizumab monotherapy. A biomarker-based therapeutic approach may be associated with improved response to different combination therapies of immune checkpoint inhibitors and may improve overall outcomes in NSCLC. The randomized, multicenter, open-label, phase 2 KEYNOTE-495 trial ( NCT03516981 ) will evaluate the clinical usefulness of biomarker-informed, pembrolizumab-based combination therapy in patients with treatment-naive, advanced NSCLC. Methods: This is a group-sequential, adaptive randomization trial. Patients will have histologically or cytologically confirmed treatment-naive, advanced NSCLC, documented absence of EGFR and B-Raf mutations and ALK and ROS1 gene rearrangements, measurable disease per RECIST v1.1, and ECOG PS 0-1. Tumor tissue from patients will be initially screened for 2 validated, independent, next-generation biomarkers: T cell–inflamed gene expression profile (GEP) and tumor mutational burden (TMB). Based on results of biomarker screening, patients will be assigned to 1 of 4 groups: TMBlowGEPlow, TMBhighGEPlow, TMBlowGEPhigh, and TMBhighGEPhigh. Within each group, patients will be randomly assigned to receive pembrolizumab 200 mg Q3W intravenously (IV) combined with either MK-4280 200 mg Q3W (anti–LAG-3) IV or lenvatinib 20 mg orally once daily, with the randomization assignment adaptively modified based on interim efficacy analyses. Response will be assessed by imaging every 9 weeks for the first year and every 12 weeks thereafter using RECIST v1.1. Treatment will continue for 35 cycles (~2 years). Patients in the pembrolizumab + lenvatinib arm who complete 35 treatments may continue with lenvatinib monotherapy until disease progression or toxicity. Treatment arms may be terminated during the interim analysis due to safety, prespecified futility criteria, or both. Primary end point is investigator-assessed objective response rate (RECIST v1.1). Secondary end points are progression-free survival, overall survival, and safety. Recruitment and screening are ongoing in more than 8 countries. Clinical trial information: NCT03516981.

A phase Ia/b study of TIM-3/PD-L1 bispecific antibody in patients with advanced solid tumors

TPS2654

Background: Programmed cell death 1 immune checkpoint inhibitors (anti-PD-1, anti-PD-L1) have demonstrated clinical benefit in a subset of patients with manageable safety across a variety of tumor types. T-cell immunoglobulin and mucin-domain-containing molecule-3 (TIM-3) can be co-expressed with PD-1 on exhausted T-cells and may be upregulated in tumors refractory to anti-PD-1 therapy (Koyama et al. 2016). Pre-clinical studies demonstrated that blockade of both PD-1 and TIM-3 improved survival of tumor-bearing mice compared to blocking anti-PD-1 only (Koyama et al. 2016). LY3415244 is a TIM-3/PD-L1 bispecific antibody that has the ability to target and inhibit both TIM-3 and PD-L1 and the potential to overcome primary and acquired anti-PD-(L)1 resistance by a novel mechanism to bridge TIM-3- and PD-L1-expressing cells. Methods: Study JZDA is a multicenter, nonrandomized, open-label, Phase 1a/1b study of LY3415244 in patients with advanced solid tumors. In Phase 1a, subjects with any tumor type who are either PD-(L)1 inhibitor-naïve or exposed are eligible. In Phase 1b, expansion cohorts are planned in subjects with PD-(L)1-experienced NSCLC, urothelial carcinoma, and melanoma. Patients with malignant mesothelioma are not required to have received prior anti-PD-(L)1 therapy. The primary objective is to assess safety and tolerability of LY3415244 and identify the recommended Phase 2 dose (RP2D) in Phase 1a (dose escalation). Safety and tolerability of the RP2D will be assessed in Phase 1b (dose expansion). The secondary objectives are to assess the pharmacokinetics of LY3415244 in Phase 1a/1b and assess early antitumor activity of LY3415244 in Phase 1b cohorts. Pre- and on-treatment biopsies will be obtained to explore potential biomarkers of response. During Phase 1a, dose escalation cohorts will proceed via a modified toxicity probability interval-2 (mTPI-2) design with a 1-cycle (28-day) dose-limiting toxicity (DLT) observation period. LY3415244 will be dosed intravenously every 2 weeks. Data from Phase 1a will determine the RP2D, which will be used for all cohorts in Phase 1b. The study is currently open to enrollment. Clinical trial information: NCT03752177.

Neoadjuvant nivolumab in resectable non-small cell lung cancer: Extended follow-up and molecular markers of response

8524

Background: Improved therapy is needed for patients (pts) with early-stage non-small cell lung cancer (NSCLC), as the majority relapse after curative resection. Our group reported the first trial of neoadjuvant PD-1 blockade in resectable NSCLC, finding therapy to be safe and feasible. Here we report extended clinical follow-up and long-term molecular response data from this trial. Methods: IV nivolumab 3 mg/kg was given every 2 weeks for 2 doses prior to surgery in 20 pts with resectable NSCLC at Johns Hopkins and MSKCC. Blood for correlative studies was taken prior to each dose of nivolumab, prior to surgery, 2-4 weeks post-surgery, and during long-term follow up. In a subgroup of pts, longitudinal molecular data was assessed in peripheral blood for circulating tumor DNA (ctDNA) and dynamics of tumor-infiltrating T-cell clonotypes. Results: At median follow up of 30 months (m), 15 of 20 pts are disease-free and alive. Two pts have died (one from relapsed disease). Median recurrence free survival (RFS) has not been reached. The 24m RFS rate is 69% (95% CI: 51-93). Thus far, presence of ctDNA at diagnosis and major pathologic response (MPR - ≤10% viable tumor in resected specimen) do not associate with RFS. One long-term immune-related adverse event has occurred (skin, G3). All pts who on pathologic review had ≥30% reduction in viable tumor in response to nivolumab demonstrated clearance of detectable ctDNA from blood prior to surgery. Pts with MPR experienced expansion of neoantigen-specific T-cells in peripheral blood. In one patient with ongoing disease free status, expansion of tumor-associated T-cells has persisted in peripheral blood beyond 15m from surgery. By contrast, in a patient who had detectable peri-operative ctDNA and 75% residual disease at surgery, minimal T-cell expansion was observed in peripheral blood, with a decreasing frequency of expanded T-cell clones over time that correlated with eventual cancer relapse. Conclusions: Long-term follow up reinforces the safety of neoadjuvant nivolumab in resectable NSCLC. Analysis of ctDNA and peripheral T-cell expansion in responders compared with non-responders suggests potential biomarkers for response and surveillance. While RFS data is encouraging, phase 3 trials are ongoing to evaluate efficacy of PD-(L)1 blockade in early-stage NSCLC. Clinical trial information: NCT02259621.

Outcomes to first-line pembrolizumab in patients with non-small cell lung cancer and a PD-L1 tumor proportion score ≥90%

9111

Background: In non-small cell lung cancers with a programmed death-ligand 1 (PD-L1) tumor proportion score (TPS) of ≥50%, first-line treatment with the PD-1 inhibitor pembrolizumab improves survival compared to platinum-doublet chemotherapy. Whether higher PD-L1 expression levels within the TPS range of 50-100% predict for even greater benefit to pembrolizumab is currently unknown. Methods: In this multicenter retrospective analysis, we analyzed the impact of PD-L1 expression levels on the overall response rate (ORR), median progression-free survival (mPFS), and median overall survival (mOS) in patients who received commercial pembrolizumab as first-line treatment for advanced NSCLC with a PD-L1 TPS of ≥50%. Results: Among 196 patients with NSCLC treated with first-line pembrolizumab, the ORR was 43.8% (95%CI: 36.8-51.1). At a median follow-up of 12.6 months (95%CI: 11.6-13.7), the mPFS was 6.2 months (95% CI: 4.2-8.2) and the mOS was not reached. The median PD-L1 TPS among patients who experienced a response to pembrolizumab was significantly higher than in patients with stable or progressive disease (TPS 90% vs 70%, P < 0.001), so a TPS cut point of 90% was chosen for further analysis. Baseline clinicopathological characteristics were well-balanced between patients with a PD-L1 TPS of 50-89% vs 90-100%. Compared to patients with a PD-L1 TPS of 50-89% (N = 114, 58.2% of the cohort), patients with a TPS of 90-100% (N = 82, 41.8% of the cohort) had a significantly higher ORR (61.0% versus 31.6%, P < 0.001), a significantly longer mPFS (13.2 versus 3.7 months, HR: 0.48 [95% CI: 0.33-0.71], P < 0.001), and a significantly longer mOS (NR versus 16.0 months, HR: 0.38 [95% CI: 0.21-0.70], P = 0.002). After adjusting for ECOG performance status and smoking history, PD-L1 TPS of 90-100% was significantly associated with improved mPFS (HR: 0.51 [95% CI: 0.34-0.75], P < 0.001) and mOS (HR: 0.38 [95% CI: 0.21-0.70], P = 0.001). Conclusions: Among patients with NSCLC and a PD-L1 TPS ≥50%, clinical outcomes are improved in the subgroup of patients with a PD-L1 TPS of ≥90%. These findings have implications for treatment selection as well as for clinical trial interpretation and design.

Molecular circulating tumor DNA response to identify long-term survival in patients receiving immunotherapy with initial radiologic stable disease

2546

Background: Early on-treatment changes in ctDNA may identify responders to immunotherapy and complement radiologic assessment of benefit. Here we investigate how early changes in ctDNA associate with long-term survival following treatment with immunotherapy, and if differential patterns in molecular ctDNA response (MCR) among patients with radiologic stable disease (SD) at first on-treatment scan could identify patients deriving benefit from treatment. Methods: Paired pre- and on-treatment (week 6-8) plasma samples from 3 cohorts of patients treated with durvalumab (D) +/- tremelimumab (D+T) were evaluated (NCT01693562, NCT02087423, NCT02261220). CtDNA was profiled with the 73-gene Guardant 360 assay. Nonsynonymous variants were summarized per patient to calculate variant allelic frequency changes (dVAF) and on-treatment variant allele frequency (pVAF). A combination of dVAF and pVAF was used to define MCR. Results: The reduction of ctDNA (dVAF<0) and undetectable on-treatment ctDNA (pVAF=0) were each associated with improved OS and PFS. An optimal threshold for MCR was determined from one cohort, then applied to the other cohorts. MCR associated with significantly improved PFS and OS across all three cohorts (Table). MCR was then applied to a pooled subgroup of patients with initial radiologic SD from all three cohorts (n=78). Patients with radiologic SD and MCR were significantly more likely than those without MCR to achieve radiologic CR or PR (pooled Odds ratio 12.7, p<0.001), had improved PFS (stratified pooled HR 0.36, p<0.001), and improved OS (stratified pooled HR 0.38, p=0.005). Conclusions: MCR is an early on-treatment tool that may identify patients with improved long-term survival and patients with radiologic SD who derive clinical benefit from immunotherapy. MCR may be a supportive endpoint in prospective clinical trials. MCR and survival benefit. [Table: see text]

Real-world experience and molecular features of response to immune checkpoint blockade in patients with recurrent small cell lung cancer

8556

Background: Immune checkpoint blockade (ICB) is now a routine component of treatment in recurrent small cell lung cancer (SCLC). We evaluated the response to ICB in patients (pts) with recurrent SCLC and genomic features of response using next-generation sequencing (NGS). Methods: Pts with recurrent SCLC treated with ICB were identified. The majority of pts were treated outside of a clinical trial to focus emphasis on the real-world experience. Tumor mutation burden (TMB) and the landscape of somatic variants were determined by targeted NGS using MSK-IMPACT. Objective response rate (ORR) to ICB was determined using RECIST v1.1. PFS and OS were measured from the start of ICB and analyzed using Kaplan-Meier. Results: Between December 2013 and October 2018, 108 pts with SCLC were treated with ICB (57 subjected to NGS). Pts received PD-1 monotherapy alone (n = 28) or in combination with CTLA-4 blockade (n = 80). Median line of therapy was 2 (range 1-6). ORR was 14% (15/108, 95% CI 8-22%). From the start of ICB, median PFS was 1.4 months in non-responders and 10.8 months in responders (HR 0.2; 95% CI 0.13-0.32). Median OS was 6.3 months in non-responders and undefined in responders (range 8-44 months) (HR 0.26, 95% CI 0.16-0.44). Four responders remain on ICB treatment. TMB in the ICB-treated cohort was similar to that of an unselected cohort (n = 233) of SCLC (median 8.8 Mt/MB vs 8.2 Mt/MB, p = 0.71). Clinical benefit was enriched among those with a higher TMB (upper vs middle/lower tertile PFS HR 0.48, 95% CI 0.28-0.84, p = 0.01 and ORR 26% [5/19] vs ORR 8% [3/38]). Rates of whole genome duplication and commonly altered genes in SCLC ( TP53, RB1, KMT2C/D, NOTCH1/2/4, PTPRD, APC) were similarly distributed across responders and non-responders. Completion of whole-exome sequencing and PD-L1 testing is in progress. Conclusions: In pts with recurrent SCLC receiving routine clinical care, the ORR to ICB is comparable to reports from clinical trials. A high TMB was associated with a longer median PFS and better response. Further investigation into the genomic landscape of recurrent SCLC is needed to identify biomarkers predictive of response to ICB.

Severe immune-related adverse events are common with sequential PD-(L)1 blockade and osimertinib

BACKGROUND

Concurrent programmed death-ligand-1 (PD-(L)1) plus osimertinib is associated with severe immune related adverse events (irAE) in epidermal growth factor receptor (EGFR)-mutant non-small-cell lung cancer (NSCLC). Now that PD-(L)1 inhibitors are routinely used as adjuvant and first-line treatments, sequential PD-(L)1 inhibition followed by osimertinib use may become more frequent and have unforeseen serious toxicity.

METHODS

We identified patients with EGFR-mutant NSCLC who were treated with PD-(L)1 blockade and EGFR- tyrosine kinase inhibitors (TKIs), irrespective of drug or sequence of administration (total n = 126). Patient records were reviewed to identify severe (NCI-CTCAE v5.0 grades 3-4) toxicity.

RESULTS

Fifteen percent [6 of 41, 95% confidence interval (CI) 7% to 29%] of all patients treated with sequential PD-(L)1 blockade followed later by osimertinib developed a severe irAE. Severe irAEs were most common among those who began osimertinib within 3 months of prior PD-(L)1 blockade (5 of 21, 24%, 95% CI 10% to 45%), as compared with >3-12 months (1 of 8, 13%, 95% CI 0% to 50%), >12 months (0 of 12, 0%, 95% CI 0% to 28%). By contrast, no severe irAEs were identified among patients treated with osimertinib followed by PD-(L)1 (0 of 29, 95% CI 0% to 14%) or PD-(L)1 followed by other EGFR-TKIs (afatinib or erlotinib, 0 of 27, 95% CI 0% to 15%). IrAEs occurred at a median onset of 20 days after osimertinib (range 14-167 days). All patients with irAEs required steroids and most required hospitalization.

CONCLUSION

PD-(L)1 blockade followed by osimertinib is associated with severe irAE and is most frequent among patients who recently received PD-(L)1 blockade. No irAEs were observed when osimertinib preceded PD-(L)1 blockade or when PD-(L)1 was followed by other EGFR-TKIs. This association appears to be specific to osimertinib, as no severe irAEs occurred with administration of other EGFR-TKIs.

Negative association of antibiotics on clinical activity of immune checkpoint inhibitors in patients with advanced renal cell and non-small-cell lung cancer

Background

The composition of gut microbiota affects antitumor immune responses, preclinical and clinical outcome following immune checkpoint inhibitors (ICI) in cancer. Antibiotics (ATB) alter gut microbiota diversity and composition leading to dysbiosis, which may affect effectiveness of ICI.

Patients and methods

We examined patients with advanced renal cell carcinoma (RCC) and non-small-cell lung cancer (NSCLC) treated with anti-programmed cell death ligand-1 mAb monotherapy or combination at two academic institutions. Those receiving ATB within 30 days of beginning ICI were compared with those who did not. Objective response, progression-free survival (PFS) determined by RECIST1.1 and overall survival (OS) were assessed.

Results

Sixteen of 121 (13%) RCC patients and 48 of 239 (20%) NSCLC patients received ATB. The most common ATB were β-lactam or quinolones for pneumonia or urinary tract infections. In RCC patients, ATB compared with no ATB was associated with increased risk of primary progressive disease (PD) (75% versus 22%, P < 0.01), shorter PFS [median 1.9 versus 7.4 months, hazard ratio (HR) 3.1, 95% confidence interval (CI) 1.4-6.9, P < 0.01], and shorter OS (median 17.3 versus 30.6 months, HR 3.5, 95% CI 1.1-10.8, P = 0.03). In NSCLC patients, ATB was associated with similar rates of primary PD (52% versus 43%, P = 0.26) but decreased PFS (median 1.9 versus 3.8 months, HR 1.5, 95% CI 1.0-2.2, P = 0.03) and OS (median 7.9 versus 24.6 months, HR 4.4, 95% CI 2.6-7.7, P < 0.01). In multivariate analyses, the impact of ATB remained significant for PFS in RCC and for OS in NSCLC.

Conclusion

ATB were associated with reduced clinical benefit from ICI in RCC and NSCLC. Modulatation of ATB-related dysbiosis and gut microbiota composition may be a strategy to improve clinical outcomes with ICI.