Dissecting the clinicopathologic, genomic, and immunophenotypic correlates of KRASG12D-mutated non-small-cell lung cancer

BACKGROUND

Allele-specific KRAS inhibitors are an emerging class of cancer therapies. KRAS-mutant (KRASMUT) non-small-cell lung cancers (NSCLCs) exhibit heterogeneous outcomes, driven by differences in underlying biology shaped by co-mutations. In contrast to KRASG12C NSCLC, KRASG12D NSCLC is associated with low/never-smoking status and is largely uncharacterized.

PATIENTS AND METHODS

Clinicopathologic and genomic information were collected from patients with NSCLCs harboring a KRAS mutation at the Dana-Farber Cancer Institute (DFCI), Memorial Sloan Kettering Cancer Center, MD Anderson Cancer Center, and Imperial College of London. Multiplexed immunofluorescence for CK7, programmed cell death protein 1 (PD-1), programmed death-ligand 1 (PD-L1), Foxp3, and CD8 was carried out on a subset of samples with available tissue at the DFCI. Clinical outcomes to PD-(L)1 inhibition ± chemotherapy were analyzed according to KRAS mutation subtype.

RESULTS

Of 2327 patients with KRAS-mutated (KRASMUT) NSCLC, 15% (n = 354) harbored KRASG12D. Compared to KRASnon-G12D NSCLC, KRASG12D NSCLC had a lower pack-year (py) smoking history (median 22.5 py versus 30.0 py, P < 0.0001) and was enriched in never smokers (22% versus 5%, P < 0.0001). KRASG12D had lower PD-L1 tumor proportion score (TPS) (median 1% versus 5%, P < 0.01) and lower tumor mutation burden (TMB) compared to KRASnon-G12D (median 8.4 versus 9.9 mt/Mb, P < 0.0001). Of the samples which underwent multiplexed immunofluorescence, KRASG12D had lower intratumoral and total CD8+PD1+ T cells (P < 0.05). Among 850 patients with advanced KRASMUT NSCLC who received PD-(L)1-based therapies, KRASG12D was associated with a worse objective response rate (ORR) (15.8% versus 28.4%, P = 0.03), progression-free survival (PFS) [hazard ratio (HR) 1.51, 95% confidence interval (CI) 1.45-2.00, P = 0.003], and overall survival (OS; HR 1.45, 1.05-1.99, P = 0.02) to PD-(L)1 inhibition alone but not to chemo-immunotherapy combinations [ORR 30.6% versus 35.7%, P = 0.51; PFS HR 1.28 (95%CI 0.92-1.77), P = 0.13; OS HR 1.36 (95%CI 0.95-1.96), P = 0.09] compared to KRASnon-G12D.

CONCLUSIONS

KRASG12D lung cancers harbor distinct clinical, genomic, and immunologic features compared to other KRAS-mutated lung cancers and worse outcomes to PD-(L)1 blockade. Drug development for KRASG12D lung cancers will have to take these differences into account.

Trial in progress: A phase 2 study of sotorasib as first-line treatment in patients with stage IV non–small cell lung cancer (NSCLC) whose tumors harbor a KRAS p.G12C mutation (CodeBreaK 201)

TPS9150

Background: Chemo-immunotherapy regimens represent a standard of care for the first-line treatment of metastatic NSCLC, yet clinical outcomes in patients bearing tumors that lack PD-L1 expression [PD-L1 Tumor Proportion Score (TPS) < 1%)] or harbor a serine/threonine kinase 11 ( STK11) mutation remain poor. Sotorasib is a selective, irreversible small molecule KRASG12C inhibitor that is approved for the treatment of patients with locally advanced or metastatic KRAS p.G12C-mutated NSCLC following failure of at least one prior line of systemic therapy and has previously demonstrated robust antitumor activity in subgroups of KRAS p.G12C mutant NSCLC with PD-L1 TPS <1% and/or STK11 co-mutations. We hypothesized that sotorasib may represent an effective first-line therapy for subgroups of NSCLC patients who may have suboptimal chemo-immunotherapy outcomes and a high unmet clinical need. Methods: This phase 2, open-label, global study is designed to evaluate the efficacy and safety of sotorasib (960 mg or 240 mg daily) as first-line treatment in approximately 170 patients with KRAS p.G12C-mutated, metastatic NSCLC with PD-L1 TPS <1% as determined by immunohistochemical assay and/or presence of STK11 mutation as determined by next-generation sequencing (NGS). Key eligibility criteria include patients with untreated metastatic NSCLC without active brain metastases. Patients will be stratified by known presence of STK11 mutation. The primary endpoint is objective response assessed by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. Secondary endpoints include disease control, duration of response, time to response, progression-free survival per RECIST 1.1, overall survival, safety and tolerability, and pharmacokinetic profile. Enrollment began in January 2022 and is ongoing. Contact Amgen Medical Information for more information. Clinical trial information: NCT04933695.

Chemo-immunotherapy outcomes of KRAS-G12C mutant lung cancer compared to other molecular subtypes of KRAS-mutant lung cancer

9088

Background: KRAS mutations are identified in approximately 30% of NSCLC, with G12C mutations being the most common subtype and representing 12% of all non-small cell lung cancer cases. Novel direct inhibitors are in clinical development and have shown promising activity, although the efficacy of these agents compared to other standard therapies for lung cancer is not yet known. We hypothesized that patients with KRAS-G12C mutations may have distinct responses to chemo-immunotherapy regimens both with respect to STK11 and KEAP1 co-mutation status and compared to patients with non-G12C subtypes. Methods: Patients with KRAS-mutant lung cancers at Memorial Sloan Kettering Cancer Center and Dana Farber Cancer Institute treated with chemo-immunotherapy regimens as first line therapy for advanced/metastatic disease were identified. Subset with KRAS G12C mutations non-G12C subtypes were compared and response to therapy was assessed by investigator. Baseline characteristics were compared with the Chi-square and Fisher’s exact test for categorical data and Wilcoxon rank-rum test for continuous data. Response evaluations where performed by investigators and compared between groups with the Fisher’s exact test. Progression free survival and overall survival was calculated from start of therapy to date of progression or death/last follow up, respectively and compared between groups using the Cox proportional-hazards model. Results: We identified 137 patients with KRAS -mutant NSCLC treated with chemo-immunotherapy: 45% (62/137) had mutations in KRAS-G12C and 55% harbored non-G12C mutations (17% G12V, 15% G12D, 4% G12A, 4% G12S, 3% G13D). The median OS was 21 and 14 months for G12C and non-G12C patients, respectively (p = 0.24). ORR to chemo-immunotherapy for patients harboring a KRAS-G12C mutation was 40% (25/62) compared to 31% (23/75) in non-G12C subtypes (p = 0.3). Median PFS was similar for both G12C and non-G12C subtypes (7.3 vs 6.1 months, respectively, p = 0.12). Concurrent STK11 mutation was identified in 40% of patients with KRAS-G12C and KEAP1 alterations were observed in 32% of patients. In patients with KRAS-G12C, co-mutation in STK11 and/or KEAP1 was associated with shorter PFS (15.8 vs 5.1 months, p = 0.01). 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. Treatment outcomes to chemo-immunotherapy are similar in patients with G12C and non-G12C subtypes. Outcomes are poor for patients with concurrent STK11 and/or KEAP1 mutations representing a significant unmet need.

Association of a very high tumor mutational load with increased CD8+ and PD-1+ T-cell infiltration and improved clinical outcomes to PD-(L)1 blockade across different PD-L1 expression levels in non-small cell lung cancer

9018

Background: Although high TMB correlates with improved outcomes to immune checkpoint inhibitors (ICI) in patients (pts) with non-small cell lung cancer (NSCLC), an optimal TMB cutoff to discriminate cancers most likely to respond to ICI has not been identified. Whether TMB impacts outcomes to ICI in different PD-L1 levels subgroups is also unclear. Methods: Unbiased recursive partitioning (URP) was used to identify an optimal TMB cutoff for objective response rate (ORR) in two independent cohorts of pts with NSCLC treated with ICI at DFCI and MSKCC. TCGA was interrogated to find differences in tumor immune cell subsets according to the TMB cutoff identified. Multiplexed immunofluorescence (IF) for CD8, PD-1, PD-L1, Foxp3, and CK7 was also performed on NSCLC samples at the DFCI. Results: In the DFCI (N=686) and MSKCC (N=672) cohorts, URP found an optimal TMB cutoff for ORR at 19 mutations/megabase (mut/Mb), corresponding to the ̃90th percentile in each cohort. Median progression-free (PFS) and overall survival (OS) were significantly longer in NSCLCs with TMB ≥19 mut/Mb vs <19 mut/Mb, in both cohorts (Table). After harmonizing TMB between DFCI OncoPanel and MSK-IMPACT NGS platforms, URP confirmed an optimal TMB cutoff for ORR at the 90th percentile in the combined cohort, which also associated with longer PFS/OS to ICI (Table). A TMB ≥90th percentile correlated with longer PFS/OS to ICI among NSCLCs with PD-L1 levels ≥50% and 1-49%, and longer PFS among those with PD-L1 <1% (Table). Cell subset transcriptome analysis from the TCGA showed higher proportions of CD8+ T cells (P=0.02) and M1 macrophages (P<0.01) among NSCLCs with a TMB ≥ vs <90th percentile. IF confirmed increased CD8+, CD8+ PD1+ T-cell infiltration (P<0.01), and increased CD8+/Foxp3+ ratio in NSCLC with very high TMB Conclusions: A very high TMB is associated with better outcomes to ICI and a distinct immunophenotype in NSCLC. Rational integration of TMB and PD-L1 expression may identify NSCLCs most likely to respond to ICI.[Table: see text]

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.

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]

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.

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.

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.

Validation of broad panel clinical sequencing-based genomic risk stratification in patients with advanced lung adenocarcinomas

9113

Background: We recently established the ability of broad-panel clinical sequencing data to stratify overall survival of patients with advanced lung adenocarcinomas in a single institutional experience (Shen, Riely et al., JCO Precision Oncology 2019). Here we sought to assess its generalizability to a broader range of patients (including patients from multiple community and academic sites) using a different sequencing panel, with an integrated electronic health record and genomic database. Methods: We identified 2,779 next-generation sequencing-tested patients with advanced lung adenocarcinomas from the Flatiron-Foundation Medicine Clinico-Genomic database. A genomic risk model developed from the initial discovery cohort (n=1,054) was used to calculate a risk score for each patient in the validation cohort, scaled between 0 and 10, indicating the risk of cancer specific mortality. Results: Patients in the validation cohort were classified into four risk categories with median survival ranging from 37.6 months (95% CI: 32.9-43.8) in the low risk group (n=534) to 10.9 months (95% CI: 8.0-16.5) in the highest risk group (n=75), representing a hazard ratio of 3.0 (95% CI: 2.2-4.1) and closely matching the discovery cohort observations. A smaller proportion of patients were deemed high risk in the validation cohort (2.7% vs 10% in the discovery cohort). There were some differences in the frequencies of the most common genomic alterations between the validation and discovery cohorts, including TP53 (57.3% vs 55.1%) , KRAS (32.8% vs 30%), EGFR (18.6% vs 29.4%) as well as overlapping STK11 and KEAP1 co-mutations (2.4% vs 10%). Conclusions: We demonstrate that a clinical tumor sequencing-based genomic risk stratification strategy can be applied broadly across cohorts and different sequencing panels and platforms, to improve the understanding of heterogeneity in clinical outcome for patients with metastatic lung adenocarcinomas and the mutation and co-mutational patterns that underlie such heterogeneity.

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.

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.

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.

Pulse-continuous dose erlotinib as initial targeted therapy for patients with EGFR-mutant lung cancers with untreated brain metastases

9039

Background: Clarke (Neurooncol 2010) reported responses with intermittent high pulse doses of erlotinib (leading to higher concentrations in CSF) given to patients with EGFR-mutant central nervous system metastases developing on standard erlotinib doses. In a phase 1 study of pulse-continuous dose erlotinib, no patient developed progression in existing or new brain or leptomeningeal metastases (Yu Ann Oncol 2016). This phase 2 trial tested pulse-continuous dose erlotinib in patients with lung cancers with EGFRmutations with brain metastases. Methods: Patients had no prior EGFR TKI or radiation to the brain and at least 1 target brain metastasis. All received initial daily "pulse" doses of erlotinib 1200 mg days 1&2 and "continuous" 50 mg doses days 3-7 (doses and schedule from the Yu Phase 1 study), weekly until progression. The co-primary endpoints were overall and brain metastasis response by RECIST 1.1. Results: We enrolled 19 patients with EGFR-mutant lung cancers: median age 61yrs (range 45-80), 74% women, 95% Karnofsky PS ≥80%, 1 leptomeningeal disease, 33% prior pemetrexed-based chemotherapy. The median size of target brain metastases was 13 mm (range 10-19 mm). 32% were on dexamethasone for cerebral edema. The partial response rate overall was 74% (95% CI 51-89%) and also 74% in brain metastases. Of 10 patients with progression, 9/10 occurred in non-brain sites (4 EGFRT790M, 1 with progression in brain as well), 1 with leptomeningeal. The median progression free survival was 10 mo (range 7-NR mo). Pulse doses were reduced in 68% (median delivered pulse dose 1050 mg days 1&2, range 600-1200 mg). Incidences of any gradeof rash and diarrhea were 84% and 63% respectively. There were no grade 4 or 5 toxicities. Conclusions: Pulse-continuous dose erlotinib alone controlled brain and leptomeningeal metastases in 89% (95% CI 67-98%) of patients with EGFR-mutant lung cancers with central nervous system spread pretreatment, with an overall response rate of 74% and progression free survival and rates of rash and diarrhea comparable to series with erlotinib 150 mg daily. Supported by Astellas, CA 129243, CA 008748. NCT01967095 Clinical trial information: NCT01967095.

Response to osimertinib following treatment with EGF816 in patients with T790M EGFR mutant NSLCLC

e20673

Background: Third generation (3rd gen) epidermal growth factor (EGFR) tyrosine kinase inhibitors (TKIs) have been developed to treat EGFR T790M-mediated resistance to EGFR TKIs by inhibiting EGFR T790M, as well as EGFR L858R and EGFR exon 19 deletions. The mechanisms of resistance to third-generation EGFR TKIs are largely unknown and clinical cross-resistance among 3rd gen EGFR TKIs has not been routinely evaluated. Osimertinib is an FDA-approved irreversible 3rd gen EGFR TKI. In patients with EGFR T790M mutant NSCLC, the response rate (ORR) to osimertinib is 61%. EGF816 is a covalent, irreversible, 3rd gen EGFR TKI in clinical development. In early phase data of EGF816, the ORR was 47% and disease control rate was 87% in patients with EGFR T790M mutant NSCLC. To assess clinical cross-resistance between EGF816 and osimertinib, we evaluated the clinical outcomes of patients treated with osimertinib in patients previously treated with EGF816 during the phase I/II trial. Methods: Patients with metastatic EGFR mutant lung adenocarcinoma were identified who were previously treated with EGF816 and received osimertinib after progression of disease on EGF816 (NCT02108964). All patients had documented T790M mutation prior to treatment with EGF816. The best overall response to osimertinib was determined by RECIST 1.1 criteria. Duration of clinical benefit was defined as duration of osimertinib therapy. Results: Fourteen (3 men, 11 women, median age 58 [range 33-77]) patients met eligibility criteria at our centers. The ORR to subsequent osimertinib therapy was 14% (1 CR, 1 PR, 8 SD, 4 POD). Patients continued treatment with osimertinib for a median of 9 months (95% CI 3.8-10.1, [median follow up 11 months, range 1-13 months]). 5 patients are still on osimertinib to date (one patient each 3+, 6+, 8+, 11+, and 12+ months). Conclusions: This series suggests a potentially meaningful clinical benefit for patients with sequential therapy with two different third-generation EGFR inhibitors, emphasizing the importance of understanding resistance mechanisms (genetic alteration of target, bypass signaling, pharmacology, etc.) and raising the possibility of the need for multiple third generation EGFR TKIs in clinical practice.

Lung cancers with mutations in EGFR exon 18: Molecular characterization and clinical outcomes in response to tyrosine kinase inhibitors

9029

Background: Little data is available to guide clinical management of individuals with less common oncogenic drivers such as exon 18 mutations (ex18m) in EGFR. To better understand the impact of these rare mutations on treatment outcomes, we reviewed clinicopathologic data in patients (pts) with ex18m treated with tyrosine kinase inhibitors (TKI) in EGFR-mutant lung cancers. Methods: Pts with EGFR ex18m were detected via molecular diagnostics using Sequenom™, FoundationOne™ or MSK IMPACT™ NGS testing from 2003-2016. We reviewed their clinical data for molecular alterations in EGFR, treatment outcomes in response to TKI (time on treatment) and median overall survival (OS). Results: We identified mutations in EGFR ex18m in 63 pts. Median age at diagnosis was 68; 63% were women; 29% never smokers. Overall, 74 ex18m were found in 63 pts, including: G719A = 38, G719S = 11, G719C = 8, E709K = 6, E709_T710delinsD = 6, E709A = 3, G719D = 2. E709 and G719 co-mutations in ex18 were found in 9 pts, and 1 pt was found to have 3 separate tumors, each with a distinct ex18m. 29/63 (46%) patients with ex18m had a co-occurring EGFR mutation: 9 with another ex18m; 20 with ex19-21m. Using our IMPACT NGS, the median number of co-mutations was 8 (range 1-17). Two out of 63 pts had a pre-treatment T790M mutation. The 25 pts with non-metastatic disease presented in the following stages: IA = 19; IB = 3; IIB = 1; IIIA = 2; IIIB = 2. 34/38 pts with metastatic disease were treated with the following first-line EGFR-TKIs: erlotinib = 28, afatinib = 5, osimertinib = 1. Median duration on TKI treatment in months was: erlotinib = 10 mo, (range 1-25), afatinib = 3 mo (range 2-9), osimertinib = 4 mo. Median OS from the date of diagnosis of metastatic disease was 22 months (95% CI 18-29). In comparison, a similar cohort of pts with sensitizing EGFR exon19del/L858R mutations had a median OS of 31 months (95% CI 28-33) (Naidoo Cancer2015). Conclusions: Almost half of ex18m occur concurrently with another EGFR mutation. Overall, ex18m pts have a shorter median OS when compared to similar patient cohorts. EGFR-TKIs appear to be an effective treatment for pts with ex18m in EGFR-mutant lung cancers.

Molecular determinants of response and resistance to anti-PD-(L)1 blockade in patients with NSCLC profiled with targeted next-generation sequencing (NGS)

9015

Background: Anti-PD-(L)1 therapy has revolutionized treatment for patients (pts) with NSCLC. We previously reported that non-synonymous tumor mutation burden (TMB) by whole exome sequencing associates with immunotherapy benefit. Targeted NGS is increasingly routine in clinical practice and may be a useful tool for predicting benefit to anti-PD-(L)1 blockade. Methods: Pts had advanced NSCLC treated with anti-PD-(L)1 (+/- aCTLA-4) therapy and profiling by hybrid-capture NGS of 341-468 genes (MSK-IMPACT). Efficacy assessed by RECIST v1.1; durable clinical benefit (DCB) defined as PR or SD > 6mo. TMB and copy number alteration burden (“fraction of genome altered”, FGA) were normalized by size of genome covered. Comparisons were also made to a cohort of all NSCLCs profiled by MSK-IMPACT (n = 1679). Results: Of 437 evaluable pts treated with anti-PD-(L)1, 197 (45%) had NGS profiling, of whom 30% had DCB. TMB was higher in those with DCB vs no DCB (mean 10.2 vs 7.1 SNV/MB, p = 0.02) and compared to all NSCLCs ( < 0.0001). DCB was more common and PFS was longer in pts with > vs < 85th percentile TMB of all NSCLCs (Odds ratio 2.3, 95% CI 1.1-4.9, p = 0.03; HR = 0.59, p = 0.004), but were similar when dichotomized at the 50th or 75th percentile. FGA was higher in pts with no DCB compared to all NSCLCs (p = 0.02). Molecular signatures related to deficient homologous-recombination-based DNA repair and smoking were more common in DCB vs no DCB (p = 0.042, p = 0.058) and vs all NSCLCs (p = 0.026, p = 0.01). Compared to all NSCLCs profiled by NGS, alterations in STK11and EGFRwere enriched in no DCB (p = 0.0008, p = 0.02). Alterations in JAK2and CD274(PD-L1) were uncommon (2.1%, 1.6%) but exclusively associated with no DCB. For a subset (n = 52) of these cases also profiled by whole exome sequencing, comparison with targeted NGS will be presented. Conclusions: In pts with NSCLC, targeted NGS profiling is a routinely available tool that can provide insight into predicting benefit with anti-PD-(L)1 therapy. Increased TMB associates with clinical benefit. Increased copy number alterations (FGA) and alterations in genes including STK11, JAK2, and CD274 may associate with resistance to anti-PD-(L)1 therapy.

PD-L1 expression and response to immunotherapy in patients with MET exon 14-altered non-small cell lung cancers (NSCLC)

8512

Background: MET exon 14 skipping alterations ( METΔ14) are present in 4% of NSCLCs. Response to MET inhibition has been observed in ongoing prospective trials (44% response rate, phase 1 trial of crizotinib; Drilon et al ASCO 2016), however responses to other types or therapy, such as immunotherapy, is unknown. We evaluated the immunophenotype of METΔ14 lung cancers and response to PD-(L)-1-based immunotherapy. Methods: Pts with recurrent/metastatic NSCLC were eligible. METΔ14 was identified by broad hybrid capture-based next-generation sequencing (MSK-IMPACT). PD-L1 expression was determined by immunohistochemistry. Response to immune therapy was evaluated by RECIST v1.1. Results: 63 pts with METΔ14-positive non-small cell lung cancers were identified; 41 (65%) had sufficient tissue for PD-L1 analysis. Patient characteristics: median age 71 years, 58% female, median pack year smoking 5.85 years, histology: 73% (30/41) adenocarcinoma, 20% (8/41) pleomorphic carcinoma, 7% (3/41) squamous cell. Tumor PD-L1 expression was ≥50% in 44% (18/41, 95% CI 30-59%), 1-49% in 17% (7/41, 95% CI 8-32%), and < 1 in 39% (16/41, 95% CI 26-54%). The median age for patients with METΔ14 and PD-L1 positive (≥1%) tumors was 65 years (range 49-87); 60% (15/25) of patients were female; Histology: 72% (18/25) adenocarcinoma, 24% (6/25) sarcomatoid carcinoma, and 4% (1/25) squamous cell carcinoma. Immunotherapy was given to 15 pts: nivolumab (5), pembrolizumab (3), atezolizumab (2), durvalumab (1), and ipilimumab+nivolumab (4). The overall response rate to immunotherapy was 13% (2/15, 95% CI 3-39%). Overall response was 33% (1/3; 95% CI 6-80%) in patients with tumors PD-L1 ≥50%, and 20% (1/5, 95%CI 2-64%) in patients with tumors PD-L1 0%. Time on therapy ranged from 2 weeks to 9.6+ months. Conclusions: A substantial proportion of NSCLCs harboring METΔ14 alterations express PD-L1. Despite frequent PD-L1 expression, responses to immunotherapy were overall uncommon and lower than that observed with targeted therapy for this genomically defined subset of patients with lung cancers. Further exploration of this subset may reveal important mechanisms of immunotherapy resistance in PD-L1 expressing tumors.

Analysis of outcomes in metastatic pancreatic cancer: Real-world experience in academic cancer centers

458

Background: FOLFIRINOX is an active regimen for metastatic pancreatic cancer demonstrating a median overall survival of 11.1 months at the expense of significant treatment-related toxicity. Dose modifications are routinely used in clinical practice however there is little data regarding impact on outcomes and use of second line therapy. In this study we report on the treatment course and outcomes of 92 patients treated at two academic centers. Methods: We conducted an IRB-approved retrospective cohort study of patients with metastatic pancreatic adenocarcinoma treated with first line FOLFIRINOX between 2011 and 2015. Hazard ratios were calculated by Cox proportional hazard models and median survival was estimated using Kaplan-Meier method. Results: 92 patients were identified with a median follow-up of 13.2 months (range 1.2-47.3 mo); 57 males (62%), ECOG 0/1 = 75 (82%). Fifty-four percent required dose reductions of >25% in at least one of three component drugs within the first 6 cycles [95% CI 0.44, 0.65]. Irinotecan was dose reduced in 43% of patients (n=39) while 64% required modification or discontinuation of 5FU. Ten patients (11%) received the full dose of FOLFIRINOX as originally published and 17 patients (25%) discontinued FOLFIRINOX due to toxicity. 60% of patients demonstrated disease control at first imaging assessment after 4-6 cycles of treatment. Median PFS was 7.11 months (95% CI: 5.06-8.51) and OS 13.01 months (95% CI: 9.17-16.95). There was a decrease in PFS and OS associated with a dose reduction of two or more drugs with a HR of 1.68 (95% CI 1.01-2.82, p=0.048) and 1.98 (95% CI 1.08-3.65, p=0.027) respectively. Sixty-seven patients [73%] went on to receive 2nd line therapy [n=67] with 55% receiving gemcitabine-based regimens, the majority with nab-paclitaxel [82%]. Forty-two patients demonstrated progressive disease [63%]. Conclusions: Modest FOLFIRINOX dose modifications are prevalent in clinical practice and are not associated with a reduction in efficacy. A median survival of 13 months with dose modified FOLFIRINOX is compelling. Dose reduction of 2 or more agents was associated with diminished survival. Second line therapy following FOLFIRINOX was associated with modest activity.