Triple blockade of Ido-1, PD-L1 and MEK as a potential therapeutic strategy in NSCLC

BACKGROUND

Despite the recent progress in the treatment and outcome of Non Small Cell Lung Cancer (NSCLC), immunotherapy has still significant limitations reporting a significant proportion of patients not benefiting from therapy, even in patients with high PD-L1 expression. We have previously demonstrated that the combined inhibition of MEK and PD-L1 in NSCLC patients derived three dimensional cultures exerted significant synergistic effect in terms of immune-dependent cancer cell death. However, subsequent experiments analyzing the expression of Indoleamine 2,3-dioxygenase-1 (Ido-1) gene expression demonstrated that Ido-1 resulted unaffected by the MEK inhibition and even increased after the combined inhibition of MEK and PD-L1 thus representing a potential escape mechanism to this combination.

METHODS

We analyzed transcriptomic profile of NSCLC lung adenocarcinoma cohort of TCGA (The Cancer Genome Atlas), stratifying tumors based on EMT (Epithelial mesenchymal Transition) score; in parallel, we investigated the activation of Ido-1 pathway and modulation of immune cytokines productions both in NSCLC cells lines, in peripheral blood mononuclear cells (PBMCs) and in ex-vivo NSCLC spheroids induced by triple inhibition with an anti-PD-L1 monoclonal antibody, the MEK inhibitor and the Ido-1 inhibitor.

RESULTS

In NSCLC lung adenocarcinoma patient cohort (from TCGA) Ido-1 gene expression was significantly higher in samples classified as mesenchymal according EMT score. Similarly, on a selected panel of NSCLC cell lines higher expression of MEK and Ido-1 related genes was detected in cells with mesenchymal phenotype according EMT score, thus suggesting a potential correlation of co-activation of these two pathways in the context of EMT, with cancer cells sustaining an immune-suppressive microenvironment. While exerting an antitumor activity, the dual blockade of MEK and PD-L1 enhances the secretion of pro-inflammatory cytokines (IFNγ, TNFα, IL-12 and IL-6) and, consequently, the expression of new immune checkpoints such as Ido-1. The triple inhibition with an anti-PD-L1 monoclonal antibody, the MEK inhibitor and the Ido-1 inhibitor demonstrated significant antiproliferative and proapoptotic activity on ex-vivo NSCLC samples; at the same time the triple combination kept increased the levels of pro-inflammatory cytokines produced by both PBMCs and tumor spheroids in order to sustain the immune response and simultaneously decreased the expression of other checkpoint (such as CTLA-4, Ido-1 and TIM-3) thus promoting an immune-reactive and inflamed micro-environment.

CONCLUSIONS

We show that Ido-1 activation is a possible escape mechanism to immune-mediated cell death induced by combination of PD-L1 and MEK inhibitors: also, we show that triple combination of anti-PD-L1, anti-MEK and anti-Ido-1 drugs may overcome this negative feedback and restore anti-tumor immune response in NSCLC patients' derived three dimensional cultures.

SWOG S2012: Randomized phase II/III trial of first line platinum/etoposide (P/E) with or without atezolizumab (NSC#783608) in patients (pts) with poorly differentiated extrapulmonary small cell neuroendocrine carcinomas (NEC)

TPS4179

Background: Poorly differentiated, extrapulmonary small cell NEC are rare cancers with median overall survival (OS) < 1 year. Treatment is extrapolated from small cell lung cancer (SCLC) with use of P (cisplatin or carboplatin) + E. More effective treatment regimens and predictive biomarkers are needed to improve outcomes. In SCLC, induction therapy with combination of P/E + PD-L1 checkpoint inhibitor atezolizumab and maintenance atezolizumab improved OS (12.3 months vs 10.3 months; HR 0.70, 95% CI 0.54 – 0.91, P = 0.007) vs P/E alone (Horn L, et al. N Engl J Med 2018). No study to date has compared PD-1/PD-L1 inhibition during induction only vs during induction and maintenance therapy. In SCLC, distinct molecular subtypes can be identified by the presence of specific transcription factors (e.g., ASCL1, NEUROD1, POU2F3) or an Inflamed gene signature (SCLC-I), with SCLC-I pts more likely to benefit clinically from the addition of immunotherapy (Gay CM, et al. Cancer Cell 2021). In this study we plan to test the benefit of adding atezolizumab to induction P/E plus maintenance vs P/E alone, as well as the role of adding maintenance atezolizumab vs observation after induction chemo-immunotherapy. We also plan to correlate tumor- and blood-based subtype biomarkers with response to therapy. Methods: Eligible pts ≥18 years old have evaluable, histologically confirmed extrapulmonary small cell NEC, Zubrod PS ≤2, and are allowed to have up to 1 cycle of P/E prior to enrollment. P (cisplatin 75 mg/m2 or carboplatin AUC 5, iv) on day 1, E 100 mg/m2 iv on days 1-3, and atezolizumab 1200 mg iv on day 1 of q21 day cycles. Treatment consists of an induction phase x 4 cycles, and if no disease progression, a maintenance/observation phase given until disease progression for up to 1 year. Pts are randomized to 1 of 3 arms: A) Induction P/E + atezolizumab → maintenance atezolizumab B) Induction P/E + atezolizumab → observation C) Induction P/E → observation. The primary endpoint is to compare the OS (from randomization) between arms in a fixed sequence: A vs C → B vs C → A vs B. Secondary endpoints include comparing OS (from start of maintenance/observation), progression free survival, response rate, duration of response, and safety/tolerability across arms. Tumor and blood samples will be banked for future biomarker analyses, including immunohistochemistry of transcription factors on tissue and whole exome sequencing on tumor and circulating tumor DNA. With 189 pts, the study is powered to detect an improvement in 12-months OS from 35% to 57.5% (HR 0.53). Both phase 2 and phase 3 portions include interim analyses. Accrual will not pause for phase 2 analysis, expected early 2024. This study was activated December, 2021 and is open to accrual across the NCI National Clinical Trials Network (NCTN). Clinical trial information: NCT05058651.

Clinical outcome and potential benefits of post-progression immunotherapy for patients with metastatic NSCLC with primary resistance to ipilumumab and nivolumab in the LONESTAR phase III study

9049

Background: Primary resistance to immune checkpoint inhibitor (ICI) therapy remains a major challenge in clinical oncology. Here, we describe the clinical outcome of patients who experienced radiologic progression within 12 weeks of therapy with nivolumab and ipilimumab (I+N) for metastatic non-small cell lung cancer (mNSCLC). Methods: The LONESTAR study is an ongoing phase III study (NCT03391869). Study enrolls patients with immunotherapy naïve mNSCLC (prior chemotherapy is allowed). All patients receive I+N for 12 weeks and are randomized to experimental therapy vs. control arm if they did not have disease progression. Patients who experience radiologic progression per RECIST v1.1 are not randomized and removed from the study. Treatment beyond progression is allowed if they clinically benefit from the systemic therapy. We prospectively collected clinicopathologic and radiologic outcome data from patients who experienced radiologic progression within 12 weeks of I+N therapy and have not randomized to investigational therapy. We described the primary progression pattern. We collected subsequent treatment, radiologic, and toxicity data and calculated clinical outcomes, including progression-free survival (PFS) and overall survival (OS). Results: Of the 194 patients who received at least one dose of I+N therapy, 72 patients had clinical and/or radiologic progression at ≤ 12 weeks. Thirty-five (35; 48%) patients did not receive subsequent treatment, 21 (29%) patients received subsequent 2nd line systemic therapy, and 16 (22%) patients were continued on I+N beyond radiologic progression due to ongoing clinical benefit. Among patients treated with 2nd line therapy, 13 patients were treated with platinum doublet +/- anti-PD-(L)1, seven (7) patients were treated with single-agent chemotherapy +/- VEGF inhibitor, and one (1) patient was treated with targeted therapy. The PFS for the 2nd line therapy was 6.5 months (95%CI: 4.8, 8.9), and OS was 10.4 months (95%Cl: 6.6, 16.1). Among the 16 patients treated with I+N beyond progression, 13 had a mixed response to induction therapy, where primary progression was most frequently observed in mediastinal lymph nodes. LCT with radiotherapy was utilized with I+N in 10 patients. The median duration of post-progression treatment with I+N plus LCT was 8.7 months (95%Cl: 5.9, 22.3) and 5.6 months (95%Cl 4.4, 11.5) with I+N alone. The OS was 19.5 months (95% CI: 6.2,18.7). Conclusions: In this study cohort, primary resistance to I+N was observed in 37% of the patients, and in a subset of these patients treated with post-progression I+N, either alone or in combination with LCT, durable clinical benefit was observed. Further studies are warranted to identify which patients are most likely to benefit from post-progression I+N. Clinical trial information: NCT03391869.

Results of a phase 1b study of osimertinib plus sapanisertib or alisertib for osimertinib-resistant, EGFR-mutant non–small cell lung cancer (NSCLC)

9105

Background: The aurora kinase and mTOR pathways are implicated in resistance to EGFR inhibitor osimertinib. Here, we investigated the safety and efficacy of the aurora kinase inhibitor alisertib and the mTOR inhibitor sapanisertib in combination with osimertinib. Methods: This is a phase 1b study with dose finding and expansion portions (NCT04479306). The dose finding portion used a Bayesian optimal interval (BOIN) design to assess two arms: osimertinib 80 mg daily in combination with alisertib 20 mg, 30 mg, and 40 mg daily day 1-21 of 28-day cycle (osi-ali arm) and osimertinib 80 mg daily in combination with sapanisertib 2 mg and 3 mg daily (osi-sapa arm). Dose limiting toxicities (DLTs) were predefined in the protocol. Patients with EGFR (L858R/exon 19 deletion) mutant NSCLC whose disease have progressed on osi and up to one additional line of systemic therapy were assigned, at investigator discretion, to either study arm. Tumor biopsy was mandatory at study entry and optional upon progression. Results: As of February 1, 2022, 40 patients are enrolled (20 in each arm). One DLT was observed in each arm: grade 3 nausea in ali-osi arm and grade 3 AST elevation in osi-sapa arm. Grade 3 treatment emergent adverse events (TEAEs) occurred in 10% of each arm, and no grade 4 TEAEs were observed. The most common TEAEs in osi-ali arm was leucopenia (45%) and anemia (35%) while in osi-sapa arm, hyperglycemia (45%) and stomatitis (40%). In osi-ali arm (n = 20), median progression free survival (mPFS) was 1.9 months while objective response rate (ORR) and disease control rate (DCR) were 5% (95% CI: 0.1 ̃ 24.9%) and 40% (95% CI: 19.1 ̃ 63.9%), respectively. In osi-sapa arm (n = 16, evaluated for response to date), mPFS was 4.6 months while ORR and DCR were 12.5% (95% CI: 1.6 ̃ 38.3%) and 68.7% (95% CI: 35.7 ̃ 82.7%), respectively. Conclusions: Osimertinib with alisertib or sapanisertib is well tolerated in osimertinib-resistant, EGFR mutant NSCLC. The sapanisertib combination, but not the alisertib combination, demonstrates antitumor activity suggesting that mTOR inhibition warrants further exploration in this population. Biomarker analysis is ongoing to identify the molecular determinants of response and resistance to sapasertib. Clinical trial information: NCT04479306.

Driver mutations to predict for poorer outcomes in non-small cell lung cancer patients treated with concurrent chemoradiation and consolidation durvalumab

8528

Background: The use of durvalumab after chemoradiation in locally advanced non-small cell lung cancer (NSCLC) patients significantly improves overall survival. However, it is unclear whether this benefit applies to all genetic subtypes of lung cancer. We hypothesize that patients with driver mutation NSCLC may derive less benefit from consolidation durvalumab. Methods: Using the Genomic Marker-Guided Therapy Initiative (GEMINI) database at MD Anderson, we identified 134 patients who were treated with chemoradiation followed by durvalumab for NSCLC. We segregated patients with driver mutations to targetable (EGFR, ALK translocation, ROS1 fusion, MET exon 14 skipping, RET fusion, and/or BRAF) (N = 24) and those driven by canonical KRAS mutations (N = 26). The rest (N = 84) had none of these mutations. We gathered demographic, treatment, and outcome data and compared progression-free survival (PFS) and overall survival (OS) using the Kaplan-Meier method. We used multivariate regression analysis to account for demographic and treatment variables. Results: For our cohort, median age at diagnosis was 64.8, 52% were female (n = 70), and median follow up was 1.5 years. 86% of patients have a history of smoking (n = 115). 21% had squamous cell histology (n = 28). 2 patients had stage IIA disease, 6 had stage IIB, 48 had stage IIIA, 56 had stage IIIB, 13 had stage IIIC, and 9 had stage IV. 73 patients had progression after durvalumab and 37 patients died. Patients with driver mutations had significantly worse median PFS compared to those without driver mutations (8.9 mo vs 26.6 mo; HR 2.62 p < 0.001). Patients with KRAS mutations had particularly poor PFS (Median 7.9 mo, HR 3.34, p < 0.001), while patients with targetable driver mutations trended to worse PFS (Median 14.5 mo, HR 1.96, p = 0.056). The median OS for the cohort was 4.8 yrs with no significant differences based on driver mutation status. On multivariate analysis, only driver mutation status was associated with PFS, but not OS. For patients with first progression, we found the targetable driver group to have significantly improved time to second objective progression (PFS2) compared to the KRAS (HR 0.28, p = 0.011) or non-mutated group (HR 0.38, p = 0.025). All patients in the targetable driver group received targeted therapy after first progression. Conclusions: Our results suggest that patients with driver mutations have worse PFS compared to patients without these mutations after chemoradiation. However, patients with targetable oncogene driver mutations have significantly improved prognosis after initial progression compared to the other groups, likely due to targeted therapy, suggesting that these therapies, including novel approaches towards KRAS mutants, should be further explored in this setting.

Semaphorin-PlexinD1 signaling limits angiogenic potential via the VEGF decoy receptor sFlt1

Sprouting angiogenesis expands the embryonic vasculature enabling survival and homeostasis. Yet how the angiogenic capacity to form sprouts is allocated among endothelial cells (ECs) to guarantee the reproducible anatomy of stereotypical vascular beds remains unclear. Here we show that Sema-PlxnD1 signaling, previously implicated in sprout guidance, represses angiogenic potential to ensure the proper abundance and stereotypical distribution of the trunk's segmental arteries (SeAs). We find that Sema-PlxnD1 signaling exerts this effect by antagonizing the proangiogenic activity of vascular endothelial growth factor (VEGF). Specifically, Sema-PlxnD1 signaling ensures the proper endothelial abundance of soluble flt1 (sflt1), an alternatively spliced form of the VEGF receptor Flt1 encoding a potent secreted decoy. Hence, Sema-PlxnD1 signaling regulates distinct but related aspects of angiogenesis: the spatial allocation of angiogenic capacity within a primary vessel and sprout guidance.

Determination of 1-benzo[b]thien-2-ylethanone and related impurities by high performance liquid chromatography

1-Benzo[b]thien-2-ylethanone (2-acetylbenzothiophene, 2-ABT) and related impurities were determined using a reverse-phase high performance liquid chromatography system and UV detection at 254 nm. Separation was achieved isocratically on a 4.6 mm x 25 cm, 5 microns Zorbax Rx-C8 column using an eluent which is 0.2% perchloric acid/THF in a ratio of 60:40 (v/v). The chromatographic system resolved 2-ABT and known impurities in less than 45 min with near baseline resolution. Known impurities were quantitated versus 2-ABT with corrections made for differences in detector response at the specified wavelength. Linearity for 2-ABT was demonstrated with a correlation coefficient > 0.9999. Assay precision (RSD values) for impurities at 0.5% ranged from +/- 1.8% to +/- 14%, while precision (RSD values) for the 2-ABT determination ranged from +/- 0.81% to +/- 1.1%. A variety of different chromatographic columns and conditions are discussed for the application.

Influence of Concomitant Pratylenchus brachyurus and Meloidogyne spp. on Root Penetration and Population Dynamics

Populations of Pratylenchus brachyurus on cotton were increased significantly in the presence of either Meloidogyne incognita or M. arenaria.This occurred with either simultaneous inoculation or prior invasion by M. incognita. P. brachyurus penetrated cotton roots previously invaded by, or simultaneously inoculated with, M. incognita, as well as, or better than, in the absence of M. incognita. Prior invasion by M. incognita, however, suppressed P. brachyurus populations on tomato, while it had no effect on alfalfa and tobacco. Populations of M. incognita on cotton were generally inhibited by the presence of P. brachyurus. Simultaneous inoculation with, or previous invasion by, P. brachyurus also inhibited root penetration by M. incognita. These findings emphasize the importance of host susceptibility in the study of concomitant nematode populations.