Faculty Bibliography

Background Regulatory T cells (Tregs) mediate potent tolerogenic signals, are involved in adaptive anti-tumor immune responses and T-cell reinvigoration using immune checkpoint blockers. Despite their prominent immune suppressive role, the tissue distribution and contribution of Tregs to clinical outcomes in human lung cancer is not well understood. Methods The levels and tissue distribution of Tregs and major tumor infiltrating lymphocyte (TIL) subsets were measured using simultaneous detection of FOXP3, CD4, CD8, pancytokeratin and DAPI by multiplexed quantitative immunofluorescence in 619 formalin-fixed paraffin embedded (FFPE) NSCLCs from 4 independent cohorts represented in tissue microarrays (cohort#1 [Yale, n=210], cohort#2 [Greece, n=192]; cohort#3] [80 immunotherapy-treated NSCLCs]; cohort#4 [Yale, n=137, adenocarcinomas with mutation testing). Markers were measured in different tissue compartments and cell phenotypes were used for individual cell counts and machine-learning-based spatial analysis. We studied the association between T-cell populations, tissue distribution, clinicopathologic/ molecular characteristics and outcomes. Results Tregs (DAPI+/CD4+/FOXP3+ cells) were predominantly located in the stromal compartment and represented 3-10% of the total T-cell population. The level of Tregs was positively associated with higher CD8+ Tcell infiltration across the cohorts. There was no consistent association between Treg levels and patient age, gender, smoking status, clinical stage or tumor histology. However, Tregs were significantly higher in KRAS mutated lung adenocarcinomas than in EGFR mutant or KRAS/ EGFR wild-type cases. As a single marker, the level of Tregs was not significantly associated with survival. However, the Treg to CD8 signal ratio was associated with shorter 5-year overall survival across the cohorts. Reduced survival was also seen in cases with a higher 5-nearest neighbor (5NN) mean distance between CD4+/Tregs and CD8+/CD4+ cells. Notably, the survival effect of the Treg-associated metrics was numerically higher in patients treated with immune checkpoint blockers. Conclusions Tregs are prominently less abundant than other TIL subsets in NSCLC microenvironments and they are increased in T-cell inflamed tumors. Their positive association with CD8+ cytotoxic TILs suggests their upregulation upon adaptive anti-tumor immune pressure and could explain the inconsistent reported relationship between Tregs and prognosis. Elevated Treg to CD8 signal ratio and reduced spatial clustering between CD4-Tregs and CD8-CD4 are indicative of poor outcome preferentially in NSCLC patients treated with checkpoint blockade suggesting a biomarker role

Background ALKS 4230 is an engineered fusion of IL-2 and IL-2Ralpha designed to selectively expand NK and CD8+ T cells (Figures 1 and 2). In preclinical studies, ALKS 4230 exhibited enhanced pharmacokinetic and selective pharmacodynamic properties with improved antitumor efficacy relative to IL-2 [1]. Methods ARTISTRY-1 (NCT02799095) is a phase 1/2 study investigating ALKS 4230 as monotherapy and in combination with pembrolizumab in adults with advanced solid tumors [2]. For monotherapy dose escalation, ALKS 4230 is administered intravenously over 30 minutes once daily for 5 days every 14 or 21 days. For combination therapy, the same regimen of ALKS 4230 is administered with pembrolizumab every 21 days in cohorts based on tumor type, prior anti-PD-1 therapy, and rollover from monotherapy. Outcomes include the monotherapy recommended phase 2 dose (RP2D), safety, pharmacodynamics, and antitumor activity (RECIST 1.1). Results of the completely enrolled cohorts of dose-escalation phase and of combination therapy in anti-PD-1-unapproved tumors as of June 21, 2019, are presented. Results For dose escalation, 36 patients received ALKS 4230 monotherapy <=6 mug/kg/d. Maximum tolerated dose has not been reached. Most frequent adverse events (AEs), regardless of relationship, were pyrexia (75%) and chills (72%); the majority were grades 1 or 2. Grade >=3 AEs related to ALKS 4230 occurred in 11 patients (31%) and were mainly transient leukopenia. One death from aspiration pneumonia was considered unrelated to ALKS 4230 by the investigator. ALKS 4230 induced dose-dependent increases in circulating NK and CD8+ T cells with minimal, non-dose-dependent effects on regulatory T cells (Tregs). At 3 and 6 mug/kg/d, 8 of 14 patients with evaluable scans had stable disease. One patient with heavily pretreated pancreatic adenocarcinoma had prolonged stable disease with 6+ months of monotherapy; CA19-9 decreased from 2571 U/mL (pretherapy) to 673 U/mL (nadir). Data from 20 patients enrolled in the combination therapy cohort of PD-1-unapproved tumors indicate no new toxicities; 7 of 11 patients with evaluable scans had stable disease or better. One patient (ovarian cancer) had confirmed partial response; CA-125 normalized from a peak of 282 to 24.5 U/mL after 2 months of therapy. Conclusions ALKS 4230 is a promising agent with acceptable tolerability and preliminary clinical benefit. It selectively expanded CD8+ T cells and NK cells with minimal Treg expansion. The intravenous monotherapy RP2D was established as 6 mug/kg/d. Safety and pharmacodynamic data enabled selection of the 3 mug/kg dose for initial evaluation in combination with pembrolizumab

Background: Anti-GITR (glucocorticoid-induced TNFR-related protein) agonist and gemcitabine (gem) combination improves anti-tumor activity pre-clinically compared to either therapy alone. We investigated the effect of this combination as part of a multi-center phase 1b multi-dose escalation and expansion trial in patients (pts) with advanced solid cancers.
Method(s): Part C of the phase 1b trial enrolled adult pts with advanced solid cancers for which gemcitabine was clinically appropriate. Pts had failed at-least one prior systemic therapy, had measurable disease and were ECOG PS 0-1 at baseline. All pts received gem (1000mg/m2) IV on D1 and D8 and TRX518 on D2 of a 21-day cycle in two escalation cohorts (2mg/kg or 4mg/kg load[L] in C1 followed by 1mg/kg maintenance[M] from C2). The highest tested safe dose identified in escalation was further evaluated in expansion. Primary endpoint was safety. Secondary and exploratory endpoints included response (RECIST v1.1), PK and PD.
Result(s): (Table Presented) From January to September 2018, 26 pts were dosed;16/26 had pancreaticobiliary cancers (PBC) of which14/16 had prior gem. There was 1 treatment-related SAE (G3 anemia G4 lymphopenia, G3 hypoalbuminemia [DLT] and G3 hypokalemia [DLT]). No treatment-related deaths occurred. Of the 14 response-evaluable pts in cohorts 1 (n=2), 2 (n=5) and expansion (n=7), 57.1% (8/14) had SD. At the 4mg/kg L/1mg/kgMTRX518 dose, 66.7% (8/12) of evaluable pts had SD. 60% of PBC had clinical benefit of which 87.5% had prior gem.
Conclusion(s): In pts with heavily pre-treated advanced cancer, for which gem is clinically appropriate, TRX518 plus gem was well tolerated with no new safety signals. Preliminary evidence of clinical benefit was observed including in pts with PBC previously treated with gem. This study is ongoing

BACKGROUND:IL-15 induces the activation and proliferation of NK and memory CD8+ T cells and has preclinical antitumor activity. Given the superior activity and favorable kinetics of ALT-803 (IL-15N72D:IL-15RαSu/IgG1 Fc complex) over recombinant human IL-15 (rhIL-15) in animal models, we performed this first-in-human Phase I trial of ALT-803 in patients with advanced solid tumors. METHODS:Patients with incurable advanced melanoma, renal cell, non-small cell lung, and head and neck cancer were treated with ALT-803 0.3-6 mg/kg weekly i.v. or 6-20 mg/kg weekly s.c. for 4 consecutive weeks, every 6 weeks. Immune correlates included pharmacokinetics, immunogenicity, lymphocyte expansion and function. Clinical endpoints were toxicity and antitumor activity. RESULTS:Twenty-four patients were enrolled; eleven received i.v. and 13 received s.c. ALT-803. Of these patients, 9 had melanoma, 6 renal, 3 head and neck, and 6 lung cancer. Although total lymphocyte and CD8+ T cell expansion were modest, NK cell numbers rose significantly. Neither anti-ALT-803 antibodies nor clinical activity were observed. Overall, ALT-803 was well-tolerated, with adverse effects including fatigue and nausea most commonly with i.v. administration, while painful injection site wheal was reported most commonly with s.c. ALT-803. CONCLUSIONS:Subcutaneous ALT-803 produced the expected NK cell expansion and was well-tolerated with minimal cytokine toxicities and a strong local inflammatory reaction at injection sites in advanced cancer patients. These data, together with compelling evidence of synergy in preclinical and clinical studies, provide the rationale for combining ALT-803 with other anti-cancer agents.

Adenocarcinomas and active granulomas can both have a spiculated appearance on computed tomography (CT) and both are often fluorodeoxyglucose (FDG) avid on positron emission tomography (PET) scan, making them difficult to distinguish. Consequently, patients with benign granulomas are often subjected to invasive surgical biopsies or resections. In this study, quantitative vessel tortuosity (QVT), a novel CT imaging biomarker to distinguish between benign granulomas and adenocarcinomas on routine non-contrast lung CT scans is introduced. Our study comprised of CT scans of 290 patients from two different institutions, one cohort for training (N = 145) and the other (N = 145) for independent validation. In conjunction with a machine learning classifier, the top informative and stable QVT features yielded an area under receiver operating characteristic curve (ROC AUC) of 0.85 in the independent validation set. On the same cohort, the corresponding AUCs for two human experts including a radiologist and a pulmonologist were found to be 0.61 and 0.60, respectively. QVT features also outperformed well known shape and textural radiomic features which had a maximum AUC of 0.73 (p-value = 0.002), as well as features learned using a convolutional neural network AUC = 0.76 (p-value = 0.028). Our results suggest that QVT features could potentially serve as a non-invasive imaging biomarker to distinguish granulomas from adenocarcinomas on non-contrast CT scans.

BACKGROUND:In RET-rearranged lung cancers, data on the frequency of brain metastases and, in particular, the outcomes of multikinase inhibitor therapy in patients with intracranial disease are not well characterized. METHODS:A global, multi-institutional registry (cohort A, n=114) and a bi-institutional data set (cohort B, n=71) of RET-rearranged lung cancer patients were analyzed. Patients were eligible if they had stage IV lung cancers harboring a RET rearrangement by local testing. The incidence of brain metastases and outcomes with multikinase inhibitor therapy were determined. RESULTS:The frequency of brain metastases at the time of diagnosis of stage IV disease was 25% (95%CI 18%-32%) in all patients from both cohorts. The lifetime prevalence of brain metastasis in stage IV disease was 46% (95%CI 34%-58%) in patients for whom longitudinal data was available. The cumulative incidence of brain metastases was significantly different (p=0.0039) between RET-, ROS1-, and ALK-rearranged lung cancers, with RET intermediate between the other two groups. While intracranial response data was not available in cohort A, the median progression-free survival (PFS) of multikinase inhibitor therapy (cabozantinib, vandetanib, or sunitinib) in patients with brain metastases was 2.1 months (95%CI 1.3-2.9 months, n=10). In cohort B, an intracranial response was observed in 2 of 11 patients (18%) treated with cabozantinib, vandetanib (±everolimus), ponatinib, or alectinib; the median overall PFS (intracranial and extracranial) was 3.9 months (95%CI 2.0-4.9 months). CONCLUSIONS:Brain metastases occur frequently in RET-rearranged lung cancers, and outcomes with multikinase inhibitor therapy in general are suboptimal. Novel RET-directed targeted therapy strategies are needed.