A phase 1b/2a study of safety and efficacy of NT-I7 in combination with anti-PD-L1 (atezolizumab) in patients with anti-PD-1/PD-L1 naïve or relapsed/refractory (R/R) high-risk skin cancers: The phase 1b report

9561

Background: Novel immunotherapy approaches have changed the treatment landscape of patients (pts) with high-risk cancers like melanoma, Merkel cell carcinoma (MCC) and cutaneous squamous cell carcinoma (cSCC). However, despite the widespread use of checkpoint inhibitors (CPI) in these indications, most pts either fail to respond or eventually have progressed. NT-I7 (efineptakin alfa) is a long-acting human IL-7 that can increase the number and functionality of T-cells in peripheral blood and within the tumors. NT-I7 in combination with atezolizumab (atezo), may augment the efficacy in high-risk skin cancers. Methods: This is a phase 1b/2a study to evaluate the safety and efficacy of NT-I7 in combination with atezo in pts with CPI- naïve or relapsed/refractory (R/R) high-risk skin cancers. Phase 1b dose escalation followed a 3+3 design, in which pts who received NT-I7 IM every 3 weeks (Q3W) at 3 dose levels (DL1-3): 120, 360, and 840 µg/kg or Q6W at DL4 1200 µg/kg, and atezo IV 1200 mg Q3W. The objectives of the phase 1b were to evaluate dose-limiting toxicity (DLT), determine the MTD and the recommended phase 2 dose (RP2D), pharmacokinetics (PK), pharmacodynamics and preliminary antitumor activity. Results: As of January 14, 2022, 16 pts were enrolled in phase 1b: DL1 (n = 3), DL2 (n = 3), DL3 (n = 7), and DL4 (n = 3). The median age was 66 years [46-86], with ECOG PS 0 in 6 (37%), 1 in 7 (44%) and 2 in 3 (19%), and median number of prior therapies 1 [1-2]. One pt had a DLT at DL3 [Grade (G)3 confusion and G3 increased AST] but no DLTs were reported at DL4 and MTD was not reached. The RP2D was 1200 µg/kg Q6W of NT-I7 plus atezo 1200 mg Q3W. All pts had drug related AEs. Most AEs were G 1- 2 in 11(69%) pts; 5 (31%) in G3. There were no related G4/G5 AEs. Eleven pts had stable disease and the disease control rate was 69% (11/16). Preliminary PK analysis of DL1- 3 showed dose dependent Cmax, with Tmax at ̃24hr and T½ ranging ̃75hr to 125hr. NT-I7 dose-dependent expansion of the absolute lymphocyte count, CD3+, CD4+ and CD8+ T-cells peaked after one dose and the increase was maintained by repeat dosing until the end of treatment. Immunophenotyping of memory T-cell subsets showed a 5-fold expansion in most T-cell subsets and a 30-fold expansion of the stem cell memory CD8+ T-cell subset (Tscm) at DL4. Conclusions: This trial is the first time an IL-7 cytokine-based therapy and CPI has been assessed in UV induced high-risk skin cancers including in IO refractory pts. The combination of NT-I7 and atezo showed favorable safety and anticancer activity. NT-I7 significantly increased total lymphocyte and the T-cell compartment, with a greatest expansion of the CD8+ Tscm, a vital population for eliciting antitumor activity. Additional safety and efficacy updates will be provided by the ongoing phase 2a trial in CPI-naïve cSCC and MCC and CPI R/R MCC, cSCC and melanoma. Clinical trial information: NCT03901573.

432 Nemvaleukin alfa, a novel engineered IL-2 cytokine, in combination with the anti-PD-1 antibody pembrolizumab in patients with recurrent/metastatic head and neck squamous cell carcinoma (ION-01 study)

Background

Nemvaleukin alfa (nemvaleukin, ALKS 4230) is a novel engineered cytokine that selectively binds to the intermediate-affinity IL-2R to preferentially activate and expand anti-tumor CD8+ T and NK cells with minimal expansion of regulatory T cells (Treg), thereby leveraging antitumor effects of the IL-2 pathway while mitigating potential toxicity that limits use.1 Nemvaleukin single-agent activity has been demonstrated in checkpoint inhibitor-experienced patients, and deep and durable responses have been achieved in combination with pembrolizumab in multiple tumor types (eg, breast, head and neck, gastrointestinal, genitourinary, gynecological).2

Methods

ION-01 (NCT04144517) is a nonrandomized trial in adult patients with histologically/cytopathologically confirmed diagnosis of metastatic/recurrent head and neck squamous cell carcinoma. Eligible patients have progressive disease after ≥8 weeks on anti-PD-(L)1 therapy. The primary endpoint is the rate of new or improved antitumor response after the addition of nemvaleukin. Secondary objectives include characterization of the antitumor response and evaluation of safety and tolerability of the combination regimen. Patients receive intravenous nemvaleukin (3 μg/kg) once daily for the first 5 days and pembrolizumab (200 mg) on day 1 of each 21-day cycle. Tumor imaging and biopsies were performed at baseline and at pre-specified times. We present preliminary safety and antitumor activity (RECIST v1.1) data as of June 2021.

Results

Fourteen patients with progressive disease received combination therapy with nemvaleukin and pembrolizumab; 8 had no prior response to pembrolizumab, 6 had previous best response of stable disease or partial response. Mean (± SD) age was 62 ± 12 years, 86% were male, and all were Caucasian. Prior anti-cancer therapy included radiotherapy (93%) and surgery (50%). ECOG performance status was 0 (14%) and 1 (86%) at baseline. Treatment-related adverse events of any grade in ≥30% of patients were chills (64.3%), pyrexia (57.1%), fatigue (42.9%), and nausea (35.7%). Five patients had stable disease as best response. One patient achieved a partial response (complete response in the target lesion) and remains on treatment (8+ cycles). Expansion of CD8+ T and NK cells with minimal Treg expansion was observed.

Conclusions

Nemvaleukin and pembrolizumab combination therapy was generally well tolerated; adverse events were consistent with those observed with intravenous nemvaleukin in ARTISTRY studies [2]. Peripheral immune cell expansion profiles are comparable to that observed with the same regimen in the ARTISTRY 1 phase 1 study. Emerging data from pretreatment and on-treatment paired biopsies will further characterize specific antitumor effects of nemvaleukin and pembrolizumab in this patient population.

Acknowledgements

The authors would like to thank all the patients who are participating in this study and their families. The study is sponsored by Alkermes, Inc. Medical writing and editorial support was provided by Parexel, and funded by Alkermes, Inc.

Trial Registration

ClinicalTrials.

gov NCT04144517

References

Lopes JE, Fisher JL, Flick HL, et al. ALKS 4230: a novel engineered IL-2 fusion protein with an improved cellular selectivity profile for cancer immunotherapy. J Immunother Cancer 2020;8:e000673. doi: 10.1136/jitc-2020-000673.

Boni V, Winer IS, Gilbert L, et al. ARTISTRY-1: Nemvaleukin alfa monotherapy and in combination with pembrolizumab in patients (pts) with advanced solid tumors. J Clin Oncol 2021;39(Suppl 15):abstr 2513.

Ethics Approval

This study was approved by Quorum Review IRB (now Advarra IRB), approval number QR 33752.

299 Broad T antigen-specific CD8+ T cell repertoire is associated with response to PD-1 blockade in virus positive merkel cell carcinoma

Background

Merkel cell carcinoma (MCC) is an aggressive human skin cancer primarily induced by Merkel Cell Polyomavirus (MCPyV) driven by expression of the oncogenic T antigens (T-Ags): Large T and Small T antigen. Checkpoint inhibition therapy blocking the programmed cell death protein-1 (PD-1) pathway has proven effective with a clinical response rate up to 58%,1 highlighting the critical role of immune surveillance for tumor control. Yet, evidence for the impact of T-Ag-specific T cells following immunotherapy is still limited.

Methods

Potential CD8+ T cell epitopes derived from the T-Ags and the Viral capsid protein 1 (VP1) were predicted with netMHCpan 4.0 as 9- and 10-mer peptides with a rank score <2 for binding to 33 different HLA class I types. Peripheral blood mononuclear cells (PBMC) were obtained from 24 MCPyV+ MCC patients prior and post anti-PD-1 therapy initiation (CITN-09/Keynote-017). T cell recognition of the MCPyV-derived peptides during therapy was evaluated using the high-throughput technology of DNA barcode labeled pMHC multimers. Phenotypic characteristics of multimer-binding T cells were evaluated for selected patients.

Results

Across all patients, 40 T-Ag-specific CD8+ T-cell populations were detected recognizing 31 epitopes restriction to 14 different HLA class I types. T-Ag-specific CD8+ T cells were detected in responders (complete and partial response, n=17) during therapy with a trend of increased number of responses observed after therapy initiation. Whereas only a single T-Ag-specific population was detectable in non-responders (stable and progressive disease, n=7). Moreover, the T cell repertoire after therapy initiation was significantly increased in the responder group compared to non-responder with the T-Ag-specific T cells showing an activated effector memory phenotype.

Conclusions

The current study indicates that the T-Ag-specific T cells are associated with clinical benefit to checkpoint inhibitor therapy. Furthermore, the broad identification of novel T-Ag-derived T cell epitopes could potentially facilitate the use of targeted T cell therapy to enhance T cell recognition and clearance of MCC in combination with checkpoint inhibition.

Acknowledgements

Supported by the Cancer Immunotherapy Trials Network (CITN)

Reference

Nghiem P, Bhatia S, Lipson E. Three-year survival, correlates and salvage therapies in patients receiving first-line pembrolizumab for advanced Merkel cell carcinoma. J Immunother cancer 2021;9:e002478.

A new interpretable machine learning approach for single-cell data discovers correlates of clinical outcome in cancer immunotherapy

High-dimensional cytometry is routinely used to characterize patient responses to cancer immunotherapy and other treatments, producing a wealth of datasets ripe for exploration but whose biological and technical heterogeneity make them difficult to analyze with current tools. We introduce a new interpretable machine learning method for single-cell mass and flow cytometry studies, FAUST, that robustly performs unbiased cell population discovery and annotation and enables data integration across studies and platforms. FAUST returns biologically interpretable cell phenotypes that can be compared across studies, making it well-suited for the analysis and integration of complex datasets. We use FAUST to perform candidate biomarker discovery and validation by applying it to flow and mass cytometry datasets from melanoma anti-PD-1 trials in order to discover and validate new CD4+ and CD8+ effector-memory T cell correlates of outcome co-expressing PD-1, HLA-DR, and CD28. Existing state-of-the-art computational discovery approaches as well as prior manual analyses did not detect any statistically significant T cell correlates associated with anti-PD-1 treatment these data. We use FAUST to replicate the discovery of published myeloid cell correlates and validate these by identifying them de novo in independent trials. FAUST’s phenotypic annotations are used to perform cross-study integration diverse data sets, allowing hypothesis-driven inference about cell sub-populations through a Phenotypic and Functional Differential Abundance (PFDA) framework. We showcase this approach on data across multiple trials. These results establish FAUST as a powerful new approach for unbiased discovery in single-cell cytometry.

A randomized phase II study of atezolizumab plus recombinant human IL-7 (CYT107) or atezolizumab alone in patients with locally advanced or metastatic urothelial carcinoma (mUC): A Cancer Immunotherapy Trials Network Trial (CITN-14)

TPS4586

Background: Atezolizumab is a regulatory-approved PD-L1 antagonistic antibody for the post-platinum mUC setting. Responses to atezolizumab are highly efficacious in a subset of patients, but suboptimal or absent in most patients. IL-7 (CYT107) is a homeostatic growth factor that promotes proliferation, differentiation, and survival of T lymphocytes. We recently demonstrated CYT107 significantly increases peripheral absolute lymphocyte and T cell numbers in metastatic castration-resistant prostate cancer patients when administered after sipuleucel-T. We hypothesize expansion of T cells by CYT107 may improve responses to PD-L1 inhibition. To test this hypothesis, we designed a randomized trial (NCT03513952) in mUC comparing the combination of CYT107 and atezolizumab to atezolizumab alone. Methods: Patients with ECOG PS ≤2 and RECIST v1.1 measurable mUC with disease recurrence after platinum-based chemotherapy are eligible. A safety run-in of 6 patients with staggered enrollment to atezolizumab plus CYT107 will be followed by randomization if <2 patients experience a DLT. An additional 48 patients will then be randomized 1:1 to atezolizumab 1200 mg IV q3wks with or without CYT107 10 ug/kg IM qwk X 4, started 1 wk before atezolizumab. The primary endpoint is RECIST v1.1 ORR, with H0 14.8% and HA 45%, one-sided α 0.10; power 88%. An interim futility analysis will be performed after 24 randomized patients have their first disease assessment; cessation of the trial will occur if an O’Brien-Fleming futility boundary of <-0.0063 in the ORR scale is observed between the experimental and control arm. Secondary endpoints include clinical benefit rate, PFS, DOR, OS, results by PD-L1 expression stratification, and safety. Exploratory correlative evaluations of tumor-infiltrating immune cells, interferon γ expression, inflammatory gene expression, ELISPOT, T cell receptor sequencing, serum metabolite levels, gut microbiome, and PK analyses will be performed. Current state: Trial accrual has begun and is anticipated to complete around mid-2020. Clinical trial information: NCT03513952.

Abstract CT096: Clinical activity, immune and viral correlates of PD-1 blockade with pembrolizumab as first systemic therapy in patients with advanced Merkel cell carcinoma

Background: Merkel cell carcinoma (MCC) is an aggressive skin cancer linked to UV exposure and the Merkel cell polyomavirus (MCPyV). Cytotoxic chemotherapy is associated with high response rates in patients (pts) with metastatic MCC, although responses are seldom durable and median progression-free survival is only 13 weeks. MCC may be responsive to PD-1 pathway blockade as tumors often express PD-L1 and MCPyV-specific T cells express the inhibitory co-receptor PD-1.

Methods: In this open-label, phase II trial by the Cancer Immunotherapy Trials Network (NCT02267603), adults with advanced/metastatic MCC and no prior systemic therapy were enrolled. Pembrolizumab, a humanized IgG4 anti-PD-1 monoclonal antibody, was given IV every 3 weeks (2 mg/kg). Response was assessed by RECIST 1.1 every 9-12 weeks. Presence of MCPyV was assessed by measuring serum antibody titers to the MCPyV oncoprotein and/or quantifying tumor oncoprotein expression by immunohistochemistry (IHC).

Results: Twenty-six pts were treated (median duration 22 weeks, range 4 to 49 weeks as of 1/8/16 dataset). Twenty-three pts had at least one documented radiologic or clinical assessment of response. Fifteen of 23 evaluable pts (65%) responded (4 complete responses and 11 partial responses); 2 additional pts had stable disease and 6 had progressive disease as best response. Fourteen of 15 responses (93%) were ongoing at last follow-up. Ten responders had at least one follow-up evaluation with response duration ranging from 8+ to 27+ weeks beyond initial documented response. Treatment was generally well tolerated with mostly grade 1 or 2 adverse events. Two pts developed severe drug-related toxicities including grade 4 myocarditis (n = 1) and grade 4 transaminase elevation (n = 1), both of which improved with corticosteroid treatment. Both pts have ongoing tumor responses despite discontinuation of pembrolizumab. Sixteen of 26 pts (62%) were classified as having virus-positive MCC. Among the 23 evaluable pts, 9 of 14 (64%) of those with virus positive tumors responded, while 6 of 9 (67%) of pts with virus negative tumors responded. Analyses of T cells specific to MCPyV and titers of oncoprotein antibodies during therapy, as well as IHC characterization of tumor biopsies including PD-L1 expression are ongoing.

Conclusions: First-line therapy with pembrolizumab in pts with advanced MCC is associated with frequent (65%) and durable responses. Notably, the response rate was similar among pts with virus-positive and virus-negative tumors. While virus-positive tumors are known to express highly antigenic MCPyV oncoproteins, virus-negative tumors are typically UV-induced and display strikingly elevated mutational burdens generating putative neo-antigens. Thus, potentially through distinct mechanisms, both virus-positive and virus-negative MCC tumors appear to be immunogenic and frequently responsive to anti-PD-1 therapy.

Citation Format: Paul Nghiem, Shailender Bhatia, Evan Lipson, Ragini Kudchadkar, Natalie Miller, Adil Daud, Steven Fling, Philip Friedlander, Harriet Kluger, Holbrook Kohrt, Lisa Lundgren, Kim Margolin, Thomas Olencki, Sunil Reddy, Erica Shantha, William Sharfman, Elad Sharon, Michi Shinohara, John Thompson, Jennifer Yearley, Suzanne Topalian, Martin Cheever. Clinical activity, immune and viral correlates of PD-1 blockade with pembrolizumab as first systemic therapy in patients with advanced Merkel cell carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr CT096.

Biomarker Development for Cancer Immuno-oncology/Immunotherapy: Simultaneous Digital Counting of Nucleic Acids and Proteins at 800-plex

The ability to measure changes to the DNA, RNA, and protein is crucial to understanding both tumor and immune responses to therapy. NanoString® has pioneered 3D Biology™ – the ability to measure any combination of DNA, RNA, and protein simultaneously using a single detector from a small clinical sample – in order to characterize these complex interactions. Analytes of interest are labeled with fluorescent nucleic acid barcode (via direct hybridization for nucleic acids or antibody conjugated barcodes for protein) and detected via digital counting. This enables quantification of up to 800 analytes from a small sample (50,000 cells for DNA/RNA/protein, or 1–2 5μm FFPE slides for RNA alone). The cancer immunology profiling panel measures 770 mRNAs (unique signatures for 24 infiltrating immune cell types plus extensive immune-signaling pathways) plus 30 key IO proteins.

We present two examples of 3D Biology in action. First, a targeted BRAFV600E inhibitor induces expression changes of immune genes which can be detected at both the RNA and protein levels. Second, in work from ongoing collaborations with the Cancer Immunotherapy Trials Network, clinical samples from patients treated with either mono- or combination immunotherapy can be stratified by gene expression. We also show that gene signatures predict presence of immune cell populations with a high degree of concordance to flow cytometry and immunohistochemistry measurements.

Multiplexed RNA biomarkers have achieved success in predicting patient response to therapy, e.g. NanoString signatures predict response to pembrolizumab (anti-PD-1). Measuring DNA, RNA, and proteins in unison greatly expands the power of biomarker signatures to characterize responses to immunotherapy.

Broad and potent neutralizing antibodies from an African donor reveal a new HIV-1 vaccine target

Broadly neutralizing antibodies (bNAbs), which develop over time in some HIV-1-infected individuals, define critical epitopes for HIV vaccine design. Using a systematic approach, we have examined neutralization breadth in the sera of about 1800 HIV-1-infected individuals, primarily infected with non-clade B viruses, and have selected donors for monoclonal antibody (mAb) generation. We then used a high-throughput neutralization screen of antibody-containing culture supernatants from about 30,000 activated memory B cells from a clade A-infected African donor to isolate two potent mAbs that target a broadly neutralizing epitope. This epitope is preferentially expressed on trimeric Envelope protein and spans conserved regions of variable loops of the gp120 subunit. The results provide a framework for the design of new vaccine candidates for the elicitation of bNAb responses.

VIDEOGAMES, AGGRESSION, AND SELF-ESTEEM: A SURVEY

A survey was administered to 153 sixth through twelfth graders. It included items on videogame play plus self-esteem and aggression scales. Teachers also rated the children on self-esteem and aggression. Amount of videogame play correlated with aggression and not with self-esteem. About 4796 of the sample said some videogames might foster anger or aggression. Among other results was evidence that boys play videogames more than girls and are more aggressive than girls. Self-esteem and aggression were positively correlated on teacher ratings but negatively on self-ratings.

Maternal holding preferences: a consequence of newborn head-turning response

Salk observed that in an overwhelming majority of cases (80%) mothers prefer to hold their infants across the left shoulder. This preference occurs over a diversity of cultures and is not related to the hand preference of the mother. Salk suggested a fetal imprinting to the sound of the heartbeat as the mechanism responsible for this phenomenon. While such speculation is intriguing, it is not scientifically testable. 2 experiments were performed to examine a more testable hypothesis. Results of these studies suggest that the initial head-turning preference of an infant is related to the holding preference of its mother.