Davar, Diwakar

TPS2657 Background: T-cell immunoreceptor with Ig and ITIM domains (TIGIT) is an inhibitory immune checkpoint receptor expressed on subsets of T cells and NK cells. SEA-TGT is an effector-function enhanced human mAb that targets TIGIT with pico-molar affinity and blocks TIGIT’s interaction with CD155 and CD112. SEA-TGT was developed to have amplified binding to and engagement of Fcγ receptors. Enhanced effector function increases TIGIT+ T-regulatory cell depletion, enhances innate immune cell activation, and augments naïve and memory CD8+ T-cell responses. Preclinically, SEA-TGT elicits superior anti-tumor immune responses compared to other TIGIT mAbs without effector-enhanced backbones, with curative anti-tumor activity as monotherapy and in combination with other immune-modulators. Methods: This phase 1, open-label, multicenter, dose-escalation/expansion study (NCT04254107) is assessing the safety, tolerability and preliminary activity of SEA-TGT monotherapy in up to 205 adults (≥18 years) with histologically or cytologically confirmed relapsed, refractory, or progressive metastatic solid tumors (non-small cell lung, gastric/GE junction carcinomas, cutaneous melanoma, head and neck squamous cell carcinoma, bladder cancer, ovarian cancer or triple-negative breast cancer) or lymphomas (classical Hodgkin lymphoma, diffuse large B-cell lymphoma, or peripheral T-cell lymphoma, not otherwise specified). SEA-TGT will be infused on Day 1 of 21-day cycles. In Part A, the safety and tolerability of SEA-TGT will be assessed in ̃25 subjects to identify the maximum tolerated dose and recommended phase II dose (RP2D). In Part B, the safety and antitumor activity of the RP2D will be assessed in ̃180 subjects in disease-specific expansion cohorts. Primary endpoints are adverse events, laboratory abnormalities, dose-limiting toxicities, and dose-level safety and activity. Secondary endpoints are objective response (OR) rates, duration of OR, complete response, progression-free survival, overall survival, PK, and antidrug antibodies. Exploratory biomarkers of SEA-TGT-mediated pharmacodynamic (PD) effects, PK-PD correlations, and correlative analyses of predictive and PD measurements with response, toxicity, and resistance will be explored. The study was opened April 2020 and is enrolling across sites in North America and Europe. Clinical trial information: NCT04254107.

Abstract Background: Oncolytic viruses selectively infect tumors and activate antitumor immune responses via innate and adaptive pathways, which may potentiate the efficacy of immune checkpoint inhibitors. MEDI5395 is a recombinant Newcastle disease virus incorporating a granulocyte macrophage colony-stimulating factor (GM-CSF) transgene that exhibits tumor cell-specific viral replication, stimulates PD-L1 expression, and induces tumor regression in murine and patient-derived xenograft models. Increased T cell recruitment and expression of IFNγ-inducible genes observed in vitro suggest immune activation in the tumor microenvironment (TME). Antitumor activity is enhanced by concurrent PD-L1 blockade. This clinical study is evaluating IV MEDI5395 in combination with the anti-PD-L1 antibody durvalumab in patients with advanced solid tumors. Methods: This is a Phase 1, first-in-human, multicenter, open-label trial (NCT03889275) enrolling patients with breast cancer, colorectal cancer, hepatocellular carcinoma, head and neck squamous cell carcinoma, renal cell carcinoma, non-small-cell lung cancer or melanoma. Eligibility criteria include relapsed/refractory disease or intolerance to standard therapy after ≥1 prior line of treatment for recurrent/metastatic disease, and ≥1 tumor measurable by RECIST v1.1. Exclusion criteria include rapidly progressing disease precluding a break of ≥8 weeks from systemic therapy, life expectancy ≥12 weeks by GRIm Score, uncontrolled metastatic central nervous system disease, and concomitant immunosuppressive therapy. The initial dose escalation phase will enroll up to 84 patients across all eligible tumor types. Three sequentially ascending dose levels of MEDI5395 will be evaluated. Durvalumab is administered either sequentially or concurrently with MEDI5395, for up to 2 years or until radiologically confirmed disease progression, clinical deterioration, withdrawal of consent, or unacceptable toxicity. The subsequent dose expansion phase will include 2 cohorts of ~40 patients, each enrolling a single tumor type. The tumor types, MEDI5395 dose level and schedule will be selected based on dose escalation data. On-treatment biopsies of the primary tumor or a metastatic site are required in the dose escalation phase and optional in the dose expansion phase. Primary objectives are evaluating the safety, tolerability and incidence of dose-limiting toxicities of MEDI5395, and identifying the optimal dose/schedule in combination with durvalumab. Secondary objectives include assessing MEDI5395 pharmacokinetics (viremia and GM-CSF transgene expression), pharmacodynamics in the TME, immunogenicity, and initial efficacy in combination with durvalumab. The trial is actively accruing. Citation Format: Grace K. Dy, Diwakar Davar, Evanthia Galanis, Danielle Townsley, Djuro Karanovic, Maria Schwaederle, Beth Kelly, Dmitriy Zamarin, Mitesh Borad, Kevin Harrington. A phase 1 study of IV MEDI5395, an oncolytic virus, in combination with durvalumab in patients with advanced solid tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT244.