Phase 1 study of SEA-TGT, a human, nonfucosylated monoclonal antibody directed to TIGIT with enhanced immune effector function, in patients with advanced malignancies (SGNTGT-001, trial in progress)

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SITC Tumor Immune Microenvironment Workshop; April 21-22, 2022; San Diego, CA


chiles; oregon; portland


Backgound: T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory domains (TIGIT) and costimulatory receptor CD226 competitively bind to 2 ligands, CD155 and CD112, which are expressed by tumor cells and antigen-presenting cells in the tumor microenvironment [1,2]. Dual TIGIT/programmed cell death protein-1 (PD-1) blockade increased tumor antigen-specific CD8+ T-cell expansion and function in vitro and promoted potent antitumor r.esponse in vivo [3,4]. TIGIT/PD-1 dual blockade using a TIGIT monoclonal antibody (mAb) with intact Fc produced clinical responses in advanced cancer [5].

SEA-TGT is an investigational, human, nonfucosylated mAb directed against TIGIT. SEA-TGT binds to TIGIT, blocking inhibitory checkpoint signals directed at T cells. SEA-TGT enhances binding to activating FcγRIIIa and decreases binding to inhibitory FcγRIIb; this depletes immunosuppressive regulatory T cells and amplifies naive and memory T cells, potentially augmenting the PD-1 inhibition effects. Preclinically, at suboptimal doses, SEA-TGT plus anti-PD-1 mAbs had superior antitumor activity than either agent alone [6].


Safety and antitumor activity of SEA TGT in ~377 adults (≥18 years) will be evaluated in this phase 1, multicenter, open-label, dose-escalation/expansion study. Part A will assess the safety/tolerability of SEA TGT to determine maximum tolerated and recommended doses. Part B will assess the safety and antitumor activity of the recommended dose in disease-specific expansion cohorts. Part C will assess SEA-TGT plus sasanlimab in dose-expansion cohorts after an initial safety run-in. Patients with histologically/cytologically confirmed relapsed/refractory/progressive metastatic solid tumors including non-small cell lung cancer (NSCLC); head and neck squamous cell carcinoma (HNSCC); gastric/gastroesophageal junction carcinoma; cutaneous melanoma, bladder, cervical, ovarian, or triple-negative breast cancer; or selected lymphomas will be eligible for Parts A and B. Part C will enroll patients with histologically confirmed advanced NSCLC (high [tumor proportion score (TPS) ≥50%] and low [TPS=1–49%] PD ligand 1 [PD-L1] expression), cutaneous melanoma, and HNSCC without previous anti–PD-1/PD-L1 therapy exposure. SEA TGT will be administered on Day 1 of 21-day cycles.

Laboratory abnormalities, adverse events, dose-limiting toxicities, and dose-level safety and activity are primary endpoints. Secondary endpoints are objective response (OR) and complete response (CR) rates, duration of OR/CR, progression-free survival, overall survival, pharmacokinetics (PK), and antidrug antibodies. Exploratory analysis will include pharmacodynamics (PD), PK/PD relationships, biomarkers, and resistance to SEA-TGT. This trial is recruiting in North America and Europe.

Results: N/A

Conclusions: N/A

Trial Registration: NCT04254107

Clinical Institute



Earle A. Chiles Research Institute



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