Triumvira Immunologics Presents Initial HER2-Positive Solid Tumor Clinical Data at ESMO

Early signals of clinical activity observed in second dosing cohort with one partial response

TAC01-HER2 was safe and well-tolerated in the first two dosing cohorts of TACTIC-2 Phase 1/2 clinical trial

AUSTIN, Texas & HAMILTON, Ontario–(BUSINESS WIRE)–Triumvira Immunologics (“Triumvira”), a clinical-stage company developing novel, targeted autologous and allogeneic T cell therapeutics that co-opt the natural biology of T cells to treat patients with solid tumors, today announced positive initial clinical data from its ongoing TACTIC‑2 Phase 1/2 trial of TAC01-HER2 in patients with human epidermal growth factor receptor 2 (HER2) positive solid tumors. Initial clinical data demonstrate TAC01-HER2 was well-tolerated in both dosing cohorts and early signals of clinical activity were observed in the higher of the two dosing cohorts, demonstrating a 75% disease control rate, including one partial response. These initial results were presented in a poster at the European Society for Medical Oncology (ESMO) 2022 Congress.

“Every milestone achievement bolsters our confidence as we leverage our novel, versatile TAC platform to develop a T cell therapy that is less toxic than existing T cell therapies yet effective in killing target-bearing solid tumors,” said Deyaa Adib, M.D., Chief Medical Officer of Triumvira. “These initial data encourage us as HER2 is a well-validated target with growing clinical significance. There remains a large treatable patient population beyond breast and gastric cancers with tremendous unmet need across the spectrum of HER2 expression, especially low and intermediate, and we believe TAC-T cell therapies can be an effective way of treating these patients.”

The first two dosing cohorts of the trial enrolled eight patients with advanced, metastatic, unresectable HER2-positive solid tumors who had experienced up to two prior lines of therapy including HER2 targeted therapies. Early signals of clinical activity were observed in the second dosing cohort (6-8 x 10⁵ cells/kg) with a disease control rate of 75%. A partial response was observed in a patient with stage IVb metastatic gastric cancer who was heavily pre-treated and defined as 3+ HER2 by immunohistochemistry (IHC). CT scans taken 29-days after dosing showed a 36.5% reduction in tumor size in target lesions compared to baseline and the size of numerous metabolically active lymph nodes associated with the mass decreased. Two patients with significant disease burden within the second cohort, one with colorectal cancer and one with gall bladder cancer, have been observed with stable disease with no change in tumor measurements compared to baseline.

Triumvira is on track to complete enrollment of the Phase 1 portion of the study by the end of 2022, identify the optimal dose and initiate the Phase 2 registration component of the trial in the first quarter of 2023. The first patient in the Phase 1 dose level 3 (1-3 x 10⁶ cells/kg) portion of the study has already been treated.

Benjamin L. Schlechter, M.D., a GI medical oncologist at Dana-Farber Cancer Institute, and an investigator on the TACTIC-2 study, added, “Gastric adenocarcinoma remains a deadly disease with poor outcomes. The safety profile of TAC01-HER2 has been well differentiated compared to other approved CAR-T cell therapies. Additionally, the partial response in the study in a patient with metastatic gastric cancer is promising and underscores the potential of this novel cell therapy to treat patients who need it most.”

Initial safety data demonstrated that TAC01-HER2 is safe and well-tolerated with no dose limiting toxicities (DLTs) in the two cohorts. No cytokine release syndrome (CRS) or immune effector cell-associated neurotoxicity (ICANS) were observed. All serious adverse events (SAEs) were confirmed to be unrelated to TAC01-HER2.

The poster, titled “A Phase I/II Trial Investigating Safety and Efficacy of Autologous TAC T Cells Targeting HER2 in Relapsed or Refractory Solid Tumors,” is available at: https://triumvira.com/a-phase-i-ii-trial-investigating-safety-and-efficacy-of-autologous-t-cell-antigen-coupler-tac-t-cells-targeting-her2-in-relapsed-or-refractory-solid-tumors-tactic-2-august-2022/.

About the Phase 1/2 TACTIC‑2 Clinical Study

The ongoing Phase 1/2 trial is a multicenter open-label clinical study to determine safety, Maximum Tolerated Dose (MTD) or Recommended Phase 2 Dose (RP2D), pharmacokinetic profile and efficacy of autologous cell therapy TAC01-HER2 in patients with HER2-positive relapsed or refractory solid tumors. TAC01-HER2 consists of genetically engineered autologous T cells expressing T-cell Antigen Coupler (TAC) that recognizes human epidermal growth factor receptor 2 (HER2). The study will enroll approximately 135 patients across five sites in the U.S. and Canada. In Phase 1, patients will be dosed across four doses with data safety monitoring before initiation of each cohort. Additional information on the study can be found at: NCT04727151.

About Triumvira Immunologics

Triumvira Immunologics, Inc. (“Triumvira”) is a clinical-stage company developing unique, non-gene edited, first-in-class targeted autologous and allogeneic T cell therapeutics that co-opt the natural biology of T cells to treat patients with solid tumors. The company’s proprietary T cell Antigen Coupler (TAC) technology is a robust and versatile platform that activates natural T cell functions differently from cell therapies such as CAR-T and engineered T cell receptor (TCR) therapies. Triumvira is headquartered in Austin, Texas with research facilities in Hamilton, Ontario.

Contacts

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