TAC01-HER2 Cell Therapy Demonstrates Promising Clinical Activity in HER2+ Solid Tumors

Use of the novel cell therapy TAC01-HER2 yielded positive clinical results and was well-tolerated among a group of patients with HER2-positive solid tumors, according to a press release from Triumvira Immunologics, the manufacturer of the investigational treatment.

Interim data from the phase 1/2 TACTIC-2 trial (NCT04727151) were shared in a poster for at the Society for Immunotherapy of Cancer’s (SITC) 37th Annual Meeting from November 8-12, 2022.

Investigators of the trial reported a 67% disease control rate in cohort 3 (n = 3), where patients received 1 to 3 x 106 cells/kg of TAC01-HER2 treatment. Signs of continued clinical activity were observed in 1 patient with stage IV gastroesophageal junction cancer and another patient with stage IV breast cancer. One patient from cohort 2 with stage IVb metastatic gastric cancer continues to derive a clinical benefit after experiencing an observed partial response. Additionally, the other 2 patients from cohort 2, 1 with stage IV colorectal cancer and 1 with stage IV gall bladder cancer, continue to experience clinical benefit with stable disease while having no change in tumor measurements compared to baseline over 3 months.

“These updated interim data showed compelling responses in cancer patients treated with TAC01-HER2,” Benjamin L. Schlechter, MD, a gastrointestinal medical oncologist at Dana-Farber Cancer Institute, an instructor in medicine at Harvard Medical School, and an investigator on the TACTIC-2 study, said in the press release. “Patients entered the study with refractory disease and were a heavily pre-treated population that had experienced multiple lines of prior therapies. The interim safety and efficacy data show that TAC01-HER2 could potentially improve the lives of cancer patients with significant unmet medical need.”

TAC01-HER2 is a novel therapy that involves genetically engineered autologous T cells expressing T-cell Antigen Coupler (TAC) that recognizes and targets HER2, activating cells via the endogenous T cell receptor. The open-label, multicenter phase 1/2 TACTIC-2 trial was designed to establish the safety, maximum tolerated dose, recommended phase 2 dose, pharmacokinetic profile, and efficacy of TAC01-HER2 in patients with relapsed or refractory HER2-positive solid tumors. Study treatment consisted of lymphodepletion followed by TAC01-HER2 as a single intravenous infusion.

The primary end point of the trial was to determine the incidence of treatment-emergent adverse effects (TEAEs) based on CTCAE v5.0 guidelines. Secondary end points included identifying the overall response rate and overall survival both measured for up to 24 months.

Patients aged 18 years and older who had a recent tumor sample to confirm HER2-protein expression on tumor cell surface and relapsed or refractory disease after at least 2 prior lines of therapy were eligible to enroll on the trial. Additional inclusion criteria included having measurable disease per RECIST v1.1, an ECOG performance status of 0 or 1, a life expectancy of at least 12 weeks, and adequate organ function. Patients were unsuitable for enrollment if they had an acute inflammatory neurological disorder, an autoimmune disease or infection, or an acute cardiovascular disease.

The data safety monitoring committee of the trial reported that TAC01-HER2 produced no dose-limiting toxicities among 11 patients across 3 cohorts. The most frequent AEs observed were cytopenia associated with lymphodepletion chemotherapy, and most serious AEs were unrelated to TAC01-HER2 treatment. In cohort 3, 2 patients had grade 1 cytokine release syndrome (CRS) and another patient had grade 2 CRS.

Reference

Triumvira Immunologics announces updated data from ongoing TACTIC-2 trial of TAC01-HER2 in patients with HER2 positive solid tumors. News release. Triumvira Immunologics. November 11, 2022. Accessed November 14, 2022. http://bit.ly/3TzUC5w