An exploratory investigator-initiated trial via intrathecal or intracerebroventricular delivery of B7H3-specific allogeneic universal CAR-T cells in patients with recurrent high-grade gliomas.

23 Background: The MT027, developed by T-Maximum, is a B7-H3 (CD276)-directed genetically modified allogeneic T cell, targeting CD276-overexpressed tumor cells. Here, we reported a first-in-human, single-center, open-label investigator-initiated trial (IIT) via intrathecal or Intracerebroventricular delivery targeting recurrent high-grade glioma (ChiCTR2100047968). Methods: As of March 7, 2024, a total of 50 adult patients with recurrent high-grade glioma, B7H3+ expression, and KPS ≥40 were enrolled and administered at least one dose of MT027 (FAS), of whom, 32 received at least 3 doses (PPS1), 15 subjects with ≥3 doses and at least 1 efficacy visit (PPS2). 4 dose levels of 1.0, 1.5, 2.0, 2.5×10 7 cells per injection were administered once every 4 weeks. Results: The overall results demonstrated the favorable tolerability, safety, PK/PD characteristics, and preliminary efficacy. In FAS, the most common AE were fever and headache, without any CRS, ICANS, GvHD, or drug-related death. There were 4 cases (8%) of grade 3 AE or greater and 3 cases (6%) of SAEs. The copies of CAR in all groups reached 10000-100000 copy/ug, and persisted for > 60 days after a single dose. After multiple doses, the MT027 CAR-T cell numbers maintained at a high level (median 8850 copies /μg (range: 200-385900)) and for a long time. The levels of IL6, TNF-α and IFN-γ in CSF increased significantly and maintained for a long time. The mOS was 13.54 m (95% CI: 7.45; 19.63) and 20.73 m (95% CI: 16.12; 25.34) in PPS1 and PPS2, respectively. The 12-month OS rate was 53.30% (95%CI: 37.5%-75.7%) and 84.60% (95%CI: 67.1%-100%) in PPS1 and PPS2, respectively (historical data: 14%). The objective response rate (ORR) was 33% and the disease control rate (DCR) was 80% in PPS2. Conclusions: In patients with relapsed high-grade glioma, the intrathecal or ICV administration of MT027 cell therapy was found to be safe and well-tolerated. The toxicity of grade 3 or above was 1/5 of similar products. The pharmacokinetics and pharmacodynamics of single-dose and multiple-dose treatments were stable. MT027 exhibited longer persistence in the body of the patients, and the cell numbers and cytokine responses induced in vivo were 1-2 orders of magnitude higher than those of similar products. MT027 cell therapy demonstrated the excellent efficacy in treating relapsed high-grade glioma, with significantly prolonged overall survival and higher objective response rate compared to the historical data and similar product data. Currently, we are preparing for the IND filing in US (expected in 2024) with the recurrent glioblastoma as the first indication. Clinical trial information: ChiCTR2100047968 .