From Donor to Therapy: How Robust Manufacturing Shapes the TCR repertoire and Cytotoxic Power of Donor-Derived Allogeneic ex vivo Expanded and Activated γδ T Cell Products

Background & Aim

Gamma-delta (γδ) T cell levels have been shown to positively correlate with Oncology outcomes. (γδ) T cells do not initiate GvHD and kill cancer via multiple innate ligands. A clinical trial (NCT03533816) is examining if a single infusion of donor-derived allogeneic ex vivo expanded and activated γδ T cells (EAGD) improves outcomes for leukemia patients undergoing haploidentical BMT with reduced intensity conditioning. The manufacturing for γδ T cells may require long processing > 10 days. To understand the impact on the manufactured cells, the starting material and final product were analyzed to identify changes in cell activation, potency and function.

Methodology

This study includes analysis of a subset of EAGD products used in the INB-100 Phase 1 trial, manufactured from donors using a proprietary protocol. The starting material and final infused clinical product were analyzed for TCR repertoire and gene expression.

Results

The manufacturing shifted the TCR repertoire from αβ-TCR to γδ-TCR expression, with preferential expansion of Vγ9 clones. The diversity of αβ-TCR clones was significantly reduced, p < 0.01, in the final product, while γδ-TCR diversity remained similar. Gene expression analysis revealed consistent upregulation of cellular markers of cytotoxicity (eg. INFG, GZMB, PRF1), activation, and immune cell trafficking/stimulation. Expression profiles were consistent across products, demonstrating robustness and reproducibility of the manufacturing.

The initial cohorts are fully enrolled, an expansion of up to 15 additional patients is being actively recruited and treated at dose level 2, the recommended phase 2 dose (RP2D). All patients in the initial 10 patient cohort passed one year without relapse, to-date no AML patients have relapsed with median OS of 23.3 as of Jan 17, 2024, with a manageable safety profile. Notably, circulating γδ T cell expansion and persistence of up to 1 year was observed, suggesting prolonged γδ T cell effector durability.

Conclusion

The proprietary manufacturing generates consistent robust and cytotoxic γδ T cell products with similar gene expression shifts from different donors. The clinical products exhibit, at the gene expression level, cytotoxicity, immune recruitment, and tissue trafficking capabilities. Subjects infused with EAGD product show durable relapse-free survival, comparing favorably with the ∼50% expected 1-year relapse-free survival for HaploCy BMT, suggesting they may have improved outcomes with gamma-delta T cells post-transplant.