Table 5.
Results of regulatory T cell (Treg) drug product stability testing after at least 12 months of storage.
| Parameter | Con1 |
Con2 |
Con3 |
Con4 |
Acceptance criteria | Criteria passed | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| Release | >12 months | Release | >12 months | Release | >12 months | Release | >12 months | |||
| CD4 (%) | 99.6 | 99.7 | 99.2 | 99.2 | 98.6 | 98.7 | 99.4 | 99.3 | ≥90.0 | Yes |
| CD25 (%) | 98.9 | 95.7 | 98.6 | 98.3 | 85.5 | 81.9 | 93.3 | 93.8 | ≥80.0 | Yes |
| CD127 (%) | 0.0 | 1.4 | 0.1 | 2.5 | 0.7 | 1.6 | 0.0 | 1.2 | ≤10.0 | Yes |
| CD8 (%) | 0.0 | 0.1 | 0.0 | 0.0 | 0.1 | 0.1 | 0.0 | 0.1 | ≤0.5 | Yes |
| CD19 (%) | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | ≤1.0 | Yes |
| CD56/16 (%) | 0.0 | 0.4 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | ≤1.0 | Yes |
| Suppression at ratio 1 + 1 (%) | 99.5 | 95.2 | 81.4 | 99.4 | 98.2 | 96.1 | 99.9 | 98.4 | ≥80.0 | Yes |
| Suppression at ratio 5 + 1 (%) | 96.1 | 80.8 | 60.4 | 85.9 | 97.2 | 66.9 | 99.4 | 79.2 | ≥60.0 | Yes |
| Suppression at ratio 10 + 1 (%) | 85.4 | 66.5 | 52.5 | 65.9 | 61.6 | 61.8 | 83.2 | 70.8 | ≥50.0 | Yes |
| viable cells/ml (×106) | 10.5 | 9.3 | 6.3 | 9.1 | 10.8 | 9.8 | 8.2 | 7.9 | ≥5.0 | Yes |
| Cell viability (%) | 96.7 | 78.7 | 92.8 | 79.7 | 96.8 | 84.1 | 96.9 | 74.1 | ≥50.0 | Yes |
| Sterility | ng | ng | ng | ng | ng | ng | ng | ng | ng | Yes |
| Endotoxin (IE/ml) | <30 | <30 | <30 | <30 | <30 | <30 | <30 | <30 | <30 | Yes |
| Mycoplasma | neg | neg | neg | neg | neg | neg | neg | neg | neg | Yes |
Treg were thawed after a minimum of 24 h after production or after at least 12 months of storage at ≤−150°C and analyzed for lot-release. CD4, CD25, CD127, CD8, CD19, and CD56/CD16 indicate surface expression on the final Treg product. Suppression at ratio 1 + 1, 1 + 5, and 1 + 10 indicate the amount of suppression within the first generation of proliferating CD8+ responder cells by the final Treg product. Viable cells per milliliter indicate the total number of life retrieved Treg in the final Treg product. Viability indicates the percentage of life cells in the final Treg product. Sterility indicates bacterial growth contaminating the final Treg product.
ng, no growth; neg, negative.