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3282 Successful Manufacturing of CAR T-Cells with Small Volume Peripheral Blood from Healthy Donors Using the Clinimacs Prodigy Device

Program: Oral and Poster Abstracts
Session: 711. Cell Collection and Processing: Poster III
Hematology Disease Topics & Pathways:
apheresis, Technology and Procedures, cell expansion
Monday, December 7, 2020, 7:00 AM-3:30 PM

Katie Palen1*, Parameswaran Hari, MBBS, MD2, Nirav N. Shah, MD3 and Bryon Johnson, PhD4

1Medical College of Wisconsin, Milwaukee, WI
2Division of Hematology and Oncology, Department of Medicine, Medical College of Wisconsin, Brookfield, WI
3Division of Hematology and Oncology, Department of Medicine, Medical College of Wisconsin, Milwaukee, WI
4Division of Hematology, Oncology and Bone Marrow Transplantation, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI


In recent years, CAR T-cell therapy has emerged as a potentially curative intent treatment for some patients with relapsed, refractory hematologic malignancies. Despite the exciting results, not all patients are able to receive CAR T-cells due to manufacturing failures. T-cells for CAR products are typically autologous and isolated from heavily pre-treated patients, which might account for some of the manufacturing failures and suboptimal clinical efficacy. T-cells collected either early into cancer diagnosis or prior to diagnosis may improve CAR T-cell expansion and limit manufacturing failure. We evaluated the feasibility of generating a CAR T-cell product manufactured from 50 ml of healthy donor blood.


Collaborators at Cell Vault collected 50 ml of whole blood from 3 healthy donors, isolated peripheral blood mononuclear cells (PBMCs), and cryopreserved the cells in cryovials at 5e6/vial (1.05-1.35e8 total cells). The vials were shipped to the Medical College of Wisconsin and stored frozen in liquid nitrogen until use. All PBMC vials for a given donor were thawed and pooled. Thawed PBMCs (0.93-1.17e8 cells) were loaded onto a CliniMACS Prodigy device, CD4 and CD8 T cells enriched by immunomagnetic sorting, and T cells placed in the culture chamber with IL-7, IL-15 and TransAct reagent to induce proliferation. On the second day of manufacturing, T cells were transduced with a lentiviral CAR vector encoding anti-CD19, 4-1BB and CD3z. Final CAR T-cell products for these pre-clinical studies were harvested on day 8 of manufacture.


Starting enriched T-cell numbers from the 3 healthy donors ranged from 4.0-4.8e7 cells, the cells were 74-79% CD4/8+, and the average CD4/CD8 ratio was 1.4. On the day of CAR T harvest (day 8), total cells in the chamber had expanded to 3.6-4.6e9 cells (74-115 fold expansion), the cells were >99% CD3+, and the average CD4/CD8 ratio was 2.9 (Table 1). Final cell numbers were similar to what previously published CAR T manufacturing runs on the CliniMACS Prodigy (Zhu et al., Cytotherapy, 2018), that started with 1x108 enriched T-cells obtained from apheresed mononuclear cells. Cell surface CD19 CAR expression on the final cell products varied from 19.2-48.1%. While more than 50% of the starting T cells had a naïve (CD62L+ CD45RO-) phenotype, the final cell products contained greater than 80% central-memory (CD62L+ CD45RO+) T cells. Finally, the number of CD19 CAR T cells obtained from these pre-clinical manufacturing runs ranged from 7.82e8 to 2.21e9 cells.


50 ml of cryopreserved PBMCs was adequate to manufacture clinically relevant CAR T-cell therapy doses from healthy donors not previously exposed to chemotherapy. Sufficient numbers of CAR T-cells were obtained to dose an 80 kg individual with at least 9e6 cells/kg which is greater than prescribed commercial doses of CD19 CAR T-cells. Further studies are indicated to determine if T-cells collected prior to disease modifying chemotherapies result in an improved product. These results demonstrate feasibility for generating CAR T cells from small volumes of whole blood collected at a time point before a cancer patient has been treated with multiple lines of therapy that could negatively impact starting T cell numbers and function.

Disclosures: Hari: GSK: Consultancy; Amgen: Consultancy; BMS: Consultancy; Takeda: Consultancy; Incyte Corporation: Consultancy; Janssen: Consultancy. Shah: TG Therapeutics: Consultancy; Celgene: Consultancy, Honoraria; Incyte: Consultancy; Kite Pharma: Consultancy, Honoraria; Cell Vault: Research Funding; Miltenyi Biotec: Honoraria, Research Funding; Lily: Consultancy, Honoraria; Verastim: Consultancy. Johnson: Miltenyi Biotec: Research Funding; Cell Vault: Research Funding.

*signifies non-member of ASH