Meeting the demands of msc production for clinical studies

Abstract

Background & Aim The Marcus Center for Cellular Cures (MC3) at Duke University recently completed a Phase I clinical trial (NCT03099239) using human cord tissue-derived mesenchymal stromal cells (hCT-MSCs) for the treatment of autism spectrum disorder. For this trial, 12 patients ages 2 – 11 years were sequentially dosed with 1, 2, or 3 doses of 2 million MSC/kg post thaw administered intravenously every 2 months. A manufacturing process was developed for our GMP facility to produce the required doses in a flexible and reproducible manner. Methods, Results & Conclusion For the trial, 3 lots of hCT-MSCs were manufactured from cord tissue obtained from 3 term healthy male babies delivered after elective routine C-section. After transporting the cord to the Robertson GMP Laboratory, the tissue was cut and digested in a tissue dissociator. The resulting cell suspension was plated in tissue culture flasks for P0 culture in Prime-XV MSC Expansion XSFM culture medium (Irvine Scientific) supplemented with 1% platelet lysate (PL). After harvest, P0 cells were cryopreserved, with a subset of cells expanded for P1 in XSFM without PL, and with a larger cryopreservation and expansion process for P2. For both P1 and P2, cells were seeded at 1000/cm2. Cells at the end of P2 were frozen in multi-compartment cryo-bags at the appropriate concentration for final dose administration. Prior to release to the patient, each lot of P2 hCT-MSC was characterized by flow cytometry for typical MSC markers, tri-lineage differentiation, and the ability to suppress T-cell proliferation. Manufacturing process data for each donor are presented in Table 1. For 2 donors, additional P2 cells were produced from P1 vials during the course of the trial (e.g., “remanufactured” lots) when the original batch was not enough to meet demand. We calculated that after P0 the cells underwent 10.5 doublings on average after the end of P2, with a mean doubling time in P1 – P2 of 31.2 hours. The final thawed and prepared P2 cell product had a mean viability of 75% prior to administration to the patient. Preparations are underway for a Phase II clinical trial and the subsequent need for a larger scale and more efficient manufacturing process. We are developing a streamlined process using closed systems for cell expansion, concentration, and cryopreservation of the MSC product that is semi-automated and will minimize the use of clean room facilities. Comparability of the MSC product using the new process will be confirmed prior to use in the Phase II trial.