Manufacturing and validation of Good Manufacturing Practice-compliant regulatory dendritic cells for infusion into organ transplant recipients.

BACKGROUND AIMS: Regulatory (or "tolerogenic") dendritic cells (DCregs) are a highly promising, innovative cell therapy for the induction or restoration of antigen-specific tolerance in immune-mediated inflammatory disorders. These conditions include organ allograft rejection, graft-versus-host disease following bone marrow transplantation and various autoimmune disorders. DCregs generated for adoptive transfer have potential to reduce patients' dependence on non-specific immunosuppressive drugs that can induce serious side effects and enhance the risk of infection and certain types of cancer. Here, our aim was to provide a detailed account of our experience manufacturing and validating comparatively large numbers of Good Manufacturing Practice-grade DCregs for systemic (intravenous) infusion into 28 organ (liver) transplant recipients and to discuss factors that influence the satisfaction of release criteria and attainment of target cell numbers. RESULTS: DCregs were generated in granulocyte-macrophage colony stimulating factor and interleukin (IL)-4 from elutriated monocyte fractions isolated from non-mobilized leukapheresis products of consenting healthy adult prospective liver transplant donors. Vitamin D3 was added on day 0 and 4 and IL-10 on day 4 during the 7-day culture period. Release and post-release criteria included cell viability, purity, phenotype, sterility and functional assessment. The overall conversion rate of monocytes to DCregs was 28 ± 8.2%, with 94 ± 5.1% product viability. The mean cell surface T-cell co-inhibitory to co-stimulatory molecule (programmed death ligand-1:CD86) mean fluorescence intensity ratio was 3.9 ± 2.2, and the mean ratio of anti-inflammatory:pro-inflammatory cytokine product (IL-10:IL-12p70) secreted upon CD40 ligation was 60 ± 63 (median = 40). The mean total number of DCregs generated from a single leukapheresis product (n = 25 donors) and from two leukapheresis products (n = 3 donors) was 489 ± 223 × 106 (n = 28). The mean total number of DCregs infused was 5.9 ± 2.8 × 106 per kg body weight. DCreg numbers within a target cell range of 2.5-10 × 106/kg were achieved for 25 of 27 (92.6%) of products generated. CONCLUSIONS: High-purity DCregs meeting a range of quality criteria were readily generated from circulating blood monocytes under Good Manufacturing Practice conditions to meet target cell numbers for infusion into prospective organ transplant recipients.

Impact of contracted manufacturing organization protocols on operations in an aca demically based Current Good Manufacturing Practice facility.

Immunotherapy of cancer and other diseases is often dependent on adoptive transfer to patients of cellular products generated in Current Good Manufacturing Practice (cGMP) facilities. With the availability and approval of various cellular products for therapy, cell production facilities are experiencing unprecedented growth in demand for services. Increasingly, these services involve processing of externally generated cells for transfer to the bedside. The arrival of cells from external manufacturing facilities for processing and eventual infusion of cell therapy products into patients creates a new layer of responsibility and adds to an already demanding list of the existing procedures in academic cGMP facilities. Sponsors introduce their own requirements for the handling of cells that the laboratory must incorporate and follow. The challenges of creating additional access to cleanrooms, writing new standard operating procedures, expanding personnel training, altering pre-existing schedules and incorporating additional monitoring for safety of external products alter the balance of laboratory operations. Adjustments for accommodating externally manufactured products are numerous and varied, as each sponsor has requests that are product-specific. If cells produced by several different external manufacturers are handled by the same facility, the negative impact on the regular activities in this facility may be considerable. Here the authors provide a review of operational challenges that an academic-based laboratory faces and discuss solutions that could ameliorate the difficulties related to an increasing volume of industry-sponsored trials. The solution may be the development under the auspices of the Foundation for Accreditation of Cellular Therapy or the Food and Drug Administration of regulations that will guide the processing of products manufactured by external companies and make these regulations broadly applicable in all cGMP facilities.