AUTOMATING THE PROCESS FOR COMMERCIALIZATION
The process for generating this autologous DC immunotherapy has been consistent and robust for the RCC and HIV indications
during Phase II clinical trials. Elutriation and culture bags have moved key cellular processes to functionally closed, single-use
disposable units. However, some manipulations and processing are still performed using manual methods, including open manipulations
in biological safety cabinets. Although this approach may be feasible for the number of batches required for clinical trials,
it is not practical for commercial manufacturing because every patient requires a new batch of material to be produced.
Advanced RCC has a relatively low incidence of an estimated 9400 new cases in the US in 2010 (11–13). This number alone would
mean a considerable number of batches to manufacture per year. An HIV product would likely require manufacturing for more
than three times as many patients per year in the US, compared with an advanced RCC product. Even more staggering is the number
of patients for Provenge (sipuleucel-T), the first approved autologous cellular therapy produced by Dendreon. Provenge was
approved for metastatic castrate-resistant (i.e., hormone refractory) prostate cancer, an indication for which more than 100,000
patients are treated per year (11, 14). These numbers of batches per year require feasible processing methods to meet the
demands of commercial manufacturing for autologous cellular therapies.
If a company used the method described above to manufacture an autologous DC immunotherapy, which could generate years of
drug product with one leukapheresis, the process scale would remain the same for commercialization. The company would not
need to scale up for autologous therapies. The question would be how to scale out or address the throughput needed for commercialization.
Answering this question was the goal of an automation project that developed novel manufacturing equipment. The cornerstone
of the developed approach is the incorporation of single-use, functionally closed disposables throughout the process. This
method was recognized as crucial for autologous cellular-therapy manufacturing to eliminate cross-contamination concerns and
minimize turnaround time between processes, given the throughput needs.
Automated cellular equipment. Personnel began the process by adapting the cellular processing methods to incorporate elutriation and culture bags. Equipment
to perform the remaining cellular-processing steps at the scale required for autologous cellular therapies, however, did not
exist. Therefore, two similar instruments were designed with the functionality to perform each of these process stages, including
processing the autologous plasma collected during the leukapheresis procedure for use in drug-product formulation, and designing
custom disposable sets to handle the nuances of each process. The reason for designing two instruments was to create one for
plasma and monocyte processing, which are less complex. The second instrument addressed the unique needs and volumes required
for mature DCs, such as the electroporation step, including handling the addition of precise volumes of RNA normalized to
the DC concentrations, and formulation.
The programming and disposables were designed so that reagents and the cellular inputs for each process were connected to
the appropriate disposable set using standard functionally closed disposable manipulation methods (e.g., tube welding). The
design incorporated the removal of culture bags or other process outputs using tube-sealing methods. Therefore, the cellular
equipment would never be exposed to patient material, and all products and processing will be closed, thus eliminating potential
contamination events and product losses resulting from open manipulations. Although it is always crucial to minimize batch
failures, the need is greater for autologous cellular therapies, given that each batch is specifically manufactured for a
patient, and the patient undergoes leukapheresis to provide the starting cellular material for manufacturing. Because the
high variability of the biological starting material influences manufacturing success, personnel need to incorporate any possible
additional controls during manufacturing to ensure the generation of product. Processing with single-use, functionally closed
disposables and automated methods is a way to significantly improve process control.
The development of the automated cellular equipment and associated disposable sets began with identifying the key processing
steps and needs. Moving from elutriation to culture (or freezing to thawing and then culture) required media-exchange steps
and the ability to resuspend and distribute cells in a functionally closed disposable component. Similarly, harvesting the
DCs, electroporation, culturing following electroporation, and final formulation all required cell-concentration and media-exchange
steps. Methods for reliably and accurately addressing this manipulation of cells were developed for even the small-volume
manipulations required for electroporation or formulation (i.e., 5–30 mL) while not compromising processing time when large-volume
manipulations (large volume for an autologous cellular therapy means as much as 5 L) are required. Overall, the time required
for cellular processing using automated equipment is similar to that for the manual methods. The majority of the time required
for cellular processing, however, is dedicated to incubation to generate DCs from monocytes, followed by culturing for maturation
and culturing for recovery after electroporation.