CASE STUDY: SINGLE-USE BIOREACTORS FOR VACCINE MANUFACTURE
Eric Calvosa, manager, cell culture and virology development; Nicolas Sève, process engineer; Jean-Marc Guillaume, head of
bioprocessing upstream development, all at Sanofi Pasteur.
Sanofi Pasteur's KITE program has led to a number of key initiatives that have provided tangible benefits. In one example,
we wanted to evaluate the effectiveness of scaling up a vaccine manufacturing process using disposable bioreactors.
A number of commercially significant viral vaccine processes are based on adherent mammalian cell lines. In the process examined
in this case study, a Vero-based cell culture had been expanded in serum-free media and scaled up in increasingly larger stainless
steel bioreactors, with the pilot scale established at 180 L. The objective was to examine the potential for driving out cost
by moving this process to a fully disposable process design, starting from the seed train and expanding up to a 500-L scale
In this evaluation, we focused on the following areas:
- the specifics of bioreactor design in relation to Vero cell amplification and productivity
- how to manage biosafety
- how to qualify disposable technologies
- what effect the implementation of disposable bioreactors would have on our facility footprint.
The exercise demonstrated that it is feasible to scale up the Vero cell culture in a disposable bioreactor up to 500 L using
the Nucleo series of bioreactors from ATMI. Good virus yield and productivity were obtained in Nucleo 20-, 200-, and 500-L
bioreactors, achieving performance comparable to that seen in the 180-L stainless steel process.
In addition, major benefits were seen when implementing a disposable process from seed to large-scale cell expansion and infection.
A significant time savings was achieved for rapid cell expansion when thawing large volumes of prepared banks and seeding
directly in a disposable Nucleo 20. With the disposable set up, the time from initial equipment reception to the first harvest
was only four weeks, compared to more than six months for stainless steel.
Facility and Engineering Design
As part of the feasibility analysis for scaling up to a 500-L scale bioreactor, we carried out a biosafety "what if" review,
covering aspects such as prevention of bag failure through the addition of safety pressure sensors on the bag and water traps
on the exhaust filter, bag stress validation, and connection of a sampling line. For overall disposable bioreactor protection,
the bag was installed with a retention tray placed under the bioreactor to recover any leaks or fluid in the event of bag
rupture. The retention tray can be fitted with a soft wall isolator cabinet for viral production steps.
We also carried out an evaluation of the relative impact on qualification and maintenance of working with the Nucleo as opposed
to the stainless steel bioreactor. We were able to demonstrate a decrease in preventative maintenance, reduced shutdown time,
and higher turnover. We also compared the timeline for process design, installation, and qualification, and were able to demonstrate
a very significant reduction, from 20.5 months to 6 months (Table 1).
Table 1. Comparison of the time required for equipment ordering, installation, and qualification of a 180-L stainless steel
bioreactor and a 500-L single-use bioreactor. The single-use bioreactor saved 14.5 months.
In terms of overall footprint requirements in a classified area, we were able to demonstrate an equivalent footprint between
the Nucleo 1000 (1,000-L) and a 200-L stainless steel bioreactor, and the footprint of the Nucleo 500 is 2.5 times smaller
than the equivalent 500-L stainless steel bioreactor. In a classified area, such footprint reductions can lead to significant
savings because of reduced utility requirements to maintain the space.