The patent covers novel MDCK cells that have been adapted to grow in serum-free culture medium as well as cultivation techniques MedImmune uses to increase vaccine production titres.
According to the patent the modified cells support replication of attenuated influenza virus to a log10 TCID50/mL of at least 7, which is a significant advance on previous highest viral titres – around 4 log10 TCID50/mL - described in the literature.
MDCK, or Madin-Darby canine kidney cells, are used for the production of viral vaccines and for influenza vaccines in particular. Novartis, for example, chose a MDCK cell line as the primary expression system for its vaccine plant in Holly Springs, North Carolina.
The MedImmune patent also covers incubation conditions that generate the maximum vaccine yield, methods to produce vaccines combined with excipients that provoke the desired immune response as well as details of how such compositions can best be administered.
Each flu season the drug industry races to identify the circulating viral strain to develop and produce vaccine and make it as rapidly as possible. This annua race means that, although influenza vaccine manufacturing methods are well established, any potential ways of accelerating the process attract attention.
However, the Ebola epidemic sweeping West Africa coupled with the lack of any vaccines mean that, this year, accelerating vaccine production is even more of a focus for the industry.
For potential Ebola vaccines, the focus has been on rapidly increasing the availability of even the most developmental of candidates. In September GSK said its Okairos unit was working to accelerate production.
Simialraly, calls to increase the availability of candidate Ebola treatment ZMapp have prompted developer Mapp Biopharmaceuticals to consider other production systems with, just last week, reports suggesting the firm was looking at using tobacco and animal cell lines.