The most recent licensees include CSL of Australia and Nobilon, part of Akzo Nobel's recently acquired firm Organon, not to mention GlaxoSmithKline (GSK) who has also licensed the technology Vivalis announced last week.
All three companies have signed up to world-wide, non-exclusive licences to use Vivalis' EBx cell line technology, based on avian embryonic stem cell-derived cell lines, for the development and marketing of seasonal and pandemic human flu vaccines.
Vivalis is only issuing a limited number of licences for the technology within the human flu vaccine field, and these latest licences are just three of eight commercial licences the company has issued for various development programmes.
Financial terms of the agreements all remain confidential, but the CSL and Nobilon deals both involve an upfront payment, milestone payments and royalties on sales of the vaccine.
The GSK agreement, however, is slightly different in that Vivalis will participate in the vaccine process development which will be funded by GSK Biologicals (the global vaccine division of the company), as well as including milestone and royalty payments.
The Vivalis technology appears to be proving popular among vaccine manufacturers (Sanofi Pasteur is another commercial licensee applying the technology to develop vaccines for HIV, cancer and another undisclosed target), and offers an alternative to traditional egg-based vaccine production, which many companies are turning away from in search of safer, more efficient production techniques.
Embryonated chicken eggs and chicken embryo fibroblasts (CEF) have been the traditional tools for vaccine production, but manufacturers are becoming increasingly disenchanted with the method, which involves a lengthy manufacturing process requiring numerous eggs, the risk of infection in donor flocks, bacterial contaminants, or the inability to manufacture particularly virulent viruses.
All human flu vaccines currently available on the market are produced using this egg-based technique, though the potential value cell-based vaccine manufacture could have has been widely acknowledged within the industry.
Vivalis has developed several stable and well-characterised cell lines using its proprietary procedures, which are based on the valuable properties of embryonic stem cells.
As well as maintaining the characteristics of embryonic stem cells (such as genetic stability, diploid karyotype, indefinite cell proliferation), the cells also possess other "industrial-friendly" features, according to the company.
These additional attributes include proliferation in bioreactors at high cell densities, growth in serum-free media and absence of in vivo tumorogenicity.
As well as this, Vivalis maintains that the EBx cells are highly susceptible to a series of human and animal viruses, including poxviruses and influenza A and B viruses, and also "easily amenable" to genetic engineering for the expression of foreign proteins.
Vivalis claims that its technology offers a simpler, faster, cleaner and more robust solution to vaccine production than embryonated eggs or CEF, as well as allowing significant cost savings.
As such, the firm states that the EBx cells are "currently under evaluation by most players in the human and veterinary vaccine industry".
By licensing out its embryonic stem cell lines to pharmaceutical and biotechnology companies active in the viral vaccine business, Vivalis hopes to cash in on the growing flu vaccine market that is becoming more and more prominent.
"Vivalis is confident that its different partners have the ability to capture a significant share of the human flu vaccine market which, with projected sales of over $3bn [€2.2bn] in 2010, is a strategic market for Vivalis," said the company's president, Franck Grimaud.
With concerns growing about global vaccine production capacity and fears regarding the possibility of a flu pandemic striking and demand significantly outstripping possible supplies, any new methods likely to speed up development or production of vaccines are likely to pique the interest of firms involved in vaccine manufacture.