|By Staff and Wire Reports|
|Wednesday, 18 July 2012 07:10|
How real is the threat of a global pandemic involving H5N1 or a related virus?
Very real. Two studies published this year in Nature and Science highlight the pandemic potential of viruses possessing an H5 HA, and it appears to be much easier than previously thought. The continued evolution of H5N1 viruses reinforces the need to prepare and update candidate vaccines to H5 viruses and, together, the two papers demonstrate that the natural evolution of an H5N1 virus to a transmissible, highly pathogenic human pandemic virus is possible.
(Imai et al.  doi:10.1038/nature10831 and Sander Herfst et al.  doi: 10.1126/science 1213362).
Meanwhile, it took about eight months to deliver the first meaningful doses of H1N1 vaccines to fight the swine flu epidemic that swept the United States in 2009, infecting tens of millions of Americans.
Many experts agree that the next pandemic is not a question of “if”, but of “when”.
What are Virus-Like Particles, and what role can they play in creating a flu vaccine?
The conventional process of creating influenza vaccines—customarily grown in fertilized chicken eggs—is slow and cumbersome. In contrast, vaccines created in plants offer a quicker and cheaper alternative. For example, tobacco plants can be made to grow Virus-Like Particles (VLPs)—so-called because they resemble flu viruses but lack the viral genome—which are then purified to produce vaccines. VLPs are not infectious, but they are immunogenic: When injected into animals, they induce the production of anti-viral antibodies that can block infection, as well as stimulate the immune cells to generate a long-lasting and broader immune response. This has long suggested to researchers that VLPs could be used in humans to guard against influenza relatively rapidly.
How is Medicago able to synthesize vaccines relatively cheaply, and in a matter of weeks compared to the six months currently required by conventional technologies?
Instead of using chicken eggs to produce vaccines on a scale of months, plants—such as the tobacco relative plant Nicotiana benthamiana—can be made to grow large quantities of vaccines on a scale of weeks. To create plant-based vaccines, Medicago first synthesizes the DNA sequence from the major surface protein of the latest flu strain, the Hemagglutinin (the “H” in a flu strain name). The mature tobacco leaves are then dipped into a solution containing Agrobacterium, an organism that easily transfers DNA between itself and the plants. The organism is engineered to then move the “H” DNA sequence into the plant cells without transferring its own genetic material and compromising the purity of VLPs. The tobacco leaves remain in the solution for two minutes under vacuum to remove the air from the plant leaves, soaking up the bacteria particles in between the plant cells when the vacuum is broken, and the bacteria pushing the virus DNA coding for the flu protein into the cells for replication. Following this, the plants incubate in a greenhouse for about six days, producing large amounts of VLPs in the tobacco leaves.
What are the advantages of plant-based vaccines like those being pursued by Medicago in contrast to traditional egg-based vaccine production?
Unlike traditional influenza vaccines that are manufactured with an inactivated virus, VLP-based vaccines do not require an actual sample of the virus. Another important advantage of VLPs is that they more effectively activate key aspects of the immune response to achieve potent immune stimulation and to provide immunological memory. VLP-based vaccines have also been shown to provide protection against different strains of a virus other than those for which the vaccine was formulated.
At what stage of testing is Medicago’s avian flu H5 pandemic vaccine candidate?
Medicago has completed a Phase I and a Phase II clinical trial of the H5 pandemic flu VLP vaccine candidate. Immune response analyses demonstrated lower effective doses than with current egg-based vaccines. A Phase I clinical trial for a one-dose H5N1 VLP vaccine with a new adjuvant is expected to be initiated in partnership with the Infectious Disease Research Institute (IDRI), with interim data expected in the second half of this year.
Can Medicago’s technology be adapted to create a seasonal influenza vaccine?
Yes. In June 2011, the Company completed its U.S. phase I H1N1 influenza VLP vaccine candidate ("H1N1 vaccine") clinical trial. All vaccine doses were found to be safe, well tolerated and also induced a solid immune response that met the CHMP criteria, even with a single dose of 5 µg. Based on these results and subject to regulatory approval, Medicago intends to proceed with a U.S. Phase IIa trial for its seasonal quadrivalent vaccine with the recommended H1N1, H3N2 and two B influenza strains.
How has the opening of Medicago’s facility in North Carolina enhanced your ability to create vaccines?
Following the receipt of a US$21 million funding award from DARPA, Medicago has developed a 97,000-square-foot vaccine facility in Research Triangle Park, North Carolina. This state of-the-art facility is a large, cost-effective and scaled-up facility for Medicago’s VLP plant-based vaccine technology, ultimately for the delivery of current good manufacturing practice (cGMP)-grade vaccine. Medicago intends to demonstrate the capacity to produce 10 million doses per month of influenza vaccines, with the potential for further expansion in the future.
What is your timeline for developing a Rotavirus VLP vaccine candidate in tandem with Mitsubishi Tanabe Pharma Corporation? Once the vaccine has been created, can you project its cost and how quickly it can be synthesized to meet demand?
In March 2012, Medicago established a strategic alliance with Mitsubishi Tanabe Pharma Corporation to develop and commercialize at least three new vaccines. Medicago is eligible to receive up to C$33 million in upfront and milestone payments for the first target, a rotavirus VLP vaccine candidate. The upfront payment of C$3 million was received and Mitsubishi Tanabe will fund all research and development costs, as well as regulatory and commercialization responsibilities. Medicago will also receive royalty payments on future sales. Agreements for the additional two vaccines will be decided upon in the next three years.
Work on the Rotavirus candidate has been initiated and Medicago expects to disclose initial data in the fourth quarter of 2012. As this project is in the early stages of development, it is too early to project the cost of the product at this time. However, using Medicago’s rapid and cost-effective technologies, the goal is to provide a highly effective Rotavirus VLP vaccine with a low cost of goods.
Will the Rotavirus vaccine research take place at your Quebec or North Carolina facilities, or at Mitsubishi Tanabe’s facilities in Japan?
The research related to the Rotavirus VLP vaccine candidate is ongoing in our research facility in Quebec City.
What are the biggest challenges for the company right now?
We believe that Medicago is well-positioned for the future, and has successfully completed a number of significant milestones over the past year including the completion of the facility in North Carolina, clinical trials for both H1 and H5 VLP vaccines candidates, and a research collaboration with a top 10 pharma company. In addition, the company has established partnerships with U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), IDRI and a strategic alliance with Mitsubishi Tanabe Pharma Corporation. Looking ahead, the completion of the DARPA project and continued work on our partnered and internal pipeline remain the major focus for Medicago.
Can you give us a sense of where the company stands financially speaking?
At the end of the first quarter of 2012, Medicago had $37 million in cash. The company expects to end 2012 with approximately $20 million in cash.