BioPharm: What would you identify as key developments in vaccine delivery systems?
Thorpe: The mix of primary containers used for vaccines has changed over the past decade. The predominant use of multi-dose vials has been partly affected by the removal of Thimerosal as a preservative and affected also by moves to unit dose packaging in single-dose vials and prefillable syringes.Prefillable syringe use has expanded greatly as vaccine producers recognize the value of this packaging format in reducing overfill, which is critical in the case of higher price/cost vaccines that may be in short supply or have a window of time in which to be produced.
New routes of delivery are being explored and are reaching the market. In the area of flu vaccine, there has been growth in intranasal delivery. Recently, an influenza vaccine was launched by Sanofi using an intradermal delivery system that has the potential to provide benefits of dose sparing, shorter needle/less pain and improved immune response. The intradermal (ID) route is under evaluation for many newer vaccines, with more than 70 clinical trials actively using ID delivery. The ability to create an ID injection in an effective and reliable way continues to be a challenge, although West is developing technology that may help improve current practices.
BioPharm: Are there differences in the way you would formulate or package vaccine products intended for different markets (i.e., developed versus developing countries)? Is this something that a developer should consider when designing a product?
Thorpe: There are certainly considerations for vaccine packaging that have to be taken into account depending on the region served. Considerations such as regional clinical preference (i.e., needle length and gauge) and distribution systems including cold chain storage capabilities may affect the number of doses per package.
Also, the vaccine market segment served must be considered. Is the drug a campaigned product such as influenza vaccine? Is the segment pediatric, adult/travelers, or perhaps an immunization campaign in the developing world? In the latter case, auto-disable devices are important. Other regions may require needle-stick safety protection systems when safety legislation similar to what has been in place in the US since 2000 is adopted around the world. Such legislation is expected to be implemented in the EU in 2013.
BioPharm: Are there differences in how you would formulate or package different vaccines types, particularly emerging vaccines, such as nanoparticle-based vaccines and DNA vaccines?
Thorpe: Many newer vaccines are being formulated to take advantage of the improved clinical effectiveness of the intradermal delivery route. The move toward intradermal delivery leads to a need for more effective systems for packaging and delivery, and the need to consider all aspects of the system in an integrated way. Design of thes systems should include consideration of the drug itself, the container, and the delivery system or device, as well as consideration of who would be administering the dose and in what environment.
BioPharm: There are several alternatives to the traditional syringe for vaccine delivery: microneedle and needle-free delivery devices, for instance. Where do you see these products fitting into the marketplace, and how widespread do you think their adoption will be? What are the relative advantages and disadvantages of these systems?
Thorpe: These systems are potential niche products for vaccine delivery, similar to what has been seen with nasal and intradermal delivery. All of these systems attempt to address the issue of needle phobia, which can be addressed by means other than eliminating the needle. The key issue with these delivery techniques, specifically for technologies such as needle-free or jet injection, is assurance that the vaccine is reaching the intended target area, the intramuscular space. There are also issues of cross-contamination, cost, and potential wet injections that can limit use of this technology.
Traditional vaccine delivery enssures that the dose is delivered to the proper site, is cost effective and, in the case of prefilled syringes, that the correct dose is delivered while eliminating most of the wasted overfill in vials.
Glenn Thorpe, vice-president of strategic market development, syringe systems, at West Pharmaceutical Services.