There are certain key differences between the processes of developing and manufacturing a vaccine and producing a new drug that serve as additional barriers to vaccine development. For one thing, vaccines are generally derived from living pathogenic organisms which are more complex in terms of their molecular structures and the processes needed to control and produce them than the components of other pharmaceutical products (Layton & Lenfestey, 2005; Scherer, 2004).
Furthermore, unlike with drugs, vaccine trials and development of production facilities take place simultaneously, as production facilities must be up and running prior to licensure (Honeycutt, Robinson, & Layton, 2005). This requirement has major implications on the start-up costs for manufacturing a vaccine, as the processes of building a plant, honing manufacturing techniques, and training staff can cost as much as $300 to $400 million (Murphy, 2002), depending on the production technology required.
As one might expect given differences such as these in the processes and complexity involved in developing a vaccine versus a new drug, disparities between biopharmaceutical and pharmaceutical products have also been reported in development times, costs, and phase transition probabilities. While biopharmaceutical products such as vaccines may have slightly higher transition probabilities for some clinical phases than drugs, DiMasi & Grabowski (2006) find that costs per clinical phase may be significantly higher for biopharmaceutical products, depending on how costs are measured and compared. With regard to phase length, a chart included in DiMasi & Grabowski (2006) (reproduced in Figure 7 below) shows that total time to market is longer for vaccines, a finding reflected in the parameters chosen for our model (as discussed below).
Figure 7: Clinical and Development and Regulatory Approval Times by Product Type
Source: DiMasi & Grabowski, 2006