Although not one of the current billion-dollar, best-selling medicines is a vaccine, a prominent consulting firm is predicting that four major types of vaccines have the potential to become pharmaceutical profit leaders over the next decade: influenza, pneumococcus, HIV and hepatitis C.

In order to identify the most promising indications, analysts at Massachusetts-based Decision Resources quantified the unmet need for vaccines against specific diseases and the sizes of susceptible populations in the major pharmaceutical markets, which are Europe, Japan and the US. The list was narrowed by considering the scientific feasibility of developing vaccines for each disease within the next 10 years.

Although influenza vaccines are widely available, physicians and patients have complained that the need for a painful injection each year discourages some patients from getting vaccinated. In response, pharmaceutical companies have developed inhaled flu vaccines, including Aviron/American Home Products' FluMist and Berna's Nasalflu; the latter already is marketed in Europe. The initial response to these vaccines suggests that similar products now in development will enjoy considerable market success.

HIV vaccine research has also intensified in recent years, although Decision Resources analyst and report author, John Lebbos, cautions that predictions for this vaccine market hinge on basic research, as first-generation HIV vaccines might not have sufficient efficacy to be market successes. Currently, the lead HIV vaccine is VaxGen's Aidsvax, which is in Phase III clinical trials. The value of this market will also rest on the ability of the poorer countries that comprise the epicenter of the disease to buy vaccines through the newly proposed Global Purchase Fund (Nature Med. 7, 647; 2001).

For both HIV and hepatitis C virus, “what's going to be critical in the future is identifying the most effective conserved epitopes to induce a T-cell response, and doing that on a developmental platform that's efficient,” says Lebbos. Chiron has entered Phase II clinical trials with a hepatitis C virus subunit vaccine, but new bioinformatics and high-throughput strategies may bring a new generation of rationally designed vaccines that could be therapeutic as well as prophylactic.

The appearance of antibiotic-resistant bacterial strains is the main factor driving pneumococcal meningitis vaccine development, with one vaccine already approved in the US (Wyeth-Lederle's Prevenar) and others in clinical trials. Sales of Prevenar hit $400 million in the first year—a long way from the $6 billion sales of the leading prescription drug omeprazole, but good revenue for a vaccine.