How Many Successes and How Many Failures? Vaccine Development for the US Market, 1995-2008

Background:
In recent years, there have been an unprecedented number of new vaccines recommended for children, adolescents, and adults. This apparent success of research and development for vaccines may contrast with the track record of therapeutic drug development, which indicates that there are many failed prospects for each success. No similar analysis for prophylactic vaccines is available.

Objectives:
To characterize successes and failures in prophylactic vaccine development during the period 1995-2008.

Methods:
The investigators queried a proprietary industry database (Pharmaprojects) to identify prophylactic non-influenza vaccines in preclinical or any phase of clinical trials development for two “cohorts” of vaccines—those present in 1995 and those present in 2000. The investigators tracked the development of cohort vaccines to determine if they were licensed in the United States (ie, succeeded), ceased development (ie, failed), or remained in active development. Follow-up was for 8 years (to use the same duration for both cohorts). Vaccines in the 1995 cohort were excluded from the 2000 cohort.

Results:
Among 142 vaccines in development in 1995, by 8 years later 5% (n=7) had been licensed, 75% had ceased development, and 20% remained in active development. This translated to a failure:success ratio of 15:1. Among 167 vaccines in development in 2000, 2% (n=4) had been licensed 8 years later, while 82% had ceased development and 16% remained in active development. This translated to a failure:success ratio of approximately 27:1.

Conclusions:
Recent recommendations of several newly developed vaccines reflect greater vaccine development activity. However, there has also been an increasing ratio of failures to successes. Increasing proportions of failures may drive up research and development costs for manufacturers, with potential implications for future investment in vaccine development.