Containing drug development costs and speeding compounds through the pipeline is always a big issue, but clinical trials are becoming more expensive anyway. Why? One answer is the increasing complexity of the studies - the number of procedures for each clinical trial rose 49 percent from the 2000 to 2003 period to the 2004 to 2007 timeframe, and the total effort per protocol jumped 54 percent.
For instance, the average number of eligibility criteria used to screen volunteers rose 58 percent, which contributed to a 21 percent decline in volunteers enrolling in trials. But the larger number of procedures per protocol dissuades volunteers from completing trials - retention rates dropped 230 percent, according to the Tufts Centers for the Study of Drug Development, which reviewed data from 8,325 study protocols that was gleaned from a database from more than 75 drugmakers.
Breaking it down further, Phase I and II protocols experienced the biggest annual growth in complexity and execution as more data is gathered in these earlier phases. Similarly, there was a significant growth in Phase IV as more post-marketing data is collected for safety and marketing purposes (here is a press release; the report requires a subscription).
Protocols in anti-infectives, immunology, oncology, CNS and cardiovascular disease had the highest total number of procedures in Phase I studies. For therapeutic areas showing positive growth in the number of procedures in Phase II protocol from 2002 to 2007 - hematology, dermatology and oncology - the growth in work burden exceeded growth in total procedures. And across all therapeutic areas, the total number of procedures grew at a 12.5 percent compounded annual growth rate.
And what about Phase III protocols? Immunology, CNS, oncology, anti-infectives, and endocrine disorders were the most complex as measured by the total number of procedures per protocol during 2002 and 2007. The average work burden per protocol for only three therapeutic areas - CNS, oncology and antiinfectives - exceeded the aggregate average across all therapeutic areas. And the typical Phase III protocol had an average of 148 total procedures more than five times the number of unique procedures.
Phase IV protocols in endocrine disorders saw the fastest growth in total procedures and very high growth in work burden. And in the 2002 to 2007 timeframe, the overall growth rate in total procedures in Phase IV studies for each of the five top therapeutic areas was dwarfed by the overall growth in work burden.