The average cost per patient of running Phase III clinical trials for new medicines in the US is now more than $26,000, according to a new report from Cutting Edge Information.

With typical study cohorts encompassing anything from 1,000 to 5,000 patients, it is hardly surprising that Phase III would be the most costly stage of clinical development overall. The benchmarking data released by Cutting Edge suggest, though, that expanding patient numbers does not achieve economies of scale, as the later trial phases become increasingly complex.

A survey of pharmaceutical and biotechnology companies conducted by Cutting Edge for its report, Clinical Operations: Accelerating Trials, Allocating Resources and Measuring Performance, found that Phase II trials in the US were somewhat less expensive on a per patient basis, with the average cost falling to just over $19,300. For Phase I studies, which involve only a fraction of the patients used in Phase III, costs are still estimated at nearly $15,700 per patient.

While Cutting Edge does not have directly comparable cost data for 2005, external figures and its own limited data for 2004 indicate that per-patient trial costs in the US “have gone up fairly substantially," said research team leader Jon Hess. He added that wasted time was a major factor in driving up trial costs, both within pharmaceutical companies and through contract research organisations.

One of the reasons larger trials did not generate economies of scale on a per-patient basis was that there were few fixed costs to be spread out over an expanded cohort, Hess explained. Costs for clinical research associates/monitors, investigators, trial supplies, data entry work, etc, “all scale up in lock step as you moved to larger patient groups," he commented. Moreover, Phase III tended to be the most scientifically demanding and rigorous of the three pre-approval stages, and they usually lasted longer than Phase I or II trials. By Peter Mansell