A Closer Look at Clinical Trial Success Rates

A study involving 406,038 entries of clinical trial data suggests that clinical trial success rates are higher than previously thought.

Clinical trials are a key stage on the path of drug development. Correspondingly, the probability of success (POS) of a clinical trial is a key input to clinicians, investors, regulators, and policymakers when evaluating the risk vs reward of developing a certain drug.

This study was the largest of its kind to date, analysing a dataset with 406,038 entries corresponding to 185,994 unique clinical trials of over 21,000 compounds. The researchers developed an automated algorithm that models the path of drug development process and uses a “path-by-path” approach that traces the proportion of drug development projects that that make it from one phase to the next in order to compute POS statistics.

Overall, the researchers found that 13.8% of all drug development programs advance from phase 1 to gaining approval, which is higher than the estimates reported by other studies that used a ‘phase-by-phase’ approach. Moreover, there is variability in clinical trial success rates depending on therapeutic group. Overall POS ranges from 33.4% for vaccines (for infectious diseases) to only 3.4% for oncology.

Interestingly, the overall POS of clinical trials that use biomarkers to select patients is almost double the POS of trials that did not use biomarkers (10.3% vs. 5.5%). This is especially true in oncology, and may partly be because the use of biomarkers allows the selection of patients who are more likely to produce a positive response. However, when trials that evaluated the use of novel biomarkers as an indicator of therapeutic efficacy / toxicity were included in addition to trials that use biomarkers for patient selection, there was no significant increase in overall POS.

"We hope to provide this information on a regular basis—it’s not just a one-shot deal," says Andrew Lo, senior author of the study. "Our goal is to show all stakeholders the lay of the land so that they can make more informed decisions about where and how to direct their resources."