Phase 2 Trials Often Halted Due to Enrollment Problems


Oncology trials are most susceptible – see lung cancer analysis as a prime example

Take us up on our challenge to rank the top 5 companies with the highest rate of Phase 2 trial terminations, and get a free Phase 2 trial audit report

When we talk about failure in clinical trials, many people automatically focus on Phase 3, so Phase 2 failures receive less attention. As part of our regular assessment of success and failure factors across the spectrum of trials, we at Phesi have noticed consistent trends in Phase 2 failures among big pharma companies. Those trends have inspired us to take a deeper dive to see what’s going on.

Using our dynamic, real-time database, we analyzed 5,062 Phase 2 global #clinicaltrials across 17 top pharma companies (see list below). We found a median Phase 2 termination rate of 14% within those companies, one of which terminated as many as one-third of its Phase 2 trials. Of a set of 253 terminated Phase 2 trials, 133, or 53%, ended because of patient enrollment difficulties. The rest of the terminations were attributed to efficacy and/or safety issues.

Clinical development risks, including trial termination for legitimate reasons, are a fact of life in drug development, but need not be accepted as par for the course. Phesi’s proprietary protocol design analysis platform allows us to help our clients to optimize protocols and minimize trial termination rates.

Unlike some benchmark reports that ”name and shame” the lower-performing clinical development organizations without offering constructive guidance, Phesi’s platform helps our clients define baseline performance parameters, understand the causes of termination, and provide actionable recommendations to improve trial success rates. The platform is uniquely capable of doing this with a high level of granularity in a matter of days.

To highlight this phenomenon, the following chart shows enrollment rate trends in Phase 2 non-small cell #lungcancer (NSCLC) protocols. Each bubble represents a Phase 2 NSCLC trial, and the enrollment cycle time is proportional to size of the bubble.

Here’s a closer look at these results: 43/76 of these trials included patients with late-stage disease (stages III and IV), with a median enrollment cycle time of 741 days. For 10 Phase 2 #NSCLC trials that included patients at stage III only, the median enrollment cycle time was prolonged to 1,582 days.

Using our global analytics platform, it can take us just a few hours to identify the deviation of protocol design elements from mode value, which is a statistical term describing the most prevalent value among analyzed samples. This helps us identify risk factors to operational feasibility and trial delivery. Multiple deviations from the modal values, such as the one illustrated above, usually lead to trial termination post-initiation, due to enrollment issues.

Clinical trial termination in 17 pharma companies, listed alphabetically

Allergan, Amgen, AstraZeneca, Bayer, Boehringer Ingelheim, Bristol-Myers Squibb, Eli Lilly and Company, Gilead Sciences, GlaxoSmithKline, Hoffmann-La Roche, Janssen Research & Development, LLC, Merck Sharp & Dohme Corp., Novartis, Novo Nordisk, Pfizer, Sanofi, and Takeda

Blinded rankings, in order of decreasing percentage of Phase 2 trial termination

Try and rank the top 5 out of these 17 companies in order of percentage of terminated trials, and receive an unblinded, detailed report of our Phase 2 analysis, free of charge. Send your ranking to

HINT: A company with heavy #oncology and/or innovative drug portfolio will have a higher Phase 2 trial termination rate.

Privacy Preferences
When you visit our website, it may store information through your browser from specific services, usually in form of cookies. Here you can change your privacy preferences. Please note that blocking some types of cookies may impact your experience on our website and the services we offer.