Trials for Rare Cancers Are More Successful than those for Common Cancers

Area of Science:

• Oncology
• Clinical Trial Design
• Drug Development

Background:

• Rare cancers present challenges in clinical research despite their potential for early efficacy signals.
• Understanding trial success rates and failure factors is crucial for rare cancer drug development.
• Comparing rare versus common cancer trials can inform future research strategies.

Purpose of the Study:

• To compare the success rates of clinical trials involving rare cancers versus common cancers.
• To identify factors influencing trial outcomes over time, particularly for rare cancer studies.
• To investigate common reasons for trial failure in rare and common cancer cohorts.

Main Methods:

• Analysis of 32,145 completed clinical trials from Trialtrove.
• Comparison of outcomes and failure reasons for trials focusing on rare cancers, mixed rare/common cancers, and common cancers.
• Stratification by treatment type, trial phase, and sponsor type, with sensitivity analyses using different rare cancer definitions.

Main Results:

• Trials enrolling exclusively rare cancers had a 42.2% success rate, significantly higher than common cancer trials (38.2%).
• Trials including at least one rare cancer also showed elevated success rates (42.5%).
• Poor enrollment was not a common failure cause; business-related failures increased, driven by industry sponsors, especially in recent years.

Conclusions:

• Initiating trials in rare cancers may increase the probability of success when therapies are applicable to both rare and common cancers.
• Rare cancer trials demonstrate a higher success rate, suggesting strategic enrollment can benefit research.
• The landscape of trial failures is shifting, with business-related factors becoming more prominent than enrollment issues.