Efficacy, safety and tolerability of drugs studied in phase 3 randomized controlled trials in solid tumors over the...

Area of Science:

• Oncology
• Clinical Trials
• Drug Development

Background:

• Newly approved cancer drugs may have worse safety than in registration trials.
• Limited data exist on the efficacy-toxicity balance of drugs in unselected phase 3 RCTs, including those without regulatory approval.

Purpose of the Study:

• To evaluate the efficacy and toxicity of experimental drugs compared to controls in phase 3 RCTs for advanced cancers.
• To assess the proportion of trials meeting primary endpoints and the safety profiles of experimental therapies.

Main Methods:

• Searched ClinicalTrials.gov for phase 3 RCTs in advanced breast, colorectal, lung, or prostate cancer (Jan 2005-Oct 2016).
• Extracted efficacy data (HRs for PFS and OS) and safety data (ORs for toxic death, discontinuation, grade 3/4 AEs) from publications.
• Conducted a meta-analysis on data from 143 RCTs (88,603 patients).

Main Results:

• Experimental drugs improved progression-free survival (HR 0.80) and overall survival (HR 0.87) compared to controls.
• Increased risks observed for toxic death (OR 1.14), treatment discontinuation without progression (OR 1.64), and grade 3/4 adverse events with experimental drugs.
• 57% of included RCTs met their primary endpoint; nearly half showed worse safety for experimental therapies.

Conclusions:

• Phase 3 RCTs show experimental cancer drugs offer modest efficacy gains but carry significant toxicity risks.
• The efficacy-toxicity balance must be carefully considered, especially in unselected patient populations.
• Clinicians and researchers should weigh the benefits against the safety concerns of novel cancer treatments.