The CREST trial showed benefit driven by patients with carcinoma in situ (CIS), while the Potomac trial showed a lack of benefit in the same subgroup. This stark inconsistency demonstrates that subgroup analyses, even for stratified factors, can be unreliable and are a weak basis for regulatory decisions or label restrictions.

Novo Nordisk ran a nearly 4,000-patient Phase 3 Alzheimer's trial despite publicly stating it had a low probability of success. This strategy consumes valuable patient resources, raising ethical questions about whether a smaller, definitive Phase 2 study would have been a more responsible approach for the broader research ecosystem.

Progress in drug development often hides inside failures. A therapy that fails in one clinical trial can provide critical scientific learnings. One company leveraged insights from a failed study to redesign a subsequent trial, which was successful and led to the drug's approval.

The most valuable lessons in clinical trial design come from understanding what went wrong. By analyzing the protocols of failed studies, researchers can identify hidden biases, flawed methodologies, and uncontrolled variables, learning precisely what to avoid in their own work.

The traditional drug-centric trial model is failing. The next evolution is trials designed to validate the *decision-making process* itself, using platforms to assign the best therapy to heterogeneous patient groups, rather than testing one drug on a narrow population.

After a decade on the market and multiple shifts in endpoints, Sarepta's definitive Phase 3 study for its DMD drugs failed. This outcome casts doubt on the entire accelerated approval framework for slowly progressive diseases, where surrogate endpoints may not translate to clinical benefit, leaving regulators and patients in a difficult position.

Praxis Interactive's essential tremor drug succeeded in Phase 3 despite an earlier data monitoring committee (DMC) recommendation to stop for futility. This rare outcome shows that interim analyses on a small fraction of patients can be misleading due to high variance, and continuing a trial against DMC advice can be a winning strategy.

Novo Nordisk's large semaglutide Alzheimer's trial failure highlights a critical design flaw: launching a massive study without first using smaller trials to validate mechanistic biomarkers and confirm central nervous system penetration. This serves as a cautionary tale for all CNS drug developers.

Biotech leaders must stop viewing commercialization as a post-approval task. The critical window is Phase 2 clinical trials. By embedding patient journey and quality of life insights into secondary endpoints, companies can build a compelling value proposition for payers and physicians. Waiting until Phase 3 is too late.