A letter to the Editor of NAM Journal responding to Peter Groenen.
Filipova D. Fox L. Gossman M. Herrmann K. Knight A. et al. (2026). Six decades of evidence: biological factors predominate among reported reasons for clinical drug failure: A response to “Persistent clinical attrition does not establish animal models as a root cause of drug-development failures” by Peter MA Groenen. NAM Journal 2(100136).doi.org/10.1016/j.namjnl.2026.100136.