Crossover in trials
When patients in a trial's control arm are allowed to switch to the experimental drug after their cancer progresses. It is fair to patients but blurs the survival comparison, because the control group has now had the drug too.
Overview
Crossover is common in trials of drugs already approved elsewhere or clearly active (imatinib in GIST, osimertinib in FLAURA, 177Lu-PSMA in VISION and PSMAfore, where 84% of controls crossed over) and explains why such trials often show large progression-free survival gains but little or no overall survival difference. Statistical corrections (rank-preserving structural failure time, inverse probability of censoring weighting) estimate what survival would have been without crossover but rely on assumptions and are treated cautiously by regulators, who may still demand an OS trend. In regulatory debates, crossover cuts both ways: it can hide a true survival benefit or excuse its absence.
Similar pages
not linked directly; found by shared links- TermPSA50 / PSA90 response
Shares TheraP (ANZUP 1603), Prostate cancer.
- TermSalivary gland toxicity (xerostomia) from PSMA radioligand therapy
Shares PSMAfore, VISION, Lutetium-177.
- IdeaAdding a checkpoint inhibitor to PSMA radioligand therapy
Shares TheraP (ANZUP 1603), VISION, Lutetium-177.
- Key paperLuPSMA trial: single-arm phase 2 study of 177Lu-PSMA-617 in metastatic castration-resistant prostate cancer
Shares TheraP (ANZUP 1603), VISION, Lutetium-177.
- TermmCRPC and mHSPC (castration-resistant vs hormone-sensitive prostate cancer)
Shares PSMAfore, VISION, Prostate cancer, Lutetium-177.
- AgentCabazitaxel
Shares TheraP (ANZUP 1603), Prostate cancer, Lutetium-177.
- PersonScott T. Tagawa
Shares VISION, Lutetium-177.
- PersonMichael J. Morris
Shares PSMAfore, VISION, Prostate cancer, Lutetium-177.