In ovarian cancer trials, many patients in the placebo group later receive a PARP inhibitor. This crossover "pollutes" the data, making it difficult to prove a statistically significant overall survival benefit for frontline PARP maintenance, despite its clear effectiveness.

The trial allowed patients in the placebo group to receive retifanlimab upon progression (crossover). This common design dilutes the observed overall survival difference. While initial results were not statistically significant, updated data revealed a clinically meaningful 10.6-month median OS improvement.

The Podium 303 study's design allowed placebo patients to receive retafanilumab upon progression. This crossover contaminated the control arm, likely diluting the true overall survival benefit and making the first-line combination therapy appear less statistically significant than it actually is.

In trials like ASCENT-4, where over 80% of the control arm received sacituzumab govitecan upon progression, the true overall survival (OS) benefit is obscured. This makes progression-free survival (PFS) a more reliable endpoint for evaluating the drug's first-line efficacy.

Positive Phase 3 trials in intermediate HCC met their primary Progression-Free Survival (PFS) endpoints. Criticizing them for not showing an overall survival benefit—an endpoint they weren't powered for—is a retrospective invalidation that risks discarding clinically meaningful advances.

In pivotal ADC trials like ASCENT-03 and 04, over 80% of patients in the control (chemotherapy) arm received the ADC upon progression. This high crossover rate makes interpreting overall survival (OS) data difficult, as the control group's outcomes are artificially improved by subsequent access to the novel drug.

The control arm in the EMBARK study was blinded to PSA results, preventing physicians from intervening with standard-of-care AR antagonists at PSA progression. This design likely delayed subsequent effective therapies, making the control arm underperform and potentially exaggerating the overall survival benefit of the experimental arms.

A significant criticism of the pivotal KEYNOTE-564 trial is that only half the patients in the control arm received standard-of-care immunotherapy upon relapse. This lack of subsequent optimal treatment complicates the interpretation of the overall survival benefit, raising questions about its true magnitude.

Exploratory analysis shows that while patients with 100% PTEN loss have a much worse natural history than those with 90% loss, the therapeutic effect of capivasertib is stable across this spectrum. The drug effectively targets the pathway regardless of the magnitude of loss, making it a robust option for this entire subgroup.