Data from the Podium 303 crossover arm shows that giving retafanilumab monotherapy after progression on chemotherapy yields a dismal 5.8% response rate. This confirms that the synergistic effect of combining chemo and immunotherapy upfront is critical and cannot be replicated by sequential treatment.

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.

Data from the Podium-303 trial's crossover arm suggests that waiting to use a PD-1 inhibitor after progression on chemotherapy is less effective than using it concurrently from the start. This supports the synergistic effect of chemo-immunotherapy and favors the concurrent approach as the standard of care.

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.

The AscentO3 trial lacked an overall survival benefit for its primary endpoint because its design ethically allowed patients on the chemotherapy arm to receive sacituzumab govitecan upon progression. This 'crossover' improves care for the control group but makes it statistically difficult to demonstrate a first-line survival advantage.

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.

In the ASCENT-07 trial, investigators may have prematurely switched patients from the standard chemotherapy arm to superior, commercially available ADCs at the first hint of progression. This real-world practice can mask an experimental drug's true benefit on progression-free survival.

The common practice of switching from one ARPI to another upon disease progression is now considered ineffective for most patients. With the advent of proven alternatives like chemotherapy and lutetium, using an "ARPI switch" as the sole control arm in clinical trials is no longer ethically or scientifically sound.

The BREAKAWAY trial's OS data is from a small, crossover-allowed study, making it hard to interpret alone. However, its findings are believable because they align with and reinforce a "building body of evidence" from larger trials like PROPEL and TALA PRO 2, which also show a survival benefit for PARP inhibitor combinations.