PSA50 / PSA90 response

PSA50 is the proportion of patients whose PSA falls by at least half on treatment, and PSA90 the proportion whose PSA falls by nine tenths or more. Both are standard early-efficacy read-outs in trials of metastatic castration-resistant prostate cancer, reported under the PCWG3 recommendations, and readers meet them in the VISION and TheraP radioligand trials and on the page for xaluritamig. A PSA response correlates with, but does not replace, radiographic progression-free survival and overall survival. The endpoint can also end a development programme early: a PSA90 futility analysis stopped masofaniten's phase 2. The term extends the PSA entry, which describes the underlying marker.