{"entity":{"id":"psa50","kind":"term","name":"PSA50 / PSA90 response","aka":["PSA50 response","PSA50","PSA90","PSA90 response","50 percent PSA decline","prostate-specific antigen response rate"],"tldr":"PSA50 is the share of patients whose PSA falls by at least half on treatment, and PSA90 the share whose PSA falls by 90%.","summary":"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.","asOf":"2026-09-06","wikipedia":"https://en.wikipedia.org/wiki/Prostate-specific_antigen","links":[{"label":"PCWG3 trial design recommendations incl. PSA response reporting (Scher et al., J Clin Oncol 2016)","url":"https://doi.org/10.1200/JCO.2015.64.2702"},{"label":"Scher et al., Journal of Clinical Oncology 2008 (PCWG2): design and end points of clinical trials for patients with progressive prostate cancer and castrate levels of testosterone","url":"https://doi.org/10.1200/jco.2007.12.4487"},{"label":"Scher et al., Journal of Clinical Oncology 2016 (PCWG3): trial design and objectives for castration-resistant prostate cancer, updated recommendations","url":"https://doi.org/10.1200/jco.2015.64.2702"}],"tags":[],"related":["radiographic-progression-free-survival","bipolar-androgen-therapy"],"cancers":["prostate"],"sections":[],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["psa","radiographic-progression-free-survival","bipolar-androgen-therapy"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":["paper-scher-j-clin-oncol"],"journals":[],"dependsOn":[],"notes":["What counts as a PSA50, exactly. It is a decline of 50 percent or more from the baseline value, measured on treatment and confirmed by a second value at least four weeks later; PSA90 is the same with a 90 percent threshold. Both are proportions of patients, not times, so a PSA50 rate says nothing about how long the response lasted.","The working group that trials cite for it recommends against reporting it. PCWG2 advises against prostate-specific antigen response rates, on the grounds that thresholds such as a 50 percent decline have no demonstrated clinical significance, and asks instead for the percentage change from baseline to 12 weeks and the maximum decline at any point, reported per patient in a waterfall plot. Trials report PSA50 anyway because it is a single comparable number, which is exactly the property PCWG2 objected to.","The prostate figures a reader will meet. RESTORE: a 50 percent decline in 9 of 30 men (30 percent) on bipolar androgen therapy, and in 15 of 21 (52 percent) on enzalutamide rechallenge afterwards. TRANSFORMER: 28.2 percent on bipolar androgen therapy against 25.3 percent on enzalutamide, and 77.8 percent in men crossing over to enzalutamide. TRITON2: 54.8 percent (63 of 115) with rucaparib in BRCA-altered disease. AR-V7-positive men in Antonarakis's cohort: 0 percent on either enzalutamide or abiraterone."],"category":"Endpoints"},"route":"/terms/psa50/","neighbours":{"term":[{"id":"bipolar-androgen-therapy","kind":"term","name":"Bipolar androgen therapy (BAT)","route":"/terms/bipolar-androgen-therapy/"},{"id":"psa","kind":"term","name":"PSA (prostate-specific antigen)","route":"/terms/psa/"},{"id":"radiographic-progression-free-survival","kind":"term","name":"Radiographic progression-free survival (rPFS)","route":"/terms/radiographic-progression-free-survival/"}],"cancer":[{"id":"prostate","kind":"cancer","name":"Prostate cancer","route":"/cancers/prostate/"}],"paper":[{"id":"paper-therap-lancet-2021","kind":"paper","name":"[ 177 Lu]Lu-PSMA-617 versus cabazitaxel in patients with metastatic castration-resistant prostate cancer (TheraP): a randomised, open-label, phase 2 trial","route":"/key-papers/paper-therap-lancet-2021/"},{"id":"paper-antonarakis-ar-v7-resistance-nejm-2014","kind":"paper","name":"AR-V7 and resistance to enzalutamide and abiraterone in prostate cancer","route":"/key-papers/paper-antonarakis-ar-v7-resistance-nejm-2014/"},{"id":"paper-abida-msi-prostate-checkpoint-blockade-jama-oncol-2019","kind":"paper","name":"Prevalence of microsatellite instability in prostate cancer and response to immune checkpoint blockade","route":"/key-papers/paper-abida-msi-prostate-checkpoint-blockade-jama-oncol-2019/"},{"id":"paper-prophecy-arv7-validation-jco-2019","kind":"paper","name":"PROPHECY: prospective multicentre validation of androgen receptor splice variant 7 and hormone therapy resistance in high-risk castration-resistant prostate cancer","route":"/key-papers/paper-prophecy-arv7-validation-jco-2019/"},{"id":"paper-scher-j-clin-oncol","kind":"paper","name":"Trial Design and Objectives for Castration-Resistant Prostate Cancer: Updated Recommendations From the Prostate Cancer Clinical Trials Working Group 3","route":"/key-papers/paper-scher-j-clin-oncol/"},{"id":"paper-abida-triton2-rucaparib-brca-jco-2020","kind":"paper","name":"TRITON2: rucaparib in men with metastatic castration-resistant prostate cancer harbouring a BRCA1 or BRCA2 alteration","route":"/key-papers/paper-abida-triton2-rucaparib-brca-jco-2020/"}],"drug":[{"id":"xaluritamig","kind":"drug","name":"Xaluritamig","route":"/drugs/xaluritamig/"}],"trial":[{"id":"affirm","kind":"trial","name":"AFFIRM","route":"/trials/affirm/"},{"id":"armor3-sv","kind":"trial","name":"ARMOR3-SV","route":"/trials/armor3-sv/"},{"id":"cou-aa-301","kind":"trial","name":"COU-AA-301","route":"/trials/cou-aa-301/"},{"id":"prevail","kind":"trial","name":"PREVAIL","route":"/trials/prevail/"},{"id":"proselica","kind":"trial","name":"PROSELICA","route":"/trials/proselica/"},{"id":"swog-9916","kind":"trial","name":"SWOG 9916","route":"/trials/swog-9916/"},{"id":"tax-327","kind":"trial","name":"TAX 327","route":"/trials/tax-327/"},{"id":"therap","kind":"trial","name":"TheraP (ANZUP 1603)","route":"/trials/therap/"}],"technology":[{"id":"serum-tumour-markers","kind":"technology","name":"Serum tumour markers: proper use and misuse","route":"/technologies/serum-tumour-markers/"}]}}