{"entity":{"id":"klk2","kind":"target","name":"KLK2 (kallikrein-2)","aka":[],"tldr":"A relative of PSA that stays attached to prostate cancer cells, used as a T-cell engager address by J&J.","summary":"Human kallikrein-2 (KLK2) is an androgen-regulated serine protease that activates PSA; unlike PSA it is retained on the prostate cell membrane, which makes it a usable address for cell-surface therapies. Expression is nearly universal in prostate cancer and prostate-restricted elsewhere, so a KLK2-directed drug can engage T cells against the tumour with little on-target damage to other tissues. The lead agent is Johnson & Johnson's pasritamig (JNJ-78278343, a KLK2 x CD3 bispecific), which showed low cytokine release and PSA responses in phase 1 and is in phase 3 (KLK2-P3-01) in metastatic castration-resistant prostate cancer. Open questions are whether KLK2 expression persists in neuroendocrine or AR-independent disease and how it compares with PSMA as an engager target. The plain version: KLK2 is a cousin of PSA that stays stuck to cancer cells, so drugs can grab it.","asOf":"2026-09-06","wikipedia":"https://en.wikipedia.org/wiki/KLK2","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/KLK2"}],"tags":["t-cell-engager-target"],"related":[],"indications":["prostate"],"sections":[],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":["Prevalence not recorded: no peer-reviewed KLK2 expression series with a stated denominator was found for prostate cancer; 'nearly universal' rests on KLK2 being an androgen-regulated, prostate-restricted gene rather than on a published positivity rate."],"symbol":"KLK2","hgnc":"HGNC:6363","ensembl":"ENSG00000167751","uniprot":"P20151","entrez":"3817","biology":"Serine protease activating PSA; androgen-regulated.","whereFound":["Prostate cancer (nearly universal)"],"targetClass":"surface-antigen","prevalence":[]},"route":"/targets/klk2/","neighbours":{"indication":[{"id":"prostate","kind":"indication","name":"Prostate cancer","route":"/indications/prostate/"}]}}