# Pasritamig

Source: https://onco.cc/drugs/pasritamig/  
OnCo record `pasritamig` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Pasritamig is Johnson & Johnson's bispecific T-cell engager that binds KLK2 on prostate cancer cells and CD3 on T cells, with a deliberately low-affinity CD3 arm. In phase 1 about 40% of patients had a PSA50 response with far less cytokine release syndrome than other engagers, and a phase 3 trial began in 2025.

## Summary

Pasritamig (JNJ-78278343) is a bispecific T-cell engager that binds KLK2 on prostate cancer cells and CD3 on T cells; a deliberately low-affinity CD3 arm limits cytokine release so that it can be given in the outpatient setting. It is being developed for metastatic castration-resistant prostate cancer after an androgen receptor pathway inhibitor, with or without a prior taxane. In phase 1, about 40% of patients achieved a PSA50 response at the recommended dose, with cytokine release syndrome rates far below other engagers, and the phase 3 KLK2-P3-01 trial began in 2025. Whether PSA responses will translate into radiographic and survival benefit, and how durable responses are, remain open. For a newcomer, it is Johnson & Johnson's prostate-specific T-cell engager, notable for how little cytokine storm it caused in early trials.

## Fields

- Kind: Treatment
- Status: phase-3
- Last checked: 2026-09-06
- Code: JNJ-78278343
- Modality: Bispecific T-cell engager (KLK2×CD3)
- Mechanism: Low-affinity CD3 arm and KLK2 targeting; designed for outpatient dosing.

## Sources

- ClinicalTrials.gov: trials of Pasritamig: https://clinicaltrials.gov/search?intr=JNJ-78278343

## Connected records

- cancers: [Metastatic castration-resistant prostate cancer](https://onco.cc/cancers/prostate-mcrpc/), [Prostate cancer](https://onco.cc/cancers/prostate/)
- technologies: [T-cell engagers (bispecific)](https://onco.cc/technologies/t-cell-engager/)
- targets: [CD3](https://onco.cc/targets/cd3/), [KLK2 (kallikrein-2)](https://onco.cc/targets/klk2/)
- companies: [Johnson & Johnson](https://onco.cc/companies/johnson-johnson/)
- terms: [Cytokine release syndrome (CRS)](https://onco.cc/terms/crs/)
- trials: [A Study of Pasritamig With Docetaxel Versus Docetaxel in Participants With Metastatic Castration-Resistant Prostate Cancer](https://onco.cc/trials/nct07225946/)

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JSON: https://onco.cc/api/v1/entities/pasritamig.json