# Cinrebafusp alfa

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

## TL;DR

Cinrebafusp alfa is an experimental fusion protein from Pieris Pharmaceuticals in phase 2 trials for gastric & gastro-oesophageal junction cancer, aimed at HER2.

## Summary

Cinrebafusp alfa (PRS-343) is a fusion protein developed by Pieris Pharmaceuticals. Its target is HER2 (the sponsor names HER2 x 4-1BB). The sponsor states: Cinrebafusp alfa (PRS-343) is a HER2/4-1BB bispecific anticalin-antibody fusion protein that binds HER2 on tumour cells while engaging 4-1BB (CD137) to costimulate T cells. It is the investigational product in 1 recruiting or active industry-led phase 2 and phase 3 interventional cancer trial, in gastric & gastro-oesophageal junction cancer. The largest, NCT05190445, plans to enrol 80 participants with primary completion was scheduled for 2023-02-01 on the registry. Status reflects the highest phase registered on ClinicalTrials.gov; no efficacy results are recorded here.

## Fields

- Kind: Treatment
- Status: phase-2
- Last checked: 2026-09-11
- Also known as: Cinrebafusp alfa (PRS-343)
- Tags: pipeline; ctgov-ingest
- Code: PRS-343
- Modality: fusion protein
- Mechanism: Cinrebafusp alfa (PRS-343) is a HER2/4-1BB bispecific anticalin-antibody fusion protein that binds HER2 on tumour cells while engaging 4-1BB (CD137) to costimulate T cells.

## Sources

- ClinicalTrials.gov: trials of Cinrebafusp alfa: https://clinicaltrials.gov/search?intr=PRS-343

## Connected records

- cancers: [Gastric & gastro-oesophageal junction cancer](https://onco.cc/cancers/gastric/)
- targets: [CD137 (4-1BB, TNFRSF9)](https://onco.cc/targets/cd137/), [HER2](https://onco.cc/targets/her2/)
- companies: [Pieris Pharmaceuticals](https://onco.cc/companies/pieris-pharmaceuticals/)
- trials: [Cinrebafusp Alfa in Combination With Ramucirumab and Paclitaxel in HER2-High Gastric or GEJ Adenocarcinoma and in Combination With Tucatinib in HER2-Low Gastric or GEJ Andenocarinoma](https://onco.cc/trials/nct05190445/)

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