# CX-801

Source: https://onco.cc/drugs/cx-801/  
OnCo record `cx-801` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

CX-801 is an experimental masked cytokine from CytomX Therapeutics, in phase 1 trials for metastatic melanoma and advanced solid tumours.

## Summary

CX-801 is a masked cytokine (Probody interferon) from CytomX Therapeutics. Interferon alpha-2b masked so that it is switched on mainly in the tumour by tumour-associated proteases, aiming for a wider therapeutic window than unmasked interferon. Its furthest stage is phase 1, for metastatic melanoma and advanced solid tumours. ClinicalTrials.gov registers it in one study linked below. Whether it works in people has not been established unless a trial below reports it.

## Fields

- Kind: Treatment
- Status: phase-1
- Last checked: 2026-11-03
- Tags: pipeline; ctgov-ingest
- Code: CX-801
- Modality: Masked cytokine (Probody interferon)
- Mechanism: Interferon alpha-2b masked so that it is switched on mainly in the tumour by tumour-associated proteases, aiming for a wider therapeutic window than unmasked interferon.

## Sources

- CytomX Therapeutics: cytomx.com: https://cytomx.com/pipeline/
- CytomX Therapeutics: cytomx.com: https://cytomx.com/pipeline/
- ClinicalTrials.gov: trials of CX-801: https://clinicaltrials.gov/search?intr=CX-801

## Connected records

- cancers: [Metastatic cancer (cancer that has spread)](https://onco.cc/cancers/metastatic-cancer/)
- companies: [CytomX Therapeutics](https://onco.cc/companies/cytomx-therapeutics/)
- trials: [First In Human Study of CX-801 in Advanced Solid Tumors](https://onco.cc/trials/nct06462794/)

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JSON: https://onco.cc/api/v1/entities/cx-801.json