# UBX-303-1

Source: https://onco.cc/drugs/ubx-303061/  
OnCo record `ubx-303061` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

UBX-303-1 is an experimental oral targeted protein degrader from Ubix Therapeutics, in phase 1 trials for relapsed or refractory B-cell malignancies.

## Summary

UBX-303-1 (UBX-303061, BTK Degrader UBX-303061) is an oral targeted protein degrader (chimeric degrader; company term 'Degraducer') from Ubix Therapeutics. Breaks down Bruton's tyrosine kinase rather than only blocking it: one end binds BTK and the other an E3 ubiquitin ligase, which tags BTK for destruction. The company reports activity in preclinical models with normal BTK and with the C481S resistance mutation. Its furthest stage is phase 1, for relapsed or refractory B-cell malignancies (CLL/SLL, DLBCL, follicular, mantle cell, marginal zone lymphoma, Waldenström macroglobulinaemia). ClinicalTrials.gov registers it in one study linked below. Phase 1a/1b NCT06590961 recruiting; started 20 February 2025. 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
- Also known as: UBX-303061; BTK Degrader UBX-303061
- Tags: pipeline; ctgov-ingest
- Code: UBX-303061
- Modality: Oral targeted protein degrader (chimeric degrader; company term 'Degraducer')
- Mechanism: Breaks down Bruton's tyrosine kinase rather than only blocking it: one end binds BTK and the other an E3 ubiquitin ligase, which tags BTK for destruction. The company reports activity in preclinical models with normal BTK and with the C481S resistance mutation.

## Sources

- Ubix Therapeutics: ubixtrx.com: https://ubixtrx.com/pipeline
- Ubix Therapeutics: ubixtrx.com: https://ubixtrx.com/pipeline
- Ubix Therapeutics: api-evsrest.nci.nih.gov: https://api-evsrest.nci.nih.gov/api/v1/concept/ncit/search?term=UBX-303061&include=definitions,synonyms
- Ubix Therapeutics: clinicaltrials.gov: https://clinicaltrials.gov/api/v2/studies/NCT06590961
- ClinicalTrials.gov: trials of UBX-303061: https://clinicaltrials.gov/search?intr=UBX-303061

## Connected records

- cancers: [Metastatic cancer (cancer that has spread)](https://onco.cc/cancers/metastatic-cancer/)
- targets: [BTK (Bruton tyrosine kinase)](https://onco.cc/targets/btk/)
- companies: [Ubix Therapeutics](https://onco.cc/companies/ubix-therapeutics/)
- trials: [UBX-303061 in Subjects With Relapsed/Refractory B-Cell Malignancies](https://onco.cc/trials/nct06590961/)

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JSON: https://onco.cc/api/v1/entities/ubx-303061.json