# ARX517

Source: https://onco.cc/drugs/arx517/  
OnCo record `arx517` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

ARX517 is an experimental antibody-drug conjugate for metastatic prostate cancer, aimed at the protein PSMA. Ambrx developed it and Johnson & Johnson took it over when it bought Ambrx in 2024.

## Summary

ARX517 is an antibody-drug conjugate in which a humanised anti-PSMA IgG1 antibody is covalently conjugated to two molecules of a proprietary microtubule-disrupting toxin, AS269, according to its registry record. It came to Johnson & Johnson with the acquisition of Ambrx Biopharma, announced in January 2024. The phase 1 trial (NCT04662580), now sponsored by Janssen Research & Development as ARX517/JNJ-95298177, tests it alone or with apalutamide or abiraterone in metastatic prostate cancer and is active but no longer recruiting. A second phase 1 trial (NCT07082920) combines it with JNJ-78278343. No results are recorded here.

## Fields

- Kind: Treatment
- Status: phase-1
- Last checked: 2026-11-03
- Also known as: JNJ-95298177
- Tags: pipeline; deal-asset
- Code: JNJ-95298177
- Modality: Antibody-drug conjugate (PSMA, microtubule-disrupting payload)
- Mechanism: A humanised antibody against PSMA, a protein on prostate cancer cells, is joined at two sites to a microtubule-disrupting toxin called AS269, which stops the cancer cell dividing.

## Sources

- ClinicalTrials.gov: ARX517 phase 1 (NCT04662580): https://clinicaltrials.gov/study/NCT04662580
- ClinicalTrials.gov: JNJ-78278343 with JNJ-95298177 (NCT07082920): https://clinicaltrials.gov/study/NCT07082920

## Connected records

- cancers: [Prostate cancer](https://onco.cc/cancers/prostate/)
- technologies: [Antibody-drug conjugate (ADC)](https://onco.cc/technologies/adc/)
- targets: [PSMA](https://onco.cc/targets/psma/)
- companies: [Ambrx](https://onco.cc/companies/ambrx/), [Johnson & Johnson](https://onco.cc/companies/johnson-johnson/)
- trials: [ARX517/JNJ-95298177 as Monotherapy or Combination Therapy in Subjects With Metastatic Prostate Cancer](https://onco.cc/trials/nct04662580/)

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JSON: https://onco.cc/api/v1/entities/arx517.json