CDZR123A12107: Phase 1b/2 tulmimetostat in metastatic castrate resistant prostate cancer
Research type
Research Study
Full title
TulmiSTAR-01: A two-part, Phase 1I dose escalation and expansion followed by a randomized, open-label multicenter, Phase II2 study to assess the safety and efficacy of the combination of tulmimetostat (DZR123) and JSB462 (luxdegalutamide) vs standard of care in patients with progressive metastatic castrate resistant prostate cancer
IRAS ID
1012374
Contact name
Ilke Cadosch
Contact email
Sponsor organisation
Novartis Pharmaceuticals UK Limited
Clinicaltrials.gov Identifier
Research summary
This study is testing two new drugs—DZR123 (tulmimetostat) and JSB462—used together to treat men with advanced prostate cancer that no longer responds to hormone therapy and has spread (called progressive metastatic castrate-resistant prostate cancer, or mCRPC).
The study has three parts:
Part 1a: Find the safest and most effective dose of the drug combination.
Part 1b: See how well the chosen dose lowers PSA levels (a marker of prostate cancer) after 6 months.
Part 2: Compare the drug combo to standard treatment to see which works better.
DZR123 blocks proteins (EZH1 and EZH2) that help cancer grow. JSB462 blocks the androgen receptor, which also fuels cancer growth. Both drugs are taken as tablets once a day.
About 188 men aged 18+ will join. To qualify, participants must have mCRPC that has worsened after treatment, low testosterone, and good overall health. They must have taken certain prostate cancer drugs before and be willing to continue hormone therapy. People with serious health issues, brain cancer, or liver problems cannot join.
Participants will be monitored for side effects, how their cancer responds, and how long they live after treatment. Researchers will also study how the drugs move through the body and how long their effects last.
Follow-up includes health checks for up to 5 years after treatment ends. While these drugs may offer new hope, unknown risks are possible. Doctors will closely watch participants for any problems.REC name
South Central - Oxford B Research Ethics Committee
REC reference
25/SC/0391
Date of REC Opinion
15 Jan 2026
REC opinion
Further Information Favourable Opinion