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RecruitingLast updated: 3 March 2026

TulmiSTAR-01: Finding the right dose and assessing the safety of two new medicines, and comparing these to standard treatment, for people with progressive metastatic castrate resistant prostate cancer (mCRPC)TulmiSTAR-01: A Two-part, Phase I Dose Escalation and Expansion Followed by a Randomized, Open-label Multicenter, Phase II 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

Trial purpose

Medical clipboardCancer treatment

Tumor type

Urinary System Cancers Genitourinary

Age

People18+

Trial acronym

TulmiSTAR-01

Clinical summary

Summary

This study is looking at a new combination of two investigational medicines - tulmimetostat (also called DZR123) and JSB462 (also called luxdegalutamide) - for people with metastatic castrate-resistant prostate cancer (mCRPC) that is getting worse.

The research is happening in two main phases.

Phase I (Parts 1a and 1b): Checking safety and finding the right dose

  • Part 1a: Different dose levels of the two medicines are tested together to find out what doses are safe for people to take.
  • Part 1b: Once safe dose options are found, researchers test them in more people to choose the best dose to use in the next phase.

Phase II (Part 2): Comparing the new treatment to standard treatment

In this part, the chosen doses of the two study medicines are compared with the current standard of care for people with mCRPC who have not had chemotherapy with drugs like taxanes.

The main goal is to see whether the combination treatment helps lower PSA levels by 50% or more (PSA50), which is a sign that the cancer may be responding.

Conditions

This trial is treating people with metastatic castration-resistant prostate cancer that is progressive

Eligibility

Inclusion

  • Participant is an adult man ≥ 18 years of age.
  • Participant must have histologically and/or cytologically confirmed adenocarcinoma of the prostate without neuroendocrine or small cell features (current or prior biopsy of the prostate and/or metastatic site).
  • Participant must have ≥ 1 metastatic lesion that is present on screening/baseline CT, MRI, or bone scan imaging obtained ≤ 28 days prior to start of treatment (Part 1a dose escalation) or randomization (Part 1b dose expansion and Part 2).
  • Participant must have progressive mCRPC.
  • Participant must have a castrate level of serum/plasma testosterone (< 50 ng/dL or < 1.7 nmol/L).

  • Prior ARPI therapy:

    • Part 1a and 1b only: must have progressed on at least one prior second generation ARPI (abiraterone, enzalutamide, darolutamide, or apalutamide).
    • Part 2 only: must have progressed on one prior second generation ARPI (abiraterone, enzalutamide, darolutamide, or apalutamide).

  • Prior chemotherapy:

    • Part 1a dose escalation only: may have received ≤ 2 prior lines of chemotherapy in CRPC setting. Note: Prior chemotherapy is permitted in the HSPC setting.
    • Part 1b dose expansion/optimization only: may have received up to one prior line of chemotherapy in CRPC setting. Note: Prior chemotherapy is permitted in the HSPC setting.
    • Part 2 only: Participants must be taxane-naïve in mCRPC setting; prior chemotherapy permitted in HSPC setting only

Exclusion

  • Previous treatment with any PRC2 inhibitor, including but not limited to EZH2 inhibitors, EZH2/1 inhibitors, or embryonic ectoderm development (EED) inhibitors.
  • Previous treatment with a protein degrader compound that targets the AR.
  • Known hypersensitivity or contraindication to any of the study treatment components or its excipients or to drugs of similar chemical classes.
  • Treatment with any investigational agent within 28 days (or 5 half-lives, whichever is longer) prior to study entry.
  • Previous treatment with radioligand therapy in the mCRPC setting, except in Part 1a where participants may have received RLT in mCRPC setting.
  • Participants with evidence of mCRPC or biochemical recurrence / PSA only disease or asymptomatic prostate cancer without known metastatic disease and with no requirement for therapy and with normal PSA for ≥ 1 year prior to study entry.
  • Participants with a history of CNS metastases must have received therapy (surgery, radiotherapy, gamma knife) and be neurologically stable, asymptomatic, and not receiving corticosteroids for the purpose of maintaining neurologic integrity. Those with leptomeningeal disease are eligible if those areas have been treated, are stable, and no neurological impairment is present. For those with parenchymal CNS metastasis (or a history of CNS metastasis), baseline and subsequent radiological imaging must include evaluation of the brain with MRI (preferred) or CT with contrast.

Other protocol-defined inclusion/exclusion criteria may apply.

Inclusion

  • Your cancer has spread to other parts of the body (metastatic) or has grown into nearby parts of the body (locally advanced).
  • You have had treatment but your cancer has gotten worse or has not responded to the treatment you have been given.

Exclusion

  • You have had certain treatments, surgical procedures or drugs.
Message

Clinical trials have complex eligibility criteria, and other criteria may apply for this trial. Ask your doctor about whether this trial could be right for you.

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Recruiting hospitals

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More information

Trial Identifiers

Information on this page is partially produced from ClinicalTrials.gov, EU Clinical Trials Register *. View further details about this trial on the registry via the links below:

Trial sponsor

Novartis Pharmaceuticals

Scientific Title

TulmiSTAR-01: A Two-part, Phase I Dose Escalation and Expansion Followed by a Randomized, Open-label Multicenter, Phase II 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

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