A Phase 1/2 interventional study of Tulmimetostat and Darolutamide in Metastatic Hormone-Sensitive Prostate Cancer (mHSPC), sponsored by Novartis Pharmaceuticals. Recruiting at 31 sites in 14 countries. Open to male participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-29.
Sponsored by Novartis Pharmaceuticals · Phase 1/2, Interventional, and Treatment
The purpose of this study is to evaluate the safety, tolerability, and efficacy of two different treatment combinations of tulmimetostat in participants with de novo or recurrent metastatic hormone-sensitive prostate cancer (mHSPC). Phase I aims to determine the recommended dose(s) for expansion (RDE) of tulmimetostat in combination with darolutamide or abiraterone. Phase II is designed to further evaluate the efficacy and safety of tulmimetostat in combination with darolutamide compared with darolutamide alone in participants with mHSPC.
This is a Phase I/II, open-label, global, multicenter study evaluating tulmimetostat in combination with androgen receptor pathway inhibitors in participants with de novo or recurrent metastatic hormone-sensitive prostate cancer (mHSPC). The study consists of two phases:
Phase I (Dose Escalation)
Phase I includes two treatment groups:
The primary objective of Phase I is to determine the recommended dose(s) for expansion (RDE) of tulmimetostat in each combination regimen through a parallel dose-escalation design guided by a Bayesian Logistic Regression Model (BLRM). Enrollment will follow a staggered approach between the two groups. Participants may have received prior taxane-based chemotherapy and/or prior androgen receptor pathway inhibitor (ARPI) therapy and must not have received prior radioligand therapy. Participants will continue androgen deprivation therapy (ADT) to maintain castrate testosterone levels (\<50 ng/dL or \<1.7 nmol/L) according to investigator choice and local prescribing information. In Group B, abiraterone will be administered with prednisone or prednisolone according to local prescribing information.
Phase II (Dose Expansion) Phase II is a randomized, open-label, multicenter dose-expansion study designed to further characterize the recommended dose(s) of tulmimetostat in combination with darolutamide and to provide proof-of-concept for the efficacy and safety of tulmimetostat plus darolutamide compared with darolutamide alone.
Eligible participants are adult men with de novo or recurrent mHSPC who have not received prior radioligand therapy and may have received prior taxane-based chemotherapy and/or prior ARPI therapy (excluding darolutamide), with a maximum prior ARPI exposure of 4 months in the mHSPC setting. Participants will continue ADT throughout the study according to investigator choice and local prescribing information. Based on Phase I results, one or two tulmimetostat dose levels in combination with darolutamide may be evaluated.
Study Duration and Follow-up
For each participant, the study consists of a screening period, a treatment period, and post-treatment follow-up. Post-treatment follow-up includes:
The study is designed to evaluate whether inhibition of EZH1/2 with tulmimetostat in combination with androgen receptor pathway inhibition may improve clinical outcomes in men with metastatic hormone-sensitive prostate cancer.
Key Inclusion Criteria:
Prior taxane use for mHSPC is permitted:
Prior ARPI is allowed in both Phase I and Phase II:
Prior ARPI use in mHSPC is permitted but not mandated. If participants meet all study eligibility criteria, they are required to stop their prior ARPI after providing informed consent and remain off ARPI until Cycle 1 Day 1, when study treatment is initiated.
Participants with ongoing ARPI are eligible for a switch from their ongoing ARPI therapy if they have not progressed to CRPC disease, and meet any of the criteria, indicative of suboptimal biochemical response, or intolerability, as assessed by the Investigator:
Intolerance and non-compliance: Participant's inability to tolerate or comply with the prescribed ARPI. The site should maintain documentation to support the appropriateness of therapy changes resulting from intolerance or non-compliance.
Key Exclusion Criteria:
Participants with CNS metastases are excluded unless:
Other inclusion/exclusion criteria may apply
Tulmimetostat administered orally once daily (QD) at escalating dose levels in combination with darolutamide 600 mg orally twice daily (BID). Participants will continue androgen deprivation therapy (ADT) throughout the study.
Drug: Tulmimetostat · Drug: Darolutamide · Drug: Androgen Deprivation Therapy (ADT)
Tulmimetostat administered orally once daily (QD) at escalating dose levels in combination with abiraterone 1000 mg orally once daily (QD). Participants will continue androgen deprivation therapy (ADT). Abiraterone will be administered with prednisone/prednisolone according to local prescribing information.
Drug: Tulmimetostat · Drug: Abiraterone · Drug: Prednisone/Prednisolone · Drug: Androgen Deprivation Therapy (ADT)
Tulmimetostat Dose 1 orally once daily (QD) in combination with darolutamide 600 mg orally twice daily (BID). Participants will continue androgen deprivation therapy (ADT).
Drug: Tulmimetostat · Drug: Darolutamide · Drug: Androgen Deprivation Therapy (ADT)
Tulmimetostat Dose 2 orally once daily (QD) in combination with darolutamide 600 mg orally twice daily (BID). Participants will continue androgen deprivation therapy (ADT). This arm will be included if two recommended dose(s) for expansion are selected from Phase I.
Drug: Tulmimetostat · Drug: Darolutamide · Drug: Androgen Deprivation Therapy (ADT)
Darolutamide 600 mg orally twice daily (BID). Participants will continue androgen deprivation therapy (ADT).
Drug: Darolutamide · Drug: Androgen Deprivation Therapy (ADT)
Tulmimetostat is an oral dual EZH1/EZH2 inhibitor administered once daily. In Phase I, escalating dose levels will be evaluated in combination with darolutamide or abiraterone. In Phase II, one or two dose levels selected from Phase I will be evaluated in combination with darolutamide.
Also known as: DZR123
Darolutamide 600 mg administered orally twice daily (BID).
Abiraterone 1000 mg administered orally once daily (QD) in combination with prednisone/prednisolone according to local prescribing information.
Oral corticosteroid administered with abiraterone in Phase I Group B according to local prescribing information.
Background therapy consisting of a gonadotropin-releasing hormone (GnRH) agonist/antagonist or prior orchiectomy to maintain castrate testosterone levels (\<50 ng/dL \[\<1.7 nmol/L\]). All participants will continue ADT throughout study participation.
Phase I (Group A and Group B): Dose-limiting toxicities (DLTs)
A dose-limiting toxicity was defined as an adverse event or abnormal laboratory value that was not clearly attributable to the underlying disease or an extraneous cause, occurred during the first 28 days of treatment with tulmimetostat, and met the protocol-defined dose-limiting toxicity criteria. Adverse events were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0. Dose-limiting toxicities were included in the Bayesian Logistic Regression Model used to support dose-escalation decisions.
Time frame: From the first dose of study treatment through the end of Cycle 1, up to 28 days
Phase I (Group A and Group B): Incidence rate of Adverse Events (AEs) and Serious Adverse Events (SAEs)
The incidence, type, frequency, seriousness, and severity of adverse events and serious adverse events will be summarized. Severity will be graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0.
Time frame: From the first dose of study treatment through the 30-day safety follow-up, assessed up to approximately 79 months
Phase I (Group A and Group B): Number of Participants with dose adjustments
The number of participants with dose reductions, dose interruptions, or permanent discontinuations, including the reasons for the dose adjustments, will be summarized by treatment group and dose cohort.
Time frame: From the first dose of study treatment through the 30-day safety follow-up, assessed up to approximately 79 months
Phase I (Group A and Group B): Dose Intensity
Dose intensity, calculated as the actual cumulative dose received divided by the actual duration of exposure, and relative dose intensity, calculated as the dose intensity divided by the planned dose intensity, will be summarized using descriptive statistics for each study drug.
Time frame: From the first dose of study treatment through the 30-day safety follow-up, assessed up to approximately 79 months
Phase I (Group A and Group B): Duration of exposure to each study drug
The duration of exposure, in months, to each study drug will be summarized using descriptive statistics by treatment group and dose cohort.
Time frame: From the first dose of study treatment through the 30-day safety follow-up, assessed up to approximately 79 months
Phase II (Group A): Prostate-Specific Antigen (PSA) response rate of < 0.2 ng/mL at Month 6
Prostate-Specific Antigen (PSA) response rate is defined as the proportion of participants who achieved a prostate-specific antigen level below 0.2 ng/mL at Month 6, confirmed by a second prostate-specific antigen assessment performed at least 3 weeks later.
Time frame: At Month 6, with confirmation by a second prostate-specific antigen assessment performed at least 3 weeks later
Phase I (Group A): Plasma concentrations of Tulmimetostat and Darolutamide
Plasma concentrations of tulmimetostat and darolutamide will be evaluated using pharmacokinetic samples collected from participants across the evaluated dose levels in Phase I, Group A.
Time frame: Cycles 1 and 2, Day 1: 0, 0.5, 1, 2, 3, 4, 6, and 8 hours post-dose; Cycle 1, Day 2: 0 and 24 hours post-dose for tulmimetostat; Cycle 1, Days 8 and 15: 0 and 2 hours post-dose; Cycles 3 to 5, Day 1: pre-dose. Each cycle is 28 days
Phase I (Group A): AUC of Tulmimetostat and Darolutamide
The area under the concentration-time curve from time zero to the last quantifiable concentration, the area under the concentration-time curve from time zero extrapolated to infinity, and the area under the concentration-time curve over a dosing interval at steady state will be derived, as applicable, and summarized using descriptive statistics.
Time frame: Cycles 1 and 2, Day 1: 0, 0.5, 1, 2, 3, 4, 6, and 8 hours post-dose; Cycle 1, Day 2: 0 and 24 hours post-dose for tulmimetostat; Cycle 1, Days 8 and 15: 0 and 2 hours post-dose; Cycles 3 to 5, Day 1: pre-dose. Each cycle is 28 days
Phase I (Group A): Maximum Observed Plasma Concentration (Cmax) of Tulmimetostat and Darolutamide
The maximum observed plasma concentration of tulmimetostat and darolutamide will be derived, as applicable, and summarized using descriptive statistics.
Time frame: Cycles 1 and 2, Day 1: 0, 0.5, 1, 2, 3, 4, 6, and 8 hours post-dose; Cycle 1, Day 2: 0 and 24 hours post-dose for tulmimetostat; Cycle 1, Days 8 and 15: 0 and 2 hours post-dose; Cycles 3 to 5, Day 1: pre-dose. Each cycle is 28 days
Phase I (Group B): Plasma concentrations of Tulmimetostat and Abiraterone
Plasma concentrations of tulmimetostat and abiraterone will be evaluated using pharmacokinetic samples collected from participants across the evaluated dose levels in Phase I, Group B.
Time frame: Cycles 1 and 2, Day 1: 0, 0.5, 1, 2, 3, 4, 6, and 8 hours post-dose; Day 2: 0 and 24 hours post-dose; Days 8 and 15: 0 and 2 hours post-dose; Cycles 3 to 5, Day 1: pre-dose. Each cycle is 28 days.
Phase I (Group B): AUC of Tulmimetostat and Abiraterone
The area under the concentration-time curve from time zero to the last quantifiable concentration, the area under the concentration-time curve from time zero extrapolated to infinity, and the area under the concentration-time curve over a dosing interval at steady state will be derived, as applicable, and summarized using descriptive statistics.
Time frame: Cycles 1 and 2, Day 1: 0, 0.5, 1, 2, 3, 4, 6, and 8 hours post-dose; Day 2: 0 and 24 hours post-dose; Days 8 and 15: 0 and 2 hours post-dose; Cycles 3 to 5, Day 1: pre-dose. Each cycle is 28 days.
Phase I (Group B): Maximum Observed Plasma Concentration (Cmax) of Tulmimetostat and Abiraterone
The maximum observed plasma concentration of tulmimetostat and abiraterone will be derived, as applicable, and summarized using descriptive statistics.
Time frame: Cycles 1 and 2, Day 1: 0, 0.5, 1, 2, 3, 4, 6, and 8 hours post-dose; Day 2: 0 and 24 hours post-dose; Days 8 and 15: 0 and 2 hours post-dose; Cycles 3 to 5, Day 1: pre-dose. Each cycle is 28 days.
Phase II (Group A): Radiographic progression free survival (rPFS)
Radiographic progression free survival (rPFS) is defined as the time from randomization to the first documented disease progression according to Prostate Cancer Working Group 3-modified Response Evaluation Criteria in Solid Tumors, version 1.1, as assessed by the investigator, or death from any cause, whichever occurred first.
Time frame: From randomization until the first documented radiographic disease progression or death from any cause, whichever occurs first, assessed up to approximately 79 months
Phase II (Group A):Overall survival (OS)
Overall survival (OS) is defined as the time from randomization to death from any cause.
Time frame: From randomization until death from any cause, assessed up to approximately 79 months
Phase II (Group A): Objective Response Rate (ORR)
Objective response (OR) is defined as the proportion of participants with a best overall response of confirmed complete response or partial response according to Prostate Cancer Working Group 3-modified Response Evaluation Criteria in Solid Tumors, version 1.1, as assessed by the investigator.
Time frame: From randomization until disease progression, death, or the last adequate tumor assessment, assessed up to approximately 79 months
Phase II (Group A): Best Overall Response (BOR)
Best Overall response (BOR) is defined as the best response recorded from the start of study treatment until disease progression or recurrence according to Prostate Cancer Working Group 3-modified Response Evaluation Criteria in Solid Tumors, version 1.1, as assessed by the investigator.
Time frame: From randomization until disease progression or death from any cause, whichever occurred first, assessed up to approximately 79 months
Phase II (Group A): Duration of Response (DOR)
Duration of response (DOR) is defined, for participants with a confirmed complete or partial response, as the time from the first documented response until the first documented disease progression according to Prostate Cancer Working Group 3-modified Response Evaluation Criteria in Solid Tumors, version 1.1, as assessed by the investigator, or death from any cause.
Time frame: From the first documented complete or partial response until disease progression or death from any cause, whichever occurred first, assessed up to approximately 79 months
Phase II (Group A): Prostate-Specific Antigen 50 (PSA50) response rate
Prostate-Specific Antigen 50 (PSA50) response is defined as a reduction of at least 50% from baseline in prostate-specific antigen at any post-baseline time point, confirmed by a second prostate-specific antigen assessment performed at least 3 weeks later.
Time frame: From randomization until the last prostate-specific antigen assessment, assessed up to approximately 79 months
Phase II (Group A): Prostate-Specific Antigen (PSA) Response below 0.1 ng/mL
Prostate-Specific Antigen (PSA) Response below 0.1 ng/mL is defined as achievement of a prostate-specific antigen level below 0.1 ng/mL at any post-baseline time point.
Time frame: From randomization until the last prostate-specific antigen assessment, assessed up to approximately 79 months
Phase II (Group A): Time to castration-resistant prostate cancer (CRPC)
Time to castration-resistant prostate cancer was defined as the time from randomization to the first occurrence of prostate-specific antigen progression, radiographic progression based on bone lesions, or radiographic progression based on soft-tissue or visceral lesions.
Time frame: From randomization until prostate-specific antigen progression, radiographic progression in bone, or radiographic progression in soft-tissue or visceral lesions, whichever occurred first, assessed up to approximately 79 months
Phase II (Group A): Incidence rate of Adverse Events (AEs) and Serious Adverse Events (SAEs)
The analysis of adverse events will include categorization by type, frequency, and severity, as graded by the NCI CTCAE version 5.0.The incidence, type, frequency, seriousness, and severity of adverse events and serious adverse events will be summarized by treatment arm. Severity will be graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0.
Time frame: From the first dose of study treatment through the 30-day safety follow-up, assessed up to approximately 79 months
Phase II (Group A): Number of Participants with dose adjustments
The number of participants with dose reductions, dose interruptions, or permanent discontinuations, including the reasons for the dose adjustments, will be summarized by treatment arm.
Time frame: From the first dose of study treatment through the 30-day safety follow-up, assessed up to approximately 79 months
Phase II (Group A): Dose Intensity
Dose intensity, calculated as the actual cumulative dose received divided by the actual duration of exposure, and relative dose intensity, calculated as dose intensity divided by planned dose intensity, will be summarized using descriptive statistics for each study drug and treatment arm.
Time frame: From the first dose of study treatment through the 30-day safety follow-up, assessed up to approximately 79 months
Phase II (Group A): Duration of exposure to each study drug
The duration of exposure, in months, to each study drug will be summarized using descriptive statistics by treatment arm.
Time frame: From the first dose of study treatment through the 30-day safety follow-up, assessed up to approximately 79 months
Phase II (Group A): Plasma concentrations of tulmimetostat and darolutamide in participants included in intensive pharmacokinetic sampling
Plasma concentrations of tulmimetostat and darolutamide will be evaluated in selected participants receiving tulmimetostat in combination with darolutamide.
Time frame: Cycles 1 and 2, Day 1: 0, 0.5, 1, 2, 3, 4, 6, and 8 hours post-dose; Cycle 1, Day 2: 0 and 24 hours post-dose for tulmimetostat; Cycle 1, Days 8 and 15: 0 and 2 hours post-dose; Cycles 3 to 5, Day 1: pre-dose. Each cycle is 28 days
Phase II (Group A): Plasma concentrations of Tulmimetostat
Plasma concentrations of tulmimetostat will be evaluated using pharmacokinetic samples collected from participants receiving tulmimetostat across the evaluated Phase II dose levels.
Time frame: Cycles 1 and 2, Day 1: 0 and 2 hours post-dose; Cycles 3 to 5, Day 1: pre-dose. Each cycle is 28 days
Phase II (Group A): Time to first symptomatic skeletal event (TTSSE)
Time to first symptomatic skeletal event (TTSSE) is defined as the time from the first dose of study treatment to the first occurrence of a new symptomatic pathological bone fracture, spinal cord compression, tumor-related orthopedic surgery, radiation therapy to relieve bone pain, or death from any cause, whichever occurred first, as assessed by the investigator.
Time frame: From the first dose of study treatment until the first symptomatic skeletal event, assessed up to approximately 79 months
Plan to share: Yes — Novartis is committed to sharing with qualified external researchers, access to patient-level data and supporting clinical documents from eligible studies. These requests are reviewed and approved by an independent review panel on the basis of scientific merit. All data provided is anonymized to respect the privacy of patients who have participated in the trial in line with applicable laws and regulations. This trial data availability is according to the criteria and process described on www.clinicalstudydatarequest.com
No publications or documents are linked to this record.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Bulbo-Spinal Atrophy, X-Linked→
Novartis Pharmaceuticals