A Study of HLD-0915 in Patients With Metastatic Castration Resistant Prostate Cancer (mCRPC)

Phase 1/2 Study of HLD-0915 in Patients With Metastatic Castration Resistant Prostate Cancer (mCRPC)

Assessment of the safety and efficacy of HLD-0915 as monotherapy in patients with metastatic castration resistant prostate cancer (mCRPC) that have progressed on prior systemic therapies, once a recommended dose for expansion (RDE) has been determined in Phase 1 of the trial.

Study Overview

• Status: Recruiting
• Conditions: Prostate Cancer Metastatic Disease; Prostate Cancer (Adenocarcinoma)
• Intervention / Treatment: Drug: HLD-0915

Detailed Description

This is a Phase 1/2, open-label study of the safety, tolerability, pharmacokinetics (PK), pharmacodynamics, and anti-tumor activity of oral single-agent HLD-0915. Patients on the study must continue androgen deprivation therapy (ADT) unless surgically castrated,

The study will include an initial Phase 1 portion to determine the maximum tolerated dose (MTD) and/or recommended dose(s) for expansion (RDEs) of HLD-0915 as monotherapy and Phase 2 expansion cohorts to further evaluate the efficacy and safety of HLD-0915.

Phase 1 of this study is an open-label, dose-escalation and cohort expansion study in patients with mCRPC that have progressed after prior systemic therapies. Patients will be enrolled in monotherapy dose-escalation cohorts using a Bayesian optimal interval with backfill (BF-BOIN) design. Patients are treated in cohort size of 3 with the enrollment staggered between cohorts.

Phase 2 of this study will evaluate the anti-tumor activity of HLD-0915 administered at the RDEs in patients with mCRPC. Phase 2 study design and patient population will be based on the outcomes of Phase 1 of the trial.

• Study Type: Interventional
• Enrollment (Estimated): 33
• Phase: Phase 2; Phase 1

Contacts and Locations

• Study Contact: Name: Medical Monitor; Phone Number: 475-273-6214; Email: ProstateClinicalTrial@haldathera.com

Study Locations

• United Kingdom
  • Surrey
    • Sutton, Surrey, United Kingdom, SM2 5PT
      • Recruiting
      • Royal Marsden Hospital
• United States
  • Colorado
    • Denver, Colorado, United States, 80218
      • Recruiting
      • Sarah Cannon Research Institute at HealthONE
  • Connecticut
    • New Haven, Connecticut, United States, 06520
      • Recruiting
      • Yale - New Haven Hospital - Yale Cancer Center
  • Florida
    • Sarasota, Florida, United States, 34232
      • Recruiting
      • Florida Cancer Specialists
  • Massachusetts
    • Boston, Massachusetts, United States, 02114
      • Recruiting
      • Massachusetts General Hospital
  • Michigan
    • Grand Rapids, Michigan, United States, 49546
      • Recruiting
      • START Midwest, LLC
  • New York
    • New York, New York, United States, 10065
      • Recruiting
      • Evelyn H. Lauder Breast and Imaging Center (BAIC)
  • South Carolina
    • Myrtle Beach, South Carolina, United States, 29572
      • Recruiting
      • Carolina Urologic Research Center, LLC
  • Tennessee
    • Nashville, Tennessee, United States, 37203
      • Recruiting
      • SCRI Oncology Partners
  • Texas
    • Austin, Texas, United States, 78758
      • Recruiting
      • NEXT Austin
    • Houston, Texas, United States, 77030
      • Recruiting
      • The University of Texas M.D. Anderson Cancer Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Key Inclusion Criteria:

All patients must meet the following criteria to be eligible for Phase 1 study participation:

1. Males of age 18 years at the time of signing the informed consent form (ICF).
2. Able to understand and voluntarily sign an informed consent document prior to any study-related assessments/procedures.
3. Patients must have histological, pathological, and/or cytological confirmation of adenocarcinoma of the prostate.
4. Patients must have prior orchiectomy and/or ongoing androgen-deprivation therapy and a castrate level of serum testosterone.
5. Patients must have progressed on prior line(s) of therapy.
6. Patients must have progressive mCRPC defined as having demonstrated PSA progression on the prior regimen. PSA progression may have occurred with or without accompanying radiographic progression.
7. Eastern Cooperative Oncology Group (ECOG) performance status 0-1.
8. Life expectancy of at least 3 months.
9. Adequate hematological, renal, and hepatic function.
10. Able to swallow an oral medication.
11. Willing and able to adhere to the study visit schedule and other protocol requirements.
12. Patients on a stable bisphosphonate or denosumab regimen for 30 days prior to enrollment are eligible.

Key Exclusion Criteria:

Patients with any of the following will be excluded from participation in Phase 1 of the study:

1. Has experienced a recent major bleed or has a known bleeding disorder.
2. Tumors exhibiting neuroendocrine or small cell carcinoma component by histopathology.
3. Receiving continuous corticosteroids at prednisone-equivalent dose of >10 mg/day.
4. Has received systemic anti-cancer therapy (cytotoxic chemotherapy, biologic agent, checkpoint inhibitors, or radiation therapy) or investigational drugs within 2 weeks prior to first dose of study drug with certain exceptions requiring longer washout periods.
5. History of myocardial infarction or unstable angina within 6 months prior to enrollment, or clinically significant cardiac disease.
6. Known clinically significant active or chronic infection.
7. Acute or chronic uncontrolled renal disease, pancreatitis, or liver disease.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Sequential Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: HLD-0915; Oral HLD-0915 administered as a single agent on a 21-day treatment cycle.	Drug: HLD-0915; A treatment cycle consists of 21 days. Treatment may continue until disease progression or study discontinuation (withdrawal of consent, intercurrent illness, unacceptable adverse event or any other changes unacceptable for further treatment, etc.)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Phase 1: Frequency of dose-limiting toxicities (DLTs)	21 days
Phase 1: Frequency and severity of AEs and serious adverse events (SAEs), including abnormal clinical observations, abnormal ECG parameters, abnormal laboratory assessments and abnormal vital signs changed from baseline	21 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Phase 1: Plasma concentrations of HLD-0915 as a function of time post-dosing		21 days
Phase 1: Plasma PK Parameters (Cmax)	Maximal plasma concentration of HLD-0915	21 days
Phase 1: Plasma PK Parameters (Tmax)	Time to maximal plasma concentration of HLD-0915	21 days
Phase 1: Plasma PK Parameters (T1/2)	Plasma half-life of HLD-0915	21 days
Phase 1: Plasma PK Parameters (AUC0-inf)	Plasma area under the curve of HLD-0915	21 days
Phase 1: The proportion of pts with a confirmed prostate-specific antigen (PSA) decline ≥30%, ≥50%, and ≥90%		21 days
Phase 1: Objective response rate (ORR) per RECIST in evaluable patients		21 days
Phase 1: Duration of response (DOR)		21 days
Phase 1: Radiographic progression-free survival (rPFS)		21 days
Phase 1: Time to response (TTR)		21 days
Phase 1: Change in PSA over time		21 days

Collaborators and Investigators

• Sponsor: Halda Therapeutics OpCo, Inc.

Study record dates

Study Major Dates

• Study Start (Actual): February 24, 2025
• Primary Completion (Estimated): March 1, 2027
• Study Completion (Estimated): March 1, 2027

Study Registration Dates

• First Submitted: January 20, 2025
• First Submitted That Met QC Criteria: January 27, 2025
• First Posted (Actual): January 30, 2025

Study Record Updates

• Last Update Posted (Estimated): October 16, 2025
• Last Update Submitted That Met QC Criteria: October 14, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Keywords: prostate cancer; RIPTAC; HLD-0915
• Additional Relevant MeSH Terms: Urogenital Diseases; Genital Diseases; Genital Neoplasms, Male; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Genital Diseases, Male; Prostatic Diseases; Male Urogenital Diseases; Neoplasms by Histologic Type; Neoplasms, Glandular and Epithelial; Carcinoma; Prostatic Neoplasms; Adenocarcinoma
• Other Study ID Numbers: HLD-0915-ONC-101

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No