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A Study of Extending Relugolix Dosing Intervals Through Addition of Itraconazole or Ritonavir in Prostate Cancer Patients

A Phase Ib Study of Extending Relugolix Dosing Intervals Through Addition of the CYP3A4 and Pg-P Inhibitor Itraconazole or Ritonavir in Prostate Cancer Patients

Status
Terminated
Phases
Phase 1
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT05679388
Enrollment
60
Registered
2023-01-11
Start date
2023-02-13
Completion date
2024-08-05
Last updated
2024-09-19

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Prostate Adenocarcinoma, Prostate Cancer, Prostate Cancer Metastatic

Keywords

prostate cancer

Brief summary

Researchers leading this study hope to learn about the safety of combining the study drug relugolix with another study drug called itraconazole or ritonavir in prostate cancer. This study is for individuals who have advanced prostate cancer and plans to have medical castration (the use of medications or chemicals to lower hormone production in the testicles). Your participation in this research will last up to 1 month. The purpose of this research is to gather information on the safety and effectiveness of relugolix in combination with ritonavir or itraconazole. The goal of this research is to find out if combining two medications (relugolix and itraconazole or relugolix and ritonavir) could possibly lead to using less relugolix, which is an expensive drug.

Interventions

DRUGRelugolix Pill

A medication used to treat prostate cancer. Relugolix comes as a tablet to take by mouth. It is usually taken with or without food once daily.

DRUGRitonavir

HIV antiviral It can treat HIV infection, which causes AIDS. It does not cure HIV or AIDS, but combinations of drugs may slow the progress of the disease and prolong life.

DRUGItraconazole

A drug used to treat fungal infections.

Sponsors

University of Chicago
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Subject)

Eligibility

Sex/Gender
MALE
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* Must have histologically or cytologically confirmed prostate cancer with plans to start medical castration therapy. * Age 18 or older. Because no dosing or adverse event data are currently available on the use of relugolix in combination with itraconazole or ritonavir in patients \<18 years of age, children are excluded from this study. * Eastern Cooperative Oncology Group performance status ≤2 (Karnofsky ≥60%) * Participants must satisfy the following laboratory criteria: * Testosterone \> 200 ng/dl * QTc within normal limits * Aspartate Transferase (AST)/alanine transaminase (ALT) \< 3x upper limit of normal * Ability to take oral medication and be willing to adhere to the medication regimen. * Ability to understand and the willingness to sign a written informed consent document.

Exclusion criteria

* Need for combination systemic therapy for prostate cancer including docetaxel and/or second-generation androgen receptor pathway targeted agents (i.e. abiraterone, enzalutamide, apalutamide, darolutamide, etc). * Concurrent therapy with strong interacting drugs with CYP3A4 and P-gp (See Appendix list of strong inhibitors or inducers) due to concerning possible drug-drug interactions with itraconazole, ritonavir and relugolix. Potential drug-drug interactions will also be reviewed by study investigators prior to enrollment. * History of allergic reactions attributed to compounds of similar chemical or biologic composition to relugolix, itraconazole or ritonavir. * Patients receiving treatment with another investigational drug or other intervention within 3 expected half-lives of the agent. * Serious or uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, unstable angina pectoris, or psychiatric illness/social situations that would limit compliance with study requirements. * New York Heart Association Class III of IV congestive heart failure * Known gastrointestinal malabsorption. * Active psychiatric illness/social situations that would limit compliance with protocol requirements.

Design outcomes

Primary

MeasureTime frameDescription
Testosterone Suppression of Participants as Assessed by Testosterone Levels1 month post start of treatmentTo determine whether the addition of itraconazole and ritonavir to relugolix sustains testosterone suppression as assessed by participant testosterone levels.

Secondary

MeasureTime frameDescription
Decrease in Relugolix Levels1 month post start of treatmentTo evaluate whether itraconazole or ritonavir significantly decreases relugolix clearance in participants with prostate cancer as assessed by relugolix serum levels on days 8 and 15.
Reduction in Prostate-Specific Antigens Levels of Participants After Study Treatment1 month post start of treatmentTo evaluate the efficacy of itraconazole or ritonavir combined with relugolix in patients with prostate cancer as assessed by a reduction in Prostate-Specific Antigen (PSA) levels of patients after study treatment.
Rate of Reported Adverse Events Among Participants1 month post start of treatmentTo evaluate the safety of itraconazole or ritonavir combined with longer interval relugolix dosing regimens in patients with prostate cancer as assessed by the rate of reported adverse events according to Common Terminology Criteria for Adverse Events (CTCAE) V5.

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026