Targeting gut bacteria to improve prostate cancer treatment

Phase II Trial Targeting Gut Bacterial Androgen Production to Reverse Therapeutic Resistance to Abiraterone in Patients With Metastatic Prostate Cancer

Phase 2 Interventional Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins · NCT06616597

This study is testing if adding a gut bacteria-targeting medication to standard prostate cancer treatment can help men with advanced prostate cancer respond better to their therapy.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment58 (estimated)
Ages18 Years and up
SexMale
SponsorSidney Kimmel Comprehensive Cancer Center at Johns Hopkins Academic / other
Drugs / interventionsprednisone
Locations1 site (Baltimore, Maryland)
Trial IDNCT06616597 on ClinicalTrials.gov

What this trial studies

This study aims to evaluate whether the combination of dexamethasone with or without metronidazole can restore sensitivity to abiraterone in patients with metastatic castration-resistant prostate cancer (mCRPC). The research focuses on the gut microbiome's role in producing androgens that may contribute to resistance against abiraterone therapy. Participants will receive these medications while undergoing monitoring for prostate-specific antigen (PSA) levels and other health indicators. The study seeks to understand the relationship between gut bacteria and treatment resistance in prostate cancer.

Who should consider this trial

Good fit: Ideal candidates are males aged 18 and older with metastatic prostate adenocarcinoma who have shown progression after prior abiraterone treatment.

Not a fit: Patients with active infections, certain chronic medical conditions, or those with small cell carcinoma of the prostate may not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could enhance treatment efficacy for patients with metastatic prostate cancer who have developed resistance to standard therapies.

How similar studies have performed: While the specific approach of targeting gut microbiome-related androgen production is novel, there is emerging evidence suggesting microbiome manipulation may influence cancer treatment outcomes.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Males aged 18 years of age and above.
* Prostate adenocarcinoma
* Absolute PSA ≥ 2.0 ng/mL at screening.
* PSA (+/- radiographic) progression after having been on abiraterone and prednisone for at least 12 weeks.
* Must be maintained on a GnRH analogue or have undergone orchiectomy.
* Participants must have a life expectancy ≥ 6 months
* Ability to swallow study medication tablets
* Willing to abstain from alcohol during and for 14 days after treatment with metronidazole
* Willing and able to collect urine and stool samples per protocol

Exclusion Criteria:

* Active infection or other medical condition that would make dexamethasone use contraindicated
* Any chronic medical condition requiring a higher systemic dose of corticosteroid
* Pathological finding consistent with small cell carcinoma of the prostate
* Has imminent or established spinal cord compression based on clinical findings and/or MRI.
* Chronic liver disease with Child-Pugh class C cirrhosis (see calculator in protocol)
* Bilirubin \>3x ULN or AST and ALT \>5x ULN
* Congenital prolonged QTc syndrome or QTc \> 500 msec (non-paced rhythm)
* History of pituitary or adrenal dysfunction
* Uncontrolled diabetes (Hemoglobin A1c \> 10%) or increasing doses of insulin within the past 4 weeks due to poorly controlled glucoses.
* Administration of an investigational therapeutic or invasive surgical procedure (not including surgical castration) within 30 days of Cycle 1 Day 1 or currently enrolled in an investigational drug study
* Any other serious illness or medical condition that would, in the opinion of the investigator, make this protocol unreasonably hazardous, including, but not limited to:

  * Any uncontrolled major infection.
  * Crohn's disease or ulcerative colitis.
  * Known or suspected toxic megacolon and/or known small bowel ileus.
  * Known allergy to any of the compounds under investigation.
* On antibacterial therapy within 30 days prior to administration of study treatment.
* Any condition or situation which, in the opinion of the investigator, would put the subject at risk, or interfere with the subject's participation in this study.

Where this trial is running

Baltimore, Maryland

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Prostate CancerMetastatic Prostate CancerAbirateronemicrobiomeDexamethasone
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.