Trimethoprim for Prostate Cancer

Not yet recruiting at 2 trial locations

Overseen By Brandi Weaver, BS

Age: 18+

Sex: Male

Trial Phase: Phase 2

Sponsor: The University of Texas Health Science Center at San Antonio

Must not be taking: Methotrexate, Memantine, Phenytoin

Disqualifiers: Chemotherapy, Hematological disorders, Renal disease, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Prior Safety Data This treatment has passed at least one previous human trial

Compensation: Varies

Number of Visits: 5

Duration: 3 months

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores whether Trimethoprim, a drug typically used for other conditions, can safely and effectively reduce folate levels when taken with Androgen Deprivation Therapy (ADT) in men with advanced prostate cancer. Researchers aim to determine if this approach can improve disease management. Participants will either take Trimethoprim alongside their regular prostate cancer treatment or continue with their standard treatment. Men diagnosed with prostate cancer who are about to start ADT might be suitable candidates for this trial. As a Phase 2 trial, this research focuses on assessing the treatment's effectiveness in an initial, smaller group of participants.

Will I have to stop taking my current medications?

You may need to stop taking certain medications, especially those containing folic acid or potassium, and any that might interact with trimethoprim. It's important to discuss your current medications with the trial team to see if any changes are needed.

Is there any evidence suggesting that Trimethoprim is likely to be safe for humans?

Research has shown that Trimethoprim, a medicine commonly used to treat infections, has been studied for its safety in people. Observed side effects include skin rash and increased sensitivity to sunlight. It can also cause folate deficiency, potentially lowering levels of an important vitamin in the body.

In this trial, researchers are testing the medicine at a dose of 150 mg daily for three months in men with advanced prostate cancer. They are focusing on safety and are closely monitoring for any side effects.

Doctors have a good understanding of Trimethoprim's safety due to its use in other health conditions. However, since this is a new application, not all side effects may be known yet. Researchers aim to assess how well patients tolerate this treatment and to learn more about its safety. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising?

Trimethoprim is unique because it targets the folate receptors, which are different from the usual androgen receptors targeted by current prostate cancer treatments. Most standard treatments for prostate cancer, like androgen deprivation therapy and androgen receptor pathway inhibitors, focus on reducing or blocking male hormones that fuel cancer growth. However, Trimethoprim works by blocking folate receptors, potentially cutting off a different pathway that the cancer cells need to grow. Researchers are excited because this approach may offer a new way to tackle prostate cancer, especially for patients who don't respond well to existing hormone-based therapies.

What evidence suggests that Trimethoprim might be an effective treatment for prostate cancer?

Research has shown that trimethoprim might help lower folate levels in men with advanced prostate cancer. In this trial, one group of participants will receive a folate receptor blocker alongside standard androgen deprivation therapy, which includes trimethoprim. Trimethoprim blocks folic acid, potentially enhancing the effects of hormone therapy for prostate cancer. While primarily known for reducing folate, trimethoprim also treats infections. Early studies suggest it could be a valuable addition to standard cancer treatments due to its impact on folate levels during hormone therapy. More research is needed to confirm these benefits, but the potential remains promising. ^{4 5 6 7 8}

Who Is on the Research Team?

Michael A. Liss

Principal Investigator

University of California, San Diego

Are You a Good Fit for This Trial?

This trial is for men with advanced prostate cancer who are about to start Androgen Deprivation Therapy (ADT). Participants should be willing to take Trimethoprim daily for 3 months. Specific eligibility criteria were not provided, so interested individuals should contact the study organizers for more details.

Inclusion Criteria

Normal Complete blood count (CBC), RBC folate >750nmol/L, homocysteine <15mcmol/L, and normal creatine clearance (obtained within 30 days prior to registration)

Able to stop current supplements that include folic acid

Ability to understand and willingness to provide written informed consent

Exclusion Criteria

Receiving any other investigational agents while on this study

I am under 18 years old.

I am starting chemotherapy for my metastatic prostate cancer.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive Trimethoprim, 150mg daily for 3 months, alongside standard of care androgen deprivation therapy

3 months

5-7 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment, including assessments of serum folate levels, RBC folate, PSA levels, and microbiome analysis

6 months

Long-term Follow-up

Participants' testosterone levels are monitored to determine progression-free survival

24 months

What Are the Treatments Tested in This Trial?

Interventions

• Trimethoprim

Trial Overview The study is testing if taking Trimethoprim tablets at a dose of 150mg every day can safely and effectively reduce folate levels in men undergoing ADT for advanced prostate cancer. The treatment duration is set for three months.

How Is the Trial Designed?

Group I: Trimethoprim plus androgen deprivation therapy Experimental Treatment 1 Intervention

Administration of trimethoprim to reduce folic acid levels at the time of standard of care androgen deprivation therapy.

Group II: Standard of Care treatment Active Control 1 Intervention

Standard of care treatment participants will have no intervention, only their prescribed androgen deprivation therapy.

Who Is Running the Clinical Trial?

The University of Texas Health Science Center at San Antonio

Lead Sponsor

Trials

486

Recruited

92,500+

University of California, San Diego

Lead Sponsor

Trials

1,215

Recruited

1,593,000+

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC4548650/

Comparison between ciprofloxacin and trimethoprim- ... Both three-day ciprofloxacin and TMP-SMX regimens seem to be equally effective in the antibiotic prophylaxis for transrectal prostate biopsy.

2. clinicaltrials.gov clinicaltrials.gov/study/NCT06536374

Folate Study in Men With Advanced Prostate Cancer The researchers hope to learn if Trimethoprim, 150mg taken daily for 3 months, is a safe and effective way to reduce folate levels at time of Androgen ...

3. withpower.com withpower.com/trial/phase-2-prostate-cancer-8-2024-13edb

Trimethoprim for Prostate Cancer · Info for Participants Trial Overview The study is testing if taking Trimethoprim tablets at a dose of 150mg every day can safely and effectively reduce folate levels in men ...

4. afju.springeropen.com afju.springeropen.com/articles/10.1186/s12301-025-00529-3

Fosfomycin, trimethoprim/sulfamethoxazole, or ciprofloxacin ... 5 Conclusion. Fosfomycin, ciprofloxacin, and trimethoprim/sulfamethoxazole effectively prevent post-transrectal prostate biopsy infections.

5. suo-abstracts.secure-platform.com suo-abstracts.secure-platform.com/a/gallery/rounds/21/details/3944

A Phase II, Open Label, Randomized Controlled Pilot ... Hypothesis: We hypothesize that the use of trimethoprim 150 mg OD for 3 months will act as a folic acid inhibitor at the time of androgen deprivation, where ...

6. ncbi.nlm.nih.gov ncbi.nlm.nih.gov/books/NBK513232/

Trimethoprim Sulfamethoxazole - StatPearls - NCBI Bookshelf The primary adverse effects of trimethoprim/sulfamethoxazole include rash, photosensitivity, as well as folate deficiency.[10][11] A list of the more common ...

7. mayoclinic.org mayoclinic.org/drugs-supplements/sulfamethoxazole-and-trimethoprim-oral-route/description/drg-20071899

Sulfamethoxazole and trimethoprim (oral route) Sulfamethoxazole and trimethoprim combination is used to treat infections including urinary tract infections, middle ear infections (otitis media), bronchitis, ...

8. go.drugbank.com go.drugbank.com/drugs/DB00440

Trimethoprim: Uses, Interactions, Mechanism of Action Trimethoprim is indicated for the treatment of acute episodes of uncomplicated urinary tract infections caused by susceptible bacteria.