Metronidazole for Rectal Cancer

Overseen By Michael G White, MD

Age: 18+

Sex: Any

Trial Phase: Phase 2

Sponsor: M.D. Anderson Cancer Center

Must not be taking: Disulfiram

Disqualifiers: Chemotherapy, Radiotherapy, Brain metastases, others

Stay on Your Current Meds You can continue your current medications while participating

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

Approved in 4 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: Unknown

Duration: 2 weeks

60 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests whether adding metronidazole, an antibiotic, to standard treatment can reduce certain bacteria that cause infections in people with rectal cancer. Researchers aim to determine if this approach is more effective than the standard treatment alone. Participants are randomly assigned to receive either the standard therapy alone or with metronidazole. Those with locally advanced rectal cancer who have not undergone chemotherapy for their current tumor might be suitable for this trial. As a Phase 2 trial, the research focuses on measuring the treatment's effectiveness in an initial, smaller group, offering participants a chance to contribute to important advancements in cancer care.

Do I need to stop taking my current medications for the trial?

The trial information does not specify if you need to stop taking your current medications. However, if you are on disulfiram or have had recent chemotherapy or radiotherapy, you may not be eligible to participate.

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

Research shows that metronidazole is a widely used antibiotic for various infections, providing some understanding of its safety. However, some studies have raised concerns about its long-term effects. For example, metronidazole was linked to a higher risk of certain cancers in animal studies, and reports exist of cancer in patients with Crohn's disease who took high doses of this drug. Still, these findings are not definitive for humans in general.

Regarding side effects, metronidazole often causes mild issues like nausea and headaches, which are usually manageable. The current phase of the trial indicates that researchers have gathered enough early data to confidently test it further. This suggests that while risks may exist, participants have generally tolerated the treatment well so far. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising?

Most treatments for rectal cancer involve chemotherapy, radiation, and surgery. However, metronidazole, typically an antibiotic, is being explored for its potential to enhance these standard therapies. Researchers are excited because metronidazole may improve treatment outcomes by altering the tumor's environment, potentially making cancer cells more vulnerable to therapy. This could lead to more effective treatments with fewer side effects, offering a new approach to tackling rectal cancer.

What evidence suggests that metronidazole might be an effective treatment for rectal cancer?

This trial will compare standard therapy alone with standard therapy plus metronidazole for rectal cancer. Studies have shown that metronidazole can reduce harmful bacteria, like Fusobacterium nucleatum, in tumors. These bacteria often link to colorectal cancer. Metronidazole appears to stress cancer cells, potentially damaging their DNA and inhibiting cancer growth. Some research suggests that combining metronidazole with other treatments can significantly reduce tumor size. Overall, metronidazole shows promise in combating cancer growth related to bacteria. ^{1 3 6 7 8}

Who Is on the Research Team?

Michael White, MD

Principal Investigator

M.D. Anderson Cancer Center

Are You a Good Fit for This Trial?

This trial is for individuals with rectal adenocarcinoma who are about to receive neoadjuvant therapy. Participants should not have taken antibiotics recently and must be able to undergo standard cancer treatments.

Inclusion Criteria

I haven't had chemotherapy for my current cancer.

I have another cancer, but it won't affect this trial's treatment.

My hepatitis B virus load is undetectable with treatment.

Exclusion Criteria

I have Cockayne syndrome.

I do not have any uncontrolled illnesses.

Participants who are receiving any other investigational agents

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive standard neoadjuvant therapy with or without metronidazole for 2 weeks

2 weeks

Regular visits as per standard care

Follow-up

Participants are monitored for safety and effectiveness after treatment

1 year

Periodic visits for safety and tumor response assessment

Long-term follow-up

Overall survival and recurrence-free survival assessed over two years following study completion

2 years

What Are the Treatments Tested in This Trial?

Interventions

• Metronidazole

Trial Overview The study tests if metronidazole, an antibiotic, can reduce harmful bacteria in the gut when added to usual pre-surgery cancer treatment compared to the standard treatment alone.

How Is the Trial Designed?

Group I: Standard of Care Neoadjuvant Therapy + Metronidazole Experimental Treatment 1 Intervention

Participants found to be eligible to take part in this study, will be randomly assigned (as in the flip of a coin) to receive standard therapy alone or standard therapy plus metronidazole. Participants are assigned to the metronidazole group, will also take 1 tablet of metronidazole by mouth every 8 hours for 2 weeks.

Group II: Standard of Care Neoadjuvant Therapy Active Control 1 Intervention

Participants found to be eligible to take part in this study, will be randomly assigned (as in the flip of a coin) to receive standard therapy alone or standard therapy plus metronidazole. Participants in both study groups will receive their standard of care treatment, as assigned by their treating doctor outside of the research study.

Metronidazole is already approved in United States, European Union, India, Canada for the following indications:

Approved in United States as Flagyl for:

• Pelvic inflammatory disease
• Endocarditis
• Bacterial vaginosis
• Dracunculiasis
• Giardiasis
• Trichomoniasis
• Amebiasis
• Clostridioides difficile colitis

Approved in European Union as Flagyl for:

• Pelvic inflammatory disease
• Endocarditis
• Bacterial vaginosis
• Dracunculiasis
• Giardiasis
• Trichomoniasis
• Amebiasis
• Clostridioides difficile colitis

Approved in India as Metrogyl for:

• Pelvic inflammatory disease
• Endocarditis
• Bacterial vaginosis
• Dracunculiasis
• Giardiasis
• Trichomoniasis
• Amebiasis
• Clostridioides difficile colitis

Approved in Canada as Flagyl for:

• Pelvic inflammatory disease
• Endocarditis
• Bacterial vaginosis
• Dracunculiasis
• Giardiasis
• Trichomoniasis
• Amebiasis
• Clostridioides difficile colitis

Who Is Running the Clinical Trial?

M.D. Anderson Cancer Center

Lead Sponsor

Trials

3,107

Recruited

1,813,000+

Published Research Related to This Trial

Neoadjuvant chemoradiation significantly improves surgical and long-term outcomes for patients with locally advanced rectal cancer, with 5-fluorouracil (or capecitabine) being the most effective and tolerable radiosensitizing chemotherapy option.

There is a pressing need for new radiosensitizing agents and predictive biomarkers, as current options like oxaliplatin and irinotecan show increased toxicity without substantial benefits, and further research is needed on topoisomerase I and EGFR as potential predictors of treatment response.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Current status of radiosensitizing agents for the management of rectal cancer. Illum, H.[2019]

Raltitrexed is a selective thymidylate synthase inhibitor that offers a more convenient 3-weekly administration schedule compared to the prolonged infusion of 5-fluorouracil, which can cause discomfort for patients.

Raltitrexed may be particularly beneficial for colorectal cancer patients who have experienced cardiotoxicity from fluoropyrimidines or have a significant history of cardiac disease, suggesting it could be a safer alternative in these cases.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Targeting thymidylate synthase in colorectal cancer: critical re-evaluation and emerging therapeutic role of raltitrexed. Avallone, A., Di Gennaro, E., Silvestro, L., et al.[2014]

In a study of 3096 patients with locally advanced rectal cancer, elderly patients (over 75 years) had a significantly lower 3-year overall survival rate (77.2%) compared to younger patients (88.9%), indicating age is a critical factor in treatment outcomes.

Despite the age difference, elderly patients in good health can achieve similar cancer-specific survival and disease-free survival rates as younger patients when treated with neoadjuvant chemotherapy combined with chemoradiotherapy and total mesorectal excision.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Oncologic and survival outcomes in elderly patients with locally advanced rectal cancer receiving neoadjuvant chemoradiotherapy and total mesorectal excision. He, F., Chen, M., Xiao, WW., et al.[2021]

Metronidazole is an effective treatment for various infections, including Trichomonas, amebiasis, and anaerobic infections, and is well tolerated with minimal impact on colonic flora.

While there are some concerns about potential mutagenicity and carcinogenicity in animals, the overall risk is considered low, and no increased cancer incidence has been observed in treated patients, highlighting the importance of weighing benefits against risks in treatment decisions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Metronidazole. Finegold, SM.[2019]

While metronidazole is generally considered safe for short-term use in treating conditions like trichomoniasis, concerns about its long-term safety have arisen due to three cases of young individuals developing malignancies after receiving high doses for Crohn's disease.

The authors emphasize the need for further prospective and long-term studies to investigate the potential risks of malignancy associated with prolonged metronidazole treatment, especially at higher dosages.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Occurrence of three cases of carcinoma in individuals with Crohn's disease treated with metronidazole. Krause, JR., Ayuyang, HQ., Ellis, LD.[2013]

Nitroimidazoles, including metronidazole, tinidazole, and ornidazole, are generally well-tolerated with low toxicity, and any adverse effects are usually transient and resolve after stopping treatment.

Long-term studies, including a follow-up of 771 women treated with metronidazole, indicate no significant cancer risk associated with these medications, suggesting they are safe for both short-term and long-term use in treating anaerobic infections.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety of nitroimidazoles. Roe, FJ.[2013]

In a study of 106 patients with locally advanced rectal cancer, neoadjuvant modified FOLFOXIRI chemotherapy combined with selective radiotherapy resulted in a 3-year disease-free survival rate of 78.9%, which is significantly better than historical controls receiving chemoradiotherapy.

Patients treated with mFOLFOXIRI experienced a lower incidence of anastomotic fistula (5.5%) compared to those receiving chemoradiotherapy (17.8%), indicating a potential safety advantage of this treatment approach.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Neoadjuvant Modified FOLFOXIRI With Selective Radiotherapy in Locally Advanced Rectal Cancer: Long-term Outcomes of Phase II Study and Propensity-Score-Matched Comparison With Chemoradiotherapy. Zhang, J., Li, J., Huang, M., et al.[2023]

Adjuvant radiochemotherapy significantly improves overall survival and reduces local failure rates in patients with stage II and III rectal cancer compared to surgery alone, making it the standard treatment for these patients.

Continuous infusion of 5-fluorouracil in adjuvant therapy leads to better long-term survival than bolus application, but adding leucovorin or levamisole increases toxicity without improving outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Principles of postoperative therapy in rectal carcinoma]. Folprecht, G., Köhne, CH.[2018]

A total of 2,309 cases of neurological adverse events associated with metronidazole were reported from 2011 to 2020, indicating a rising trend in these incidents.

Risk factors for developing metronidazole-associated neurological issues include liver cirrhosis, chronic kidney disease, intravenous administration of the drug, and lower body weight, suggesting that patients with these conditions should be monitored closely during treatment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Frequency and Risk Factor Analysis for Metronidazole-Associated Neurologic Adverse Events. Lee, SJ., Kim, J., Lee, KH., et al.[2023]

In a study of 41 patients with lower rectal cancer, four courses of mFOLFOX6 chemotherapy before surgery resulted in a 3-year recurrence-free survival rate of 72.8% and a local recurrence rate of 8.5%, indicating a promising long-term oncological benefit.

Patients with clinical Stage III cancer who received adjuvant chemotherapy after the initial mFOLFOX6 treatment had a significantly higher 3-year recurrence-free survival rate (76.6%) compared to those who did not receive adjuvant therapy (40.0%), suggesting the importance of additional treatment for this group.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The survival impact of preoperative FOLFOX for resectable locally advanced rectal cancer: the R-NAC-01 study. Ichikawa, N., Homma, S., Funakoshi, T., et al.[2022]

Flagyl (metronidazole) is an effective anti-infective medication primarily used to treat infections caused by anaerobic bacteria and protozoa, particularly in gastrointestinal conditions like giardiasis.

It is also commonly used as a preoperative treatment to reduce the risk of bacterial contamination in patients undergoing colorectal surgery or emergency abdominal procedures, highlighting its importance in surgical settings.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Flagyl (metronidazole hydrochloride). Claussen, DW.[2019]

In a study of 490 patients with stage IV A rectal carcinoma, a combined treatment approach involving preoperative large-fraction radiotherapy and local SHF-hyperthermia was recommended, followed by surgery 24-48 hours later, to effectively manage locally spread tumors.

For tumors that are difficult to resect, a two-stage treatment plan is suggested, starting with a relieving colostoma and administering distance gammatherapy alongside metronidazole and local SHF-therapy, with the addition of intraarterial chemotherapy using 5-fluorouracil to enhance treatment efficacy.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Definition, classification and combined treatment of locally invasive rectal neoplasms]. Knysh, VI., Kim, FP., Goldobenko, GV., et al.[2013]

In a study of 64 patients with locally advanced fixed T4 rectal cancer, neoadjuvant chemoradiotherapy combined with local hyperthermia achieved a high R0 resection rate of 92.2%, indicating effective tumor removal.

The treatment resulted in a 2-year overall survival rate of 91% and a disease-free survival rate of 83%, with manageable toxicity levels similar to standard treatment regimens.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Phase II study of concomitant chemoradiotherapy with local hyperthermia and metronidazole for locally advanced fixed rectal cancer. Barsukov, YA., Gordeyev, SS., Tkachev, SI., et al.[2020]

Irinotecan has been established as a standard treatment for advanced/metastatic colorectal cancer, showing survival benefits over best supportive care and 5-fluorouracil (5-FU) without negatively affecting patients' quality of life.

Combining irinotecan with oral capecitabine has shown promising results in terms of efficacy and safety, offering a more convenient treatment option compared to traditional infused 5-FU, and represents a potential new standard for first-line therapy.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Optimizing the use of irinotecan in colorectal cancer. Cunningham, D., Maroun, J., Vanhoefer, U., et al.[2019]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10683560/

Effects of metronidazole on colorectal cancer occurrence ... Metronidazole (MNZ) is exceedingly implicated in CRC. This study explored the roles of MNZ in mouse CRC occurrence and liver metastasis (CRLM).

2. clinicaltrials.gov clinicaltrials.gov/study/NCT06569368

Trial Utilizing Metronidazole to Optimize the Microbiome of ... Primary Objectives Quantify the ability of a standard course of metronidazole to decrease populations of anaerobic bacteria from within rectal cancers in ...

3. ascopubs.org ascopubs.org/doi/10.1200/JCO.2021.39.15_suppl.e14566

Outcome of concurrent treatment with a-CTLA4 and ... When metronidazole treatment was combined with a-CTLA4 therapy, we found ̃90% complete tumor regression. In the metronidazole and a-CTLA4 ...

4. sciencedirect.com sciencedirect.com/science/article/pii/S2772417424000748

Metronidazole delivery strategies: Optimizing cancer ... Metronidazole's anticancer potential relates to its ability to induce oxidative stress and cause DNA damage in cancer cells, primarily through the generation of ...

5. cancer.gov cancer.gov/news-events/cancer-currents-blog/2017/bacteria-colorectal-cancer

Bacteria May Aid Growth of Colorectal Cancer - NCI Erythromycin had no effect on the growth of Fusobacterium-positive tumors, but metronidazole reduced both the number of Fusobacterium in tumors ...

6. ncbi.nlm.nih.gov ncbi.nlm.nih.gov/books/NBK590895/

Metronidazole - 15th Report on Carcinogens - NCBI Bookshelf The data available from epidemiological studies are inadequate to evaluate the relationship between human cancer and exposure specifically to metronidazole.

7. accessdata.fda.gov accessdata.fda.gov/drugsatfda_docs/label/2010/012623s061lbl.pdf

WARNING Metronidazole has been shown to be carcinogenic ... There have been some reports in the medical literature of breast and colon cancer in Crohn's disease patients who have been treated with metronidazole at high ...

8. nature.com nature.com/articles/s41416-020-01082-2

Antibiotic use and risk of colorectal cancer: a systematic ... The pooled CRC risk was increased among individuals who ever-used antibiotics (ES = 1.17, 95%CI 1.05–1.30), particularly for broad-spectrum ...