Oral Squamous Cell CarcinomaPhase 2NCT06627270
Antibiotic Treatment Effects on Intratumoral Bacteria Modulation in Surgical Patients With Oral Cancer
A Phase 2 study testing Metronidazole and Chlorhexidine in people with Oral Squamous Cell Carcinoma and Oral Cancer, run by Case Comprehensive Cancer Center at 1 site in United States.
Trial summary
The goal of this phase II single arm clinical study is to evaluate the effect of antibiotics (metronidazole) and oral chlorhexidine (CHX) in reducing the bacteria load within tumors of patients undergoing surgery for oral cancer. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Oral Squamous Cell Carcinoma, Oral Cancer, Head and Neck Cancer
- What is being tested?
- Metronidazole and Chlorhexidine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 30 participants
- Where
- 1 siteUnited States
- Study dates
- 22 Jul 2025to 1 Oct 2027
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Pathologically confirmed squamous cell carcinoma of the oral cavity
- Must have planned surgery for curative intent
- Participants ≥ 18 years of age
- Participants must have the ability to understand and the willingness to sign a written informed consent document
Who cannot join
- Known allergy to metronidazole and/or chlorhexidine
- Severe liver or kidney disease as determined by history of laboratory tests
- Participants actively drinking alcohol (unable to abstain for the 10 day antibiotic period)
- Recurrent oral cancer after prior radiation or chemoradiation
- Participants with unresectable oral cancer
- Participants unable to tolerate oral rinse or unable to have metronidazole administered by mouth or by feeding tube
- Participants currently or have taken other antibiotics within the prior 30 days
- Participant is pregnant
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Case Comprehensive Cancer Center, Cleveland Clinic Foundation
Cleveland, Ohio, 44195
Natalie Silver, MD
About this study
Official title: A Phase II Single-arm Cohort Study Establishing the Effect of Antibiotic Treatment on Intratumoral Bacteria in Surgical Patients With Oral Cancer
The goal of this phase II single arm clinical study is to evaluate the effect of antibiotics (metronidazole) and oral chlorhexidine (CHX) in reducing the bacteria load within tumors of patients undergoing surgery for oral cancer.
Read the detailed description
The prognosis for patients with locally advanced, non-Human Papillomavirus (HPV) associated head and neck squamous cell carcinoma (HNSCC) remains poor. The immunosuppressive tumor immune microenvironment in HNSCC presents a significant barrier to both conventional and immune-based therapies. Recent studies have indicated that dysbiotic oral microbiota, particularly in the context of periodontal disease, can contribute to chronic oral mucosal inflammation and the recruitment of suppressive immune cell infiltrates. Bacterial-induced chronic inflammation may play a crucial role in treatment resistance in HNSCC. Understanding the impact of microbial modulation on the tumor immune microenvironment in HNSCC could lead to the identification of novel therapeutic targets.
In this single-arm phase II clinical trial, oral cancer patients will be treated with oral metronidazole and CHX rinses prior to surgery. Investigator will assess the ability for the treatment to reduce the absolute amount of intratumoral bacteria and evaluate changes in the intratumoral bacterial community and infiltrating immune cells.
- Being tested
- Metronidazole, Chlorhexidine
- Keywords
- Metronidazole, Chlorhexidine
- Medical subject headings
- Squamous Cell Carcinoma of Head and Neck, Mouth Neoplasms, Head and Neck Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
MetronidazoleDrug
Participants will receive metronidazole (500 mg t.i.d. x 10 days)
ChlorhexidineOther
Also called CHX
Mouth rinse chlorhexidine (10 ml t.i.d. x 10 days)
| Study group | Role | What they receive |
|---|---|---|
| 10 days of metronidazole and chlorhexidine | Experimental | Participants will receive metronidazole (500 mg t.i.d. x 10 days) and chlorhexidine (10 ml t.i.d. x 10 days) prior to surgical resection. Receives: Drug: Metronidazole; Other: Chlorhexidine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in absolute amount of intraumoral bacteria as quantified by 16S rRNA qPCR
The difference between pre-treatment and post-treatment tumor bacteria burden will be assessed.
Measured: Baseline, surgery (10 days post intervention)
Secondary outcomes (3)
Change in absolute amount of intraumoral bacteria in post treatment participants compared to control patients as quantified by 16S rRNA qPCR
Measured: Baseline, surgery (10 days post intervention)
Disease-free survival
Measured: Time from date of randomization to recurrence, second primary malignancy, or death, as determined by standard of care surveillance, up to three years.
Overall Survival
Measured: Time from date of randomization to recurrence, second primary malignancy, or death, as determined by standard of care surveillance, up to three years.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Oct 2024
- Study start22 Jul 2025
- Primary completion1 Oct 2026 (estimated)
- Study completion1 Oct 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Oral Squamous Cell CarcinomaStudies of the same condition, open and under way.
- More trials run by Case Comprehensive Cancer CenterThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Case Comprehensive Cancer Center
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Natalie Silver, MD, Principal investigator, Case Comprehensive Cancer Center, Cleveland Clinic Foundation
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06627270
- Sponsor's protocol ID
- CASE6324
- Status last verified
- Aug 2026
- First submitted
- 30 Sep 2024
- Last updated
- 6 Aug 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: RNAseq results will be shared upon publication, not patient identifiers will be shared
Study at a glance
From the registry record, last updated by the sponsor on 6 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase II Single-arm Cohort Study Establishing the Effect of Antibiotic Treatment on Intratumoral Bacteria in Surgical Patients With Oral Cancer
- ClinicalTrials.gov ID
- NCT06627270
- Acronym / sponsor ID
- CASE6324
- Keywords
- Metronidazole, Chlorhexidine
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- Case Comprehensive Cancer CenterUniversity, hospital or other
- Study start
- 22 Jul 2025 (actual)
- Primary completion
- 1 Oct 2026 (estimated)
- Study completion
- 1 Oct 2027 (estimated)
- First posted
- 4 Oct 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this phase II single arm clinical study is to evaluate the effect of antibiotics (metronidazole) and oral chlorhexidine (CHX) in reducing the bacteria load within tumors of patients undergoing surgery for oral cancer.
Detailed description
The prognosis for patients with locally advanced, non-Human Papillomavirus (HPV) associated head and neck squamous cell carcinoma (HNSCC) remains poor. The immunosuppressive tumor immune microenvironment in HNSCC presents a significant barrier to both conventional and immune-based therapies. Recent studies have indicated that dysbiotic oral microbiota, particularly in the context of periodontal disease, can contribute to chronic oral mucosal inflammation and the recruitment of suppressive immune cell infiltrates. Bacterial-induced chronic inflammation may play a crucial role in treatment resistance in HNSCC. Understanding the impact of microbial modulation on the tumor immune microenvironment in HNSCC could lead to the identification of novel therapeutic targets.
In this single-arm phase II clinical trial, oral cancer patients will be treated with oral metronidazole and CHX rinses prior to surgery. Investigator will assess the ability for the treatment to reduce the absolute amount of intratumoral bacteria and evaluate changes in the intratumoral bacterial community and infiltrating immune cells.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| 10 days of metronidazole and chlorhexidine | Experimental | Drug: Metronidazole, Other: ChlorhexidineParticipants will receive metronidazole (500 mg t.i.d. x 10 days) and chlorhexidine (10 ml t.i.d. x 10 days) prior to surgical resection. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Pathologically confirmed squamous cell carcinoma of the oral cavity
- Must have planned surgery for curative intent
- Participants ≥ 18 years of age
- Participants must have the ability to understand and the willingness to sign a written informed consent document
Key exclusion criteria (8 listed)
- Known allergy to metronidazole and/or chlorhexidine
- Severe liver or kidney disease as determined by history of laboratory tests
- Participants actively drinking alcohol (unable to abstain for the 10 day antibiotic period)
- Recurrent oral cancer after prior radiation or chemoradiation
- Participants with unresectable oral cancer
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| MetronidazoleParticipants will receive metronidazole (500 mg t.i.d. x 10 days) | Drug | 10 days of metronidazole and chlorhexidine |
| ChlorhexidineAlso: CHXMouth rinse chlorhexidine (10 ml t.i.d. x 10 days) | Other | 10 days of metronidazole and chlorhexidine |
Primary outcome
Change in absolute amount of intraumoral bacteria as quantified by 16S rRNA qPCR
Time frame: Baseline, surgery (10 days post intervention)
The difference between pre-treatment and post-treatment tumor bacteria burden will be assessed.
3 secondary outcomes
Change in absolute amount of intraumoral bacteria in post treatment participants compared to control patients as quantified by 16S rRNA qPCR
Time frame: Baseline, surgery (10 days post intervention)
Disease-free survival
Time frame: Time from date of randomization to recurrence, second primary malignancy, or death, as determined by standard of care surveillance, up to three years.
Overall Survival
Time frame: Time from date of randomization to recurrence, second primary malignancy, or death, as determined by standard of care surveillance, up to three years.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Aug 2026.
- Individual participant dataSharing planned: Yes. RNAseq results will be shared upon publication, not patient identifiers will be shared
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Natalie Silver, MD principal investigator
Case Comprehensive Cancer Center, Cleveland Clinic Foundation
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Metronidazole and Chlorhexidine in people with Oral Squamous Cell Carcinoma and Oral Cancer, run by Case Comprehensive Cancer Center at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 6 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Natalie Silver, MD (216-219-3267, silvern@ccf.org), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in absolute amount of intraumoral bacteria as quantified by 16S rRNA qPCR (time frame: Baseline, surgery (10 days post intervention)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Aug 2026; AzTrials last refreshed its copy on 8 Nov 2026.