A Phase 2 interventional study of Valacyclovir and Placebo in Oral Mucositis, Head and Neck Cancer (H&N) and Radiotherapy Side Effects, sponsored by Instituto Oncoclinicas. Enrolling by invitation at 1 site in Brazil. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-01-23.
Sponsored by Instituto Oncoclinicas · Phase 2, Interventional, and Supportive care
Patients receiving radiotherapy for head and neck cancer often develop oral mucositis, a painful condition that causes redness and sores in the mouth. Oral mucositis can make it difficult to eat, drink, and speak, and may interfere with cancer treatment. Some viruses from the herpesvirus family, which commonly remain inactive in the body, may become active during cancer treatment and worsen mouth sores. However, the role of these viruses in oral mucositis is not fully understood.
This study aims to understand whether herpesviruses present in the mouth are associated with the development and severity of oral mucositis in adults receiving radiotherapy for head and neck cancer. The study also evaluates whether taking an antiviral medication (valacyclovir) can reduce viral activity and improve mouth symptoms during treatment.
Participants are randomly assigned to receive either valacyclovir or a placebo while undergoing radiotherapy. Samples from the mouth and saliva are collected at different time points before, during, and after radiotherapy to detect herpesviruses. Mouth sores are regularly examined, and pain levels are recorded throughout treatment.
The results of this study may help clarify the role of herpesviruses in oral mucositis and support better strategies to prevent or manage this condition in patients receiving radiotherapy for head and neck cancer.
Oral mucositis is a frequent and clinically significant side effect of radiotherapy for head and neck cancer. While mucosal injury is primarily related to radiation exposure, additional biological factors may influence the onset and severity of this condition. Reactivation of viruses from the Herpesviridae family has been suggested as a potential contributing factor, but existing evidence is limited and inconsistent. There is currently no standard preventive antiviral strategy for oral mucositis in this population.
This study is designed to characterize the presence and changes of herpesviruses in the oral cavity of adults undergoing radiotherapy for head and neck cancer and to evaluate whether prophylactic antiviral treatment affects viral detection and clinical outcomes related to oral mucositis. The trial uses a randomized, double-blind, placebo-controlled design to reduce bias and allow for an objective assessment of antiviral prophylaxis.
Participants receive either oral valacyclovir or matching placebo during the course of radiotherapy. Oral and saliva samples are collected at predefined time points before the start of radiotherapy, during treatment, and after completion of radiotherapy. These samples are analyzed to detect and quantify human herpesviruses using molecular methods. Clinical assessments of the oral cavity are performed regularly to evaluate the presence and severity of oral mucositis, and patient-reported pain is monitored throughout treatment.
The study aims to describe the pattern of herpesvirus detection in the oral cavity over time and to explore associations between viral presence, mucositis severity, and pain. In addition, the study evaluates whether antiviral prophylaxis influences these outcomes when compared with placebo.
By improving the understanding of the relationship between herpesvirus activity and oral mucositis, this study may inform future preventive or supportive care strategies for patients receiving radiotherapy for head and neck cancer.
306 studies on the registry are indexed under Stomatitis; 75 are open to participants now.
This study's planned enrollment of 84 is above the median of 60 across 276 interventional studies indexed under Stomatitis.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
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An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants in this arm receive oral valacyclovir during radiotherapy for head and neck cancer to evaluate its effect on oral herpesvirus detection and oral mucositis outcomes.
Drug: Valacyclovir
Participants in this arm receive a matching placebo during radiotherapy for head and neck cancer for comparison with the valacyclovir group.
Drug: Placebo
Valacyclovir is administered orally during the course of radiotherapy for head and neck cancer as a prophylactic antiviral intervention.
A matching placebo is administered orally during the course of radiotherapy for head and neck cancer.
Severity of Oral Mucositis
Maximum oral mucositis severity assessed using the World Health Organization (WHO) Oral Mucositis Grading Scale, which ranges from 0 (no mucositis) to 4 (severe mucositis). Higher scores indicate worse oral mucositis severity.
Time frame: From start of radiotherapy (day 1) until 2 weeks after completion of radiotherapy.
Incidence of Ulcerative Oral Mucositis
Proportion of participants who develop ulcerative oral mucositis (World Health Organization \[WHO\] Oral Mucositis Grading Scale grade ≥ 2) during radiotherapy. The WHO Oral Mucositis Grading Scale ranges from 0 (no mucositis) to 4 (severe mucositis), with higher scores indicating worse oral mucositis severity.
Time frame: From start of radiotherapy (Day 1) until 2 weeks after completion of radiotherapy.
Oral Pain Intensity
Oral pain intensity measured using the Numeric Rating Scale for Pain, ranging from 0 (no pain) to 10 (worst possible pain). Higher scores indicate worse pain intensity.
Time frame: From start of radiotherapy (Day 1) until 2 weeks after completion of radiotherapy.
Oral Herpesvirus Detection and Viral Load Over Time
Presence and quantitative viral load of human herpesviruses in oral and saliva samples measured using real-time polymerase chain reaction (qPCR).
Time frame: From start of radiotherapy (Day 1), weekly during radiotherapy, and 1 month after completion of radiotherapy (approximately up to 12 weeks).
Plan to share: Yes — De-identified individual participant data underlying the results of this study will be made available upon reasonable request. Requests will be reviewed by the study investigators and subject to institutional approvals and data sharing agreements, in accordance with ethical and regulatory requirements.
Supporting information: Study protocol
Time frame: De-identified individual participant data and the study protocol will be available beginning after publication of the primary study results and will remain available for up to 5 years following publication.
Access criteria: Access to de-identified individual participant data and the study protocol will be provided to qualified researchers upon reasonable request. Requests will be reviewed by the study investigators and subject to approval by the sponsoring institution, execution of a data use agreement, and compliance with ethical and regulatory requirements. Only data necessary to achieve the approved research objectives will be shared.
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Studies of the drug tested here: Valacyclovir