An observational study in Radiation Toxicity, Chemotherapeutic Toxicity and Chemotherapy-induced Peripheral Neuropathy, sponsored by Bernardino Clavo, MD, PhD. Active, not recruiting at 1 site in Spain. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-25.
Sponsored by Bernardino Clavo, MD, PhD · Observational
The main objective of this study is to analyze the impact on the health-related quality of life of patients with refractory symptoms, who have been referred to the HUGCDN Chronic Pain Unit for adjuvant palliative treatment with ozone therapy between June-2022 and December-2025
Chronic Pain Unit in the absence or failure of standard treatment, or when the standard treatment is associated with high morbidity or high risk. Frequently, these patients present alterations in self-perceived health-related quality of life (HRQoL), anxiety, depression, and other symptoms. This study aims to evaluate in these patients the effect of adjuvant symptomatic/palliative ozone therapy on the HRQoL and the potential changes from baseline on several parameters after treatment.
MAIN OBJECTIVES: To evaluate in these patients: 1) the clinical effect on the HRQOL of adding ozone to the standard treatment.
SECONDARY OBJECTIVES: To evaluate in these patients changes from baseline on 2) anxiety and depression, 3) pain (if applicable), 4) grade of toxicity (if applicable), 5) requirements of invasive procedures for symptom management, 6) evolution of main symptoms, 7) evolution of oxidative stress and inflammation (if systemic ozone therapy).
METHODOLOGY: Prospective and observational study of patients referred to our Chronic Pain Unit for symptomatic/palliative treatment with ozone therapy between 2022 and 2025.
MAIN VARIABLE: 1) HRQoL through the EQ-5D-5L questionnaire
SECONDARY VARIABLE: 2) anxiety and depression through the hospital anxiety/depression (HAD) questionnaire, 3) Pain through the visual analog scale (VAS), 4) grade of toxicity in cancer patients through the CTCAE v5.0 scale, 5) the number of invasive procedures required for symptom management, 6) self -reported percentage of symptom improvement, 7) biochemical parameters of oxidative stress and inflammation.
Assessments at weeks: 0 (baseline), 16 (end of O3/O2 treatment, objective), 28 (12 weeks after the end of ozone), and 40 (24 weeks after the end of ozone, control) Length of treatment: as required; initially, planned 16 weeks. Follow-up: 24 weeks after finishing O3/O2 treatment. Planned length of the clinical trial: 49 months.
328 studies on the registry are indexed under Radiation Injuries; 96 are open to participants now.
This study's planned enrollment of 105 is below the median of 130 across 96 observational studies indexed under Radiation Injuries.
Browse Radiation Injuries studies →Bernardino Clavo, MD, PhD is the lead sponsor of 10 studies on the registry; 6 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Patients submitted to the Chronic Pain Unit of the Hospital Universitario de Gran Canaria Dr. Negrín for symptomatic/palliative treatment with ozone therapy because standard treatment does not exist, it has been unsuccessful, or it is associated with high risk or high morbidity.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
11. Known significant glucose-6-phosphate dehydrogenase deficiency (favism, acute hemolytic anemia) (for systemic ozone therapy).
12. Patients who do not meet all the inclusion 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.
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.
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.
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
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.
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.
Life expectancy
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Patients treated with ozone as adjuvant palliative therapy. The procedure of ozone administration, dosage, frequency, and duration of ozone treatment will depend on the treated symptom and clinical evolution. Usually planned 40 sessions.
Other: Ozone therapy
Systemic and/or local ozone administration. Dosage, frequency, and duration of ozone treatment will depend on the treated symptom and clinical evolution. Usually planned 40 sessions.
Change from Baseline in the health-related quality of life by the "5-level, 5-dimension EuroQol" (EQ-5D-5L) questionnaire (at the end of ozone therapy)
Self-reported evaluation of: a) 5 physical and emotional items scored in five levels, from 1 (best: I have no problem) to 5 (worst: I have extreme problem or I am unable to…) and b) additional self-assessment of health by a visual analogue scale (0 = worst health patient can imagine, 100 = best health patient can imagine)
Time frame: 16 weeks
Change from Baseline in Levels of anxiety and depression according to the hospital anxiety/depression scale (at the end of ozone therapy)
HAD scale is a self-administered questionnaire which assesses 14 items pertaining to symptoms of anxiety (seven) and depression (seven) experienced by patients. Each item is scored from 0 (better, no alteration) to 3 (worse level of alteration). For each symptom, overall score is from 0 (better, no anxiety or depression) to 21 (worse, very severe anxiety or depression).
Time frame: 16 weeks
Change from Baseline in pain score according to the visual analog scale (VAS) (at the end of ozone therapy)
Self-reported evaluation of the severity of pain according to the VAS, scored from 0 ("No pain") to 10 ("Pain as bad as you can imagine")
Time frame: 16 weeks
Change from Baseline in the grade of toxicity secondary to cancer-treatment (if applicable) according to the CTCAE v5.0 scale (at the end of ozone therapy)
Grade of toxicity secondary to cancer-treatment according to the CTCAE v5.0 (Common Terminology Criteria for Adverse Events from the National Cancer Institute) scale. Each toxicity is usually scored from 0 (asymptomatic or mild symptoms) to 5 (death).
Time frame: 16 weeks
Changes from Baseline in requirements of invasive procedures (surgery, blood transfusions, and therapeutic endoscopic procedures) required for symptom management (at the end of ozone therapy)
Number of invasive procedures (surgery, blood transfusions, and therapeutic endoscopic procedures) required for symptom management.
Time frame: 16 weeks
Changes from Baseline in the main symptoms (at the end of ozone therapy)
Self -reported percentage of symptom improvement from Baseline
Time frame: 16 weeks
Changes from Baseline in biochemical parameters of oxidative stress (if systemic ozone therapy) (at the end of ozone therapy).
Serum levels of biochemical parameters of oxidative stress
Time frame: 16 weeks
Changes from Baseline in biochemical parameters of inflammation (if systemic ozone therapy) (at the end of of ozone therapy).
Serum levels of pro-inflammatory cytokines
Time frame: 16 weeks
Change from Baseline in the health-related quality of life by the "5-level, 5-dimension EuroQol" (EQ-5D-5L) questionnaire.
Self-reported evaluation of: a) 5 physical and emotional items scored in five levels, from 1 (best: I have no problem) to 5 (worst: I have extreme problem or I am unable to…) and b) additional self-assessment of health by a visual analogue scale (0 = worst health patient can imagine, 100 = best health patient can imagine)
Time frame: 28 weeks
Change from Baseline in Levels of anxiety and depression according to the hospital anxiety/depression scale.
HAD scale is a self-administered questionnaire which assesses 14 items pertaining to symptoms of anxiety (seven) and depression (seven) experienced by patients. Each item is scored from 0 (better, no alteration) to 3 (worse level of alteration). For each symptom, overall score is from 0 (better, no anxiety or depression) to 21 (worse, very severe anxiety or depression).
Time frame: 28 weeks
Change from Baseline in pain score according to the visual analog scale (VAS).
Self-reported evaluation of the severity of pain according to the VAS, scored from 0 ("No pain") to 10 ("Pain as bad as you can imagine")
Time frame: 28 weeks
Change from Baseline in the grade of toxicity secondary to cancer-treatment (if applicable) according to the CTCAE v5.0 scale.
Grade of toxicity secondary to cancer-treatment according to the CTCAE v5.0 (Common Terminology Criteria for Adverse Events from the National Cancer Institute) scale. Each toxicity is usually scored from 0 (asymptomatic or mild symptoms) to 5 (death).
Time frame: 28 weeks
Changes from Baseline in requirements of invasive procedures (surgery, blood transfusions, and therapeutic endoscopic procedures) required for symptom management.
Number of invasive procedures ((surgery, blood transfusions, and therapeutic endoscopic procedures) required for symptom management.
Time frame: 28 weeks
Changes from Baseline in the main symptoms.
Self -reported percentage of symptom improvement from Baseline
Time frame: 28 weeks
Changes from Baseline in biochemical parameters of oxidative stress (if systemic ozone therapy).
Serum levels of biochemical parameters of oxidative stress
Time frame: 28 weeks
Changes from Baseline in biochemical parameters of inflammation (if systemic ozone therapy).
Serum levels of pro-inflammatory cytokines
Time frame: 28 weeks
Change from Baseline in the health-related quality of life by the "5-level, 5-dimension EuroQol" (EQ-5D-5L) questionnaire.
Self-reported evaluation of: a) 5 physical and emotional items scored in five levels, from 1 (best: I have no problem) to 5 (worst: I have extreme problem or I am unable to…) and b) additional self-assessment of health by a visual analogue scale (0 = worst health patient can imagine, 100 = best health patient can imagine)
Time frame: 40 weeks
Change from Baseline in Levels of anxiety and depression according to the hospital anxiety/depression scale.
HAD scale is a self-administered questionnaire which assesses 14 items pertaining to symptoms of anxiety (seven) and depression (seven) experienced by patients. Each item is scored from 0 (better, no alteration) to 3 (worse level of alteration). For each symptom, overall score is from 0 (better, no anxiety or depression) to 21 (worse, very severe anxiety or depression).
Time frame: 40 weeks
Change from Baseline in pain score according to the visual analog scale (VAS).
Self-reported evaluation of the severity of pain according to the VAS, scored from 0 ("No pain") to 10 ("Pain as bad as you can imagine")
Time frame: 40 weeks
Change from Baseline in the grade of toxicity secondary to cancer-treatment (if applicable) according to the CTCAE v5.0 scale.
Grade of toxicity secondary to cancer-treatment according to the CTCAE v5.0 (Common Terminology Criteria for Adverse Events from the National Cancer Institute) scale. Each toxicity is usually scored from 0 (asymptomatic or mild symptoms) to 5 (death).
Time frame: 40 weeks
Changes from Baseline in requirements of invasive procedures (surgery, blood transfusions, and therapeutic endoscopic procedures) required for symptom management.
Number of invasive procedures (surgery, blood transfusions, and therapeutic endoscopic procedures) required for symptom management.
Time frame: 40 weeks
Changes from Baseline in the main symptoms.
Self -reported percentage of symptom improvement from Baseline
Time frame: 40 weeks
Changes from Baseline in biochemical parameters of oxidative stress (if systemic ozone therapy).
Serum levels of biochemical parameters of oxidative stress
Time frame: 40 weeks
Changes from Baseline in biochemical parameters of inflammation (if systemic ozone therapy).
Serum levels of pro-inflammatory cytokines
Time frame: 40 weeks
Ran from Jun 2022 to primary completion in Apr 2026, 46 months.
Of 55 observational studies under Radiation Injuries, half reached primary completion within 74 months of starting (the median), counting those still running; a quarter within 35 and three quarters within 189. This study's 46 months is below that.
Since we started tracking on Sep 25, 2026, the dates moved once, on Sep 25, 2026: primary completion Dec 2025 → Apr 2026 and completion Jun 2026 → Oct 2026.
Earlier changes are on the record history on ClinicalTrials.gov ↗
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is active, not recruiting, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Bernardino Clavo, MD, PhD