Methoxyflurane versus Standard Care for Non-Traumatic Pain in the Emergency Department (PAIN-THROX) : A Multicenter, Randomized, Controlled, Superiority Trial

Overview

Sponsor-declared trial summary

Key facts

Sponsor

Centre Hospitalier Regional Universitaire De Tours

Participant type

Patients

Age range

18-64 years, 65+ years

Gender

Male and Female

Therapeutic area

Not possible to specify

Decision date (initial)

2026-06-29

Transition trial

No

Low-intervention

No

Rare-disease indication

No

Vulnerable population

No

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Therapy

The primary objective is to demonstrate the superiority of methoxyflurane in achieving rapid effective analgesia compared with standard pain management based on oral analgesics, in the emergency department waiting room, in adult patients presenting with non-traumatic painful conditions.

Secondary objectives 4

1. • To assess the effect of methoxyflurane in each of the three subgroups defined by baseline pain intensity and categorized as “moderate” pain (VAS 40–59 mm), “severe” pain (VAS 60–79 mm), and “unbearable” pain (VAS ≥ 80 mm).
2. To compare the prolonged analgesic effect (VAS at T60, T90, and T120 minutes) between the methoxyflurane group and the group receiving standard analgesic care.
3. To compare, between the two groups, the need for rescue analgesic therapy from 30 minutes after initiation of treatment.
4. To evaluate the safety profile of methoxyflurane in non-traumatic pain.

Conditions and MedDRA coding

Non-traumatic pain

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 5

1. Adult ≥ 18 years
2. Moderate to severe acute non-traumatic pain (VAS strictly greater than 39 mm)
3. Able to self-assess pain using a VAS and to independently record this on a paper form
4. Affiliated with a social security system
5. Has provided written informed consent

Exclusion criteria 10

1. Age < 18 years
2. Contraindications to methoxyflurane as described in the Summary of Product Characteristics (SmPC): o Hypersensitivity to the active substance, to any fluorinated anesthetic, or to any excipient listed in section 6.1 of the SmPC o Malignant hyperthermia: known history or genetic predisposition o History of serious adverse reactions (in the patient or relatives) following administration of inhaled anesthetics o History of signs of liver injury following methoxyflurane use or anesthesia with halogenated hydrocarbons o Clinically significant renal impairment o Altered level of consciousness from any cause, including head injury, drug or alcohol use o Clinical evidence of cardiovascular instability o Clinical evidence of respiratory depression
3. Hemodynamically unstable patient (SBP < 100 mmHg, DBP < 30 mmHg)
4. Patient who has already received methoxyflurane on the same day
5. Patient who has taken analgesic treatment prior to emergency department consultation within 4 hours of admission.
6. Pain ≤ 39 mm
7. Pregnant or breastfeeding women
8. Individuals under legal protection (guardianship, curatorship, or judicial protection)
9. Women of childbearing potential not using a highly effective method of contraception throughout the study
10. Patients currently within the exclusion period of another clinical trial.

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 1

1. The primary endpoint will be pain assessed using the Visual Analog Scale (VAS). The VAS is a simple pain assessment tool consisting of marking a point on a color-graded ruler calibrated in millimeters, allowing pain intensity to be assigned a numerical value ranging from 0 (no pain) to 100 mm (unbearable pain). Pain will be assessed at inclusion, at 3 minutes post-randomization, and then at 5, 10, 15, 20, 25, and 30 minutes using self-administered questionnaires.

Secondary endpoints 4

1. Time to onset of pain relief within the first 30 minutes.Measurement of VAS over the first 30 minutes
2. Pain measured again using the VAS at 60, 90, and 120 minutes post-randomization via self-administered questionnaires.
3. The need for rescue analgesic treatment of any class due to insufficient pain relief or pain recurrence.
4. Adverse events and serious adverse events reported in each group.

Investigational products

Investigational medicinal products (IMPs), comparators, placebo, auxiliary

Test 1

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Centre Hospitalier Regional Universitaire De Tours

Sponsor organisation

Centre Hospitalier Regional Universitaire De Tours

Address

2 Boulevard Tonnelle

City

Tours

Postcode

37000

Country

France

Scientific contact point

Organisation

Centre Hospitalier Regional Universitaire De Tours

Contact name

Mickael SOLETCHNIK

Public contact point

Organisation

Centre Hospitalier Regional Universitaire De Tours

Contact name

Mickael SOLETCHNIK

Locations

1 EU/EEA country · 3 investigational sites

By country

Investigational sites

Results and documents

Annex IV summary of results, Annex V layperson summary, and all documents registered in CTIS for this trial

Documents 7 files

Public protocol annexes, IB summaries, regulatory submissions and post-authorisation documents registered in CTIS.

Application history

1 submissions — initial application plus substantial / non-substantial modifications