EMONO for the Treatment of Peripheral Neuropathic Pain

Equimolar Mixture of Oxygen and Nitrous Oxide (EMONO) for the Treatment of Peripheral Neuropathic Pain: A Randomises, International, Multicentre, Placebo-Controlled, Phenotype-stratified Phase IIa Study

Status

Completed

Phases

Phase 2

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT02957851

Acronym

ProtoTOP

Enrollment

287

Registered

2016-11-08

Start date

2016-11-30

Completion date

2018-08-31

Last updated

2018-09-21

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Neuralgia

Brief summary

To assess the effect of 3 consecutive days of one-hour administration of Nitrous Oxide/Oxygen 50%/50% (EMONO) versus placebo as Oxygen/Nitrogen 22%/78% (synthetic medical air), in add-on therapy to chronic analgesic treatments, on average pain intensity in patients with chronic peripheral neuropathic pain. A total of 250 randomised patients to be included in all the participating centres, i.e., 125 randomised patients in each of the 2 study groups treatments

Interventions

DRUGMedical Air

DRUGEMONO

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

TREATMENT

Masking

SINGLE (Investigator)

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

* Patients with a mean pain intensity from 4 to 9 as assessed daily with a Numerating Rating Scale during the 7 day period preceding inclusion in spite of administration of usual pain treatments. * Neuropathic pain lasting for more than 3 months but less than 10 years * Definite or probable peripheral neuropathy

Exclusion criteria

* legal incapacity * patient with another concomitant chronic pain * ongoing major depression * Chemotherapy-induced peripheral neuropathic pain

Design outcomes

Primary

Measure	Time frame	Description
Pain intensity	7 days after the last administration of treatment	Numeric Rating Scale (NRS)

Secondary

Measure	Time frame	Description
Pain intensity	28 days after the last administration of treatment	Numeric Rating Scale (NRS)
Pain characteristic	28 days after the last administration of treatment	Neuropathic Pain Symptom Inventory (NPSI)
Quality of life questionnaire	28 days after the last administration of treatment	Medical Outcome Study Short Form (SF-12)
Number of patients with adverse events	through study duration, up to 31 days	—

Countries

France, Germany

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026