Substance P Challenge in Healthy Participants

What Was Tested

In this not phased trial, researchers set out to test Substance P.

The objectives of this enabling study are to characterize the wheal and flare responses over time following skin challenges with ascending concentrations of Substance P.

This will be a 2-part study: Part 1 will aid in the understanding of the wheal and flare responses following Substance P.

Part 2 will investigate the variability of the responses.

It had two arms (groups): Substance P challenge in Part 1 (experimental) and Substance P challenge in Part 2 (experimental).

Eligible participants will receive control challenge with saline and histamine, followed by challenge with ascending concentrations of Substance P. Part 1 will include a single challenge visit.

Eligible participants will receive control challenge with saline and histamine, followed by challenge with ascending concentrations of Substance P. Part 2 will include two challenge visits.

The registry classes the interventions as drug.

Who Took Part

32 actual participants took part.

It was open to people of any sex aged from 18 years up to 50 years.

Healthy volunteers could join, not only people with the condition.

Examples of who could join: 18 to 50 years of age inclusive. Participants who are overtly healthy as determined by medical evaluation including medical history, physical examination, laboratory tests, ECGs and vital signs. Participants who responded positive to histamine skin prick test and negative to saline injection at screening. Participants with Fitzpatrick skin type I-II (Caucasian). Body weight greater than or equal to (\>=) 50 kilogram (kg) and body mass index (BMI) within the range 19-29.9 kilogram per meter square (kg/m2) (inclusive).

The full record lists 9 inclusion and 25 exclusion criteria; among the exclusions: history of risk for or actual experience of complications from skin biopsy including excess bleeding, infection, or scarring/keloid formation; abnormal blood pressure as determined by the investigator; alanine transaminase (alt) \>1.5 times upper limit of normal (uln).

How the Study Was Run

It was run as a non-randomized, sequential and open-label study.

Everyone knew when Substance P was being given (open label), which is simpler to run but leaves more room for expectations to affect what is reported.

It started in 2021-03-02 with completion listed for 2021-07-21.

It ran at 1 site in Netherlands.

Its stated primary purpose is other.

What Was Measured

Primary outcome: Part 1: Wheal Response-time Area Under the Curve (AUC) Over the 2 Hours Post-challenge Period Following Skin Challenge With Substance P- at Challenge Visit 1 (Day 1) (time frame: 0, 5, 10, 15, 20, 40, 60, 90 and 120 minutes post-challenge on Day 1 (Visit 1)). Part 2: Wheal Response-time AUC Over the 2 Hours Post-challenge Period Following Skin Challenge With Substance P- at Challenge Visit 1 (Day 1) and Challenge Visit 2 (Week 2) (time frame: 0, 5, 10, 15, 20, 30, 40, 60, 90 and 120 minutes post-challenge on Day 1 (Visit 1) and on Week 2 (Visit 2)).

It also tracked 44 secondary outcomes, for example Part 1: Number of Participants With Non-serious Adverse Events (AEs) and Serious AEs (SAEs)- Substance P Only, Part 2: Number of Participants With Non-serious AEs and SAEs- Substance P Only, Part 1: Change From Baseline in Hematology Parameter: Hemoglobin- Substance P Only at Challenge Visit 1 (Day 1), Part 2: Change From Baseline in Hematology Parameter: Hemoglobin- Substance P Only at Challenge Visit 2 (Week 2), Part 1: Change From Baseline in Hematology Parameter: Hematocrit- Substance P Only at Challenge Visit 1 (Day 1) and Part 2: Change From Baseline in Hematology Parameter: Hematocrit- Substance P Only at Challenge Visit 2 (Week 2).

What This Means in Plain Language

Put simply, this is a not phased, non-randomized trial of Substance P in 32 people.

Its size is small, so on its own it can only give an early look.

The trial is marked completed; results are posted on the registry, and this page does not restate them.

More context: the Substance P compound page, all human trials.