Table of contents

• Trial overview
• Allergy testing studies using Histamine Dihydrochloride
• Pancreatic cancer study
• Who participates in these trials
• Phases and main endpoints
• What the study measures mean

Trial overview

Across the trial data, Histamine Dihydrochloride appears mainly as a reference substance in allergy skin prick tests, where it is used as a positive control to compare skin reactions.^[1][2] The studies focus on whether allergen extracts from mites, grasses, birch, olive, and other sources produce a wheal similar to the one caused by Histamine Dihydrochloride at 10 mg/mL.^[1][2] One separate trial studies a treatment approach in pancreatic cancer and includes Histamine Dihydrochloride in the trial context through the provided data set.^[3]

Allergy testing studies using Histamine Dihydrochloride

Several Phase 2 trials use Histamine Dihydrochloride as a comparison point in prick tests, which are skin tests that help show whether a person reacts to a specific allergen.^[1][4] These studies look at the biological standardization of allergen extracts, which means they try to measure and compare the strength of different extracts in a consistent way.^[1][4]

The allergy-related trials include studies of:

• Blomia tropicalis allergen extract, where the goal is to find the concentration that gives a wheal similar to a 10 mg/mL Histamine Dihydrochloride solution.^[1]

• Lepidoglyphus destructor allergen extract, with the same type of comparison against Histamine Dihydrochloride.^[2]

• Dermatophagoides mite extracts, including Dermatophagoides pteronyssinus and Dermatophagoides farinae, again using the wheal response compared with Histamine Dihydrochloride at 10 mg/mL.^[4][5]

• Phleum pratense and Dactylis glomerata pollen extracts, where the study measures wheal size after prick testing and compares it with the histamine positive control.^[6]

These studies are not mainly testing Histamine Dihydrochloride as a treatment. Instead, they use it as a known skin reaction marker so researchers can judge how strong the allergen extracts are.^[1][4]

Pancreatic cancer study

One Phase 1 trial, called PANCEP-1, studies pancreatic cancer and evaluates the safety and tolerability of the treatment by collecting adverse events and other safety data.^[3] The trial includes people with pancreatic cancer and follows safety from Cycle 1 Day 1 through the final study visit.^[3]

The trial measures adverse events, their severity, and whether they are related to treatment, and it also uses laboratory tests, physical exams, and other safety checks.^[3] In the source data, the intervention list includes PROLEUKIN® and Ceplene, and the study is designed to assess the frequency and extent of adverse events linked to the therapy.^[3]

Who participates in these trials

The allergy trials recruit people with specific allergies, such as allergy to mites, grass pollen, birch pollen, olive pollen, or peanut allergy in young children.^[1][4][6][7] Some trials also include children and adolescents with seasonal allergic rhinitis or rhinoconjunctivitis, which means ongoing allergy symptoms affecting the nose and sometimes the eyes.^[7][8]

Other studies focus on adults with moderate to severe allergic rhinitis or rhinoconjunctivitis caused by house dust mite, birch pollen, grass pollen, or olive pollen exposure for at least two years according to the ARIA guideline.^[5][7][8][9] The pancreatic cancer trial includes people with pancreatic cancer.^[3]

Phases and main endpoints

Most of the Histamine Dihydrochloride-related allergy studies are Phase 2 trials, which usually means they are focused on finding the right test conditions and checking how well a method works in a group of patients.^[1][2][4] The peanut allergy and pollen immunotherapy studies are mainly Phase 3 trials, which compare active treatment with placebo in larger groups.^{[7][8][9][10]}

The main endpoints in the allergy extract studies are the wheal area in square millimeters and the dose-response relationship, meaning how the skin reaction changes as the concentration changes.^[1][4] Several studies also try to find the theoretical concentration of extract that gives a reaction equal to Histamine Dihydrochloride at 10 mg/mL.^[1][2][4][6]

In the larger allergy treatment trials, the main outcomes are symptom and medication scores such as CSMS and TCRS, which combine how bad the symptoms are with how much medicine is needed.^[5][7][8][9] The peanut allergy trial measures treatment responders after 12 months, while also tracking safety events, local skin reactions, and other serious reactions.^[10]

What the study measures mean

A wheal is the raised bump that can appear on the skin after a prick test, and its size helps show how strong the reaction is.^[1][4] A larger wheal usually means a stronger skin reaction, so researchers measure it carefully in these trials.^[1][4]

A positive control is a test substance expected to cause a reaction, and Histamine Dihydrochloride is used in that role in several studies.^[1][2][4][6] A negative control is a substance that should not cause a reaction, which helps show whether the test result is reliable.^[1][4]

The term biological standardization means checking and comparing the activity of allergen extracts in living people so the extracts can be measured in a consistent way.^[1][4] This helps researchers decide whether different extract concentrations behave as expected when compared with Histamine Dihydrochloride.^[1][2][4]