Birch pollen allergoid glutaraldehyde modified

Birch pollen allergoid glutaraldehyde modified is a tree pollen allergen preparation classified under ATC code V01AA05 (tree pollen). It is a structurally diverse substance of allergen origin, supplied as a solution for injection for subcutaneous use. In the clinical trial records, it is authorised as a medicine, with ROXALL Medizin GmbH as the authorisation holder.^[1]

What is birch pollen allergoid?

Birch pollen allergoid glutaraldehyde modified is an allergen-based medicine used in allergy immunotherapy for birch pollen allergy. It is also referred to in the trial records as CLU-RX-BET, with low, mid and high dose formulations. The substance is a modified tree pollen allergen, meaning the birch pollen proteins have been chemically altered with glutaraldehyde to reduce their ability to trigger allergic reactions while still training the immune system to tolerate them.^[1]

How does birch pollen allergoid work?

As an allergoid, the birch pollen proteins are modified so that they are less likely to bind to the IgE antibodies that cause allergic symptoms. When given repeatedly by subcutaneous injection, the allergoid aims to shift the immune response away from the allergic pathway and towards tolerance. The exact molecular target is not described in the registry data, but the principle of allergen immunotherapy is to desensitise the immune system to the triggering pollen.^[1]

Which conditions is it used or studied for?

• Moderate-to-severe allergic rhinitis due to birch pollen — inflammation of the nose caused by birch pollen allergy, with symptoms such as sneezing, runny nose and nasal blockage.
• Allergic rhinoconjunctivitis due to birch pollen — allergic symptoms affecting both the nose and the eyes, including itchy, watery eyes.

In the trial, participants had to have had these symptoms for at least two years, defined according to the Allergic Rhinitis and its Impact on Asthma (ARIA) guideline.^[1]

How is birch pollen allergoid given?

The allergoid is given as a solution for injection by subcutaneous use, meaning it is injected under the skin. In the trial, each dose was 0.7 millilitres, and three different strengths were tested: low, mid and high dose. The treatment was given as cluster immunotherapy, which means several injections are given close together during the build-up phase to reach the maintenance dose more quickly.^[1]

What do the clinical trials show?

One completed Phase 4 trial investigated the allergoid in 700 participants with moderate-to-severe birch pollen allergic rhinitis or rhinoconjunctivitis.^[1] The trial was interventional and compared three active doses — CLU-RX-BET low dose, mid dose and high dose — against a placebo preparation that looked, smelled and tasted the same but contained no active substance. The study aimed to establish the most effective and best-tolerated dose in terms of benefit-risk balance.^[1]

What are the trials measuring?

The primary endpoint was the absolute difference in mean Combined Symptom and Medication Score (CSMS) during the Peak Birch Pollen Period (PBPP) between each active treatment group and the placebo group. The CSMS combines how severe a person's allergy symptoms are with how much medication they need to control them, giving a single measure of the overall burden of the allergy. The peak birch pollen period is the time of year when birch pollen levels in the air are highest.^[1]

Who can take part in these trials?

The trial enrolled adults with moderate-to-severe allergic rhinitis or rhinoconjunctivitis due to birch pollen for at least two years, as defined by the ARIA guideline. The trial is now completed, so it is no longer recruiting participants.^[1]