In short
Grass pollen allergoid (Dactylis glomerata pollen enriched allergoid, mannan-conjugated, polymerised) is an investigational immunotherapy being studied for grass pollen-induced allergic rhinitis or rhinoconjunctivitis. One authorised Phase 4 trial is testing two subcutaneous concentrations (3000 mTU/mL and 9000 mTU/mL) in 450 participants, with results expected after the 2027 grass pollen season.
Key points
- Phase 4 dose-finding trial in grass pollen-induced allergic rhinitis or rhinoconjunctivitis
- 450 participants planned for enrolment
- Two subcutaneous concentrations tested: 3000 mTU/mL and 9000 mTU/mL
- Primary outcome is the Combined Symptom and Medication Score (CSMS) during the 2027 peak grass pollen season
- Trial status: Authorised, randomised, double-blind and placebo-controlled
What is grass pollen allergoid?
Grass pollen allergoid, also known by its full name Dactylis glomerata pollen enriched allergoid, mannan-conjugated, polymerised, is an investigational immunotherapy for grass pollen allergy. It belongs to the therapeutic area of immune system diseases. The substance is also known as Phleum pratense pollen enriched allergoid, mannan-conjugated, polymerised, and appears in product records under the name Mannan-conjugated allergoid (polymerized) Phleum pratense and Dactylis glomerata parenteral vaccine. The registry also lists it as part of a fixed combination in two product records, together with other grass pollen extracts including Anthoxanthum odoratum, Lolium perenne, Poa pratensis, Secale cereale, Arrhenatherum elatius, Agrostis stolonifera, Festuca rubra and Holcus lanatus pollen extract. The product is authorised as a medicine in Germany, with authorisation holder Inmunotek S.L. and HAL Allergy B.V. In the clinical trial listed in the registry, the substance appears both as the test substance and as an auxiliary product used for skin-prick testing.
How does grass pollen allergoid work?
Allergoid immunotherapy aims to modify the immune response to grass pollen allergens. A published laboratory study on allergoid-mannan conjugates reported that these conjugates can induce tolerogenic properties in human dendritic cells, which are immune cells that help regulate allergic responses. The study also found that the presence of alum, an adjuvant used in some allergy vaccines, may impair these tolerogenic effects by inhibiting a cellular pathway called mTOR and altering metabolic reprogramming in dendritic cells. This suggests that the mannan-conjugated allergoid is designed to promote immune tolerance to grass pollen.
Which conditions is grass pollen allergoid studied for?
- Grass pollen-induced allergic rhinitis or rhinoconjunctivitis — a condition in which grass pollen triggers symptoms such as sneezing, runny or blocked nose, and itchy or watery eyes. The clinical trial is specifically testing the allergoid in people with this condition.
How is grass pollen allergoid given?
The substance is formulated as a solution for injection and a solution for skin-prick test. The route of administration is subcutaneous injection for the immunotherapy product and subcutaneous use for the skin-prick test solution. In the trial, the investigational medicinal product is administered subcutaneously.
What do the clinical trials show?
The clinical development programme includes one authorised Phase 4 trial, a prospective, randomised, double-blind, placebo-controlled, multicentre, dose-finding study in 450 participants with grass pollen-induced allergic rhinitis or rhinoconjunctivitis. The trial compares two concentrations of the allergoid, 3000 mTU/mL and 9000 mTU/mL, given by subcutaneous injection, against placebo. The primary objective is to assess clinical efficacy and determine which concentration offers the best efficacy while taking safety and tolerability into account. The primary outcome measure is the mean daily Combined Symptom and Medication Score (CSMS), as defined in a position paper by Pfaar et al. (2014), over the peak grass pollen season in 2027. The CSMS combines symptom severity and the amount of rescue medication used, giving a single measure of how well the treatment controls the allergy.
What side effects are known?
The published laboratory study does not report side effects in patients. The clinical trial registry record does not list side effect data, as the trial is still authorised and has not reported results.