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Phleum Pratense

This article summarizes several clinical trials investigating the use of Phleum pratense (Timothy grass) extracts for treating allergic rhinitis. These trials explore different administration methods, dosing regimens, and combinations with other therapies to evaluate the efficacy and safety of Phleum pratense immunotherapy for grass pollen allergies.

Table of Contents

What is Phleum Pratense?

Phleum pratense, also known as Timothy grass pollen extract, is a type of allergen extract used in immunotherapy for grass pollen allergies[1]. It’s derived from Timothy grass, a common cause of hay fever. This extract is used to help your body build tolerance to grass pollen, reducing allergic reactions over time.

You might see Phleum pratense referred to by different names in medical settings or on medication labels. Some common synonyms include:

  • AVANZ Phleum pratense[1]
  • SQ Grass SLIT-tablet[6]
  • GRAZAX/GRASTEK[6]

Conditions Treated

Phleum pratense is primarily used to treat allergic conditions related to grass pollen, including:

  • Allergic rhinoconjunctivitis: This condition involves inflammation of the nose and eyes due to an allergic reaction. Symptoms may include sneezing, runny nose, itchy eyes, and nasal congestion[1].
  • Seasonal allergic rhinitis: Also known as hay fever, this condition causes allergy symptoms during specific seasons when certain plants pollinate[6].
  • Grass pollen-induced allergic rhinitis: This is a specific type of seasonal allergic rhinitis caused by grass pollen[3].

Administration Methods

Phleum pratense can be administered in several ways:

  • Subcutaneous immunotherapy (SCIT): This involves injections under the skin, typically given in a doctor’s office[4].
  • Sublingual immunotherapy (SLIT): This method uses tablets or drops placed under the tongue, which can often be taken at home[4].
  • Intralymphatic immunotherapy (ILIT): This is a newer method where the allergen is injected directly into lymph nodes. It’s still being researched and may not be widely available[5].

The treatment usually involves an initial phase with increasing doses, followed by a maintenance phase. The exact schedule can vary depending on the specific product and administration method[1].

Effectiveness

Studies have shown that Phleum pratense immunotherapy can be effective in reducing allergy symptoms and the need for medication. For example:

  • Sublingual tablets have been shown to reduce symptom scores by about 30% and seasonal rescue medication use by about 38% compared to placebo[4].
  • The effects of the treatment can persist for several years after the treatment is stopped[4].

Effectiveness is often measured using a combined symptom and medication score (cSMS), which takes into account both the severity of symptoms and the amount of medication needed to control them[7].

Side Effects and Safety

Phleum pratense immunotherapy is generally well-tolerated, but like all medical treatments, it can have side effects. These may include:

  • Local reactions at the injection or application site
  • Mild systemic reactions such as itching or mild allergy symptoms

In rare cases, more severe allergic reactions can occur. That’s why the initial doses are usually given under medical supervision[4].

The safety profile of sublingual tablets (SLIT) appears to be better than that of subcutaneous injections (SCIT), with a lower risk of severe reactions[4].

Ongoing Research

Research on Phleum pratense immunotherapy is ongoing. Some areas of current investigation include:

  • Comparing different administration methods (subcutaneous, sublingual, and intralymphatic) to determine which is most effective and has the best safety profile[4][5].
  • Studying the immunological changes that occur during treatment, such as changes in antibody levels and immune cell responses[6].
  • Investigating the potential of combining immunotherapy with other treatments, such as probiotics[8].

These ongoing studies aim to improve the effectiveness of Phleum pratense immunotherapy and potentially expand its uses in treating allergic conditions.

Aspect Details
Treatment Types Subcutaneous injections (SCIT), Sublingual tablets (SLIT), Intralymphatic injections
Main Allergen Phleum pratense (Timothy grass) pollen extract
Primary Outcomes Symptom scores, Medication use, Combined symptom and medication scores (cSMS)
Secondary Outcomes Antibody levels (IgE, IgG4), Basophil activation, Nasal airflow, Quality of life measures
Treatment Durations Varied from 60 days to multiple years
Safety Monitoring Local and systemic reactions, Adverse events
Novel Approaches Intralymphatic injections, Combination with probiotics
Study Designs Randomized, double-blind, placebo-controlled trials; some with environmental challenge chambers

FAQ

  • What is Phleum pratense and how is it used in allergy treatment? Phleum pratense, also known as Timothy grass, is a common allergen used in immunotherapy for grass pollen allergies. Extracts from this grass are used to gradually expose patients to small amounts of the allergen, helping to build tolerance and reduce allergic symptoms over time.
  • What administration methods were studied for Phleum pratense immunotherapy? The clinical trials explored several administration methods, including subcutaneous injections (SCIT), sublingual tablets (SLIT), and intralymphatic injections directly into lymph nodes. Each method aims to deliver the allergen extract effectively to stimulate the immune system.
  • What were some of the main outcomes measured in these trials? Common outcomes included changes in allergy symptoms and medication use (often measured by combined symptom and medication scores), changes in specific antibody levels (IgE and IgG4), nasal and eye symptom scores, and quality of life measures. Some trials also looked at immunological markers and long-term efficacy.
  • Were there any notable side effects or safety concerns? While specific side effects varied between trials, allergic reactions were a potential risk. Many studies included monitoring for local and systemic reactions. Generally, the treatments were well-tolerated, with sublingual tablets often showing a better safety profile compared to injections.
  • How long did the treatments typically last in these trials? Treatment durations varied widely between studies, ranging from short-term protocols of 60 days to long-term treatments lasting multiple years. Some trials investigated pre-seasonal treatment, while others looked at year-round administration. The optimal duration of treatment is still being researched.

Ongoing Clinical Trials on Phleum Pratense

  • Dose-finding study of sublingual immunotherapy with phleum pratense extract (vs sodium chloride) in patients with grass pollen allergic rhinitis

    Not yet recruiting

    2 1
    Investigated diseases:
    Investigated drugs:
    Spain

  • Study on the Effectiveness of PURETHAL Mites for Adults with Moderate to Severe Allergic Rhinitis or Rhinoconjunctivitis Due to House Dust Mite Allergy

    Not recruiting

    3 1 1
    Investigated drugs:
    Austria Bulgaria Germany Latvia Lithuania Poland

Glossary

  • Allergic rhinitis: An allergic reaction affecting the nasal passages, typically causing symptoms like sneezing, runny nose, and nasal congestion in response to allergens like pollen.
  • Immunotherapy: A treatment approach that modifies the immune system's response, in this case to allergens, by gradually exposing the body to increasing amounts of an allergen to build tolerance.
  • SCIT (Subcutaneous Immunotherapy): A form of allergy treatment where allergen extracts are injected under the skin to desensitize the immune system.
  • SLIT (Sublingual Immunotherapy): An allergy treatment method where allergen extracts are placed under the tongue, often in tablet form, to be absorbed and desensitize the immune system.
  • Intralymphatic Immunotherapy: A novel approach where allergen extracts are injected directly into lymph nodes to stimulate a strong immune response.
  • IgE (Immunoglobulin E): An antibody that plays a crucial role in allergic reactions, often measured to assess allergy severity or treatment efficacy.
  • IgG4 (Immunoglobulin G4): An antibody subclass that can be induced by allergen immunotherapy and may play a role in developing tolerance to allergens.
  • Combined Symptom and Medication Score (cSMS): A measure used in allergy trials that combines the severity of allergy symptoms with the amount of medication needed for relief.
  • Basophil Activation Test: A laboratory test that measures the response of basophils (a type of white blood cell) to allergen exposure, used to assess allergy severity or treatment efficacy.
  • Environmental Challenge Chamber: A controlled setting used in some allergy studies where participants are exposed to specific levels of allergens to assess their reactions and treatment efficacy.

References

  1. https://clinicaltrials.gov/study/NCT01454531
  2. https://clinicaltrials.gov/study/NCT01438827
  3. https://clinicaltrials.gov/study/NCT02166268
  4. https://clinicaltrials.gov/study/NCT01889875
  5. https://clinicaltrials.gov/study/NCT05191186
  6. https://clinicaltrials.gov/study/NCT02245360
  7. https://clinicaltrials.gov/study/NCT02255604
  8. https://clinicaltrials.gov/study/NCT04603456