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Welcome to the


Does Hay Fever spoil your summer?

The ARIAS Study is a clinical research study, which is looking to assess the effect of an investigational drug, IRL201104, on the allergic response in subjects who are known to be allergic to grass pollen.

We are currently recruiting adults aged 18-65 with a history of grass pollen induced allergic rhinitis for at least 2 years with heavy symptoms in May, June, or July.

This is a Phase 2a randomised, double-blind, placebo-controlled, parallel-design, allergen challenge 12-week study of IRL201104 versus placebo in adult participants with seasonal allergic rhinitis otherwise known as hay fever.

This trial may provide evidence to support the mechanism of action (how exactly the drug works), the dose and the duration of dosing of IRL201104. This information will help design a larger trial to study treatments for conditions such as yours.

Grass Allergy

Allergies happen when your immune system overreacts to a substance (an allergen such as grass pollen) that would otherwise be harmless. Hay fever, also called allergic rhinitis, affects around 25% of the UK and European population. Its symptoms generally include itchy, runny or stuffy nose and sneezing, and it can have a major impact on quality of life.

Current treatment for seasonal grass allergy includes taking over the counter or prescription medications to help reduce the symptoms, although they do not eliminate the allergy.

Before enrolling in the study, participants will be provided detailed information about all study visits and related tests and procedures.
Eligible participants will be randomized on Day 1 in a 1:1 ratio to receive either IRL201104 or placebo (a dummy medicine that looks the same as the study medicine but has no active ingredient), and will enter the double-blind treatment period. This means that neither you nor the study doctor will know if you are receiving IRL201104 or placebo.

IRL201104(8 mg) or matching placebo treatment will be given by an intravenous injection on Day 1 and thereafter once every 2 weeks for 10 weeks (6 total doses in the treatment period). Participants will return at Week 12 for the final study visit.
If you are eligible to participate in the study, you will receive compensation for your travel expenses.

Study Visits

The total study length is 12 weeks. The study visits are summarized below:

Visits every 2 weeks to provide treatment and monitor your general health and hay fever symptoms


Study LocationS

The ARIAS clinical study is led by Professor Stephen Till.

The study will be conducted in:

1. Clinical Research Facility, Guy’s Hospital, Great Maze Pond, London, SE1 9RT, and

2. Hammersmith Medicines Research (HMR), 44 Cumberland Avenue, London NW10 7EW

Contact Us

For more information about the ARIAS Study, please contact the study site below:

Clinical Research Facility, Guy’s Hospital: Call us on 020 7188 2600, email us at

HMR: email us at

Please select a location BEFORE APPLYING

Am I eligible?

Thank you for your interest in joining the ARIAS Study, please register by completing the below form.

1 Step 1
1. Are you aged between 18 and 65?
2. Do you suffer from hay fever with peak symptoms in May, June or July?
3. Have your hay fever symptoms interfered with your daily activities or sleep?
4. Do you use allergy medications (antihistamine tablets or nasal sprays) for your hay fever?
5. Do you also have hay fever symptoms in March and April for which you take regular treatment (antihistamine tablets or nasal sprays)?
6. Do you have poorly controlled asthma?
7. Have you ever had a life-threatening allergic reaction (anaphylaxis)?
8. Are you a current smoker?
9. How did you hear about us? (check all that apply)
10. Is your Body Mass Index (BMI) within the range 19 to 30 kg/m2?Please calculate using the link.