This study aims to evaluate the efficacy and safety of grass pollen immunotherapy for individuals living with allergic rhinoconjunctivitis, which is an allergic reaction affecting the nose and eyes, and may occur with or without controlled asthma. The treatment involves the use of Depigoid Grass-Mix and Depigoid FORTE Grass-Mix, which are suspensions for injection containing extracts from various grass pollens. These extracts have undergone a process to remove color and change their structure to be used for subcutaneous use, meaning they are administered by injection under the skin. A placebo will also be used during the investigation.

The research is conducted in different stages. Initially, a phase involves a double-blind process, where neither the participants nor the researchers know who is receiving the active medication or the placebo. During this stage, participants receive regular injections, and their symptoms and use of medications like antihistamines or intranasal corticoids are monitored. This is followed by an open-label phase, where the treatment details are known to everyone involved. This part of the study looks at how the body responds to different amounts of pollen through a conjunctival provocation test, which is a method used to see how the eyes react when exposed to allergens.