Efficacy and Safety of Depigmented Polymerized Grass Pollen Extracts in Patients with Allergic Rhinoconjunctivitis and Controlled Asthma: A Randomized Controlled Trial
- Trial ID
- 2025-521736-10-00
- Protocol
- 0600-PG-PSC-218
- Sponsor
- LETI Pharma S.L.U.
Trial statistics
Diseases & Conditions
Objectives
The primary objective is to evaluate the clinical efficacy of allergen immunotherapy using two concentrations of depigmented polymerized grass extracts compared to a placebo in patients with allergic rhinoconjunctivitis and or without controlled asthma. In the double-blind, randomized, controlled phase, efficacy is assessed via a combined symptom and medication score during peak grass pollen exposure following a minimum of eight injections. In the open-label phase, efficacy is determined by the change in the threshold of allergen required to elicit a positive conjunctival provocation test relative to baseline. 5
Secondary objectives include the assessment of:
- Clinical efficacy, quality of life, treatment satisfaction, resource utilization, and immunological parameters throughout the entire grass pollen season.
- Efficacy within the asthma patient subset during the pollen peak and throughout the pollen season.
Participants
The sponsor did not provide information regarding the total number of participants. The study population consists of patients with allergic rhinoconjunctivitis, which may occur with or without controlled asthma. Eligible individuals include both males and females from various age groups, specifically those aged 5 years or older. Inclusion requires a diagnosis of moderate or severe disease according to ARIA criteria, while asthmatic participants must have stable disease managed according to GINA guidelines. Participants are required to possess a mobile device capable of supporting a specific application and must reside in their usual location during the pollen season. The study population is characterized by the ability to comply with the protocol and maintain contact with the investigator.
Plans and Procedures
This Phase 5 clinical trial employs a double-blind, randomized, controlled design to evaluate the efficacy and safety of two concentrations of depigmented polymerized allergen extracts, specifically 1000DPP/ml and 3000DPP/ml, compared to a placebo in patients with allergic rhinoconjunctivitis with or without controlled asthma. The study is divided into two distinct stages. The first stage is a double-blind phase focusing on the assessment of the combined symptom and medication score (cSMS) during the peak grass pollen season following a minimum of eight subcutaneous injections. The second stage is an open-label phase designed to evaluate changes in the allergen threshold required to achieve a positive conjunctival provocation test (CPT) after the pollen season compared to baseline. Study procedures begin with a screening visit to ensure eligibility based on clinical criteria, such as age and disease stability. Participants will receive treatment via subcutaneous injection using a suspension formulation. The estimated recruitment period begins in April 2026, with the trial expected to conclude by October 2029. Participation is contingent upon the ability to comply with the protocol and maintain contact with the trial site for safety monitoring.
Treatment
Depigoid Grass-Mix (1000 DPP/ml) is an investigational suspension for injection containing depigmented polymerized extracts of Phleum pratense, Festuca elatior, Dactylis glomerata, Poa pratensis, and Lolium perenne pollen. The administration route is subcutaneous at a dose of 0.5 ml.
Depigoid FORTE Grass-Mix (3000 DPP/ml) is an investigational suspension for injection containing depigmented polymerized extracts of Phleum pratense, Festuca elatior, Dactylis glomerata, Poa pratensis, and Lolium perenne pollen. The administration route is subcutaneous injection at a dose of 0.5 ml.
The placebo used in this study is a suspension consisting of the solvent utilized in the formulation of the investigational medicinal products.
Conjunctival Provocation Test Grass-Mix LETI 30 HEP/ml is an auxiliary solution for provocation test containing Phleum pratense, Lolium perenne, Poa pratensis, Festuca elatior, and Dactylis glomerata pollen extracts. This product is intended for ocular use at a dosage of 30 DF.
Efficacy
The assessment of efficacy in the double-blind, randomised, controlled phase is conducted through the evaluation of the combined symptom and medication score (cSMS), measured on a scale of 0-6. This score is collected via a mobile App during the peak grass pollen season after a minimum of 8 injections. The medication component of the score includes 0 for no medication, 0.5 for antihistamine eye drops, 1 for oral antihistamine, and 1.5 for intranasal corticoid. Secondary efficacy parameters during this phase include the mean cSMS throughout the entire grass pollen season, as well as asthma symptoms and asthma medication score.
In the open-label phase, clinical efficacy is evaluated by measuring the change in the amount of allergen required to achieve a positive conjunctival provocation test (CPT) compared to baseline following the pollen season.
Inclusion and Exclusion Criteria
Inclusion Criteria
- Participants aged ≥5 years of age at the time of signing consent or assent.
- Participants suffering from moderate or severe allergic rhinoconjunctivitis (ARIA)
- Asthmatic participants must be, in the Investigator’s judgement, with controlled disease according to Global Initiative on Asthma (GINA) guidelines
- Participants/legal representatives who have understood and signed the informed consent or informed assent (see Section 10.1.4).
- Participants or guardians need to have a mobile phone which can support the cSMS App and access to internet and/or mobile service.
- Participants who are able to remain at their usual place of residence for the majority of the pollen season.
- Participants are capable of complying with the study protocol.
- Preexisting stable disease is allowed unless otherwise specified in the exclusion criteria in Section 5.2, as established by medical history and physical examination and as determined by the Investigator. Preexisting stable disease is defined as not requiring significant change in therapy or hospitalization for worsening disease during the 28 days before enrolment.
- Agree to actively stay in contact with the trial site for the duration of the trial for the participant’s own safety
Exclusion Criteria
- Previous treatment with any type of AIT in the previous 5 years
- Sensitisation to Alternaria alternata
- Sensitisation to mites if clinically relevant
- Sensitisation to epithelia if the participant lives or has frequent contact with animals.
- Sensitisation to other co-seasonal allergens
- Participants receiving treatment with biologics
- Uncontrolled asthma at the time of immunotherapy administration, according to the GINA guidelines or unstable asthma
- Female participants of non-childbearing potential may be enrolled in the study. Nonchildbearing potential is defined as pre-menarche, current bilateral tubal ligation or occlusion, hysterectomy, bilateral ovariectomy. Female participants of childbearing potential may be enrolled in the study, if the participant: o has practiced adequate contraception for 1 month prior to study intervention administration, and o has a negative pregnancy test on the first day of study intervention administration, and o has agreed to continue adequate contraception during the entire study treatment period (see Section 10.4).
- Lactating.
- Any contraindication for treatment with SC allergen specific immunotherapy according to information of product use.
- Participants who have required systemic corticosteroids in the 12 weeks prior to the inclusion (screening) in the trial.
- Participants who have previously suffered a serious secondary reaction during the skin prick test (systemic reactions after SPT, which can be classified using World Allergy Organisation 2010 (WAO-2010) reactions and serious according to regulatory definition of serious adverse reaction).
- Participants clinically unstable at the time of the inclusion (screening) in the trial (acute asthmatic exacerbation, respiratory infection, febrile fever, acute urticaria, etc); rescreening is permitted (see Section 5.4).
- Any other clinical condition that, in the opinion of the Investigator, might pose additional risk to the participant due to participation in the study.
- Participants with Investigator-determined chronic urticaria, severe dermographism, severe atopic dermatitis, sunburn, active psoriasis with lesions in areas where skin tests will be performed, or a history of hereditary angioedema.
- Participants with any condition that represents an absolute contraindication to the administration of adrenaline (heart disease, etc).
- Participants undergoing immunosuppressive treatment (except topical immunosuppressants).
- Participants with any other disease not associated with the moderate or severe rhinoconjunctivitis or asthma, but of potential severity and that could interfere with the treatment and follow-up (epilepsy, psychomotor deterioration, malformations, multi-operated, kidney diseases, etc).
- Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination (no laboratory testing required).
- Participants whose status prevents them from providing cooperation and/or who presents with severe psychiatric disorders.
- Participants with known allergy to other vaccine components different from grass allergen extract.
- Participants with chronic lower airway diseases other than asthma such as emphysema or bronchiectasis.
- Direct relatives of the Investigator.
Trial Status by Country
| Country | Status | Start of Recruitment | Planned Patients |
|---|---|---|---|
 Portugal | Recruiting | 01 Apr 2026 | 56 |
 Spain | Recruiting | 01 Apr 2026 | 268 |
Sites & Investigators
Investigational Products
Details about the medicinal products being studied in this clinical trial.
| Product Name | Role in Trial | Formulation | Administration | Max Daily Dose | Treatment Duration | EU MP Number |
|---|---|---|---|---|---|---|
The placebo to be used in the clinical trial is the solvent used in the investigational medicinal products’ (IMPs) formulation. The resulting product is a suspension. | Placebo | N/A | — | — | — | N/A |
Depigoid Grass-Mix1000 DPP/ml | Test | SUSPENSION FOR INJECTION | SUBCUTANEOUS USE | 0.5 | 156 | PRD12294837 |
Depigoid FORTE Grass-Mix3000 DPP/ml | Test | SUSPENSION FOR INJECTION | SUBCUTANEOUS INJECTION | 0.5 | 156 | PRD12295734 |
Conjunctival Provocation Test Grass-Mix LETI 30 HEP/ml | Other | SOLUTION FOR PROVOCATION TEST | OCULAR USE | 30 | 1 | PRD12962435 |