Prospective, Randomized, Multinational, Multicenter, Double-blind, Placebo and Active Controlled Trial in 4 Parallel-groups of Patients Suffering From Seasonal Allergic Rhinitis

Inclusion Criteria: Only patients fulfilling all of the following criteria at screening Visit 1 should be included in the present trial: * Male or non-pregnant, non-lactating female patient aged between 12 and 65 years (valid for Poland) OR between 18 and 65 years (valid for Bulgaria, Moldova and Germany) inclusive on the date of consent. * Female patient of childbearing potential abstaining from sexual intercourse or using a reliable method of contraception (e.g., condom with spermicide, intra uterine device, oral, injected, transdermal or implanted hormonal contraceptives, or had in the past a female sterilization e.g. tubal ligation, hysterectomy, oophorectomy, salpingectomy) for 30 days before enrolment and agree to continue its use during the trial. * A minimum of two seasons of previous history of at least moderate seasonal allergic rhinitis (SAR) to the pollen/allergens in season at the time the trial is being conducted. * Patient must have the following SAR symptoms: (i) nasal congestion, and at least one of the following; (ii) rhinorrhea; (iii) nasal itching; or (iv) sneezing. Nasal congestion plus one other nasal symptom score both rated by the patient as at least moderate in severity (≥2 on a 0-3 scale) and Total Nasal Symptom Score (TNSS) ≥6.0 over the last 24 hours. * Negative SARS-CoV-2 Rapid Antigen Test result at screening visit. * For adults (≥18 years): Informed consent to participate in the trial provided in written form; For adolescents (≥12 - \<18 years): own patient informed consent/ assent to participate in the trial and the informed consent from all parent(s)/ legal guardian(s) provided in written form. Inclusion criteria at Visit 2 (selection for randomization): Only patients fulfilling at Visit 2 the following inclusion criteria will be randomized in the trial: * Pollen-specific immunoglobulin E (sIgE) test ≥EAST class 3 (at least 3.5 kU/l). * Negative serum (hCG) pregnancy test (for female patient only). * Patient selected for randomization must have the following SAR symptoms over 3 days during the 3- to 5-day baseline period: (i) nasal congestion, and 1 or more of the following; (ii) rhinorrhea; (iii) nasal itching; or (iv) sneezing. * The mean TNSS must be ≥6.0 over 3 days out of the last 3-5 days of the Placebo run-in period; additionally, the mean nasal congestion score and mean of 1 other nasal symptom score both must be ≥2 (on a 0-3 scale) over 3 days out of the last 3-5 days of the Placebo run-in period. Exclusion Criteria: Patients presenting any of the following criteria will NOT be included in the trial: * Simultaneous participation in other clinical trials. * Use of any investigational drug within 30 days prior to enrolment (Visit 1). * Clinically significant medical condition (such as cardiovascular, hepatic, neurological, hematological, renal, gastrointestinal, endocrine or other major systemic disease) that, in the judgement of the investigator, would interfere with the trial, require treatment, or make implementation of the protocol or interpretation of the trial results difficult. * Any known hypersensitivity to azelastine or other antihistamines, mometasone or other steroids, or any of the components of the trial nasal sprays. * Structural nasal abnormalities symptomatic enough to cause nasal obstruction, as judged by the investigator, or any recent nasal surgery or trauma that is not completely healed. * Any other nasal conditions, including infectious rhinitis, sinusitis, rhinitis medicamentosa, atrophic rhinitis, and perennial rhinitis (PAR) (coexisting PAR will be allowed if SAR shows clear exacerbations). * History of upper respiratory tract or sinus infection that required antibiotic therapy with the last dose within 14 days prior to screening. * Treatment for oral candidiasis within 30 days of starting the trial. * Presence of untreated fungal, bacterial or viral systemic infection, or infection of the ear, nose, and throat or oral cavity of any character. * Presence of ocular herpes simplex or cataracts, or a history of glaucoma. * Vaccination within 14 days prior to screening visit. * History of habitual abuse of nasal decongestants (rhinitis medicamentosa). * History of non-response to intranasal steroids. * History of non-response to antihistamines. * Recent exposure or being at risk to chicken pox or measles exposure. * The patient is receiving immunotherapy or has received immunotherapy in the last 24 months. * Use of anti-immunoglobulin E antibodies within 6 months prior to screening visit. * Use of any of the following drugs: 1. Systemic corticosteroid therapy within 60 days prior to screening visit. 2. Topical (intranasal, inhaled, ocular) corticosteroid therapy within 30 days prior to screening visit. 3. Immunosuppressive drugs and immunomodulating drugs (e.g., omalizumab, mepolizumab or dupilumab) within 30 days prior to screening visit. 4. Cromolyn sodium or nedocromil within 14 days prior to screening visit. 5. Tricyclic antidepressants within 14 days prior to screening visit. 6. Histamine H1 antagonists (any generation of antihistamines) i.e., loratadine, cetirizine, desloratadine, levocetirizine, fexofenadine, hydroxyzine, etc. within 14 days prior to screening visit. 7. Leukotriene modifiers within 7 days prior to screening visit. 8. Nasal or oral decongestants (including anticholinergic agents, oxymetazoline, ephedrine or pseudoephedrine, and other vasoconstrictors) and mucolytics (like guaifenesin), or other medications that could mask the symptoms of rhinitis, e.g., major tranquilizers, anti-epileptic agents, within 3 days prior to screening visit. This includes over-the-counter preparations for common cold or eye drops containing any of the above-mentioned agents. 9. Nasal sprays or washes with any medication, including saline, within 24 hours prior to screening visit. * Planned to travel outside of the geographical region (as judged by the investigator according to regional pollination calendar) for \>3 consecutive days during the trial. * Member of the investigational trial staff or a member of the family of the investigational trial staff. * History of alcohol or drug abuse within the last 5 years. * History of non-compliance with medication regimens or treatment protocols in previous clinical studies. * Legal incapacity (for adults only) and/or other circumstances rendering the patient unable to understand the nature, scope and possible consequences of the trial. * Patients who are known or suspected to be in custody or submitted to an institution due to a judicial order.