A Clinical Study Investigating OM-85-IN Safety and Tolerability in Healthy Volunteers and Mild Allergic Asthma Patients

Inclusion Criteria:

1. Male and female subjects aged 18 to 55 years. Women will be considered for inclusionif they are:

• Not pregnant, as confirmed by pregnancy test, and not breastfeeding.

• Of non-childbearing potential, or

• Of childbearing potential and using a highly effective method of contraception .

2. Body mass index (BMI) ≥18 and ≤32 kg/m2.

3. Part II : History of mild asthma that is well controlled with Step 1 treatmentaccording to GINA guidelines 2023 for at least 12 months prior to the ScreeningVisit, i.e., a history of respiratory symptoms such as wheeze, shortness of breath,chest tightness, cough, and limitation of airflow induced by aeroallergens.

4. Part II: Forced Expiratory Volume in the first second (FEV1) ≥80% of predicted atScreening Visit.

5. Part II : Positive skin prick test to common aeroallergens such as tree, weed, grassor house dust mites within 12 months prior to the Screening Visit

6. Part II : Production of adequate sputum with ≥2 x 105 total non-squamous cellswithin 12 months to 2 weeks prior to V1A (Day -8)

7. Part II : Positive reaction to Nasal Allergen Challenge (NAC) within 12 months to 2weeks prior to baseline

Exclusion criteria:

1. Any clinically relevant abnormal findings in physical examination, clinicalchemistry, haematology, urinalysis, vital signs, lung function or electrocardiogram (ECG) at Screening Visit, which, in the opinion of the Investigator, may either putthe subject at risk because ofvparticipation in the study or may influence theresults of the study, or the subject's ability to participate in the study."

2. Use of prohibited medication prior to study enrolment

3. Part II - Long-term, daily treatment with inhaled corticosteroids.

4. Part II - Exacerbation of asthma defined according to the GINA guideline 2023 as aprogressive increase in symptoms of shortness of breath, cough, wheezing or chesttightness and progressive decrease in lung function, i.e., they represent a changefrom the patient's usual status that is sufficient to require treatment changeswithin 1 month prior to the Screening Visit.

5. Part II - Concomitant allergies to seasonal aeroallergens which are anticipated tobe or become active during study participation.

6. Known allergy to IMP active substance and/or excipients or the challenge agentcomponents.

7. Specific immunotherapy in the past 3 years before Baseline, ongoing treatment withany specific immunotherapy or plan to receive such treatment during studyparticipation.

8. Previous or ongoing treatment with other bacterial lysates and/or probiotics (dietary supplements, medicinal products and/or other health products) within 30days before Baseline.

9. Patients with pathological skin modifications in the test area (e.g., acute orchronic eczema or skin infections), with disturbed skin reactivity (e.g.,hyperkeratosis, ichthyosis, urticaria factitial), or with acute, generalizedhypersensitivity reactions.

10. Participation in any other clinical study within 30 days prior to Screening.

11. Past or present disease, which as judged by the Investigator, may affect the outcomeof this study.

12. Positive serology test for hepatitis B surface antigen (HBsAg), hepatitis B coreantibodies, hepatitis C virus antibodies (HCV-Ab) or human immunodeficiency virus (HIV) antibody at Screening Visit

13. History or presence of clinically significant hypertension

14. History of anaphylactic shock, generalised exanthema, angioedema or hypotensioncaused by the allergen used for NAC, or any medicinal product in the past.

15. History of drug or alcohol abuse in the past 12 months.

16. Current smokers or ex-smokers for less than 6 months or more than 10 pack years.Current vapers (users of e-cigarette products) or ex-vapers for less than 6 months.

17. Part II : Negative reaction in the baseline NAC