A Study to Investigate GB-0895 Adjunctive Therapy in Adults and Adolescents With Severe Uncontrolled Asthma (SOLAIRIA-1)

1. Adults and adolescents ≥ 12 and ≤ 80 years of age.

2. Documented physician diagnosis of asthma for ≥ 2 years.

3. Subjects must be on medium to high dose ICS for ≥ 12 months before Screening Visit 1plus at least 1 additional asthma controller (e.g., LABA, LAMA) ≥ 3 months beforeScreening Visit 1 with no change in ICS or controller(s) for at least three months.

4. Subjects must have a well-documented history of at least two asthma exacerbationsrequiring systemic corticosteroid treatment despite the use of medium-to-high doseICS in the past 12 months before Screening Visit 1.

5. Adults ≥ 18 years of age at Screening Visit 1, a pre-BD FEV1 <80% predicted atScreening Visit 1.

6. Adolescents 12 to < 18 years of age at Screening Visit 1: A pre-BD FEV1 < 90%predicted OR, FEV1:Forced Vital Capacity (FVC) ratio < 0.80.

7. Positive BD responsiveness test: Increase of at least 12% and 200 mL in FEV1 between 15 and 60 minutes after the administration of a short-acting β2-agonist (SABA) atleast once during the screening period.

8. ACQ-6 score ≥ 1.5 at the Screening Visit.

9. Weight ≥40 kg at the Screening Visit 1

Exclusion Criteria:

1. Subjects who experience a clinically significant asthma exacerbation within 12 weeksbefore the Screening Visit or during the run-in period and require a change inasthma maintenance therapy.

2. Other concurrent respiratory disease other than asthma, including (but not limitedto) current infection, bronchiectasis, pulmonary fibrosis, bronchopulmonaryaspergillosis, tuberculosis, diagnosis of chronic pulmonary disease (including butnot limited to emphysema and/or chronic bronchitis), or a history of lung cancer.

3. Eosinophilic disease (e.g., eosinophilic granulomatosis with polyangiitis,eosinophilic esophagitis).

4. Any cardiovascular, gastrointestinal, hepatic, renal, neurological, musculoskeletal,infectious, endocrine, metabolic, hematological, psychiatric, or major physicalimpairment that is not stable in the opinion of the Investigator and could affectsubject safety, influence study findings or interpretation, or impede completion ofthe study.

5. Clinically significant infection that is unresolved and requires systemicantibiotic, antifungal, antiparasitic, or antiviral medications precedingenrollment.

6. A current malignancy or previous history of cancer within 5 years before screening.

7. Clinically significant infection that is not resolved before study enrollment.

8. Subjects with a known, pre-existing helminth parasitic infestation within 6 monthsbefore Screening Visit 1.

9. Current smokers or subjects with a smoking history ≥10 pack-years, and subjectsusing vaping products, including electronic cigarettes.

10. Former smokers with a smoking history of <10 pack-years and users ofvaping/e-cigarette products must have stopped for at least 6 months before ScreeningVisit 1 to be eligible.

11. Hepatitis B, C, or HIV.

12. Major surgery within 8 weeks before Screening Visit 1 or planned surgical proceduresrequiring general anesthesia or inpatient status for >1 day during the study.

13. Use of any anti-IL-5 therapy (e.g., mepolizumab, reslizumab, benralizumab,depemokimab) within 12 months before Screening Visit 1 or other monoclonalantibodies used for asthma within 4 months or 5 half-lives.

14. Prior use (at any time) of any anti-TSLP or anti-TSLP receptor biologics, approved (e.g., tezepelumab) or investigational.

15. Treatment with systemic immunosuppressive/immunomodulating drugs (e.g.,methotrexate, cyclosporine) within 12 weeks prior to randomization.

16. Receipt of an investigational biologic within 4 months or 5 half-lives, OR receiptof an investigational non-biologic within 30 days or 5 half-lives before ScreeningVisit 1.

17. Known history of sensitivity to any component of the study treatment formulation.

18. History of life-threatening anaphylaxis following any biologic therapy.

19. Concurrent enrollment in another clinical study involving investigational product (IP).

20. Subject has been randomized in the current study or previous GB-0895 studies.

21. Any clinically meaningful abnormal finding in physical examination, vital signs,ECG, hematology, serum chemistry, or urinalysis that, in the opinion of theInvestigator, may put the subject at risk, influence study results, or impede studycompletion.

22. Cirrhosis (with or without hepatic dysfunction) or other active or clinicallysignificant liver disease.

23. Receipt of immunoglobulin or blood products within 30 days before Screening Visit 1.

24. Receipt of live attenuated vaccines within 30 days before randomization and duringthe study, including the follow-up period.

25. Receipt of the T2 cytokine inhibitor suplatast tosilate within 15 days beforeScreening Visit 1.

26. Subjects treated with bronchial thermoplasty in the last 12 months before ScreeningVisit 1.

27. Unwillingness or inability to follow study procedures, including poor adherence toasthma controller medications, in the opinion of the Investigator.

28. Women who are pregnant, lactating, or planning to become pregnant during the study.

29. History (or suspected history) of alcohol misuse or substance abuse within 2 yearsbefore Screening Visit 1.