A Study of Orelabrutinib in Patients With Secondary Progressive Multiple Sclerosis

Inclusion Criteria: 1. 18 to 60 years of age, inclusive, at the time of signing the informed consent. 2. Participant must have a previous diagnosis of RRMS in accordance with 2024 McDonald criteria 3. Participant must have a current diagnosis of SPMS in accordance with the clinical course criteria revised in 2013 4. Participant must have documented evidence of disability progression independent of clinical relapse observed during the 24 months before screening. A written summary of the clinical evidence of disability progression must be discussed and aligned between the Investigator and the Sponsor's dedicated qualified person(s). 5. Absence of clinical relapses for at least 24 months. Exclusion Criteria: 1. The patient has been diagnosed with primary progressive MS (PPMS) according to 2024 McDonald diagnostic criteria 2. Immunologic disorder other than MS or any other conditions requiring corticosteroid therapy. 3. History or current diagnosis of other neurological disorders that may mimic MS 4. History or current diagnosis of progressive multifocal leukoencephalopathy 5. Active, clinically significant viral, bacterial, or fungal infection 6. History of any other significant active medical condition 7. History of suicidal behavior within 6 months prior to Screening 8. Any prior history of malignancy 9. Patients on anticoagulation, or antiplatelet therapy 10. Patients took strong/moderate CYP3A inhibitors or strong/moderate CYP3A inducers within 14 days 11. Clinically significant laboratory abnormalities at Screening. 12. Vaccination with live or live-attenuated virus vaccine within 1 month prior to Screening 13. History of alcohol abuse or alcohol use disorder or other drug abuse within 12 months prior to screening.