A Study of Orelabrutinib in Patients With Primary Progressive Multiple Sclerosis

Inclusion Criteria:

• 18 to 60 years of age, inclusive

• Diagnosed with Primary Progressive MS (PPMS) according to 2017 McDonald criteria

• Participant must have documented evidence of disability progression observed duringthe 24 months before screening.

• Expanded disability status scale (EDSS) score between 3.0 to 6.5 points, inclusive,at Screening.

Exclusion Criteria:

• Diagnosed with relapsing-remitting MS (RRMS) or secondary progressive MS (SPMS)

• Immunologic disorder other than MS or any other conditions requiring oral,intravenous (IV), intramuscular, or intra-articular corticosteroid therapy.

• History or current diagnosis of other neurological disorders that may mimic MS

• History of any other significant active medical condition

• History of suicidal behavior within 6 months prior to Screening

• Any prior history of malignancy if no recurrence within 5 years

• Patients on anticoagulation, or antiplatelet therapy will be excluded

• Patients took strong/moderate CYP3A inhibitors or strong/moderate CYP3Ainducerswithin 14 days

• Clinically significant laboratory abnormalities at Screening.

• Any allergy, contraindication, or inability to tolerate orelabrutinib or any of theexcipients in the study intervention

• Vaccination with live or live-attenuated virus vaccine within 1 month prior toScreening

• History of alcohol abuse or alcohol use disorder or other drug abuse within 12months prior to screening.