Eligibility criteria
Sex: AllAge: 18 Years and olderHealthy volunteers: No
Inclusion Criteria:
* Participant must be a minimum of 18 years of age inclusive at the time of signing the informed consent form (ICF)
* Participant has Myasthenia Gravis Foundation of America (MGFA) Class I with any ocular weakness at Screening through Baseline. The participant may have weakness in muscles of eye (ie, extraocular muscles that move the eyeball, including the medial rectus, lateral rectus, superior rectus, inferior rectus, superior oblique, and inferior oblique, orbicularis oculi muscles, and levator palpebrae superioris) but must have normal strength in all other facial, bulbar, and limb muscles.
* Study participant has been diagnosed with Ocular Myasthenia Gravis (oMG) with consistent ocular clinical features at Screening and supported by:
* Documented presence of autoantibodies against acetylcholine receptor (AChR) or muscle-specific kinase (MuSK), OR
* Documented absence of autoantibodies against AChR or MuSK; in this case, documented abnormal repetitive nerve stimulation (RNS) or single fiber electromyography (SFEMG) (as defined in the adjudication manual) and at least 1 of the following should be met:
* Documented positive ice test (Ptosis recovers with the ice test \[applied 2 minutes (min) to the ptotic lid\] with \>2mm improvement)
* History of positive edrophonium chloride (Tensilon) test (or equivalent tests used to establish oMG diagnostic as per current practice)
* Demonstrated objective improvement in oMG signs with acetylcholinesterase inhibitor (AChEIs), plasma exchange (PLEX), intravenous immunoglobulin (IVIg), subcutaneous immunoglobulin (SCIg) or corticosteroids (CSs)
* Participant has an Myasthenia Gravis Impairment Index (MGII) ocular score (Patient-Reported Outcome (PRO) part) ≥6 with at least 2 ocular items with a score of ≥2 at both Screening and Baseline visits.
* Participant reported ocular symptom(s) onset \<3 years before Screening or ≥3 years provided they have demonstrated response (ie, improvement in ptosis or diploplia) to treatment (IVIg, PLEX, SCIg, pyridostigmine, and/or CSs) in the past year.
* Participant has no pupillary abnormality except those resulting from prior localized eye disease or surgical intervention.
* Participant who:
* is currently receiving background treatment for oMG symptoms at the time of Screening and has been receiving treatment for oMG with a stable dose for at least 30 days prior to Screening, OR
* is not receiving any background treatment at the time of Screening
* Participant has a body weight ≥35kg at Baseline.
Exclusion Criteria:
* Participant has any clinically significant medical or psychiatric condition (including an alcohol or drug use disorder), recent major surgery (including thymectomy \[within 3 months of Screening\], solid organ, stem cell or marrow transplant), planned major surgery (including thymectomy) during study participation, and/or significant laboratory abnormality that, in the opinion of the investigator, could jeopardize or would compromise the study participant's ability to participate in this study.
* Participant has been diagnosed with other diseases that lead to eyelid dropping, peripheral muscle weakness, or diplopia, including other autoimmune diseases that would interfere with an accurate assessment of the oMG clinical symptoms or other neurological diseases, such as congenital myasthenic syndromes, mitochondrial diseases, and muscular dystrophies.
* Participant has a known hypersensitivity to other anti-Fc receptor (FcRn) medications, to any components of the study medication (including the excipient polysorbate 80) or has a known history of hyperprolinemia, since L-proline is a constituent of the rozanolixizumab formulation.
* Participant has active neoplastic disease or has received treatment for neoplastic disease within 5 years of study entry (except for basal or squamous cell carcinoma of the skin, carcinoma in situ of the uterine cervix, carcinoma in situ of the breast, or incidental histological findings of prostate cancer \[Tumor, Node, Metastasis (TNM) stage T1a or T1b\] that has been definitely treated with standard of care approaches).
* Participant has a clinically relevant active infection (eg, tuberculosis (TB) infection) or a history of serious infection (resulting in hospitalization or requiring intravenous (iv) antibiotic treatment) within 6 weeks before the Baseline Visit.
* Participant has renal impairment, defined as glomerular filtration rate less than 30milliliter/min/1.73m2 at Screening.
* Participant has been previously treated with FcRn inhibitors.
* Participant has been treated with any of the immunosuppressive medications, biologics, or other therapies, in the specified prohibitive timeframe.
