The study looks at adults who have nerve damage linked to Sjogren’s disease-associated sensorimotor polyneuropathy, the type that affects both feeling and movement, or sensory polyneuropathy, the type that only affects feeling. The medication being tested is a subcutaneous injection called efgartigimod, given once a week. Some participants will receive a matching placebo that looks the same but does not contain the active drug.

The purpose of the study is to determine whether weekly injections of the drug improve nerve symptoms compared with the placebo. Participants will receive an injection each week for several months and will attend regular visits where doctors will check nerve function using a questionnaire called the mTCNS (a score that rates how severe the nerve problems are). Other questionnaires will also be used, such as the Norfolk QoL-DN (a quality‑of‑life survey for nerve disease), the clinESSDAI and ESSDAI (measures of overall disease activity), the NPQ (a questionnaire about pain), a NRS rating for difficulty thinking, and patient‑ and clinician‑rated impression scales (PGIS, PGIC, CGIS, and CGI). Fatigue will be measured with the FACIT-Fatigue questionnaire.

Throughout the study, safety will be monitored by checking vital signs, heart rhythm, blood tests, and any side effects that may occur. Participants will have the opportunity to report any adverse events, and the study team will evaluate the seriousness of any findings. The overall design allows comparison of the drug’s effect with the placebo while keeping participants and investigators unaware of which treatment is being given.