This study is looking at a medicine called efgartigimod to see if it is safe for adults with a condition called Primary Sjögren's Syndrome (pSS). People with pSS have too many harmful IgG autoantibodies in their bodies. These are proteins that attack healthy parts of the body. This study will check if efgartigimod can help by lowering these bad proteins.

Key points:

• The study lasts 48 weeks, with participants receiving efgartigimod once enrolled.
• Participants should have completed a prior efgartigimod study and must not have quit taking the study drug in that prior study.
• Risks include having diseases like cancer or heart problems or becoming pregnant during the study.

To join, you must have finished a previous efgartigimod study, be of legal age, agree to use birth control if needed, and be able to follow study rules. If you are pregnant, planning to have surgery, or have severe health issues, you cannot join. This study will help doctors understand how safe efgartigimod is for long-term use in people with pSS.