Hello. I looked at your other requests to see if you mentioned infusions already. It may be possible to have a nurse come to you to have the infusions done but maybe not. Depends on what is involved. Plus, according to the Benlysta site, it seems kind of invloved. http://www.benlysta.com/lupus-medication/benlysta-treatme... gives more detail if this is what you are asking about.
Anyway, Happymom is right. Medically necessary treatment is covered under ADA. If these infusions are medically necessary, your employer cannot prevent you from getting them. They must accomodate you if it would not cause an extreme hardship to their business. Maybe you could schedule them for the end of day or early morning so that you have most of your work covered. It looks like they would be every 2 weeks or so according to the site though you could have a reaction so be prepared for that. Definitely look into this. Be prepared with an action plan for coverage of your work if they balk at it. Show you're prepared with all your facts.
I had a friend that needed chemo and she had to be accommodated for her treatments. Though after a while they said that her taking a day per week was affecting the job and they could not do so any longer. All about profits--plus they let 100 other people go 3 weeks later.