Many if not most countries have preferred front-line treatments, usually decided by a combination of overall costs. These costs will include things like actual monetary cost, how closely you need to be monitored by your doctors (blood tests and stuff), how severe side effects are, how much the reduce disability in the long term, the ability of patients to stick with it and things like that.

Right. And some countries choose to have first-line treatments that prioritize lower cost over efficacy of therapy. It's great as a taxpayer, not so great at a patient.

Some countries prescribe Rituximab as quasi off-label for MS. Basically same drug for all intents and purposes as Ocrevus.

I think Sweden uses Rituximab openly for MS. In the US I've heard some neuros prescribe Rituximab if insurance won't cover O.

Rituximab was shown to be inferior in a head to head comparison against ocrelizumab.