How do you approach transitioning MS patients from Ocrevus to Tysabri or vice versa?

From Ocrevus to Tysabri: I time the first Tysabri infusion to be 6 months after the last Ocrevus infusion, when the patient would be due for their next Ocrevus anyway. I do not wait for CD19/20 repletion, since Tysabri should not affect/be affected by B cell status.

From Tysabri to Ocrevus: this is...