Long-Term Efficacy of Anti-CD20 Therapies in MS: What the Evidence Shows

With the first anti-CD20 therapy approved for MS now more than ten years in clinical use, in this episode titled "Long-Term Efficacy of Anti-CD20 Therapies in MS: What the Evidence Shows," Dr. Williams asks Dr. Krieger what the long-term evidence reveals about efficacy — and whether there have been any surprises.

Dr. Krieger identifies three sources of long-term data: direct clinical experience, real-world evidence, and long-term extension data from trials. The five- and ten-year publications from these trials are now emerging, and the efficacy findings are uniformly consistent: profound suppression of new disease activity — relapses and new MRI lesions — is maintained for as long as patients remain on therapy.

In practice, breakthrough disease on a B-cell depleting agent is now rare enough to constitute a "unicorn" event at his center, prompting collegial review and even reconsideration of the underlying diagnosis. Notably, though inflammatory activity is effectively suppressed, progression can still occur — a finding that does not indict B-cell therapies per se, but rather highlights incomplete treatment of the underlying pathobiology, particularly PIRA (progression independent of relapse activity).

Dr. Greenberg describes a shift in the nature of patient contacts at his clinic: calls about relapses have disappeared; calls now center on prior authorization and care coordination. Suppressing relapses has, paradoxically, "unmasked" progressive disease that was previously obscured by relapse noise — giving the field a clearer window to understand and target progression.

In the next episode, "Managing Infection Risk and Safety Monitoring with Anti-CD20 MS Disease Modifying Therapy," the panel discusses how to counsel patients about infection risk, what to monitor, and the emerging recognition of non-infectious complications.