Focus Turns to Unmet Needs in ITP, Related Autoimmune Diseases After Rilzabrutinib Approval: David Kuter, MD, DPhil

Following the FDA approval of rilzabrutinib (Wayrilz; Sanofi) for immune thrombocytopenia (ITP), a rare autoimmune disorder, David Kuter, MD, DPhil, highlights the most pressing areas of ITP research in an interview with The American Journal of Managed Care^®.

Watch parts 1 and 2 to learn what rilzabrutinib's approval means for patients with ITP and how it differs from existing treatment options.

This transcript has been lightly edited; captions were auto-generated.

Transcript

What do you consider the most pressing unanswered questions in ITP research?

I think the major challenges in ITP are several. One, and I think the [rilzabrutinib] story illustrates a good effort to try to address, which is patients who are, in quotation marks, "refractory" to multiple kinds of therapies. This is a drug that we added to that list of patients to help them.

But I think the unmet medical needs in ITP are several. One is to be able to cure the disease, and, so far, we haven't been able to show that. Longer-term studies with both rilzabrutinib and other new therapies for ITP may offer a chance of a long-term treatment-free remission, where patients could come off drugs and not need any therapy, or potentially have the disease disappear. We're not quite at that stage, but curative therapies for ITP would be valued.

I think, finally, the other unmet medical need, and we haven't addressed that with any of the new medications, is how do we treat pregnant women with ITP? Most of our therapies for ITP and pregnancy are limited to IVIG [intravenous immunoglobulin] and corticosteroids, which ties our hands in a large respect because of our ability to use other medications. So, those are the 3 aspects of unmet medical need I would think about.

Maybe one last thing about unmet medical need is that there are patients who have what's called secondary ITP; this is ITP related to other diseases. All of the studies done with all the medications in ITP and all the currently approved medications for ITP address what's called primary ITP.

As time goes by, we come to realize that for many ITP patients, and maybe most ITP patients, it's due to something else, some other immune disorder, some other autoimmune process, some low-grade B-cell lymphoma. These are things that are called secondary ITP. I think many of the therapies we already use in secondary ITP, but it would be nice to have a study with any of the agents, new or old, to show that they work equally well in secondary ITP as they do in primary ITP.

The other thing I'd add to this discourse would be that ITP is the poster child for a whole class of autoimmune cytopenias; patients who have antibodies to red cells, antibodies to white cells, the same disease processes apply to them. What's interesting about the therapies in ITP is that what works in ITP, such as rituximab, works well in warm antibody hemolysis, which is a less common disorder.

What we know from the studies we've already done with rilzabrutinib is that it works well in ITP, as I just described to you, but it works well in warm antibody hemolysis, to the point that this may be a major therapy for antibodies attacking red cells. I would also infer that this drug is also being developed in IgG4-related disease, which is another autoimmune condition, and it may play a role even in diseases like sickle cell disease, where inflammation may be a primary aspect of the disease. If I had to speculate, it is also possible in a disease which has not yet been studied by anybody in any great degree, which is antiphospholipid antibody syndrome, which is another autoimmune condition with the same general mechanisms, where a BTK inhibitor may affect a broad spectrum of the immune system.