Written by: David Clark, PhD, chair of the Coalition for Hemophilia B

NOTE: This article is not intended as medical advice. Readers should seek the advice of their own physician. Because information regarding COVID-19 (novel coronavirus) is ever changing, readers are also asked to check for frequent updates.

Novo Nordisk has sent a letter to healthcare professionals warning them that Rebinyn, their factor IX product, can interfere with some of the clotting assays used to monitor COVID-19 disease progression in patients.

We have seen that many COVID-19 patients develop thrombosis. Thrombosis is the formation of a clot (a thrombus) inside a blood vessel. It is a dangerous condition because not only can the clot cut off blood flow in that vessel, it can also break loose and travel to other parts of the body. A thrombus that breaks loose is called an embolism. If the embolism gets stuck in a major organ and blocks blood flow there, it can cause significant damage, even death. The conditions, which are called thromboembolic complications, can result in various disorders such as deep vein thrombosis (DVT), disseminated intravascular coagulation (DIC), pulmonary embolism (PE), and/or strokes (embolism in the brain).

Rebinyn interferes with some of the clotting assays that doctors treating COVID patients are relying on. Other hemophilia treatment products may also affect these assays, but so far, Novo is the only company that we’ve heard from.

The COVID patients who develop thromboembolic complications are treated with anticoagulants, like heparin, that must be dosed based on the results of clotting assays. Rebinyn interferes with some of these clotting assays that doctors are relying on to provide safe treatment. Other hemophilia treatment products may also affect these assays, but so far, Novo is the only company that we’ve heard from.  (On the hemophilia A side, Roche/Genentech reports that Hemlibra also interferes with some clotting assays.

Another article in this series discusses hemophilia and COVID-19. One of its major recommendations is to involve your hemophilia treatment center (HTC) or hematologist if you are being treated for COVID-19. This is one of the reasons. Most physicians don’t know much about hemophilia, and they know even less about the products we use. We also know very little about COVID-19 and its treatment. You can at least solve the problem of little hemophilia-related knowledge by involving your treater. Also, make everyone aware if you have been in any kind of clinical study for anything. Don’t just think that it doesn’t involve hemophilia and/or COVID. We keep finding that COVID affects a lot more than we know.

If you are being treated for COVID-19, involve your HTC or hematologist.

Please don’t stop taking your factor, whether it’s Rebinyn or another product. That can only make things worse. Just get the help you need.