The future of plasma-derived medicinal products (PDMP)

Good morning, you all. I'm Daniele Focosi. I'm a hematologist and transfusion physician at the Pisa University Hospital in Italy. I'm going to talk to you about the future of plasma-derived medicinal products or PDMP, as we will shorten in the rest of this talk.

I have no conflict of interests to disclose concerning the topic of this talk.

I'm going to introduce you to the table of contents during this one hour talk. At first, we will discuss the types of PDMP and their main indications. Then I will focus on the Italian case study for what concerns PDMP usage and collections. Then I will focus on a special type of PDMP which is COVID-19 convalescent plasma, which is a topic of utmost interests in the last three years. Finally, I will discuss the perspectives for the intravenous immunoglobulins or IVIG in the setting of COVID-19, especially for the immune-compromised patients.

At first, let's have a look at the different types of PDMP. The most used type is definitively albumin, which represents the main protein in human serum. Albumin has a half-life as short as 12-16 hours, and these are commercially available at two different concentrations. The first one is the isooncotic formulation at 5%, and the second formulation is at 20-25% concentration, so it is hyper-oncotic. The main indications for usage of albumins are evacuative paracentesis, high-volume therapeutic plasmapheresis, bacterial peritonitis, and as a minor indications albumin can also be used in patients with severe burns, hemorrhagic shock, major surgery, protein-losing enteropathies, and nephrotic syndrome. The second most commonly use PDMP, is immunoglobulins. It is mostly used as an intravenous formulation, but it is increasingly used as a subcutaneous formulation, as we will see later. There are three main concentrations of immunoglobulins, 5, 10, and 50 g/l. In commercially available immunoglobulins mostly consist of IgG subclasses of immunoglobulin, meaning that they are poorly representative of IgA, and IgM subclasses. The main indications for immunoglobulins are primary and secondary hypogammaglobulinemias as a replacement therapy and at high doses, the other major indication is instead autoimmune diseases. The most common autoimmune diseases are ITP, Immune Thrombocytopenic Purpura, Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathies and Kawasaki syndrome. These are the official indications. But most of the usage actually stems from plenty of off-label uses, which is generating scarcity of the product. We are having in these years a pipeline of small molecules that will hopefully reduce the demand for immunoglobulins. The main class is the blockers of the neonatal Fc receptor, which basically reduce the clearance of the immunoglobulins that are reinfused. Then we have the third major class of PDMP, which are the clotting factors. They are mainly used as a replacement therapy in patients with coagulopathies. We have different types of clotting factors. The main two are Factor VIII and Factor IX concentrates, which are used for hemophilia A and hemophilia B respectively. Factor VIII concentrates can also include Von Willebrand factor, which is another very important protein for the stability of coagulation. Another side indication is Von Willebrand disorder, which is a different type of inherited coagulant. As you can see, there are plenty of different plasma derived clotting factors already available in the market. But they are suffering mounting competition from recombinant clotting factors. This basically means that we can forecast a reduction in the demand for plasma-derived clotting factors from both recombinant clotting factors and upcoming gene therapies for what concerns hemophilia. But plasma-derived clotting factors is not limited to Factor VIII and IX because we also have prothrombin complex concentrates, which are also available for different indications, and we've quite a varied formulation on the market. Then we have other minor plasma derived clotting factors, such as antithrombin III, and activated protein C concentrates. These do not represent the majority of usage, but can be somewhat lifesaving so there are often drugs which can be very useful in daily practice.