Last week we shared new about Sevenfact, a commercial blood clotting recombinant product made from transgenic rabbits. But that made me think: maybe we should step back and review what types of factor products there are to begin with.
There are different kinds of factor concentrates, all with distinct brand names and made by different companies, but all blood-clotting factor concentrates are classified as one of two types:
• Plasma derived • Recombinant
The major difference between the two types is the origin of the factor, called the source material.
• Plasma-derived factor originates from human blood plasma.
- Recombinant factor originates from genetically engineered mammalian cells containing the human gene for factor (not from human blood).
You might think that recombinant products have an advantage because they don’t come from human blood, but some still contain extraneous (unwanted) proteins—human and even animal. To understand the differences among products, you first need to know how various factor products are manufactured.
Plasma-derived factor concentrates are categorized by their degree of purity. Recombinant factor concentrates are categorized by how they are produced. Different—although very similar—manufacturing processes can create products with slight molecular differences in the factor protein and with varying degrees of extraneous proteins in the final product. Here are classifications of factor products, based on varying degrees of purity or differing manufacturing processes:
• intermediate purity • high purity • ultrapure (monoclonal)
• first generation • second generation • third generation • fourth generation
Several recombinant factor products also have a prolonged half-life, allowing you to infuse less frequently. The first of these new products was introduced in 2014.
Why are there so many kinds of manufacturing processes? Why not just use one method to produce factor? In some cases, it’s partly a legal matter: if manufacturer A creates an effective way to produce factor, then A usually patents the process. No one else can use it. Manufacturer B will need to find another way! So manufacturers have developed a variety of slightly differing processes to produce factor.
It’s also a matter of purity and safety. Different products use differing source material and require specific types of manufacturing methods to ensure safety. Due to varying production methods and the type of factor, the relative purity of the final products varies. Purity and safety are two terms you must understand to know which brand of factor to choose, because not all factor concentrates are created equal.
Do you know the difference between purity and safety? It’s easy to confuse them. We’ll review them next week!
Excerpted from Raising a Child with Hemophilia, Laureen A. Kelley 2016