As vaccinations are key to better health for people around the world, and due to the variability of the global climate, vaccines must maintain stability and effectiveness under a variety of conditions. Animal- and plasma-derived proteins are currently used as stabilizing components in formulations of vaccines and other protein-based therapeutics.

Products containing animal- or plasma-derived proteins, such as gelatin and albumin, respectively, have the potential to induce harmful inflammatory or immune responses in humans and pose risk of contamination with potentially life-threatening pathogens, such as viruses or prions that cause the human form of mad cow disease. The use of animal-derived products is also a religious or cultural issue for many of the world's people.

In addition, the current process of making gelatin by denaturing collagen (a protein extracted from the skin, bones, and tissues of animal carcasses) yields a highly variable material, which presents a significant challenge to those who use these protein mixtures in the manufacture of other products. These animal-derived gelatin preparations consist of a mixture of protein fragments of different sizes, different isoelectric points, and different gelling properties, and often exhibit lot-to-lot variability. The physiochemical properties of gelatin also vary depending on method of extraction, amount of thermal denaturation employed, and electrolyte content of the resulting material. Gelatin hydrolysates represent a specialized preparation for use in situations where gel formation is undesirable. Gelatin hydrolysates are commonly used as stabilizers in liquid vaccine formulations. This class of gelatin requires additional processing steps such as thermal hydrolysis or treatment with a protease.

Because of these potential health risks and manufacturing issues, there is a significant need for safe and effective alternatives to animal- and human-derived proteins for use as stabilizers in vaccines and other biological therapeutics and for use in numerous other pharmaceutical, medical, and consumer products that are prevalent in our everyday lives.

Development of synthetic gelatin for use in vaccine and biologic stabilization
To meet this market need, FibroGen has developed a recombinant gelatin technology that uses a yeast expression system and a completely defined fermentation and purification process to produce human sequence gelatins. FibroGen has developed a battery of analytical tests to monitor its production process and confirm the high quality and purity of the Company's gelatins. Development efforts are focused on creating non-immunogenic gelatins and have been confirmed through collaborations with groups specializing in gelatin allergies. FibroGen's process has been scaled-up in the Company's pilot plant to supply clinical and commercial materials.

FibroGen has developed FG-5009, a synthetic gelatin molecule optimized for use as a stabilizing component in vaccine and biologic formulations. In vitro stabilization studies have demonstrated that synthetic gelatin is equivalent to the animal-derived gelatin stabilizer in commercially available vaccines. The safety of FG-5009 was examined in human volunteers at doses similar to, and significantly greater than, the dosage of animal-derived gelatin found in marketed vaccines and was found to be safe and non-immunogenic.

More information about FG-5009 can be found on the Products in Development section of this Web site.