Up to the 1990s, the available bovine lung and porcine intestinal sourced heparins
were used interchangeably as essential life-saving anticoagulants for many different
surgical interventions. In the United States, the bovine product gradually fell out
of favour because the porcine-sourced heparin was more potent and, in the 1990s, concerns
regarding bovine spongiform encephalopathy (BSE) agents and the risk of variant Creutzfeldt–Jakob's
disease for humans. These factors caused a withdrawal of bovine sources of heparin
from many markets worldwide.
Since that time, increased testing and knowledge about controls to prevent transmission
of BSE agents has led to a dramatic decrease in reported BSE cases (e.g., two reported
cases worldwide in 2016[1]). In addition, the global supply of heparin is a critical World Health Organization-designated
essential drug and the use of pigs as the primary source has risks associated with
pig disease and potential instability due to other factors. Therefore, the U.S. Food
and Drug Administration hosted Science Board meetings in 2014 and 2016[2] to discuss the potential re-introduction of bovine heparin to the U.S. market and
in 2018[3] reiterated interest in seeing bovine heparin products return to use.
Notably, in some countries like Brazil where cattle are prevalent, bovine heparin
continued to be used clinically after the BSE crisis in the 1990s. Subsequently, even
in Brazil the use of bovine heparin was discontinued with the implementation of new
monograph requirements in 2008 for greater than 180 IU/mg for unfractionated heparin.
The new monograph requirements essentially designated the use of porcine-sourced heparin,
because bovine intestinal heparin has ca. ½ the potency w/w compared with porcine heparin. In 2017, the differences in chemical
composition and potency led the Brazilian Pharmacopeia to establish separate drug
monographs for porcine and bovine heparin.
In the current article by Tovar et al,[4] a straightforward application of bovine heparin fractionation with anion exchange
chromatography to produce a heparin with similar chemical composition, potency and
safety profile to porcine heparin is demonstrated. If such a porcine-like heparin
product could be made commercially from a bovine source and obtain approval from regulators,
a single heparin drug from different animal sources with different geographical distribution
with consistent quality could improve supply chain stability for this important drug.
