Approaches to enable large scale heparin bio-manufacturing - ABSTRACT Unfractionated heparin (UFH) and Low Molecular Weight heparins (LMWH) are the most important sulfated polysaccharide drugs used to treat thrombosis and other clotting disorders, which are among the leading cause of deaths in the US. The combined worldwide annual sales of unfractionated heparin and low molecular weight heparins are more than $ 10 billion. Nearly 300 metric tons of heparin is produced worldwide each year from animal tissues (mostly porcine), derived from over 750 million pigs across several million small pig farms. Several LMWHs have been approved for use in over 100 million medical procedures annually worldwide as clinical anticoagulants / antithrombotics, despite the fact that they vary significantly in their structural properties and pharmacological activities. Climate change, intentional adulteration (as happened in the 2007-2008 heparin crisis), and zoonotic diseases such as African Swine flu (which decimated nearly half of the hog population in China in 2018), underscores the need for an alternative, reliable modern drug production process for heparin, which is listed as a critical medicine by World Health Organization. In fact, the National Defense Authorization Act (NDAA) passed by US Congress in 2023 highlights the urgency to secure the heparin supply chain in the US. Despite numerous challenges faced in securing a reliable heparin source, animal-derived heparins are still the drugs of choice for the treatment or prevention of thrombo-embolitic disorders in over 100 million humans worldwide annually. Several groups pioneered the original chemical synthesis of the homogeneous ATIII-binding pentasaccharide, the active sequence in heparin shown to be critical for part of heparin’s anticoagulant activity. This involved numerous chemical steps, and the final product was obtained with a very low overall yield. Furthermore, since no antidote is available to neutralize the pentasaccharide drug, it requires close monitoring following administration to minimize bleeding risks. Recently developed biotechnological approaches to produce synthetic UFH and LMWH offer several advantages. We propose here our biotechnological approach to expeditiously synthesize heparin-like anticoagulants using engineered microbial cellular factories using modern fermentation procedures and modern molecular tools rather than relying on animal sources.
