We strive to strategically protect the proprietary technologies that we believe are important to our business, including building a comprehensive global portfolio of patents intended to cover our product candidates, their methods of use, related technology and other inventions that are important to our business. Currently we own, or have licenses to, over 220 issued patents or allowed patent applications with predicted expiration dates ranging from 2026 to 2034. We also rely on know-how, trade secrets and continuing technological innovation and in-licensing opportunities to develop, strengthen, and maintain our proprietary position in the field of extracellular tRNA synthetase biology, and their receptors and related biology.
Our efzofitimod (ATYR1923) patent portfolio is comprised of a number of patent families related to the iMod domain, related splice variants, combinations with other therapeutics, and next-generation product forms with modified therapeutic activity or pharmacokinetic characteristics. Our efzofitimod patent portfolio currently includes, as of May 2019, four patent families, and includes issued patents in the US, Japan, China, Australia, Hong Kong and Europe.
Our pipeline of extracellular tRNA synthetase proteins is covered by a series of 21 patent families, which are directed to all 20 human cytosolic tRNA synthetases.