Halozyme Therapeutics, Inc. has entered into a definitive agreement to acquire Elektrofi, Inc., a biopharmaceutical company with a breakthrough ultra-high concentration microparticle technology for biologics, branded Hypercon.   The transaction, which is comprised of an upfront payment of $750 million and up to three $50 million milestone payments contingent on three separate product regulatory approvals, was unanimously approved by the Boards of Directors of both Halozyme and Elektrofi....