PROSPECTUS SUMMARY

This summary is not complete and does not contain all of the information that you should consider before investing in our common stock. This summary highlights selected information contained elsewhere in this prospectus. You should read the entire prospectus carefully, including the more detailed information regarding our company, the risks of purchasing our common stock discussed under “Risk Factors,” and our financial statements and the accompanying notes , before making an investment decision.

Our Business

Effective March 11, 2004, pursuant to the Agreement and Plan of Merger (the “Merger Agreement”), dated as of January 28, 2004, among privately held DeliaTroph Pharmaceuticals, Inc., dba Hyalozyme Therapeutics, Inc. (“Halozyme”), Global Yacht Services, Inc. (“Global”) and Hyalozyme Acquisition Corporation (“Merger Sub”), a wholly owned subsidiary of Global, the Merger Sub merged with and into Halozyme, with Halozyme remaining as the surviving corporation (the “Merger”).

Halozyme Therapeutics, Inc. (Halozyme) is a therapeutically driven biopharmaceutical company dedicated to the development and commercialization of recombinant human enzymes for the infertility, ophthalmology, and oncology communities. The company’s broad product portfolio is based on intellectual property covering the family of human enzymes known as hyaluronidases. The company’s lead products offer a safe and pure alternative to existing slaughterhouse-derived extracts that carry risks of animal pathogen contamination and immunogenicity. The commercialization of Halozyme’s highly versatile enzyme technology within proven markets will enable the company to significantly impact the quality of medicine.