Halozyme Therapeutics Inc. plunged the most in almost eight years after U.S. regulators requested more information on the company’s blood product used to boost weak immune systems, delaying the treatment’s possible approval.
Halozyme declined 24 percent to $8.56 at the close of New York trading, its biggest drop since August 2004. The San Diego-based company is developing the injection of immune globulin with Baxter International Inc., whose shares fell the most in two years.
Halozyme and Baxter said the U.S. Food and Drug Administration asked for more information about the treatment, known as HyQ. The experimental drug is used to boost patients’ defense against diseases, with Deerfield, Illinois-based Baxter. They will have to do more studies about long-term use of the drug, and said they also expect to go before an outside panel that advises the FDA.
“The companies expect these requests to require additional time to complete and to delay the companies’ anticipated regulatory review and approval timeline,” Halozyme and Baxter said in a statement today.
HyQ is in the third of three stages of testing usually required for approval by U.S. regulators.
Baxter, based in Deerfield, Illinois, declined 6.8 percent to $54.10.