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Injectable Hyaluronidase Approved by FDA

Cheryl A. Thompson

A formulation of hyaluronidase for injection, absent from the U.S. market since 2001, was approved yesterday by the Food and Drug Administration (FDA) for use in improving the dispersion and absorption of other drugs, such as anesthetic agents. Hospitals that want to use the product before the end of this year may need to revise their policy on medication samples.

Ista Pharmaceuticals President Vicente Anido Jr. said during a teleconference today that the company worked with FDA to resolve the absence of an injectable hyaluronidase product for use in ophthalmic surgeries.

The new product, known as Vitrase, is a sterile preservative-free lyophilized powder containing purified ovine testicular hyaluronidase, an enzyme that modifies the permeability of connective tissue. Wydase, the hyaluronidase product previously prepared by Wyeth, was made from cows.

According to the FDA-approved labeling for Vitrase (PDF), the product may be used not only to increase the absorption and dispersion of other injected drugs but also to improve the absorption of rehydrating fluids administered by subcutaneous injection and the resorption of radiopaque agents during subcutaneous urography.

Patients with a hypersensitivity to hyaluronidase must not receive the product. Vitrase's labeling does not state that the product is contraindicated in patients with a hypersensitivity to sheep, the source of the enzyme.

The labeling states that the most commonly reported adverse event with the administration of hyaluronidase is a local reaction at the injection site.

Tom Mitro, Ista vice president of sales and marketing, said the product will initially be available in vials containing 6,200 units of lyophilized hyaluronidase that will be distributed as samples to ophthalmologists and other physicians.

"We're going to begin sampling in the July time frame," he said. "We'll be ready for commercialization near the end of 2004."

Mitro said the company plans to seek FDA's permission to market the product in vials containing 150 units of hyaluronidase in 1 mL of a ready-to-use solution well-suited for enhancing the absorption and dispersion of other injected drugs. Once that approval is obtained, commercial sales of both Vitrase vial sizes will begin.

The product will be distributed by Allergan Inc., although the initial samples will be disseminated by Ista, Anido said. Cardinal Health in Albuquerque, New Mexico, is named in the labeling as the manufacturer.

Erin R. Fox, a drug information specialist with the Drug Information Service at the University of Utah in Salt Lake City, said Ista's decision to provide only samples of the product for the upcoming half year means that hospitals may need to reexamine their policies on medication samples.

"Most hospitals have a no-sample policy," she said, "and they're going to have to change that" if they want to let physicians administer the new hyaluronidase product on-site until pharmacies can purchase the vials.

According to the product's labeling, the 6,200-unit vials are to be reconstituted to an initial concentration of 1,000 units/mL and then diluted to the concentration, 50-300 units/mL, appropriate for the intended purpose. Each Vitrase package contains the multipurpose vial, a 1-mL syringe, and a 5-micrometer filter needle. Before use, the vials are to be stored at 2–8 degrees C. The reconstituted solution can be stored at room temperature but must be used within six hours of preparation.

Mitro said physicians can request samples of Vitrase and pharmacies can obtain information on commercial availability by enrolling in the product availability program at or 877-484-8727.