Chiron Vision's Vitrasert implant is cleared for marketing in European Union.

EMERYVILLE, Calif.--(BW HealthWire)--March 25, 1997--Chiron Vision, a business of Chiron Corporation (NASDAQ:CHIR), announced today that the European Commission has granted a marketing authorization for the Vitrasert(TM) Implant in all 15 countries of the European Union.

The market clearance follows a recommendation of approval for the Vitrasert Implant by the Committee for Proprietary Medicinal Products (CPMP), which reviewed the product on behalf of the European Agency for the Evaluation of Medicinal Products (EMEA). The Vitrasert Implant is the first drug delivery system to provide local, sustained therapy of the eye for the treatment of cytomegalovirus (CMV) retinitis in people with AIDS. The Vitrasert Implant releases the antiviral agent ganciclovir (Cymevene(R); F. Hoffmann-La Roche Ltd., Basel, Switzerland) directly to the disease site. In November, 1996, the CPMP recommended the Vitrasert Implant as a first-line therapy against CMV Retinitis.

In March 1996, Chiron Vision and its partner Roche Laboratories began selling the Vitrasert Implant in the United States. To date, Chiron Vision had provided the Vitrasert Implant in Europe under named-patient access basis.

"We are pleased to make the Vitrasert Implant widely available to people with AIDS throughout Europe," said William Link, Ph.D., chairman and chief executive officer of Chiron Vision.

CMV retinitis affects an estimated 30,000-60,000 people annually worldwide. CMV retinitis usually begins as a white infiltrate within the retina, and can progress rapidly to cause destruction of retinal tissue. Cumulative retinal damage caused by the disease can lead to detachment of the retina, occurring in up to 50 percent of patients with AIDS-related CMV retinitis, and permanent loss of vision.

"The Vitrasert Implant is a treatment option for people with CMV retinitis in Europe that represents a significant improvement in control of retinitis over current therapy," said Judy F. Gordon, D.V.M., vice president, Research & Development and Scientific Affairs at Chiron vision.

Chiron Vision recently received approval for the Vitrasert Implant in the United States and Brazil, and is pursuing registration in other countries around the world.

Clinical Trial Results

Data from Chiron Vision's Phase III trial of 188 AIDS patients with newly diagnosed CMV retinitis have demonstrated that time to disease progression was significantly delayed for patients who received the Vitrasert therapy, compared with those on intravenous (I.V.) Cymevene. The study showed that eyes treated with the Vitrasert Implant had a median time to progression of 194 days, versus 72 days for eyes on I.V. treatment.

In addition, results of a clinical study reported by the National Eye Institute (NEI) in the `Archives of Ophthalmology' showed that the median time to progression of peripheral CMV retinitis in newly diagnosed patients was 226 days. Those who received no immediate treatment or those assigned to deferred treatment progressed in 15 days.

Chiron Vision, headquartered in Claremont, California, researches, develops, manufactures and markets products for the surgical correction of vision, including intraocular lenses (IOLs), phacoemulsification instruments, viscoelastics, corneal shapers, excimer lasers and drug delivery systems. Chiron Vision is among the world's leading sellers of IOLs and related products.

Chiron Corporation, headquartered in Emeryville, California, is a diversified, science-driven healthcare company that combines diagnostic, vaccine and therapeutic strategies for controlling disease. Chiron participates in four global healthcare markets: diagnostics, including immunodiagnostics, critical care diagnostics and new quantitative probe tests; therapeutics, with an emphasis on oncological, infectious, neurological and cardiovascular disease; pediatric and adult vaccines; and ophthalmic surgical products for the correction of vision. Chiron also conducts research and development in the fields of biological proteins, gene therapy and combinatorial chemistry.

F. Hoffmann-La Roche is a research-based health care company with headquarters in Basel, Switzerland. Roche is a leading health care company dedicated to the research, development and delivery of diagnostic tests, treatment and services for people with life-threatening illnesses.

CONTACT: Chiron Vision

Missy Lowery, 909/399-1258

or

Chiron Corporation

Kimberly Sankaran, 510/923-2412

(Corporate Communications)