Chiron and DepoTech Announce Additional Phase 3 Clinical Trial Results for DepoCyt; New Drug Delivery Technology Enhances Effect of Cancer Drug.

EMERYVILLE, Calif.--(BUSINESS WIRE)--Oct. 21, 1996--Chiron Corporation (NASDAQ:CHIR) and DepoTech Corporation (NASDAQ:DEPO) today announced additional results of a Phase 3 clinical trial of DepoCyt(TM), an anti-cancer drug, in patients with neoplastic meningitis (NM) arising from solid tumors.

Of 24 evaluable patients treated with DepoCyt, the median survival was 168 days compared to 87 days for 29 evaluable patients receiving the control drug, methotrexate (MTX). These 53 patients were evaluable for the survival analysis based on prospectively defined criteria. For all solid tumor patients, mean time to NM disease progression as measured by neurological examination or death from any cause was 108 days for those receiving DepoCyt compared to 48 days for those receiving MTX.

The companies previously announced that DepoCyt showed a higher complete response rate compared to MTX. Following a recent review of these and other trial data, the companies agreed that a New Drug Application (NDA) for DepoCyt would be submitted as soon as practicable.

The clinical trial was a multicenter, controlled, non-blinded study of DepoCyt, in which a total of 61 patients were randomized to treatment either with DepoCyt or MTX, a chemotherapy agent that is the current standard of care for NM arising from solid tumors. Patients initially received a dose of DepoCyt every 14 days, compared to twice per week dosing with MTX.

"We are gratified that these data appear to support consistently the potential value of DepoCyt over the current standard of treatment," said Edward L. Erickson, president and chief executive officer of DepoTech.

"We look forward to working together with DepoTech to submit the DepoCyt NDA," said Magnus Lundberg, president, Chiron Therapeutics.

Neoplastic meningitis occurs when metastases from solid tumors, leukemia, or lymphoma spread to the tissue surrounding the brain and spinal cord. Of the approximately 65,000 cancer patients who are afflicted with this disease annually in the U.S., most have NM arising from solid tumors. Conventional therapy requires frequent, repeated injections and has limited efficacy.

DepoCyt is an injectable, sustained-released formulation of the chemotherapy agent cytarabine encapsulated in DepoFoam(TM), DepoTech's proprietary lipid-based drug delivery technology. When commercially available, DepoCyt will be marketed by Chiron in the U.S., Canada and Europe, and manufactured by DepoTech at its San Diego production facilities.

Chiron and DepoTech plan to continue pivotal Phase 3 studies of DepoCyt in NM arising from leukemia and lymphoma. In addition, a multicenter Phase 4 study of DepoCyt for the treatment of NM arising from solid tumors in the U.S. and Canada is underway to collect further data relating to safety and efficacy. Chiron is currently conducting clinical trials of Depocyt in Europe.

Chiron Corporation is a science-driven healthcare company that combines diagnostic, vaccine, and therapeutic strategies for controlling disease. Headquartered in Emeryville, Calif., near San Francisco, and with operations on four continents, Chiron had revenues in 1995 of more than $1 billion. Chiron participates in four global healthcare markets: diagnostics, including immunodiagnostics, critical care diagnostics and new quantitative probe tests; therapeutics, with an emphasis on oncology and infectious disease; pediatric and adult vaccines; and ophthalmic surgical products for the correction of vision.

Chiron also has research programs underway in gene therapy, combinatorial chemistry, cancer, infectious and cardiovascular disease and critical care through its Chiron Technologies business unit.

DepoTech is a drug delivery company dedicated to the development and manufacture of innovative sustained-released therapeutic products based on DepoFoam. Products are being developed to treat major unmet medical needs in the fields of cancer, infectious diseases, pain management and rheumatology. -0-

Note to Editors: This press release contains forward-looking statements regarding DepoTech and Chiron. Actual results could differ materially from those described in this press release as a result of a number of factors, including, but not limited to the following:

There can be no assurance that any product in the DepoTech and Chiron collaborative product pipeline will be successfully developed or manufactured, or that final results of human clinical trials will be supportive of regulatory approvals required to market products, or that final regulatory approval will be received in a timely manner, if at all, or that patient and physician acceptance of these products will be achieved.

CONTACT: Chiron Corporation

Larry Kurtz, 510/601-2476

or

DepoTech Corporation

Edward L. Erickson, 619/625-2424

or

StratiPoint Group for DepoTech Corporation

Mike Jackman, 415/388-3216