Serono and Ivax Corporation announced positive results from two clinical trials with a new proprietary oral formulation of cladribine, a potential new treatment for multiple sclerosis (MS). The study results showed that the formulation of oral cladribine which has been developed by Serono and Ivax has met the targets for an orally administered product, with blood levels of cladribine in the expected therapeutic range. Efficacy studies of oral cladribine in MS patients are planned to start late 2004.

Previous Phase II and Phase III clinical trials have demonstrated the positive effect of injectable cladribine in patients with MS. In these trials, cladribine caused a dramatic reduction in new lesion development in the brain as seen on magnetic resonance imaging (MRI) scans. Patients with relapsing remitting MS receiving cladribine also experienced clinical benefits.

"As the originator of Rebif, a current reference treatment for multiple sclerosis, Serono has a long-term commitment to patients with multiple sclerosis," said Ernesto Bertarelli, CEO of Serono. "This is a major step in the development of the first oral disease modifying treatment for multiple sclerosis."

Dr. Phillip Frost, CEO and chairman of Ivax commented, "We are very pleased to report the important progress which has been made with our partner Serono in the development of cladribine as a novel oral therapy for multiple sclerosis. With the successful completion of these clinical trials, another of our products advances in its clinical development."

Cladribine is being developed by Serono and Ivax under a worldwide agreement signed in October 2002.

Cladribine is a purine nucleoside analogue that disrupts the proliferation of certain white blood cells, particularly lymphocytes, which are involved in the pathological process of multiple sclerosis.

Multiple sclerosis is a chronic, inflammatory condition of the nervous system and is the most common, non-traumatic, neurological disease in young adults. Multiple sclerosis affects approximately two million people worldwide. While symptoms can vary, the most common symptoms of multiple sclerosis include blurred vision, numbness or tingling in the limbs and problems with strength and coordination. The relapsing forms of multiple sclerosis are the most common.