GENEVA, Switzerland, April 30 /PRNewswire/ -- Merck Serono (NYSE: SRA), a division of Merck KGaA, Darmstadt, Germany, and its partner ZymoGenetics, Inc. (NASDAQ: ZGEN) today announced the initiation of a Phase II clinical trial to evaluate the safety and efficacy of atacicept in patients with relapsing multiple sclerosis (RMS).

"This trial with atacicept underlines Merck Serono's long-term commitment to patients with multiple sclerosis," said Dr. Anton Hoos, Head of Global Development at Merck Serono. "Atacicept has the potential to complement existing MS drugs by offering a novel mode of action and convenient administration."

"Patients with multiple sclerosis need more treatment options," said Nicole Onetto, M.D., Senior Vice President and Chief Medical Officer of ZymoGenetics. "Our preclinical models have shown biological activity of atacicept in multiple sclerosis and, because of the growing body of supporting data in the literature indicating the importance of B cells and antibodies in the pathology of multiple sclerosis, we believe there is strong rationale for the clinical testing of atacicept in patients with RMS."

The four-arm randomized, double-blind, placebo-controlled, multicenter study will evaluate the safety and efficacy of atacicept in patients with RMS over 36 weeks of treatment. The primary objective of the study is to evaluate the efficacy of atacicept in reducing central nervous system inflammation in subjects with RMS as assessed by frequent MRI measures.

Approximately 300 RMS patients meeting the eligibility criteria will be randomly assigned to receive one of three subcutaneous doses of atacicept or placebo for 36 weeks. Patients will be followed up until week 48.

About atacicept

Merck Serono and ZymoGenetics are developing atacicept (formerly referred to as TACI-Ig) as a potential treatment of autoimmune diseases, such as systemic lupus erythematosus (SLE), lupus nephritis (LN), rheumatoid arthritis and multiple sclerosis, as well as B-cell malignancies.

Atacicept contains the soluble TACI receptor that binds to the cytokines BLyS and APRIL. These cytokines are members of the tumor necrosis factor family that promote B-cell survival and autoantibody production associated with certain autoimmune diseases such as systemic lupus erythematosus. Current data indicates that levels of BLyS and APRIL are elevated in patients with rheumatoid arthritis, lupus erythematosus, B-cell malignancies and multiple sclerosis. Atacicept has been shown to affect several stages of B-cell development and may inhibit the survival of cells responsible for making antibodies.

About Merck Serono and multiple sclerosis

Merck Serono is a leader in multiple sclerosis (MS) with Rebif(R) (interferon beta-1a), a disease-modifying drug used to treat relapsing forms of MS, which is registered in more than 80 countries worldwide. In addition to Rebif(R), the Company also offers a second therapy within its US portfolio of MS therapies: Novantrone(R) (mitoxantrone for injection concentrate) for worsening forms of MS. Full prescribing information for these products can be obtained by contacting the Company or visiting its website. Additional therapeutic options are currently under development at Merck Serono, including oral cladribine, currently in Phase III and potentially the first oral therapy for MS, as well as several products in early stage development. Merck Serono also is taking a leading role in developing an understanding of the role of genetics in MS.

About multiple sclerosis

Multiple sclerosis (MS) is a chronic, inflammatory condition of the nervous system and is the most common, non-traumatic, neurological disease in young adults. The World Health Organization estimates that up to 2.5 million people suffer from MS worldwide. While symptoms can vary, the most common symptoms of MS include blurred vision, numbness or tingling in the limbs and problems with strength and coordination. The relapsing forms of MS are the most common.

About Merck Serono

Merck Serono is the division for innovative prescription pharmaceuticals of Merck, a global pharmaceutical and chemical group. Headquartered in Geneva, Switzerland, Merck Serono discovers, develops, manufactures and markets innovative small molecules and biopharmaceuticals to help patients with unmet medical needs. Its North American business operates in the United States and Canada as EMD Serono.

Merck Serono has leading brands serving patients with cancer (Erbitux(R)), multiple sclerosis (Rebif(R)), infertility (Gonal-f(R)), endocrine and cardiometabolic disorders (Glucophage(R), Concor(R), Saizen(R), Serostim(R)), as well as psoriasis (Raptiva(R)).

With an annual R&D investment of around EUR 1bn, Merck Serono is committed to growing its business in specialist-focused therapeutic areas including neurodegenerative diseases, oncology, fertility and endocrinology, as well as new areas potentially arising out of research and development in autoimmune and inflammatory diseases.

About Merck

Merck is a global pharmaceutical and chemical company with total revenues of EUR 7.1 billion in 2007, a history that began in 1668, and a future shaped by 31,681 employees in 60 countries. Its success is characterized by innovations from entrepreneurial employees. Merck's operating activities come under the umbrella of Merck KGaA, in which the Merck family holds an approximately 70% interest and free shareholders own the remaining approximately 30%. In 1917 the U.S. subsidiary Merck & Co. was expropriated and has been an independent company ever since.

For more information, please visit http://www.merckserono.net or http://www.merck.de

Merck Serono : 9 Chemin des Mines, 1202 Geneva, Switzerland, http://www.merckserono.net. Media Relations : Tel.: +41-22-414-36-00