ROCKLAND, Mass., March 2, 2011 – EMD Serono, Inc., an affiliate of Merck KGaA, Darmstadt, Germany, announced today that it received a complete response letter (CRL) from the U.S. Food and Drug Administration (FDA) on the new drug application (NDA) for Cladribine Tablets, EMD Serono's proprietary investigational oral formulation of cladribine, as a therapy for relapsing-remitting multiple sclerosis (MS).

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A complete response letter is issued by the FDA when the Agency's review of a file is complete and the application cannot be approved in its present form. In the complete response letter, the FDA concluded that substantial evidence of Cladribine Tablets' effectiveness was provided by the CLARITY(1) study. However, the FDA has requested the Company provide an improved understanding of safety risks and the overall benefit-risk profile either through additional analyses or by additional studies. EMD Serono intends to request an end-of-review meeting with the FDA to clarify next steps and to identify whether data from completed and ongoing clinical studies can address the Agency's questions.

"Our commitment to transform the way people living with MS approach their therapy options remains steadfast," said Fereydoun Firouz, President and CEO of EMD Serono, Inc. "We look forward to working with the FDA to address the safety issues in its letter and will continue to move toward identifying a path that provides patients and physicians the opportunity to have access to Cladribine Tablets in the treatment of MS."

EMD Serono remains committed to completing the ongoing clinical trials with Cladribine Tablets. These trials, which are fully enrolled, will provide additional information on the efficacy and safety of Cladribine Tablets in MS. Top-line results from the CLARITY EXTENSION and ORACLE MS(2) studies are expected by the end of 2011. Top-line results from the ONWARD(3) study are expected in the first half of 2012.

Cladribine Tablets are approved and available under the trade name Movectro® in Australia and Russia as a treatment of relapsing-remitting MS and are under regulatory review in other countries.

About Cladribine Tablets

EMD Serono's oral formulation of cladribine (Cladribine Tablets) is an investigational treatment for patients with relapsing forms of multiple sclerosis (MS). Cladribine is a small molecule that may interfere with the behavior and the proliferation of certain white blood cells, particularly lymphocytes, which are thought to be involved in the pathological process of MS. Cladribine Tablets were approved in Russia in July 2010 and in Australia in September 2010 as a treatment of relapsing-remitting MS and are under regulatory review in other countries.

The clinical development program for Cladribine Tablets includes:

- The CLARITY (CLAdRIbine Tablets treating MS orallY) study and its extension: a two-year Phase III placebo-controlled trial designed to evaluate the efficacy and safety of Cladribine Tablets as a monotherapy in patients with relapsing-remitting MS and the CLARITY EXTENSION two-year Phase III study designed to provide data on the long-term safety and efficacy of extended administration of Cladribine Tablets for up to four years.

- The ORACLE MS (ORAl CLadribine in Early MS) study: a two-year Phase III placebo-controlled trial designed to evaluate the efficacy and safety of Cladribine Tablets as a monotherapy in patients at risk of developing MS (patients who have experienced a first clinical event suggestive of MS). This trial was announced in September 2008.

- The ONWARD (Oral Cladribine added oN to interferon beta-1a in patients With Active Relapsing Disease) study: a Phase II placebo-controlled trial designed primarily to evaluate the safety and tolerability of adding Cladribine Tablets treatment to patients with relapsing forms of MS, who have experienced breakthrough disease while on established interferon-beta therapy. This trial was announced in January 2007.

- The PREMIERE (PRospective observational long-term safEty registry of Multiple sclerosis patIEnts who have participated in CladRibinE clinical trials) registry: an eight-year observational safety registry of patients who have participated in Cladribine Tablets clinical trials, designed to support the evaluation of the long-term safety of Cladribine Tablets in MS.

About multiple sclerosis

Multiple sclerosis (MS) is a chronic, inflammatory condition of the central nervous system and is the most common, non-traumatic, disabling neurological disease in young adults. It is estimated that approximately two million people have 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 EMD Serono, Inc.

EMD Serono, Inc., an affiliate of Merck KGaA, Darmstadt, Germany, is a leader in the US biopharmaceutical arena, integrating cutting-edge science with unparalleled patient support systems to improve people's lives. The company has strong market positions in neurodegenerative diseases, with Rebif® (interferon beta-1a), as well as in endocrinology, with Saizen® (somatropin (rDNA origin) for injection), Serostim® (somatropin (rDNA origin) for injection) and EGRIFTA™ (tesamorelin for injection). EMD Serono is a leader in reproductive health, with Gonal-f® (follitropin alfa for injection), Luveris® (lutropin alfa for injection) and Ovidrel® Prefilled Syringe (choriogonadotropin alfa injection). In addition, EMD Serono is growing its expertise and presence in the area of oncology, with more than 10 projects currently in development. With a clear focus on the patient and a leadership presence in the biopharmaceutical industry, EMD Serono's US footprint continues to grow, with more than 1100 employees around the country and fully integrated commercial, clinical and research operations in the company's home state of Massachusetts.

For more information, please visit www.emdserono.com

About Merck KGaA

Merck is a global pharmaceutical and chemical company with total revenues of euro 9.3 billion in 2010, a history that began in 1668, and a future shaped by more than 40,000 employees in 67 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 www.merckserono.com or www.merck.de

SOURCE EMD Serono, Inc.