Merck KGaAMerck KGaA has temporarily suspended the clinical program for Stimuvax® (BLP25 liposome vaccine) in all recruiting studies worldwide as a result of a suspected unexpected serious adverse reaction (SUSAR). This decision was taken in alignment with the U.S. Food and Drug Administration's (FDA) clinical hold placed on the Investigational New Drug (IND) application for Stimuvax.

A patient participating in a Phase II exploratory clinical trial with the therapeutic cancer vaccine in patients with multiple myeloma developed encephalitis. The patient was randomized to an experimental arm of Stimuvax in combination with an intensified schedule of low-dose cyclophosphamide, which is not used in the other Stimuvax studies.

Effective immediately, the company has temporarily suspended recruitment into and treatment of patients already enrolled into the recruiting Stimuvax clinical trials. This action is a precautionary measure while we are diligently investigating the cause of this adverse event.

The Phase III clinical program, consisting of the non-small cell lung cancer (NSCLC) studies START and INSPIRE and the breast cancer study STRIDE, is impacted as well as the other recruiting studies. The company considers patient safety of paramount importance and will continue to work closely with the regulatory authorities, particularly with the FDA, to evaluate the implications of the adverse reaction on the clinical development program for Stimuvax and determine the most suitable course of action.

About Stimuvax
Merck is investigating the use of Stimuvax® (BLP25 liposome vaccine) in the treatment of NSCLC and breast cancer. The vaccine was granted fast-track status in September 2004 by the FDA. Merck obtained the exclusive worldwide licensing rights from Oncothyreon Inc., Seattle, Washington, USA. Stimuvax is being developed in Europe by Merck KGaA and in the United States by its affiliate, EMD Serono Inc.

The INSPIRE study is a multi-national, Phase III, double-blind, placebo-controlled, randomized clinical trial designed to evaluate the efficacy, safety and tolerability of Stimuvax in subjects suffering from unresectable, stage III NSCLC and demonstrating either stable disease or objective response following primary chemo-radiotherapy. The study will enrol approximately 420 unresectable, stage III NSCLC patients across China, Hong Kong, Korea, Singapore and Taiwan. Study participation is expected to last for a minimum of 24 months.

START is a multi-center, randomized, double-blind, placebo-controlled Phase III study that will evaluate patients with documented unresectable stage IIIA or IIIB NSCLC who have had a response or stable disease after at least two cycles of platinum-based chemo-radiotherapy. The study will involve more than 1,300 patients in approximately 30 countries.

STRIDE is a randomized, double-blind, controlled, multi-center Phase III study designed to determine if Stimuvax® can extend progression free survival in patients treated with hormonal therapy who have inoperable, locally advanced, recurrent or metastatic breast cancer. Overall survival, quality of life, tumor response and safety will also be assessed in this study.

About Merck KGaA
Merck is a global pharmaceutical and chemical company with total revenues of € 7.7 billion in 2009, a history that began in 1668, and a future shaped by approximately 33,000 employees in 61 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.