Genzyme Withdraws Bioenvision’s European Filing of Evoltra® in Elderly AML Patients

Date: March 19, 2008

Will Resubmit With New Data from Ongoing Studies

CAMBRIDGE, Mass.— Genzyme Corp. (Nasdaq: GENZ) today announced the withdrawal of the European application to extend the Evoltra® (clofarabine) product label to include the treatment of elderly patients with acute myeloid leukemia (AML). This application and the data on which it was based were filed by Bioenvision, Ltd. before the company was acquired by Genzyme last year.

In a letter to the European Medicines Agency (EMEA) on behalf of Bioenvision, Genzyme states that the withdrawal is based on the EMEA’s Committee for Medicinal Products for Human Use (CHMP) assessment that the data from the BIOV121 study are not sufficient to support a recommendation for market approval at this time. Bioenvision is now a wholly-owned subsidiary of Genzyme.

“As we expected, the filing that Bioenvision submitted to the EMEA was not sufficient to support approval in adult AML and our subsequent conversations with the CHMP have confirmed this assessment,” stated Mark J. Enyedy, president of Genzyme Oncology, a business unit of Genzyme Corp. “We have engaged in a positive dialogue with the Rapporteurs regarding the requirements for approval and will develop a new submission to include data from one or more ongoing clinical studies of clofarabine in this patient population for submission possibly as early as the fourth quarter of this year.”

In the United States, Genzyme has completed enrollment for a pivotal study in previously untreated, older adult patients with AML who are unlikely to benefit from standard intensive induction chemotherapy. Data from this study, known as CLASSIC II, are expected to provide substantial evidence for expanding the current product label into adult AML. Preliminary data has been accepted for presentation at ASCO this spring and a supplemental new drug application (sNDA) for clofarabine is expected to be filed in the second half of this year. It is possible that data from this study also could be considered for part of a new filing with EMEA.

Evoltra is currently indicated for the treatment of acute lymphoblastic leukemia (ALL) in pediatric patients who have relapsed or are refractory to at least two prior regimens. The withdrawal of the European application of Evoltra in adult AML has no consequences for patients enrolled in current clinical trials or compassionate use programs.

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