PRESS RELEASE: Genzyme Corporation Myeloma Trial Succeeds, Drug Filing Seen

Genzyme Corporation Myeloma Trial Succeeds, Drug Filing Seen

CAMBRIDGE, Mass., Aug. 2 -- Genzyme Corp. today announced that its second phase 3 trial of Mozobil (plerixafor) has successfully met its primary and secondary endpoints, demonstrating positive results in multiple myeloma (MM) similar to those reported two weeks ago in non-Hodgkin's lymphoma.

The combined strength of these two trials -- in which patients with two types of cancer achieved more rapid and effective mobilization of stem cells in preparation for transplant than patients treated with current therapies -- will support Mozobil's regulatory approval, commercialization, and likely adoption as a standard of care in transplantation.

The randomized, double-blind, placebo-controlled trial included 302 patients who were undergoing a hematopoietic stem cell transplant (HSCT) for multiple myeloma at medical centers in the United States, Canada, and Europe. Like the previous trial, it examined the effectiveness of Mozobil in increasing the number of hematopoietic stem cells collected for a transplant, comparing the stem cell yield from patients treated with Mozobil following G- CSF to patients treated with placebo following G-CSF.

In the primary efficacy endpoint, 72 percent of patients treated with Mozobil and G-CSF achieved the target threshold for collection of at least 6 million CD34+cells/kg from the peripheral blood with two days or fewer of apheresis sessions, compared with 34 percent of patients in the G-CSF/placebo group. This two-fold increase was statistically significant in favor of the Mozobil-treated patients (p<0.0001). Like the previous trial, these results exceed the 20 percent absolute difference prospectively defined through the FDA's Special Protocol Assessment as a successful result.

The median number of days to achieve the target of 6 million cells was one day for the Mozobil/G-CSF group and four days for the G-CSF/placebo group. Over half of patients treated with Mozobil and G-CSF reached the target cells in the first day of apheresis. By comparison, it took four days for a similar percentage of the G-CSF/placebo group to reach this threshold.

Secondary outcomes were consistent with the primary endpoint, showing a statistically significant result in favor of Mozobil in the number of patients who reached the target threshold of at least 6 million CD34+cells/kg from the peripheral blood with four days of apheresis, and the number of patients who reached at least two million cells collected in four days.

Other secondary outcomes were also supportive, including the success of engraftment, the number of days needed to engraft, and the durability of the engraftment for the first 100 days. The trial also robustly met the primary endpoint specified by the European Agency for the Evaluation of Medicinal Products (EMEA) -- a composite of successful mobilization and engraftment.

Mozobil was well tolerated in the trial, with the most common adverse events being mild gastrointestinal effects and redness at the site of injection. The only serious adverse event deemed related to treatment occurred in the G-CSF/placebo group.

"Taken together, these two pivotal trials paint a dramatic picture of the role that Mozobil will play in the treatment of patients with lymphoma and multiple myeloma," said Henri A. Termeer, chairman and chief executive officer, Genzyme. "Mozobil has shown the ability to quickly and predictably prepare a patient for a transplant, providing a strong clinical and economic argument in favor of its use in all autologous transplant procedures. We will work aggressively to gain regulatory approval in these transplant settings, while also pressing forward to unlock the full potential of Mozobil in allogeneic transplantation, chemosensitization, cardiovascular disease, and other promising applications."

Commercialization plans

Based on these results Genzyme expects to file for US and European regulatory approval in both multiple myeloma and lymphoma in the first half of 2008. The company anticipates receiving priority review, and marketing approval by the end of 2008. Genzyme plans to launch the product early in 2009. Mozobil will be marketed by Genzyme's existing transplant business, which has a commercial presence in more than 50 countries worldwide.

Approximately 55,000 autologous and allogeneic stem cell transplants are performed each year for multiple myeloma, Hodgkin's and non-Hodgkin's lymphoma, and other conditions in markets where Genzyme has a commercial infrastructure, including the United States, Europe, Latin America and the Asian Pacific countries. Genzyme believes that over time Mozobil will be used in the majority of these procedures, fueling peak sales of the product in the transplant setting of more than $400 million annually.

In addition to its currently studied use in autologous HSCT, Genzyme is initiating a number of phase 1/2 trials and investigator-initiated trials to study its use in other settings. An investigator-initiated trial in allogeneic HSCT is already underway, examining whether Mozobil can improve the stem cell yield from healthy unrelated donors. In addition, studies examining whether Mozobil can improve the efficacy of chemotherapy and/or immunotherapy in various forms of chronic lymphocytic leukemia and acute myelogenous leukemia will also begin later this year. Genzyme is also pursuing preclinical work to explore the role that Mozobil may play in cord blood transplantation, solid organ transplantation, cardiovascular disease, HIV, renal ischemic disease, and prevention of metastasis in oncology.

About Mozobil

Mozobil, a novel small molecule CXCR4 chemokine antagonist, has been shown in multiple earlier studies to rapidly and effectively increase the number of stem cells in circulation in the blood. Once circulating in the blood, stem cells can be collected for use in a stem cell transplant. Mozobil has been granted orphan drug status in the United States and European Union and the pivotal trials have undergone Special Protocol Assessment by the FDA and Protocol Assistance by the EMEA. Genzyme intends to commercialize Mozobil through its existing global transplant business to hematologists and hematopoietic stem cell transplant centers in more than 50 countries throughout the world. Genzyme has been developing Mozobil since its acquisition of AnorMED, Inc. in 2006.

About Genzyme

One of the world's leading biotechnology companies, Genzyme is dedicated to making a major positive impact on the lives of people with serious diseases. Since 1981, the company has grown from a small start-up to a diversified enterprise with more than 9,500 employees in locations spanning the globe and 2006 revenues of $3.2 billion. In 2007, Genzyme was chosen to receive the National Medal of Technology, the highest honor awarded by the President of the United States for technological innovation. In 2006 and 2007, Genzyme was selected by FORTUNE as one of the "100 Best Companies to Work for" in the United States.

With many established products and services helping patients in nearly 90 countries, Genzyme is a leader in the effort to develop and apply the most advanced technologies in the life sciences. The company's products and services are focused on rare inherited disorders, kidney disease, orthopaedics, cancer, transplant, and diagnostic testing. Genzyme's commitment to innovation continues today with a substantial development program focused on these fields, as well as immune disease, infectious disease, and other areas of unmet medical need.

This press release contains forward-looking statements, including the statements regarding: Genzyme's expectations regarding peak sales of Mozobil, the value of the successful multiple myeloma and non-Hodgkin's lymphoma trials to Mozobil's regulatory, commercialization and standard of care prospects, the role Mozobil will play in the treatment of patients with lymphoma and multiple myeloma, the strength of the clinical and economic arguments favoring use of Mozobil, Genzyme's ability to work aggressively to gain regulatory approval, Genzyme's ability to unlock the full potential of Mozobil in allogeneic transplantation, chemosensitization, graft-versus-host disease and other potential applications, Genzyme's anticipated timing associated with regulatory submissions for US and European regulatory approvals, the expectation of priority review and marketing approval for Mozobil, Genzyme's global commercialization plans for Mozobil, the size of the transplant market, the expectation that Mozobil will be used in a majority of stem cell transplants, Genzyme's ongoing and planned research, preclinical and clinical studies relating to autologous and allogeneic HSCT, cord blood transplantation, solid organ transplantation, peripheral arterial disease, HIV, renal ischemic disease, and prevention of metastasis in oncology. These statements are subject to risks and uncertainties that could cause actual results to differ materially from those projected in these forward-looking statements. These risks and uncertainties include, among others, the failure of Mozobil to receive regulatory approvals for multiple myeloma or non- Hodgkin's lymphoma, a possible delay in regulatory approvals, the uncertainties of launching a new product on a global scale following receipt of applicable regulatory approvals due to misestimates of the time and resources required to do so, or for other reasons, the failure of Mozobil to receive favorable pricing or reimbursement; the possibility that Mozobil will not meet current expectations with respect to adoption in the transplant market, the possible inaccuracies of Genzyme's analysis with respect to markets and number of potential patients for Mozobil, the risks associated with research, preclinical and clinical studies for other applications of Mozobil and the risks and uncertainties described in reports filed by Genzyme with the Securities and Exchange Commission under the Securities Exchange Act of 1934, as amended, including without limitation the information under the heading "Factors Affecting Future Operating Results" in the Management's Discussion and Analysis of Financial Condition and Results of Operations section of the Genzyme Quarterly Report on Form 10-Q for the quarter ending March 31, 2007. Genzyme cautions investors not to place substantial reliance on the forward-looking statements contained in this press release. These statements speak only as of the date of this press release, and Genzyme undertakes no obligation to update or revise the statements.

Genzyme(R) is a registered trademark and Mozobil(TM) is a trademark of Genzyme Corporation. All rights reserved.

Conference Call Information

Genzyme Corporation will host a conference call today at 11:00 a.m. Eastern Time to discuss Mozobil. To participate in the call, please dial 773-799-3828 and refer to pass code "Genzyme." A replay of this call will be available by dialing 203-369-0672. This call will also be Webcast live on the investor events section of Replays of the call and the Webcast will be available until midnight on August 9, 2007.

Genzyme's press releases and other company information are available at and by calling Genzyme's investor information line at 1-800-905-4369 within the United States or 1-678-999-4572 outside the United States.

Media Contact: Investor Contact: Dan Quinn Sally Curley (617) 768-6849 (617) 768-6140
Genzyme Corp.

CONTACT: Media, Dan Quinn, +1-617-768-6849, or Investors, Sally Curley,+1-617-768-6140, both of Genzyme Corporation

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