SC TO-T/A

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE TO
(Amendment No. 7)

TENDER OFFER STATEMENT

UNDER SECTION 14(D)(1) OR SECTION 13(E)(1) OF THE SECURITIES EXCHANGE ACT OF 1934

BIOENVISION, INC.

(Name Of Subject Company (Issuer))

GENZYME CORPORATION
WICHITA BIO CORPORATION

(Names of Filing Persons (Offerors))

Common Stock, par value $0.001 per share
(including the associated preferred stock purchase rights)
Series A Convertible Participating Preferred Stock, par value $0.001 per share

(Title of Class of Securities)

09059N100

(CUSIP Number of Common Stock)

Peter Wirth
Genzyme Corporation
500 Kendall Street
Cambridge, MA 02142
Telephone: (617) 252-7500

(Name, address and telephone number of person authorized
to receive notices and communications on behalf of filing persons)

with copies to:

Paul Kinsella
Ropes & Gray LLP
One International Place
Boston, Massachusetts 02110
Telephone: (617) 951-7000

CALCULATION OF FILING FEE

Transaction Valuation*	Amount Of Filing Fee**
$371,289,096.20	$11,398.58

*Estimated solely for purposes of calculating amount of filing fee in accordance with Rule 0-11 under the Securities Exchange Act of 1934. The transaction value is based upon the offer to purchase 61,791,222 outstanding shares of Common Stock of Bioenvision, Inc. at a purchase price of $5.60 cash per share and 2,250,000 outstanding shares of Series A Convertible Participating Preferred Stock at a purchase price of $11.20 cash per share, plus any accrued and unpaid dividends. Such number of outstanding shares of Common Stock represents the total of 55,035,740 issued and outstanding shares of Common Stock, outstanding options with respect to 5,973,000 shares of Common Stock and outstanding warrants with respect to 782,482 shares of Common Stock, in each case as of June 1, 2007. Such number of outstanding shares of Series A Convertible Participating Preferred Stock represents all issued and outstanding shares of Series A Convertible Participating Preferred Stock as of June 1, 2007. The transaction value is also based on an estimate of $58,253 accrued and unpaid dividends on Series A Convertible Participating Preferred Stock as of July 2, 2007.

**The amount of filing fee is calculated in accordance with Rule 0-11 of the Securities Exchange Act of 1934, as amended, and Fee Rate Advisory No. 7 for fiscal year 2007 issued by the Securities and Exchange Commission. Such fee equals 0.00307% of the transaction value.

xCheck the box if any part of the fee is offset as provided by Rule 0-11(a)(2) and identify the filing with which the offsetting fee was previously paid. Identify the previous filing by registration statement number or the Form or Schedule and the date of its filing.

Amount Previously Paid:	$11,398.58
Form or Registration No.:	Schedule TO-T
Filing Party:	Genzyme Corporation
Date Filed:	June 4, 2007

oCheck the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

Check the appropriate boxes below to designate any transactions to which the statement relates:

xthird-party tender offer subject to Rule 14d-1.

oissuer tender offer subject to Rule 13e-4.

ogoing-private transaction subject to Rule 13e-3.

oamendment to Schedule 13D under Rule 13d-2.

Check the following box if the filing is a final amendment reporting the results of the tender offer:   o

This Amendment No. 7 amends and supplements the Tender Offer Statement on Schedule TO filed with the Securities and Exchange Commission on June 4, 2007 (as previously amended and supplemented, the “Schedule TO”) relating to a tender offer by Wichita Bio Corporation, a Delaware corporation (the “Offeror”) and a wholly-owned subsidiary of Genzyme Corporation, a Massachusetts corporation (the “Parent”), to purchase all the outstanding shares of Common Stock, par value $0.001 per share, including associated preferred stock purchase rights (the “Common Shares”), of Bioenvision, Inc., a Delaware corporation (the “Company”), at a purchase price of $5.60 per Common Share, net to the seller in cash, without interest thereon, less any applicable withholding taxes, and to purchase all outstanding shares of the Company’s Series A Convertible Participating Preferred Stock, par value $0.001 per share (the “Series A Preferred Shares,” and together with the Common Shares, the “Shares”) at a purchase price of $11.20 per Series A Preferred Share, net to the seller in cash, plus all accrued but unpaid dividends, without interest thereon, less any applicable withholding taxes, upon the terms and subject to the conditions set forth in the Offer to Purchase dated June 4, 2007 (as previously amended and supplemented, the “Offer to Purchase”) and in the related Letter of Transmittal (the “Letter of Transmittal” which, together with the Offer to Purchase, as each may be amended and supplemented from time to time, constitute the “Offer”).

Capitalized terms used herein and not defined herein have the respective meanings assigned such terms in the Offer to Purchase and the Schedule TO.

ITEM 11.  ADDITIONAL INFORMATION

Item 11 of this Schedule TO is hereby amended and supplemented by adding the following:

The initial period of the Offer expired at 12:01 a.m. (New York City time) on July 10, 2007.  The Depositary for the Offer has advised the Parent and the Offeror that as of 12:01 a.m. (New York City time) on July 10, 2007, approximately 8,706,644 Common Shares and 2,250,000 Preferred Shares had been tendered and not withdrawn from the Offer, representing a total of 15.82% of the 55,035,740 outstanding Common Shares as of June 27, 2007 and 100% of the outstanding Preferred Shares as of June 27, 2007.  Included in these figures are 123,114 Common Shares tendered by notice of guaranteed delivery.  The Offeror has accepted for payment all Common and Preferred Shares validly tendered during the initial period of the Offer.

On July 10, 2007, the Parent and Offeror issued a press release announcing the results of the Offer.  The full text of the press release issued by the Parent and Offeror is attached hereto as Exhibit (a)(5)(S) and is incorporated herein by reference.

ITEM 12.  EXHIBITS

(a)(1)(A)	Offer to Purchase for Cash dated June 4, 2007.*
(a)(1)(B)	Form of Letter of Transmittal.*
(a)(1)(C)	Form of Notice of Guaranteed Delivery.*
(a)(1)(D)	Form of Letter to Brokers, Dealers, Banks, Trust Companies and Other Nominees.*
(a)(1)(E)	Form of Letter to Clients for Use by Brokers, Dealers, Banks, Trust Companies and Other Nominees.*
(a)(1)(F)	Form of Guidelines for Certification of Taxpayer Identification Number on Substitute Form W-9.*
(a)(2)	None.
(a)(3)	None.
(a)(4)	None.
(a)(5)(A)	Joint Press Release issued by Genzyme Corporation and Bioenvision, Inc. dated May 29, 2007 (incorporated herein by reference to Exhibit 99.1 to the Current Report on Form 8-K filed by Genzyme Corporation on May 29, 2007).*
(a)(5)(B)	Transcript of Conference Call held by Genzyme Corporation and Bioenvision, Inc. on May 29, 2007 (incorporated herein by reference to the Tender Offer Statement on Schedule TO filed by Genzyme Corporation on May 29, 2007).*

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(a)(5)(C)	Summary Advertisement published in the Wall Street Journal on June 4, 2007.*
(a)(5)(D)	Complaint filed by Brian Trombley, Dan J. Thomas, Jr. and John Hawn, on behalf of themselves and all other public shareholders of Bioenvision, Inc., on June 7, 2007, in the Court of Chancery in the State of Delaware, New Castle County (incorporated herein by reference to Amendment No. 1 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 12, 2007).*
(a)(5)(E)	Complaint filed by Gerald Ortsman, on behalf of himself and all other public shareholders of Bioenvision, Inc., on June 8, 2007, in the Court of Chancery in the State of Delaware, New Castle County (incorporated herein by reference to Amendment No. 2 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 15, 2007).*
(a)(5)(F)	Complaint filed by Leonard Gerstle c/f Jeremy Gerstle, UGMA on behalf of himself and all other public shareholders of Bioenvision, Inc., on June 13, 2007, in the Court of Chancery in the State of Delaware, New Castle County (incorporated herein by reference to Amendment No. 2 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 15, 2007).*
(a)(5)(G)	Complaint filed by Andrew W. Albstein, on behalf of himself and all other public shareholders of Bioenvision, Inc., on June 14, 2007, in the Court of Chancery in the State of Delaware, New Castle County (incorporated herein by reference to Amendment No. 3 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 18, 2007).*
(a)(5)(H)	Amended Complaint filed by Brian Trombley, Dan J. Thomas, Jr., John Hawn and Leonard Gerstle c/f Jeremy Gerstle, UGMA on behalf of themselves and all other public shareholders of Bioenvision, Inc., on June 13, 2007, in the Court of Chancery in the State of Delaware, New Castle County (incorporated herein by reference to Amendment No. 2 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 15, 2007).*
(a)(5)(I)	Motion for Preliminary Injunction in Trombley v. Bioenvision, Inc., et al., Civ. A. No. 3008, filed in the Court of Chancery in the State of Delaware, New Castle County on June 13, 2007 (incorporated herein by reference to Amendment No. 2 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 15, 2007).*
(a)(5)(J)	Motion for Expedited Proceedings in Trombley v. Bioenvision, Inc., et al., Civ. A. No. 3008, filed in the Court of Chancery in the State of Delaware, New Castle County on June 13, 2007 (incorporated herein by reference to Amendment No. 2 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 15, 2007).*
(a)(5)(K)	Complaint filed by Oppenheim Pramerica Asset Management S.A. R.L., on behalf of FCP OP Medical Biohe@lth-Trends and all other public shareholders of Bioenvision, Inc., on June 20, 2007, in the Court of Chancery in the State of Delaware, New Castle County (incorporated herein by reference to Amendment No. 4 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 25, 2007).*
(a)(5)(L)	Motion for Preliminary Injunction in Oppenheim Asset Management, et. al. v. Bioenvision, Inc., et al., Civ. A. No. 3040-VCP, filed in the Court of Chancery in the State of Delaware, New Castle County on June 20, 2007 (incorporated herein by reference to Amendment No. 4 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 25, 2007).*
(a)(5)(M)	Motion for Expedited Proceedings in Oppenheim Asset Management, et. al. v. Bioenvision, Inc., et al., Civ. A. No. 3040-VCP, filed in the Court of Chancery in the State of Delaware, New Castle County on June 20, 2007 (incorporated herein by reference to Amendment No. 4 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 25, 2007).*
(a)(5)(N)	Complaint filed by Bert Vladimir, individually and on behalf of all other public shareholders of Bioenvision, Inc., on June 7, 2007, in the Supreme Court of the State of New York, New York County (incorporated herein by reference to Amendment No. 5 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 26, 2007).*

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(a)(5)(O)	Corrected Notice of Motion for Expedited Proceedings in Vladimir v. Bioenvision, Inc., Index No. 650163-2007, filed in the Supreme Court of the State of New York, New York County, dated June 25, 2007 (incorporated herein by reference to Amendment No. 5 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 26, 2007).*
(a)(5)(P)	Memorandum of Law in Support of Plaintiff’s Order for Expedited Discovery Proceedings in Vladimir v. Bioenvision, Inc., Index No. 650163-2007, filed in the Supreme Court of the State of New York, New York County, dated June 18, 2007 (incorporated herein by reference to Amendment No. 5 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 26, 2007).*
(a)(5)(Q)	Press Release issued by Genzyme Corporation, dated June 27, 2007.*
(a)(5)(R)	Press Release issued by Genzyme Corporation, dated July 2, 2007.*
(a)(5)(S)	Press Release issued by Genzyme Corporation, dated July 10, 2007.
(b)	None.
(d)(1)	Agreement and Plan of Merger, dated as of May 29, 2007, by and between Genzyme Corporation, Wichita Bio Corporation and Bioenvision, Inc. (incorporated herein by reference to Exhibit 2.1 to the Current Report on Form 8-K filed by Genzyme Corporation on May 29, 2007).*
(d)(2)	Form of Tender and Voting Agreement, dated as of May 29, 2007, by and between Genzyme Corporation, Wichita Bio Corporation and certain shareholders of Bioenvision, Inc. (incorporated herein by reference to Annex II to Exhibit 2.1 to the Current Report on Form 8-K filed by Genzyme Corporation on May 29, 2007).*
(d)(3)	Confidentiality Agreement, dated as of April 24, 2007 by and between Genzyme Corporation and Bioenvision, Inc.*
(d)(4)	Co-Development Agreement, dated as of March 21, 2001, by and among Genzyme Corporation (originally Ilex Oncology, Inc.) and Bioenvision, Inc. (incorporated herein by reference to Exhibit 10.28 to the Current Report on Form 8-K filed by Bioenvision, Inc. on June 24, 2002).*
(d)(5)	Letter Agreement for Co-Development of an Oral Clofarabine Formulation and First Amendment to Co-Development Agreement, dated September 2, 2003, by and between Genzyme Corporation and Bioenvision, Inc. (incorporated herein by reference to Exhibit 10.28 to the Annual Report on Form 10-KSB filed by Bioenvision, Inc. on October 13, 2005).*
(d)(6)	Amendment No. 2 to the Co-Development Agreement, dated December 31, 2003, by and between Genzyme Corporation and Bioenvision, Inc. (incorporated herein by reference to Exhibit 10.26 to the Annual Report on Form 10-KSB filed by Bioenvision, Inc. on October 13, 2005).*
(g)	None.
(h)	None.

*Previously filed.

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SIGNATURES

After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

	GENZYME CORPORATION
Dated: July 10, 2007	By:	/s/ Peter Wirth
	Name:	Peter Wirth
	Title:	Executive Vice President
	WICHITA BIO CORPORATION
Dated: July 10, 2007	By:	/s/ Peter Wirth
	Name:	Peter Wirth
	Title:	Vice President

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EXHIBIT INDEX

EXHIBIT NUMBER	DOCUMENT
(a)(1)(A)	Offer to Purchase for Cash dated June 4, 2007.*
(a)(1)(B)	Form of Letter of Transmittal.*
(a)(1)(C)	Form of Notice of Guaranteed Delivery.*
(a)(1)(D)	Form of Letter to Brokers, Dealers, Banks, Trust Companies and Other Nominees.*
(a)(1)(E)	Form of Letter to Clients for Use by Brokers, Dealers, Banks, Trust Companies and Other Nominees.*
(a)(1)(F)	Form of Guidelines for Certification of Taxpayer Identification Number on Substitute Form W-9.*
(a)(2)	None.
(a)(3)	None.
(a)(4)	None.
(a)(5)(A)	Joint Press Release issued by Genzyme Corporation and Bioenvision, Inc. dated May 29, 2007 (incorporated herein by reference to Exhibit 99.1 to the Current Report on Form 8-K filed by Genzyme Corporation on May 29, 2007).*
(a)(5)(B)	Transcript of Conference Call held by Genzyme Corporation and Bioenvision, Inc. on May 29, 2007 (incorporated herein by reference to the Tender Offer Statement on Schedule TO filed by Genzyme Corporation on May 29, 2007).*
(a)(5)(C)	Summary Advertisement published in the Wall Street Journal on June 4, 2007.*
(a)(5)(D)	Complaint filed by Brian Trombley, Dan J. Thomas, Jr. and John Hawn, on behalf of themselves and all other public shareholders of Bioenvision, Inc., on June 7, 2007, in the Court of Chancery in the State of Delaware, New Castle County (incorporated herein by reference to Amendment No. 1 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 12, 2007).*
(a)(5)(E)	Complaint filed by Gerald Ortsman, on behalf of himself and all other public shareholders of Bioenvision, Inc., on June 8, 2007, in the Court of Chancery in the State of Delaware, New Castle County (incorporated herein by reference to Amendment No. 2 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 15, 2007).*
(a)(5)(F)	Complaint filed by Leonard Gerstle c/f Jeremy Gerstle, UGMA on behalf of himself and all other public shareholders of Bioenvision, Inc., on June 13, 2007, in the Court of Chancery in the State of Delaware, New Castle County (incorporated herein by reference to Amendment No. 2 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 15, 2007).*
(a)(5)(G)	Complaint filed by Andrew W. Albstein, on behalf of himself and all other public shareholders of Bioenvision, Inc., on June 14, 2007, in the Court of Chancery in the State of Delaware, New Castle County (incorporated herein by reference to Amendment No. 3 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 18, 2007).*
(a)(5)(H)	Amended Complaint filed by Brian Trombley, Dan J. Thomas, Jr., John Hawn and Leonard Gerstle c/f Jeremy Gerstle, UGMA on behalf of themselves and all other public shareholders of Bioenvision, Inc., on June 13, 2007, in the Court of Chancery in the State of Delaware, New Castle County (incorporated herein by reference to Amendment No. 2 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 15, 2007).*

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(a)(5)(I)	Motion for Preliminary Injunction in Trombley v. Bioenvision, Inc., et al., Civ. A. No. 3008, filed in the Court of Chancery in the State of Delaware, New Castle County on June 13, 2007 (incorporated herein by reference to Amendment No. 2 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 15, 2007).*
(a)(5)(J)	Motion for Expedited Proceedings in Trombley v. Bioenvision, Inc., et al., Civ. A. No. 3008, filed in the Court of Chancery in the State of Delaware, New Castle County on June 13, 2007 (incorporated herein by reference to Amendment No. 2 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 15, 2007).*
(a)(5)(K)	Complaint filed by Oppenheim Pramerica Asset Management S.A. R.L., on behalf of FCP OP Medical Biohe@lth-Trends and all other public shareholders of Bioenvision, Inc., on June 20, 2007, in the Court of Chancery in the State of Delaware, New Castle County (incorporated herein by reference to Amendment No. 4 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 25, 2007).*
(a)(5)(L)	Motion for Preliminary Injunction in Oppenheim Asset Management, et. al. v. Bioenvision, Inc., et al., Civ. A. No. 3040-VCP, filed in the Court of Chancery in the State of Delaware, New Castle County on June 20, 2007 (incorporated herein by reference to Amendment No. 4 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 25, 2007).*
(a)(5)(M)	Motion for Expedited Proceedings in Oppenheim Asset Management, et. al. v. Bioenvision, Inc., et al., Civ. A. No. 3040-VCP, filed in the Court of Chancery in the State of Delaware, New Castle County on June 20, 2007 (incorporated herein by reference to Amendment No. 4 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 25, 2007).*
(a)(5)(N)	Complaint filed by Bert Vladimir, individually and on behalf of all other public shareholders of Bioenvision, Inc., on June 7, 2007, in the Supreme Court of the State of New York, New York County (incorporated herein by reference to Amendment No. 5 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 26, 2007).*
(a)(5)(O)	Corrected Notice of Motion for Expedited Proceedings in Vladimir v. Bioenvision, Inc., Index No. 650163-2007, filed in the Supreme Court of the State of New York, New York County, dated June 25, 2007 (incorporated herein by reference to Amendment No. 5 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 26, 2007).*
(a)(5)(P)	Memorandum of Law in Support of Plaintiff’s Order for Expedited Discovery Proceedings in Vladimir v. Bioenvision, Inc., Index No. 650163-2007, filed in the Supreme Court of the State of New York, New York County, dated June 18, 2007 (incorporated herein by reference to Amendment No. 5 to the Solicitation/Recommendation Statement on Schedule 14D-9 filed by Bioenvision, Inc. on June 26, 2007).*
(a)(5)(Q)	Press Release issued by Genzyme Corporation, dated June 27, 2007.*
(a)(5)(R)	Press Release issued by Genzyme Corporation, dated July 2, 2007.*
(a)(5)(S)	Press Release issued by Genzyme Corporation, dated July 10, 2007.
(b)	None.
(d)(1)	Agreement and Plan of Merger, dated as of May 29, 2007, by and between Genzyme Corporation, Wichita Bio Corporation and Bioenvision, Inc. (incorporated herein by reference to Exhibit 2.1 to the Current Report on Form 8-K filed by Genzyme Corporation on May 29, 2007).*
(d)(2)	Form of Tender and Voting Agreement, dated as of May 29, 2007, by and between Genzyme Corporation, Wichita Bio Corporation and certain shareholders of Bioenvision, Inc. (incorporated herein by reference to Annex II to Exhibit 2.1 to the Current Report on Form 8-K filed by Genzyme Corporation on May 29, 2007).*
(d)(3)	Confidentiality Agreement, dated as of April 24, 2007 by and between Genzyme Corporation and Bioenvision, Inc.*

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(d)(4)	Co-Development Agreement, dated as of March 21, 2001, by and among Genzyme Corporation (originally Ilex Oncology, Inc.) and Bioenvision, Inc. (incorporated herein by reference to Exhibit 10.28 to the Current Report on Form 8-K filed by Bioenvision, Inc. on June 24, 2002).*
(d)(5)	Letter Agreement for Co-Development of an Oral Clofarabine Formulation and First Amendment to Co-Development Agreement, dated September 2, 2003, by and between Genzyme Corporation and Bioenvision, Inc. (incorporated herein by reference to Exhibit 10.28 to the Annual Report on Form 10-KSB filed by Bioenvision, Inc. on October 13, 2005).*
(d)(6)	Amendment No. 2 to the Co-Development Agreement, dated December 31, 2003, by and between Genzyme Corporation and Bioenvision, Inc. (incorporated herein by reference to Exhibit 10.26 to the Annual Report on Form 10-KSB filed by Bioenvision, Inc. on October 13, 2005).*
(g)	None.
(h)	None.

*Previously filed.

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EX-99.(A)(5)(S)

Exhibit 99.(a)(5)(S)

Genzyme Completes Tender Offer to Acquire Bioenvision, Inc.

Date: July 10, 2007

Proxy Statement to Be Prepared for Shareholder Meeting on Merger

Genzyme Corporation (Nasdaq: GENZ) announced today that it has completed its tender offer to acquire shares of Bioenvision, Inc. (Nasdaq: BIVN) capital stock and that a proxy statement will now be prepared by Bioenvision for a shareholder meeting to occur before the end of the year.

Genzyme will purchase approximately 22 percent of the outstanding shares of Bioenvision common stock on an as-converted basis, including the 100 percent of outstanding shares of preferred stock that have already been tendered. Each share of preferred stock can be converted into approximately two shares of common stock, and also carries a separate class vote over any merger or business combination of Bioenvision and approval of the authorization of any additional shares of Bioenvision common stock, as well as other features.

“We are proceeding with the purchase of all the Bioenvision preferred shares, as well as the common shares tendered,” stated Mark J. Enyedy, president of Genzyme Oncology, a business unit of Genzyme Corporation. “At a minimum, we are committed to playing an active and constructive role as a significant long-term shareholder of Bioenvision.”

Consistent with the merger agreement reached between Genzyme and Bioenvision on May 29, 2007, Bioenvision will now prepare a proxy statement to be mailed to its shareholders detailing the rationale for the merger and other material disclosures. This process is expected to culminate with a merger vote before the end of the year.

Genzyme agreed on May 29, 2007 to acquire Bioenvision in an all-cash transaction valued at $5.60 per outstanding common share and $11.20 per outstanding preferred share (plus accrued but unpaid dividends), or approximately $345 million.

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 9,000 employees in locations spanning the globe and 2006 revenues of $3.2 billion. Genzyme has been 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.

Important Information Regarding the Tender Offer

As of 12:01 a.m. on July 10, 2007, a preliminary total of approximately 8,706,644 shares of Bioenvision common stock and 2,250,000 shares of Bioenvision preferred stock had been tendered and not withdrawn.

Bioenvision investors and security holders are urged to read the disclosure documents filed with the Securities and Exchange Commission (the “SEC”) from time to time, including the tender offer statement filed on June 4, 2007, as amended, regarding the tender offer by Genzyme’s wholly owned subsidiary, Wichita Bio Corporation, for all of the outstanding shares of Bioenvision, Inc. Investors and security holders may obtain a free copy of the disclosure documents and other documents filed by Genzyme or Wichita Bio with the SEC at the SEC’s website at www.sec.gov. In addition, documents filed with the SEC by Genzyme or Wichita Bio may be obtained free of charge from Genzyme by directing a request to Sally Curley at (617)768-6140.

Important Information Regarding the Proxy Solicitation

Bioenvision will file with the SEC, and furnish to its shareholders, a proxy statement soliciting proxies for the meeting of its shareholders to be called with respect to the proposed merger. Bioenvision shareholders are advised to read the proxy statement when it is finalized and distributed to them because it will contain important information. Bioenvision shareholders and other interested parties will be able to obtain, without charge, a copy of the proxy statement (when available) and other relevant documents filed with the SEC from the SEC’s website at http://www.sec.gov. Bioenvision shareholders and other interested parties

will also be able to obtain, without charge, a copy of the proxy statement and other relevant documents (when available) by directing a request by mail or telephone to Bioenvision, Inc., 345 Park Avenue, 41st Floor, New York, New York 10154, Attention: James Scibetta, Chief Financial Officer, (212) 750-6700.

Bioenvision and certain of its directors, executive officers and other members of management and employees may, under SEC rules, be deemed to be “participants” in the solicitation of proxies from Bioenvision shareholders with respect to the proposed merger. Information regarding the people who may be considered “participants” in the solicitation of proxies will be set forth in Bioenvision’s proxy statement relating to the proposed merger when it is filed with the SEC. Information regarding certain of these people and their beneficial ownership of Bioenvision common stock is also set forth in Bioenvision’s proxy statement for its 2006 annual meeting of stockholders, as filed with the SEC on October 20, 2006.

Depending on the role, if any, it takes in connection with the proxy solicitation, Genzyme and certain of its directors, executive officers and other members of management and employees may, under SEC rules, be deemed to be “participants” in the solicitation of proxies from Bioenvision shareholders with respect to the proposed merger. Genzyme owns the shares of Bioenvision stock indicated above and has the relationships with Bioenvision described in the tender offer statement filed with the SEC on June 4, 2007, as amended.

Safe Harbor Statement

This press release contains forward-looking statements, including the statements regarding: expectations regarding the preparation of the proxy statement, convening a meeting to vote on the merger agreement, and Genzyme’s future ownership position in Bioenvision. 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 time periods in which Bioenvision prepares the proxy statement, solicits proxies, and holds a meeting of its shareholders; and future determinations Genzyme may make regarding retaining its ownership position. We caution investors not to place undue reliance on the forward-looking statements contained in this document. These statements speak only as of the date of this document and we undertake no obligation to update or revise the statements.