SC TO-T/A

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE TO
(Amendment No. 6)

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. 6 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 4.  TERMS OF THE TRANSACTION; ITEM 5.  PAST CONTACTS, TRANSACTIONS, NEGOTIATIONS AND AGREEMENTS; ITEM 11.  ADDITIONAL INFORMATION

Section 14 of the Offer to Purchase and Item 11 of this Schedule TO are hereby amended and supplemented by adding the following:

On July 2, 2007, pursuant to Sections 1.1 and 8.5 of the Merger Agreement, the Offeror waived the condition to the Offer requiring that there be validly tendered and not withdrawn prior to the Expiration Date that number of Common Shares which, when added to any Common Shares owned by the Offeror and the Parent, represents a majority of the issued and outstanding Common Shares (assuming, for purposes of such calculation, the exercise or conversion of all vested “in-the-money” options and “in-the-money” warrants).  Additionally, the Offeror extended the Offer until 12:01 a.m. (New York City time) on July 10, 2007.  The full text of the press release issued by the Parent on July 2, 2007 announcing the waiver of the condition to the Offer and the extension of the Offer is filed as Exhibit (a)(5)(R) hereto and is incorporated by reference.

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 2, 2007, approximately 11,140,630 Common Shares and 2,250,000 Preferred Shares had been tendered and not withdrawn from the Offer, representing a total of 20.2% 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 an aggregate of 5,434,409 Common Shares (representing 9.9% of the outstanding Common Shares as of June 27, 2007) and 2,250,000 Preferred Shares (representing 100% of the outstanding Preferred Shares as of June 27, 2007) that were tendered by officers, directors and stockholders of the Company pursuant to Tender and Voting Agreements.

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.

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(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).*
(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).*

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(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.
(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 2, 2007	By:	/s/ Earl M. Collier, Jr.
	Name:	Earl M. Collier, Jr.
	Title:	Executive Vice President
	WICHITA BIO CORPORATION
Dated: July 2, 2007	By:	/s/ Earl M. Collier, Jr.
	Name:	Earl M. Collier, Jr.
	Title:	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.
(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)(R)

Exhibit 99(a)(5)(R)

For Immediate Release	Investors	Media
July 2, 2007	Carol Miceli	Maria Cantor
	(617) 768-6602	(617) 768-6690

Genzyme Extends Tender Offer to Acquire Bioenvision, Inc.

Waives Minimum Tender Condition; 100 Percent of Preferred Shares
Now Tendered

CAMBRIDGE, Mass — Genzyme Corporation (Nasdaq: GENZ) announced today that it is waiving the condition to its tender offer that it acquire at least 50 percent of the outstanding shares of common stock of Bioenvision, Inc. (Nasdaq: BIVN) and that it is extending the tender offer for all outstanding shares of common and preferred stock of Bioenvision until 12:01 a.m. on July 10, 2007.

As of 12:01 a.m. this morning, Genzyme has received a preliminary number of tenders representing approximately 26 percent of the outstanding shares of Bioenvision on an as-converted basis, including shares tendered by directors and senior executives of Bioenvision.  The shares tendered include approximately 20 percent of the outstanding shares of Bioenvision common stock and 100 percent of the outstanding shares of preferred stock.

The preferred stock that has been tendered can be converted into common stock at an approximately two-to-one ratio and carries with it several additional features, including a separate class vote to approve any merger or business combination of

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Bioenvision, as well as a separate class vote to approve the authorization of any additional shares of Bioenvision common stock.  In addition to the separate class vote on a merger or share authorization, the preferred stock votes together with the common stock on such matters.

Under the merger agreement reached between Genzyme and Bioenvision on May 29, 2007, Bioenvision remains obligated to pursue a merger with Genzyme. Bioenvision’s ability to terminate the merger agreement upon receiving a superior proposal would expire upon Genzyme’s acceptance of the tendered shares.  The process to hold a meeting to vote on the proposed merger may take up to 60 days or longer.  If the merger were not to close, Genzyme would remain a significant common stockholder of Bioenvision and hold all the preferred stock of the company, along with its attendant rights, including the right to approve or disapprove any merger.

                “We are proceeding with this transaction and expect that Genzyme will purchase all Bioenvision shares tendered as of the new expiration date,” stated Mark J. Enyedy, president of Genzyme Oncology, a business unit of Genzyme Corporation.  “We look forward to the remaining Bioenvision shareholders tendering their shares and the vote on the proposed merger.  Regardless of the outcome of these transactions, we are committed to playing an active and constructive role as a significant long-term shareholder of Bioenvision in bringing these important therapies to patients worldwide.”

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.  Genzyme may elect to extend its offer again by giving notice of such extension to

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Bioenvision shareholders, a copy of which will be filed with the Securities and Exchange Commission and which should also be made available through the Internet at www.sec.gov.

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 2, 2007, a preliminary total of approximately 11,140,630 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.

Safe Harbor Statement

This press release contains forward-looking statements, including the statements regarding: expectations on the completion of the tender offer, Genzyme’s anticipated ownership stake in Bioenvision at the conclusion of the tender offer and expectations on the timing and success of a merger vote. 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,

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 the possibility that other closing conditions will not be met; uncertainty regarding the Bioenvision shares that will be tendered as of the new expiration date and that a merger vote may not be successful.  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.

# # #

Genzyme® is a registered trademark of Genzyme Corporation.  All rights reserved.

Genzyme’s press releases and other company information are available at www.genzyme.com 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.

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