UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

EXPLANATORY NOTE

This Amendment No. 5 (the “Amendment”) amends and supplements the statement on Schedule 13D originally filed by the Reporting Persons with the Securities and Exchange Commission (the “SEC”) on June 8, 2007 (as previously amended and supplemented, the “Schedule 13D”). Unless otherwise indicated, each capitalized term used but not defined herein shall have the meaning assigned to such term in the Schedule 13D.

Item 3.

Source and Amount of Funds or Other Consideration

The second paragraph of Item 3, as amended, of the Schedule 13D is hereby deleted and replaced with the following:

The Offer expired at 12:01 a.m. (New York City time) on July 10, 2007.  On July 10, 2007, Wichita Bio accepted for payment 8,398,098 Common Shares and 2,250,000 Preferred Shares that had been tendered and not withdrawn from the Offer, representing a total of 15.3% of the 55,035,740 outstanding Common Shares as of June 27, 2007 and 100% of the outstanding Preferred Shares as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 all Common Shares tendered by notice of guaranteed delivery that were validly delivered within three NASDAQ Global Market trading days after the July 10, 2007 expiration date of the Offer, as required by the terms of the notice of guaranteed delivery. Genzyme provided all funding required by Wichita Bio in connection with the acceptance for payment of the Common and Preferred Shares on July 10, 2007 from cash on hand.

Item 4.

Purpose of Transaction

The second paragraph of Item 4, as amended, of the Schedule 13D is hereby deleted and replaced with the following:

The purpose of entering into the Merger Agreement and the Tender and Voting Agreements, and the purpose of the Offer, was to enable the Reporting Persons to acquire control of, and ultimately the entire equity interest in, Bioenvision. On July 2, 2007, pursuant to the Merger Agreement, the Reporting Persons (a) waived the condition that there be validly tendered and not withdrawn prior to the Expiration Date that number of Common Shares which represents a majority of the issued and outstanding Common Shares (assuming, for purposes of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) and (b) extended the Expiration Date until 12:01 a.m., New York City time, on July 10, 2007. As of 12:01 a.m., New York City time, on July 10, 2007, a total of 8,398,098 Common Shares and 2,250,000 Preferred Shares were validly tendered and not withdrawn, representing approximately 15.3% of the 55,035,740 outstanding Common Shares and 100% of the outstanding Preferred Shares, both as of June 27, 2007.

Item 5.

Interest in Securities of the Issuer

Subparagraphs (a) and (b) of Item 5, as amended, of the Schedule 13D are hereby deleted and replaced with the following:

a)     As of the date hereof, the Reporting Persons own 8,398,098 Common Shares (representing 15.3% of the 55,035,740 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).  Additionally, for purposes of Rule 13d-3 under the Exchange Act, as a result of entering into the Tender and Voting Agreements, the Reporting Persons may also be deemed to possess beneficial ownership of the Stockholders’ Options and Warrants (5,058,575 options to purchase Common Stock and 75,009 warrants to purchase Common Stock). Therefore, the Reporting Persons may be deemed to beneficially own an aggregate of 18,031,682 Common Shares, representing approximately 27.9% of the fully diluted outstanding shares (assuming exercise of Stockholders’ Options and Warrants and conversion of the Preferred Shares with no accrued but unpaid dividends). The Reporting Persons and the other persons listed on Schedule I hereto, however, disclaim beneficial ownership of the Stockholders’ Options and Warrants, and this statement shall not be construed as an admission the Reporting Persons or those listed on Schedule I hereto is the beneficial owner for any purpose of the Stockholders’ Options and Warrants.

Except as set forth in this Schedule 13D, to the best of Genzyme’s knowledge as of the date hereof, neither Genzyme nor any of its directors and executive officers named in Schedule I hereto owns any Bioenvision Shares.  Except as set forth in this Schedule 13D, to the best of Wichita Bio’s knowledge as of the date hereof, neither Wichita Bio nor any of its directors and executive officers named in Schedule I hereto owns any Bioenvision Shares.

b)     As of the date hereof, the Reporting Persons have acquired the sole power to vote or direct the vote and to dispose or direct the disposition of 8,398,098 Common Shares and 2,250,000 Preferred Shares. For purposes of Rule 13d-3 under the Exchange Act, as a result of entering into the Tender and Voting Agreements, the Reporting Persons may also be deemed to have acquired the shared power to vote or direct the vote and to dispose or to direct the disposition of the Common Shares underlying the Stockholders’ Options and Warrants. Therefore, the Reporting Persons may be deemed to have acquired the shared power to vote or direct the vote and to dispose or to direct the disposition of an aggregate of 18,031,682 Common Shares, representing approximately 27.9% of the fully diluted outstanding shares (assuming exercise of Stockholders’ Options and Warrants and conversion of the Preferred Shares with no accrued but unpaid dividends).

GENZYME CORPORATION

By:

 /s/ Earl M. Collier, Jr.

Name:

Earl M. Collier, Jr. 

Title:

Executive Vice President

WICHITA BIO CORPORATION

By:

/s/ Earl M. Collier, Jr.

Name:

Earl M. Collier, Jr. 

Title:

President