SECOND AMENDMENT TO CO-DEVELOPMENT AGREEMENT

Exhibit 10.1

SECOND AMENDMENT TO CO-DEVELOPMENT AGREEMENT

This Second Amendment to Co-Development Agreement (this “Second Amendment”) is made as of May 24, 2007, by and between Southern Research Institute (“SRI”) and Bioenvision, Inc. (as successor-in-interest to Eurobiotech Group, Inc.) (“Bioenvision”).

RECITALS:

A.            SRI and Eurobiotech Group, Inc. entered into that certain Co-Development  Agreement, dated as of August 31, 1998, and that certain Amendment to the Co-Development Agreement (the “First Amendment”), dated as of March 12, 2001 (collectively, the “Co-Development Agreement”).

B.            The parties desire to further amend the Co-Development Agreement as provided herein to (i) provide that SRI will be entitled to a 7% royalty on all product sales, whether such sales are made directly by Bioenvision or by a sublicensee, sales partner or distributor, (ii) to delete the profit-sharing agreement set forth in Section 6 of the current Co-Development Agreement in exchange for an agreement by Bioenvision to pay to SRI certain milestone payments provided for in this Second Amendment, and (iii) to make certain other changes to the Co-Development Agreement in order to clarify the respective rights and obligations of the parties.

C.            The parties specifically acknowledge that certain co-development agreement, dated March 12, 2001, between Bioenvision, Inc. and ILEX Oncology, Inc., predecessor-in-interest to Genzyme Corporation (“Genzyme”, and such agreement, as amended, is the “ILEX Co-Development Agreement”), and agree that this Second Amendment does not purport to amend the Ilex Co-Development Agreement.

D.            The parties specifically acknowledge that certain License Agreement, dated and effective September 12, 2006, between Bioenvision and SRI (the “Japan License”), pursuant to which SRI granted to Bioenvision an exclusive license to manufacture, sell, market and distribute Product in Japan and “Southeast Asia” (as defined in the ILEX Co-Development Agreement”), and agree that this Second Amendment does not purport to amend the Japan License.

E.             Capitalized terms used but not otherwise defined herein shall have the meaning(s) ascribed to such terms in the Co-Development Agreement.

AGREEMENT

In consideration of the foregoing and the mutual covenants and agreements set forth in this Second Amendment and for other consideration, the receipt and sufficiency of which is hereby acknowledged, the parties hereto agree as follows:

1.                                        Article 1 “DEFINITIONS” is hereby amended by deleting the text in Sections 1.C., 1.F., 1.G., 1.H. and 1.L. (definition of “Net Income” included in the First Amendment) in their entirety and replacing each with the following text: “RESERVED.”  Article 1 is further amended by adding the following text immediately following Section 1.P. thereof:

a.                                        Direct Sales” shall mean all sales of the Product made by Bioenvision in the Territory, but not including sales by Bioenvision to a Sales Partner.

b.                                       “Indirect Sales” shall mean sales of the Product by any  Sales Partner in the Territory.

c.                                        “Net Sales Revenue” shall mean the gross revenue recognized by Bioenvision or its Sales Partner, as applicable, from the sale of the Product through normal distribution channels to a third party (other than an Affiliate of Bioenvision or a Sales Partner) in the Territory, less Allowable Costs.

d.                                       “Sales Partner” shall mean any third party to which Bioenvision grants a Sublicense of some or all of the rights licensed to Bioenvision by SRI under Article 2 or Article 3 hereof.

e.                                        “Sublicense” shall mean an agreement pursuant to which Bioenvision grants a sublicense of or otherwise transfers some or all of the rights licensed to Bioenvision by SRI under Article 2 or Article 3 hereof.  If Bioenvision enters into an agreement with such a third party pursuant to which such third party shall have the right to control the marketing and sale of the Product within a defined territory (for example, a marketing and/or distribution arrangement under which a third party will have the right to market, sell and/or resell the Product), then such an agreement shall be deemed to be a “Sublicense.”  For avoidance of doubt, in certain limited circumstances in which if Bioenvision enters into an agreement with a third party under which such third party will exercise certain of the rights licensed to Bioenvision under Article 2 hereof (other than the marketing or sale of the Product) for the benefit of Bioenvision (for example, if Bioenvision enters into a contract with a contract research organization or a contract sales organization, and Bioenvision retains the right to oversee and

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control such third party’s performance), then such arrangements shall not be “Sublicenses” and such third parties shall not be “Sales Partners.”

f.                                          “Sublicense Revenue” shall means all consideration received by Bioenvision from a third party for the grant, or in connection with the exercise of rights under, a Sublicense, but excluding royalty payments based on Indirect Sales.  Sublicense Revenue shall include all upfront license fees, milestone payments and the fair market value of any rights granted to Bioenvision to use, market, sell, distribute, develop, import or export products or technologies of a third party, in either case, received by Bioenvision from any Sales Partner pursuant to a Sublicense.  Bioenvision shall not be entitled to deduct from Sublicense Revenues any start-up costs, research and development costs, general administrative expenses or other costs.  For clarity, (i) revenues derived from Indirect Sales shall be deemed not to be Sublicense Revenue, and (ii) Bioenvision shall not be obligated to pay SRI with respect to any such monies paid to Bioenvision by a Sales Partner: (A) in exchange for shares of Bioenvision stock or other equity securities, up to the fair market value thereof; (B) to fund salaries, materials and related capital in support of specific research activities pursuant to the applicable Sublicense; or (C) for Product or other property or assets up to an amount equal to the lesser of the fair market value of such Product (meaning, the amount Bioenvision charges to third parties for similar quantities of Product sold on similar delivery, payment and other terms), property or assets, or Bioenvision’s actual cost to acquire or manufacture such Product, property or assets.

g.                                       “Allowable Costs” shall mean the following actual, documented costs incurred by the seller (either Bioenvision or Sales Partner) that relate specifically to the sale of the Product for which Net Sales Revenue is being calculated:  (i) value added, sales, or use taxes, duties or other governmental tariffs; (ii) trade, quantity and cash discounts, credits, rebates, or allowances; (iii) Product returns and bad debts; (iv) freight, shipping, transportation, and insurance charges; (v) discounts mandated by, or granted to meet the requirements of, applicable territorial laws or regulations; (vi) market based commissions paid to unaffiliated contract sales organizations under non-exclusive sales arrangements, not to exceed 8.0% unless agreed to in advance in writing by SRI; and (vii) any other customary and reasonable deductions that may be made from the sales price of the Product in the Territories.  Allowable Costs shall not include any (i) start-up costs, (ii)

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research and development costs, or (iii) corporate overhead and general administrative expenses.

All references to “sublicenses” in the Agreement shall be deemed to be deleted and replaced with the term “Sublicenses.”

All references to “sublicensees,” “distributors” and “joint ventures” shall be deemed to be deleted and replaced with the term “Sales Partner.”

2.                                        Article 5 of the Co-Development Agreement is hereby deleted in its entirety and replaced with the following:

5.             ACQUISITION

A.            Genzyme Royalties .  For purposes of the ILEX Co-Development Agreement and only for such purpose, it is agreed that the royalties received by Bioenvision from ILEX, its Affiliates or sublicensees for the sales of Clofarabine or any Product in the Field and in the Territory (as such terms are defined in the ILEX Co-Development Agreement) shall be divided between SRI and Bioenvision according to the percentage set forth in the following table:

Bioenvision will pay SRI its percentage of the royalties as