Exhibit 10.1

AMENDMENT NO. 4, dated as of June 23, 2008, to Employment Agreement, dated as of
November 3, 2003, by and between Vion Pharmaceuticals, Inc., a Delaware
corporation (the “Company”), and Alan Kessman (the “Executive”), as amended by
Amendment No. 1 thereto, dated September 13, 2005, Amendment No. 2 thereto,
dated January 3, 2006, and Amendment No. 3 thereto, dated February 13, 2008
(collectively, the “2003 Agreement”).

WHEREAS, the Executive has been acting as the Chief Executive Officer of the
Company pursuant to the 2003 Agreement; and

WHEREAS, the 2003 Agreement expires on December 31, 2008; and

WHEREAS, the Board of Directors of the Company (the “Board”) recognizes that the
Executive’s continued long-term contribution to the growth and success of the
Company is essential, and the Board desires to provide for the continued
employment of the Executive on the terms set forth in the 2003 Agreement; and

WHEREAS, the Executive is willing to continue to serve the Company on the terms
and conditions set forth in the 2003 Agreement.

NOW THEREFORE, in order to effectuate the foregoing, the Company and the
Executive wish to amend the 2003 Agreement to extend the term thereof as set
forth below. Accordingly, in consideration of the premises and the respective
covenants and agreements of the parties herein contained, and intending to be
legally bound hereby, the parties hereto agree as follows:

1. Section 2 of the 2003 Agreement is hereby amended and restated in its
entirety to read as follows:

“2. Term. The term of the Executive’s employment hereunder (the “term”) will
commence on January 1, 2004 (the “Effective Date”) and, unless sooner terminated
or extended in accordance with the terms hereof, will expire on December 31,
2009.”

2. Except as specifically amended as set forth herein, the 2003 Agreement shall
remain in full force and effect.

3. This Amendment may be executed in two or more counterparts, each of which
shall be deemed an original, but all of which together shall constitute one and
the same instrument.

[signature page follows]

 

 

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IN WITNESS WHEREOF, this Amendment No. 4 has been executed as of the date and
year first above written.

 

 

 

VION PHARMACEUTICALS, INC.

 

By: 

/s/ William R. Miller

 

 

 

William R. Miller
Chairman of the Board

 

 

/s/ Alan Kessman

 

 

 

Alan Kessman

 

 

 

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