AMENDMENT No. 2 to LICENSE AGREEMENT

Exhibit 10.21

AMENDMENT No. 2 to

LICENSE AGREEMENT

Amendment No. 2 to License (this “ Amendment ”) made as of March 8, 2007, by and between  Acuity Pharmaceuticals, Inc., a Delaware corporation, with its principal offices at 3701 Market Street, Philadelphia, PA, 19104 (“ Acuity ”) and Pathogenics, Inc ., a Delaware Corporation with its principal offices at 99 Derby Street, Suite 200, Hingham, MA 02043 (“ Pathogenics ”) .

BACKGROUND

WHEREAS, Acuity and Pathogenics entered into a License Agreement (the “ License Agreement ”) on April 13, 2006 which was amended on August 2, 2006;

WHEREAS, Pathogenics and Acuity have agreed to enter into this Amendment to amend and restate section 4.7(a) to provide that Acu