AMENDMENT NO. 1 TO SECURITIES PURCHASE AGREEMENT

This Amendment No. 1 to Securities Purchase Agreement, dated as of September 16, 2009 (this “ Amendment ”), is made by and between Rexahn Pharmaceuticals, Inc., a corporation organized and existing under the laws of Delaware (the “ Company ”), and Teva Pharmaceutical Industries Limited, a limited liability company organized and existing under the laws of Israel (the “ Purchaser ”).  Any capitalized term not defined herein shall have the meaning for such term specified in the Securities Purchase Agreement (as defined below).

WHEREAS , the Company and the Purchaser entered into a Securities Purchase Agreement, dated as of June 26, 2009 (the “ Securities Purchase Agreement ”); and

WHEREAS, the Purchaser and the Company wish to amend the Securities Purchase Agreement to   restructure the consideration payable by the Purchaser at the Initial Closing and the Second Closing and to revise the anticipated timing of the Initial Closing, as set forth herein.

NOW THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Company and the Purchaser agree as follows:

1.             Section 1.8 of the Securities Purchase Agreement is hereby deleted in its entirety and replaced with the following:

“1.8           Initial Aggregate Purchase Price ” means $3,500,000.”

2.             Section 2.1(c)(ii)(A) of the Securities Purchase Agreement is hereby deleted in its entirety and replaced with the following:

“(A)           the Initial Aggregate Purchase Price of $3,500,000 by wire transfer of immediately available funds to the account of the Company;”

3.             Section 2.1(d)(i)(E) of the Securities Purchase Agreement is hereby deleted in its entirety and replaced with the following:

“(E)            Pre-Clinical Development Requirements; R&D Program; R&D Budget .  The Purchaser and the Company shall have agreed upon (1) a set of requirements to apply to the pre-clinical development of RX-3117 (the “ Pre-Clinical Development Requirements ”); (2) the R&D Program; and (3) a budget (the “ R&D Budget ”) to govern the expenditure of the $3,500,000 of the Initial Aggregate Purchase Price to be allocated to the R&D Program as provided in Section 2.3(a);”

4.             Section 2.2(a) of the Securities Purchase Agreement is hereby deleted in its entirety and replaced with the following:

“(a)          No sooner than 60 days prior to the scheduled exhaustion (pursuant to the R&D Budget) of