15,360,254 Common Stock of Onconova Therapeutics, Inc. are subject to a Lock-Up Agreement Ending on 20-JAN-2014. These Common Stock will be under lockup for 180 days starting from 24-JUL-2013 to 20-JAN-2014.

Details:
The officers, directors and certain of the stockholders holding an aggregate of 15,360,254 shares have agreed that without the prior written consent of Citigroup Global Markets Inc., they will not dispose of or hedge any shares of common stock for a period of 180 days from the date of the prospectus.