definiens: s hall mean the efforts that a reasonable person in t he position of LICENSEE would make so as to achieve th at goal as expeditiously as practicable ; notwithstanding the foregoing, LICENSEE shall be de emed to have used Best Efforts with respect to the period preceding the achievement of a milestone if it achieves the milestone by the corresponding targ et achievement date . If LICENSEE has not achieved a mi lestone by the corresponding target achievement date, LICENSEE shall have a cure period of [ * * ] ther eafter to achieve such milestone or other mutually agreed upon milestone that represents Best Efforts . . If LICENSEE has not commenced such Best Efforts, or if applicable, achieved the milestone in questio n, by the end of such cure period, then the license granted pursuant to Section 4.1 shall thereafter co nvert to a non - exclusive license and such failure t o use Best Efforts shall not be considered a material bre ac h of this Agreement