"In accordance with the FDA’s usual practice, within 60 days of its receipt of the electronic submission of the complete set of NDA modules, the FDA is expected to determine whether the NDA is complete and acceptable for filing. As such, Kitov expects that the formal filing of the NDA by the FDA will occur by the end of the third quarter of 2017".
NDA submitted July 31 .... plus two months .... it means 1 of October (Sunday) so 2 of October they will know if FDA accepted NDA.
Regarding the 74-day letter ....
https://weinberggroup.com/nda-review-fda-submission/ "You will know within 60 days of submitting your NDA whether it has been accepted for filing (or conversely, if FDA refuses to file your application). If your application is accepted for filing (60 days after submission), then you will receive a 74-day letter, which confirms your action date, confirms standard versus priority review, and identifies any preliminary deficiencies in your application".