As an aside, getting a refuse-to-file (RTF) letter resets the clock, causing many month delays. An RTF requires the applicant to:
(1) schedule a meeting with the FDA to discuss the items in the NDA that are incomplete or need to be resolved (2+ months)
(2) edit and resubmit the NDA (2+ months)
(3) wait 2 months for the acceptance of the NDA.
This resubmission process takes > 6 months, assuming there are no new trials that the FDA recommends.
Therefore, it is critical that IPCI gets it right on the NDA submission the first time. I'd rather they have a month or two delay in order to get the NDA right the first time than to wait the 6+ months for a resubmission! Patience...