A resubmission application, also known as an “A1” application, requires a one-page introduction that addresses the comments from the review of the prior A0 application as well as marked changes in the text of the Research Strategy. You are permitted one resubmission of an unfunded application to address reviewer comments, and that resubmission must be submitted to an appropriate due date no longer than 37 months after the application due date of the initial (“A0”) application.
Any application on the same topic submitted more than 37 months from the initial application due date is considered a new application. This new application should not include the one-page introduction that is required for A1 applications, nor should it address or refer to reviewer comments. It must be submitted on the appropriate due date for new applications.
Remember that resubmission applications may have different due dates than new applications, so read the funding opportunity announcement instructions closely. If the funding opportunity announcement says that “standard dates apply” refer to the standard due date table.
Remember also that the NIH recently modified its policy on application submissions (NOT-OD-14-074). That policy does not preclude submission of a new (A0) application, rather than a resubmission (A1) application, following an unfunded application.