Is there is a way to restrict the close date from being back dated on a negotiation?

Is there is a way to restrict the close date from being back dated prior to the current close date through a negotiation amendment. In our case, if negotiations are able to be back dated through the amendment process, it could impact the bid integrity. For example, if a negotiation is set to close two weeks from today and currently has three responses, a buyer can see they have received responses from expected vendors and close early, preventing other vendors of chance to submit responses.