A company press release mentions five DLC packs "rolling out after launch" which are now available for pre-purchase in a $39.99 bundle. Trion says that this represents a 20% savings over the suggested retail price of $9.99 per pack, which begs the question of whom exactly suggests the retail prices that generous game companies subsequently discount.
In any event, Defiance is slated to launch on April 2nd. You can of course pre-order it, and if you're feeling especially impatient, you can now pre-order its DLC too. The packs will provide a new playable alien species, additional weapons, vehicles and missions, a lock box, and more.
[Source: Trion press release]