In a large skillet, sauté the sausages over medium-high, breaking up meat with a wooden spoon, until browned, about 5 minutes. Add chopped leeks to sausage in skillet and cook until softened, about 5 more minutes. Add wine and cook, stirring frequently and scraping up any brown bits on the bottom of the pan, until mostly evaporated. Stir in butter and season to taste with salt and pepper.