Heat oven to 350°F. Spray 9x5-inch loaf pan with cooking spray.
Separate dough into 8 biscuits. Separate each biscuit into 2 layers, to make total of 16 thin biscuits. Spread pumpkin pie mix on top of each. Top each with melted butter. In small bowl, mix granulated sugar and 1 teaspoon of the pumpkin pie spice; sprinkle over each.
Stack biscuits in 4 piles of 4 biscuits each. Place stacks on their sides in a row in loaf pan, making sure sides without filling are on both ends touching pan. It should look like a 16-layer sandwich with no filling on the outside ends.
Bake 40 to 45 minutes or until loaf is deep golden brown and center is baked through.
Cool loaf slightly. If necessary, run knife around edges to loosen loaf from pan. Carefully turn pan upside down on serving platter to release loaf. In small bowl, mix powdered sugar, milk, vanilla and remaining 1/2 teaspoon pumpkin pie spice. Drizzle over loaf. Serve warm.