Since it has a centre hole it will be very easy to drill out, if you can find left-hand drills that's a bonus since the screw will probably spin out while being drilled. These do exist!
Look at the other screws to see what the root diameter of the threads is. Go by steps up to just under this size. When you have just a thin shell with threads left in the hole, you can pick it out with a dental tool or something small sharp and hard. Getting a new screw is going to be a problem I think though.