They use more sophisticated domides based off Thalidomide these days (2nd gen Lenalidomide, 3rd gen Pomalidomide, and next gen Mezidomide is in trials).

But yes, it was very effective as a treatment. When it was approved for cancer use, we actually had no idea how it worked, only that it worked really well. Thalidomide has saved a few orders of magnitude more lives than it took/damaged.