A compound of Formula (I), or a metabolite thereof, or an ester of the compound of Formula (I) or the metabolite thereof, or a pharmaceutically acceptable salt of each thereofwherein: m is an integer from 2 to 5 inclusive； and n is an integer from 3 to 8 inclusive； and X1 and X2 are each independently sulfur, oxygen, a sulfinyl group or a sulfonyl group, provided that X1 and X2 are not simultaneously oxygen. Such a compound may be useful for treating, inhibiting, or preventing the progression of amyotrophic lateral sclerosis, primary lateral sclerosis, or familial amyotrophic lateral sclerosis, or a symptom of each thereof.
