An adenine compound or its pharmaceutically acceptable salt as a medicament as shown following formula (1):
wherein R
1
is optionally substituted alkyl group, etc., X is oxygen atom, etc., A is 4 to 8 membered optionally substituted saturated or unsaturated heterocyclic group containing 1 to 2 hetero atoms selected from 1 to 3 nitrogen atoms, 0 to 1 oxygen atom and 0 to 1 sulfur atom, L
1
and L
2
are independently straight or branched chain alkylene, or a single bond, R
2
is optionally substituted alkyl group, etc.