Wolven (English, Paperback, Di Toft)

The exciting adventures of a boy and his pet…werewolf! When his big, hairy hound turns into a boy, Nat discovers he’s caught up in a weird government conspiracy to train wolven as weapons!

With his big snaggly teeth, patchy black fur, and glowing golden eyes, Woody is far from the cutest of dogs, yet Nat is strangely drawn to the rough mutt that howls at the moon. And before long Nat discovers that Woody’s not a dog at all–he’s a wolven: a shape-shifter who changes from wolf to boy without much warning. A secret government agency knows about Woody’s mutant status, too, and wants to trap him and turn him into a hairy new breed of bioweapon. To escape capture, and to make sense of Woody’s strange identity, the two friends–boy and werewolf–set off on a great adventure.
Source- Gooreads.com