Yes, we rescued a dog with similar issues, she was also highly dog and human aggressive (had put five different reputable behaviorists in hospital needing stitches). She was about to be pts as being unhandlable. She's a Caucasian Ovcharka, so not an easy breed to keep or train and that's putting it mildly, especially since they have absolutely nzero interest in food or treats other than eating the minimum needed for sustinence, and will only obey their family,and only then if they respect and love them. She's currently sprawled around my feet snoozing as I type this.
It took a lot of time and patience, but she is now the most loving and fiercly loyal dog you could every meet. She's impeccably obedient and very confident, I've doing quite a bit of schutzhund training with her which she is very good at, it helped her to build her confidence and focus her mind, and got her used to taking directions from me.
With her and our other two dogs we didn't use food/treat based training, it wouldn't work (we have two Ovcharkas and one Fila Brasiliero, all rescues, all about to be pts for severe aggression) and I don't like doing it personally. Praise and affection work better than anything with ours, if they think there's a cuddle on offer they will abandon their food bowls, no matter how hungry they are. Oh, and none of ours have ever growled, snarled or shown any aggression to me ever.
Could you try praise training, so give the command then whatever kind of fuss he likes and plenty of it when he obeys? It will be a long road, but absolutely worth it in the end. We live in a country with a lot of dangerous predators, including human ones, and our dogs have defended DH, DS and I so many times, we would be dead without them. Sending 
its never easy.