I have had IT Band Syndrome in my right leg since I was a teen, I trained for my first half-marathon and marathon last year and got ITBS on the left leg too. I went to every type of doc (and got the same diagnosis everywhere), read everything on the net I could find and nothing really helped.
My advice would be: take longer steps, for most ITBS comes out on hills up and down and that is because (at least I think so) steps become shorter. If I run like the pros (really long strides, pulling my knees high and my verse high, use more of my thigh and glute muscles instead of my calf muscles) my ITBS doesn't come out.
If you train in the gym you should be able to run longer with proper form and use more muscle groups for longer.
If you run too long and you start to become tired, your steps/strides become shorter, so stick to short distances (for me that's 9km with 2km uphill running right now, on flats I can run a halfmarathon without any problems), keep an attention on your running form, if you feel weak take a couple of seconds to recover. I run twice a day, which gives my body enough time to rest and recuperate.
If it hurts too much take a week or two off.
I think that drugs that reduce inflammation are making it worse on the long term, but that is just a feeling.
For some reason cartilage drugs help me with my recovery, but I have no idea why.