My tomato plants always have what appears (to me, at least) to be the same problem. For me it generally starts around mid summer when we get some days with cool, rainy weather. The taller varieties that I grow (including Brandywine) have largely been able to survive because they grow faster than the disease progresses; however, shorter determinate types die pretty early. I've never figured out if it's a blight (which everyone around here seems to call it) or a wilt, and I've tried using Daconil and other remedies without much success.
What I HAVE had great success with is growing the plants inside a hoop house; I experimented with this last year and the Viva Italia plants that I always grow, which are always the first to succumb, kept growing until late October and were still growing strong (with almost no sign of any disease), but we had to pull them to free up the space for another project. They also produced WAY more tomatoes than they normally did in the "outside" garden. That was so successful that we were inspired to build a 16x20 greenhouse mainly for growing the tomatoes; since summer is still relatively young I won't know for a while if the good results will be duplicated this year, but I'm certainly very optimistic.
These were the tomatoes in the hoop house last year (Oct. 9)
These are the tomato plants in the new greenhouse, photo just taken today
By way of contrast -- tomatoes in the "outside garden" in mid October 2014
A huge plus for me is that I can put them out a full month early (even though both the HH and the GH are unheated), and they will also keep growing without being harmed by the early frosts.