Not that I know of, if there were a high quality commercially available food without soy or corn I would buy it instead of Oxbow.
I don't particularly like feeding soy to my rats because I avoid eating it myself as much as possible, but it's either soy or corn and I'm not sure which is worse.
You could try making your own food I suppose if you aren't already, there are a of couple recipes floating around here somewhere.
Aside from the fact that the vast majority of soy is GMO and disregarding the controversy there, soy is just generally a bad food for you and your animals. It can really disrupt hormones and thyroid function. There are many studies on it that you can browse to make a decision on whether or not to avoid soy in your and your pets' diets.