I can actually explain the age cut off in this case. As with all clinical trials, experts in FDA regulation help set up the trial. There is a concern that if people over a certain age were used, that the study would be criticized by those who want to say that LADA is different than Type 1. It is about getting results impervious to criticism so that the trial can move to the step of FDA approval if successful. The good news is, if proven to work, this therapy will be for everyone regardless of age.
But I definitely hear what you're saying. I was diagnosed over age 40 with Type 1 (after being misdiagnosed of course -- the other common thing that happens to us older onset patients). But until the diabetes world universally accepts latent onset or rapid adult onset Type 1 as the same disease, clinical trials are going to have a cut off. It's all so naysayers cannot try to knock down the legitimacy of the results on the basis of the age of the participants.