As nice as it would be to not have to run tests and clinical trials on animals, with the current technology we have there is no other reliable method of testing different kinds of treatments or products to see if they are harmful to humans. Instead, as Karen said, we have a system in place to minimize the suffering different animal subjects go through to test these experiments. When looking at it from the big perspective, the sheer abundance of rodents means using a few in an experiment does nothing to harm the survivability of the species. The higher up the chain we go in testing, the smaller the global population is, and thus using them for experimental testing when using a smaller subject like a rodent would work as well would have a bigger impact on the species. While I personally believe that the world will be better off when animal testing is no longer needed, I believe that it is a justified practice for the time being for the survival of the human race as a species.