All new drugs must undergo 2 separate tests on animals before human testing. Many reactions like this will be picked up at that stage rather although obviously due to differing physiology sometimes these reactions will not occur with the animals.
You must remember without this testing we would have no new medicines
So, obviously this is a horrible thing to happen to humans, but it's ok for animals?
I know the development of new medicines is something which is a great benefit to human life. However, it does seem that we must do this regardless of the consequences. Our own well-being is far more important than that of any animals.
OK, quality of life would be much lower and mortality rates would be higher without new medicines, however, does that justify developing them at all costs? The human race has survived thousands of years without them.
I'm not saying we shouldn't develop new medicines, of course we should, but any such development should be within the limitations of not inflicting harm to other living things.