Nowadays, you can grow old with diabetes. A safe vaccin exists for polio. Every day open heart surgeries take place succesfully. Treatments against cancer are more and more efficient. These are just a few examples of medical improvement of the past decennia. In all cases animal experiments have played an important role.
The role of animals in research is controversial. Propaganda (in both directions) is intense and often based on dubious claims and hype. The utility of replacement for animals and the extent to which they can deliver relevant clinical and safety data deemed essential before work in humans can be contemplated, is disputed by those pro and anti-animal based research.
Giving the claims and counter claims about this issue, will allow you to make your own mind up and contribute effectively to science and health policy decision making.