This is a good read, sort of. The author certainly is no vivisection opponent, but good middle-of-the-road arguments are made.
Check it out at (sigh) the msn.com site below...
http://www.slate.com/id/2142814/"Every year, in the name of medical progress, scientists breed and nurture hundreds of millions of mice, rats, and other subordinate mammals. Then they expose the critters to substances that could become the next Zocors, Prozacs, and Avastins. Since the alternative is to experiment on people, most everyone other than hardcore animal lovers accepts animal testing. Periodically, however, a spectacular failure raises new questions about the enterprise—not for ethical reasons, but scientific ones.
In March, London clinicians injected six volunteers with tiny doses of TGN1412, an experimental therapy for rheumatoid arthritis and multiple sclerosis that had previously been given, with no obvious ill effects, to mice, rats, rabbits, and monkeys. Within minutes, the human test subjects were writhing on the floor in agony. The compound was designed to dampen the immune response but it had supercharged theirs, unleashing a cascade of chemicals that sent all six to the hospital."