Lessons from the glitazones: a story of drug development

Troglitazone, the first in the thiazolidinedione class of oral hypoglycaemic agents, was launched in the USA in March, 1997. It reached Europe later that year, only to be withdrawn within weeks on the grounds of liver toxicity. Meanwhile it went on to generate sales of over $2 billion in the USA, and caused at least 90 cases of liver failure (70 resulting in death or transplantation) before it was withdrawn in March, 2000. Rosiglitazone and pioglitazone reached the US market in 1999 as first-line agents to be used alone or in combination with other drugs, but in Europe the same dossiers were used one year later to apply for a limited licence as second-line agents restricted to oral combination therapy. How should we use the glitazones? And how did they achieve blockbuster status without any clear evidence of advantage over existing therapy?