In 1991, regulations published to Accelerate the Review of Drugs for life-threatening diseases. In Decemebr, 1992, the FDA published the final rule to accelerate the approval of new drugs for serious and life-threatening diseases when the drug provides meaningful therapeutic benefit over existing products. Under these procedures FDA may approve drugs based on surrogate endpoints that reasonably predict that a drug provides clinical benefit. This clinical benefit is then confirmed through additional human studies that will be completed after marketing approval. The accelerated approval approach provides for removal of the drug from the market if further studies do not confirm the clinical benefit of the therapy.