Advisors to the US Food and Drug Administration say the benefits of Bayer's Yaz contraceptive franchise outweigh the risks but have recommended label changes.

A joint meeting of the agency's Reproductive Health Drugs Advisory Committee and the Drug Safety and Risk Management Advisory Committee saw the majority of members (15 to 11) vote that the benefits of drospirenone-containing oral contraceptives, notably Bayer's Yasmin and Yaz (drospirenone/ethinyl estradiol), outweigh the potential risks. They also voted 21 to five that the current US labels do not adequately reflect the benefit-risk profile for these products and should be revised to include information from available studies assessing the risk for venous thromboembolism.

Approved by the FDA in 2006, Yasmin follow-up Yaz quickly became the best-selling birth control pill in the USA and studies carried out by Bayer found no increased risk of blood clots. However over the last two years several large, independent studies have suggested the pills' drospirenone component may present a higher VTE risk than levonorgestrel-based rivals. The most recent analysis by the FDA estimates that 10 in 10,000 women on drospirenone drugs will experience a blood clot per year, compared with six in 10,000 women on older contraceptives.

However, the panelists believe that all available studies are somewhat flawed given the lack of information about patient weight and smoking status, which can increase the risk of clots. As such, while not definitive, panelists said the labels on the pills need to contain much more information.

Sales of Yaz and Yasmin sank surrounding the thrombosis risk and nearly 7,000 lawsuits have been filed in the USA against Bayer.