Merck said Monday that its new human papillomavirus vaccine was about 97% effective in blocking precancerous lesions caused by strains of the virus that are not stopped by Merck's vaccine Gardasil.
Merck & Co. said it expects to file for marketing approval of the new vaccine, which is designated V503, before the end of 2013. The company's vaccine Gardasil is designed to target four common strains of HPV that can cause cervical cancer and genital warts, and V503 is intended to prevent infection with a total of nine strains of the virus.
The company reported results from a late-stage clinical trial that compared V503 to Gardasil in more than 14,000 women aged 16 to 26. Merck said V503 led to a 97.1% reduction in diseases of the cervix, vulva and vagina that were caused by HPV types 31, 33, 45, 52, 58, and there was a 96.7% reduction in high-grade disease. It said the vaccine was 96% more effective than Gardasil against persistent infections.
The Whitehouse Station, N.J., company said the vaccines had similar side effects, but injection site reactions like pain and swelling were more common in patients who were given V503.
Gardasil reached the market in 2006, and Merck's revenue from the drug grew 15% to $665 million in the third quarter of 2013. The vaccine is given in three doses over the course of six months.
In June a study by the Centers for Disease Control and Prevention found that the vaccine cut viral infections in teen girls by half. The study showed that about a third of teen girls had received all three shots, but half had received at least one dose.