I’ve been paying attention to Merck’s (Whitehouse Station, NJ) Gardasil vaccine ever since I first heard of it because it’s a subject that combines biopharmaceuticals, gender issues, and the politics of public health. At first, critics contended that giving young girls Merck’s human papillomavirus (HPV) vaccine would not just prevent cervical cancer, but also promote promiscuity. This concern may have subsided, but two new wrinkles in the Gardasil story came to light on Friday.

The first was the emergence of competition for Merck’s vaccine. The US Food and Drug Administration approved GlaxoSmithKline’s (GSK, London) Cervarix, which clinical trials found to be effective in preventing precancers caused by HPV types 16 and 18, which are the most common. Cervarix had already received approval from international regulators, but it may have difficulty getting traction. Unlike Gardasil, it does not combat HPV types 6 and 11, which cause cancer and genital warts.

We noted in ePT that Natalie Morton, a 14-year-old girl, died after receiving Cervarix in September 2009. GSK expressed its sympathies to the girl’s family and recalled a batch of the vaccine. The cause of Morton’s death is under investigation, but some observers have wondered about Cervarix’s safety.

Perhaps to make assurance of success double sure, Merck had been seeking FDA approval for a new indication for Gardasil. It got this approval on Friday when the agency sanctioned the vaccine for use against genital warts in boys. This apparent coup could expand the market for Gardasil and boost its sales.

Or could it? Gardasil might not be used widely for boys because genital warts caused by HPV usually disappear without treatment. On top of that, researchers from the Harvard School of Public Health and an investigator at the US National Cancer Institute argue that it would not be cost-effective to treat boys as well as girls. In a press release available at the US National Library of Medicine, Jane Kim, the lead researcher of the Harvard team, said that “including boys in an HPV vaccination program generally exceeds what the US typically considers good value for money.”

Even if practicality and economic considerations prevent Merck from capitalizing on its new indication for Gardasil, the vaccine is well established and likely could withstand the challenge from Cervarix. More importantly, the drugs have prompted fruitful discussions about standards for drug efficacy and the public health. These exchanges help us identify and defend our priorities. The drugs have also gotten us thinking about gender equality, which, to my mind, is too often ignored.

Maybe a new development will change the Gardasil story yet again. Stay tuned.