Friday, May 8, 2009

Cervarix versus Gardasil

The battle’s on. And let the marketing campaigns and medical sniping begin.

GlaxoSmithKline said today that the results of a comparative HPV vaccine study it had sponsored showed that Cervarix generated between two and six times as many antibodies as Gardasil.

Both vaccines utilize novel “virus-like particles,” VLPs. These are created by inserting DNA into yeast cells to make a genetically-engineered ‘seed stock’. The resulting paste is cultured in a fermenter to increase cell mass and then incubated; eventually the antigen VLPs are filtered from the paste and blended with adjuvants. The paste is then cleaned and reused.

Both vaccines protect against HPV strains 16 and 18, thought to be responsible for 66 to 70 percent of cervical cancers, although one study recently showed 16 to have been losing ground to strains other than 18 (there are believed to be up to 120 strains of HPV) for some years. Gardasil also protects against two wart-causing strains.

But Cervarix also uses a novel adjuvant containing aluminium salt and monophosphoryl lipid A (MPL), and according to GSK that makes a big difference in antibody levels—a claim that made a Merck spokesman sniff disparagingly, “It's disease efficacy that's really the most important, and we certainly have very high efficacy against some very important disease endpoints."

Cervarix has been used in the EU for some time and was chosen over Gardasil by Britain for its country-wide vaccination program. However, the FDA is currently looking it over for approval in the US, where Merck has had the market to itself up until now.

Both vaccines have been associated with side-effects including paralysis, convulsions and immune disorders, although no causal link has been proven and the CDC beleives that HPV vaccines are safe.

Approval for Cervarix in the US could come by the fall—so if you think the Gardasil campaign up to now has been aggressive, honey, you ain’t seen nothin’ yet.


Nicole said...

You have talked about your girls and the Gardasil vaccine. My daughter is 13 and I am very nervous about getting her the shot's. My friends jumped right in and vaccinated their girls. Have your children recieved the vaccine?
I would like to wait a few more years to see about potential side effects. I am very confused, but I want to thank you for all your information.

Kristin said...

Nicole, no, I haven't had the girls vaccinated. It is a very difficult decision and, I think, should be based on individual circumstances. Our family isn't prone to cancer but there are a few hints at immune issues that concern me. Gardasil does seem to be a trigger for immune disorders in genetically predisposed people.

Also, we eat extremely well and include a lot of fruits and veggies in our diet; we don't smoke and nor do the girls. I've talked to them about this at length (the oldest is 16) and I think we're comfortable with waiting for the GML ointments which, if they work out, would protect against a lot more than the rather rare cervical cancer.

You do have to look at the odds. The odds are good that your child would have no major reaction. My perspective is simply that there are better alternatives (I believe) on the horizon and that the odds of getting the disease if you're healthy are already tiny, so the risk of side effects isn't worth it.

Natalie said...

One of the big differences is the stuff they put in it. Yes Gardasil has more in it but most of the stuff is poison (no kidding.) Rat poison and things like that look it up. I am still looking stuff up on the other one.

Anonymous said...

Better than getting genital warts!

Do you really want your children to get HPV? Have warty vaginas? I know I don't.

And those who do have a reaction is like 1 in a million chance. You drive your cars around carelessly, you feed them processed foods, they don't practice good hand washing technique... I think you get the picture.