More Questions Than Answers About Safety of Natazia, Bayer's New Contraceptive

Last Updated May 7, 2010 12:07 PM EDT

The FDA's approval of yet another contraceptive pill -- Bayer (BAY)'s Natazia -- is more interesting for what it doesn't say than what it does. While Bayer said Natazia is "as effective" as existing pills, it didn't make that claim regarding its safety.

A lot is riding on the success of Natazia (formerly known as Qlaira). It replaces Bayer's Yaz and Yasmin pill brands, Bayer's biggest products, whose sales declined 10 percent last quarter after they lost the patent protection that gave them exclusive marketing rights.

Those events send a humbling message to brand managers: Many products aren't successful because of your amazing, Randian strategic genius. They're successful because certain laws and patents have structured the market to ensure your success. All you had to do was not screw it up.

It is the safety issue that is most curious about the new drug. Bayer said two of its trials for Natazia were "non-comparative, open labeled, single arm studies." That's low-quality science: It means the doctors conducting the tests knew which patients got which drugs. When doctors know who's getting what, their own biases tend to creep into the results. And the study did not compare Natazia to other contraceptives, which is why Bayer can only claim Natazia is "as effective" as other pills.

A third trial was a double-blind, randomized comparative study. That's an excellent way to test a drug -- but this study was about Natazia's effect on "bleeding pattern and cycle control." Natazia doesn't have FDA approval for those conditions yet, but Bayer said in its press release they were "working with the FDA" on an approval for menstrual bleeding disorders. That fact was mentioned in the second paragraph of Bayer's release, which suggests to me that bleeding is going to be more important to Natazia's marketing than the baby-prevention.

You'll note that Bayer's own site doesn't say anything about Natazia's risks. Dig around for the full version of the release and it says this:

The use of Natazia is associated with increased risks of several serious conditions including venous and arterial thrombotic and thromboembolic events (such as myocardial infarction, thromboembolism, stroke), hepatic neoplasia, gallbladder disease, hypertension, ruptured ovarian cyst and uterine leiomyoma. The excess risk of thromboembolic events is highest during the first year of use of COC.
Blood clots are a hot-button issue at Bayer, as Yaz is currently besieged by lawsuits claiming its new combination of synthetic estrogen and progestin make it more dangerous than older pills. Indeed, Natazia contains yet another new estrogen/progestin combo: this time it's estradiol valerate and dienogest.

We don't know if the rate of blood clots with that combo is higher or lower than older pills, or even Yaz, because neither Bayer nor the FDA mentioned it. Here's what Bayer said about Natazia's safety:

The safety and efficacy of Natazia as an oral contraceptive was evaluated in two multicenter phase 3 clinical trials in North America and Europe involving 1,867 women. Natazia was found to be effective as a hormonal contraceptive in both studies.
Note that the trials studied its safety, but Bayer only tells the result for efficacy -- as in, it's "as effective" as everything else. Surely, if Natazia emerged as a safer product than older pill, that would be something Bayer might want to mention, right?


Image by Flickr user Gnarls Monkey, CC.