Pfizer’s First: Will More Drug Companies Face Lawsuits over “Ineffective” Drugs?
Last week, a California woman filed a lawsuit against Pfizer, the maker of Zoloft, alleging that Zoloft works no better than placebo, that Pfizer knew it, and that the company has run a systematic campaign to deceive doctors and the public in order to continue selling the drug. Although Pfizer and prescribing psychiatrists want the lawsuit thrown out, it exposes several weaknesses in the drug approval and marketing system that may expose other drug makers to similar lawsuits.
The Lawsuit’s Claims
The lawsuit’s complaint makes its case very simply and plainly:
Since Zoloft first entered the antidepressant market in 1991, Pfizer has engaged in a calculated campaign to mislead consumers and prescribing healthcare professionals about Zoloft’s ability to treat depression. Pfizer knew that Zoloft’s efficacy in treating depression was, at best, marginal, and, at worst, nonexistent. However, in an effort to turn a profit, Pfizer deliberately withheld material information from consumers and prescribing healthcare professionals and orchestrated a massive marketing campaign designed to convince consumers and prescribing healthcare professionals, in the face of a vast majority of clinical trial data to the contrary, that Zoloft was an effective and safe treatment for depression.
The lawsuit is filed as a class action on behalf of all people who have been prescribed Zoloft for depression. The lawsuit further states that:
- After seeing initial trials with Zoloft did not show benefit, Pfizer carefully designed two studies (the minimum number needed to secure approval) that would overcome the drug’s weaknesses and show a benefit.
- Pfizer crafted a label that concealed doubts about the drug’s efficacy
- Pfizer used paid spokesmen, ghostwritten articles, selective publication, and direct-to-consumer advertising to promote the drug’s apparent efficacy
The lawsuit further claims that it is only because of these tactics that Pfizer was able to achieve $30 billion in Zoloft sales to patients in the US.
The Science behind the Suit
This lawsuit follows work comparing the effectiveness of antidepressants and placebos. Pioneered by now-Harvard researcher Irving Kirsch, this research increasingly points out limitations of the efficacy of antidepressants. In 2009, Kirsch published a damning review of published and unpublished clinical data submitted to the FDA.
Kirsch found that only 43% of trials showed a benefit of antidepressants over placebos, and that placebos were an average of 82% as effective as antidepressants in premarketing studies. In postmarketing studies, placebos retained their effectiveness, scoring 83% of the effectiveness of antidepressants.
Kirsch also exposed what he termed the “dirty little secret” of FDA approval. Although the FDA requires two successful trials in order to grant approval for a drug, there is no limit on the number of trials a sponsor can perform in order to get those two successful trials.
For its part, Pfizer has responded by asking that the lawsuit be dismissed, calling it “groundless,” according to the Associated Press and to website Pharmalot. AP also interviewed several psychiatrists who supported Zoloft and other antidepressants, with one noting that, as a class, they may help 50-80% of patients with “major depression.” Another noted, though, that each antidepressant had only about a 35% chance of working for any given patient, but by trying different antidepressants and dosages, many patients could see results.
Problems with Pfizer’s Response
Pharmalot noted that, along with their statement, they also sent a clinical study supporting the efficacy of Zoloft. However, there are problems with the submitted article. First, it was funded by Pfizer. Second, the lead author on the study was a scholar who had been implicated in a scandal surrounding research in support of another antidepressant, Paxil. That study was labeled by New York Attorney General Eliot Spritzer as an example of “repeated and persistent fraud” by GlaxoSmithKline. The lead author was accused of academic misconduct due to ghostwriting of the article and data manipulation.
Although the submitted article itself has not been cited for data manipulation, the connection certainly leads to doubts.
Not Just Antidepressants
Antidepressants are not the only drugs that are coming under increasing criticism because of their low efficacy rates compared to their risk profile. In 2011, Eli Lilly withdrew Xigris (drotrecogin alfa) because it was shown to have little to no effectiveness. In 2010, painkillers Darvon and Darvocet were withdrawn from the market. The ostensible reason for their withdrawal was increased heart risks, but their low effectiveness likely contributed to their withdrawal. Numerous other drugs are withdrawn once they show risks but little benefits.
This lawsuit has been considered the first of its kind. However, when looking at the low effectiveness of many drugs on the market today, it likely will not be the last.