The popular erectile dysfunction drug Viagra has been the target of a flurry of lawsuits after a 2014 study found that there may be a link between the drug and melanoma. After about 30 lawsuits were filed against drug-maker Pfizer, a motion was made by several of the plaintiffs to consolidate the cases in the U.S. District Court for the Northern District of California. An April 7th order by U.S. District Judge Richard Seeborg granted the plaintiffs their motion to consolidate.
Now, over 100 suits have joined the MDL.
Pfizer did not oppose the motion to consolidate the lawsuit. They have, however, offered a statement in response to the accusations of the suit. In an email, Pfizer spokeswoman Neha Wadhwa wrote: “Viagra’s safety and efficacy have been studied in 136 clinical trials, and there is no reliable scientific evidence that the medicine causes melanoma. Pfizer stands behind this important medicine and intends to vigorously defend these lawsuits.”
The 2014 study that jump started the lawsuits against Viagra was published in JAMA Internal Medicine, a peer-reviewed medical journal published by the American Medical Association. The study found that men who used Viagra were 84% more likely to develop melanoma. The study grew out of laboratory research on how Viagra acts on cell-to-cell signaling pathways. Consequently, this work demonstrated that the drug mimics key parts of a process that lets melanoma cells spread to other parts of the body. Skin cancer that spreads is hard to control and treat, and can also lead to death.
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Over the course of the study, among the 29,929 men who said they had never used Viagra, 128 developed melanoma. Among the 1,618 Viagra users, 14 developed melanoma. In other words, 4.3 of every 1,000 who didn’t take Viagra developed melanoma compared to 8.6 of every 1,000 men who took Viagra. Therefore, the increase from 4.3 to 8.6 accounts for the 84% increase in risk that many news reports focused on.
Whether a similar connection might exist between other erectile dysfunction drugs and melanoma is not yet known. In 2000, when the study was started, Viagra was the only erectile dysfunction drug on the market. Tadalafil (Cialis) and vardenafil (Levitra), which are also marketed as treatments for erectile disfunction, weren’t approved until 2003. While avanafil (Stendra) came on the market in 2012.
In 2015 Pfizer settled a class action against it for $400 million. That class action accused Pfizer of misleading investors about off-label drug marketing. The litigation process is too early on in this case to predict any settlement outcome.
