Lawsuit Claims Sexual Dysfunction Drug Cialis Tied to Skin Cancer

PDE5 inhibitors may increase risk of melanoma

Seven men who were treated with Cialis (tadalafil) tablets for erectile dysfunction have sued Indianapolis-based Eli Lilly and Co., claiming that they later developed skin cancer that was related to the medication, according to a report in the Indianapolis Business Journal. The plaintiffs, who took Cialis for periods ranging from one year to nine years, said they were treated for various skin cancers on fingers, chest, back, and head.

The plaintiffs, from Ohio, Illinois, Texas, and other states, filed separate but similar complaints in U.S. District Court in Indianapolis, saying that Lilly knew or should have known that the drug’s mechanism of action presented “significant risk of exacerbating melanoma.” Tadalafil is a phosphodiesterase type 5 (PDE5) inhibitor.

The suits cite studies in several medical journals that the plaintiffs claim link tadalafil’s mechanism of action to melanoma. One of the studies, published in Cell Reports, determined that PDE5 inhibitors lead to increased tumor growth, although that study did not specifically study the effects of tadalafil, the suit said. Another study, published in JAMA Internal Medicine, reported that treatment with the PDE5 inhibitor sildenafil citrate, used in the erectile dysfunction drug Viagra (Pfizer), increased the risk of developing or exacerbating invasive melanoma by 84%.

“The pharmaceutical industry has known for a very long time that inhibition of PDE5 has been associated with an increased risk of melanoma,” said Kristian Rasmussen, a lawyer at the Birmingham, Alabama, firm of Cory Watson, which specializes in representing injury victims. “That information has slowly come to light over the last few years in the public domain.”

The plaintiffs are alleging negligence, fraudulent misrepresentation, defective design, and failure to properly test tadalafil and warn patients. They are seeking unspecified damages.

Lilly responded that it has reviewed the studies and has found no evidence that tadalafil causes melanoma.

Source: IBJ; August 5, 2016.