Sanofi Genzyme wins approval for breakthrough eczema drug

Outside the Sanofi Genzyme offices in Cambridge.EPA/CJ GUNTHER

Sanofi Genzyme won its biggest drug approval in years Tuesday when US regulators gave the green light to a medicine to treat forms of eczema that can cause intense itching and bleeding.

The injectable drug, with the brand name Dupixent, was approved by the Food and Drug Administration for use by adults with moderate to severe eczema. Sanofi Genzyme, based in Cambridge, developed the treatment with Regeneron Pharmaceuticals Inc., of Tarrytown, N.Y. The companies will market it jointly.

“This could be one of the most important drugs launched in 2017,” Sanofi Genzyme president David Meeker said. “There’s no question that this has the potential to be the largest [selling] drug in our portfolio. It has the potential to transform people’s lives for the better. It’s the only thing that has this kind of effect on this group of patients.”

Dupixent will have a list price of $37,000 a year, but many health insurers will ultimately pay less after negotiating discounts or rebates.

“We’re looking to capture the value we’ve created, but we’re not looking to come out with a high price,” Meeker said. “We want to get this drug to the patients that need it.”

Geoffrey C. Porges, a biotech analyst for the Boston investment bank Leerink Partners, wrote in a note to investors that insurers and other payers are likely to consider the drug “expensive, but cost-effective.”

Some analysts have projected that Dupixent, which patients inject under the skin once every two weeks, could generate as much as several billion dollars in annual revenue, topping the sales from any one of the enzyme replacement and multiple sclerosis therapies now sold by Sanofi Genzyme, the specialty care division of the French drug giant Sanofi SA.

As many as 300,000 people in the United States will initially be eligible for Dupixent, which will be prescribed by dermatologists and other specialists. Many people suffering from eczema, also known as atopic dermatitis, have disfigured skin, inflammation throughout their bodies, and severe itching that disrupts their sleep and causes bleeding.

Somerville resident Anne Warnock, a 33-year-old guitar player who manages a Cambridge restaurant, said she suffered from eczema since she was a baby until she began taking Dupixent three years ago in a clinical trial.

“My skin was incredibly inflamed, and it was really painful,” she said. “Now it’s almost completely clear. I can wear shorts, I can wear T-shirts, I can go to the beach and swim — all kinds of normal stuff that used to be difficult for me.”

Dr. Emma Guttman-Yassky, vice chair of the dermatology department at the Icahn School of Medicine, said she observed remarkable improvement among patients when she ran the late-stage clinical trial of Dupixent at Mount Sinai Medical Center in New York. One group of patients was given the Sanofi experimental drug, and another took a placebo.

“It was very clear who was taking the drug and who was taking the placebo,” Guttman-Yaasky said. “Within the first day, patients were telling us their itch was improving and they were able to sleep.”

Many patients in the trial — who came from the United States, Canada, and Mexico — arrived with red scaly patches covering most of their bodies, she said. Some had open wounds from their scratching. “Now they look like you and me,” she said. “They lead normal lives.”

The drug is a monoclonal antibody that blocks the migration of inflammatory cells, stopping the itching. Until now, most patients with atopic dermatitis have relied on steroid creams that often fail to prevent itching for those with moderate to severe cases.

Sanofi Genzyme and Regeneron are also seeking approval of Dupixent in Europe, where Sanofi would be lead marketer. And the partners have begun testing the drug compound on patients with asthma, nasal polyps, and other conditions.

Dupixent, a so-called breakthrough therapy that was awarded a priority review by the FDA, was approved one day before the agency’s declared date for making a decision.

The new drug, however, will debut under a legal cloud. Seeking to head off a challenge by Amgen Inc., Sanofi Genzyme has sued the California biotech, seeking a declaration that Dupixent doesn’t infringe on a patent it holds. That case is being heard in US District Court in Boston.