Libtayo SJS/TEN Lawsuit Filed Over Fatal Reaction To Skin Cancer Drug

The family of a woman who died of a fatal skin reaction has filed a Libtayo lawsuit, claiming the skin cancer drug does not adequately warn doctors or patients about the risk of Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN).

The complaint (PDF) was filed by Michael Krantz, on behalf of himself, his late wife, Janis Krantz, and her surviving children in the U.S. District Court for the Central District of California on September 26, naming Regeneron Pharmaceuticals and Sanofi Aventis US, LLC as the defendants.

Libtayo (cemiplimab) is a monoclonal antibody medication initially approved in 2018 for the treatment of cutaneous squamous cell carcinoma (CSCC), which is a form of skin cancer. Since then, the U.S. Food and Drug Administration has approved Libtayo for the treatment of other forms of cancer, including basal cell carcinoma and non-small cell lung cancer.

However, the Krantz family alleges that the manufacturers failed to place adequate warnings for U.S. patients and prescribing physicians about Libtayo SJS/TEN risks, even though those warnings appeared on labels outside of the U.S.

Stevens-Johnson syndrome (SJS) typically results in a severe rash and blistering in the mouth, eyes, ears nose or genital area, essentially causing the skin to burn from the inside out. In severe cases, the condition can progress to toxic epidermal necrolysis (TEN), which often results in the need for treatment in a hospital burn unit or ICU, and may cause blindness or death.

According to the lawsuit, Janis Kranz was prescribed Libtayo for the treatment of skin cancer in April 2022. Within a week, she went to the hospital suffering from rash and swelling of the face.

Doctors determined that it was likely a reaction to her first two Libtayo infusions, discontinued its use, and placed Krantz on powerful steroids.

However, this did not appear to reverse the Libtayo SJS/TEN side effects, and Janis Krantz’s condition worsened. Five days after being sent home, and just 12 days after starting Libtayo, she was taken by ambulance to a nearby emergency room.

“Her physicians noted she had blisters and sloughing of skin. Her skin had peeled off her entire back, abdomen and extremities,” her husband’s lawsuit states. “She complained that she was experiencing excruciating pain.”

Doctors diagnosed Janis Krantz as having SJS/TEN over 90% of her body, as well as secondary sepsis and respiratory failure. All of her attending physicians agreed that Libtayo had been the cause.

Janis Krantz died on April 30, with her death certificate specifically indicating that the primary cause of death was Libtayo-related SJS/TEN.

Libtayo Label Warnings

The lawsuit states that there is no warning on the manufacturer’s U.S. label that Libtayo causes SJS/TEN, even though there were incidents of such reactions recorded during the drug’s clinical trials. Instead, the initial label just noted that some drugs from Libtayo’s class had shown increased risk of these serious skin reactions in the past.

Krantz indicates the label warnings should have included information that Libtayo had been directly linked to the potentially deadly skin reactions, and that women were known by the manufacturers to face a higher risk from Libtayo than men.

In addition, between 2018 and 2022, as more Libtayo SJS/TEN data became known in scientific literature, the manufacturers strengthened the drug’s SJS/TEN label warnings in foreign countries, but did not provide the same warnings in the U.S.

The lawsuit indicates Dr. Nilesh Vora, Krantz’s prescribing physician and Medical Director of the Todd Cancer Institute, has signed a sworn declaration that he believes the warning label in the U.S. was inadequate, would have never prescribed Libtayo for Krantz if the label warning had been sufficient.

Her family presents claims of strict product liability, failure to warn, negligence, negligent misrepresentation, and gross negligence. They seek both compensatory and punitive damages.