Certain types of encephalopathy have been linked to the use of Zinbryta, a drug prescribed to treat multiple sclerosis (MS). Encephalopathy refers to a disease process affecting the structure of the brain and how it operates.

Zinbryta was approved by the U.S. Food and Drug Administration (FDA) on May 27, 2016, with the suggestion that it be saved for patients that had not responded to two or more other drug treatment regimens.

What is MS?

Multiple sclerosis is a progressively degenerative disease in which the body’s immune system attacks viable body tissue as if it were a foreign invader. In particular, it focuses on the outer covering surrounding nerve cells in the gray matter of the brain and spinal cord.

Zinbryta ostensibly was developed with the idea that its active ingredient would attach to immune cells and inhibit their hyperactive and misdirected energy.

Yet since its commercial inception, Zinbryta—generically known as daclizumab—has been plagued with side effects and associated with certain types of encephalopathy. Because of this association, the drug’s manufacturers—Biogen and AbbVie—announced in early March 2018 that they would be pulling the MS medication from the U.S. and global marketplace.

There have been at least a dozen confirmed cases of brain injury for patients taking Zinbryta. A third of those cases resulted in the death of the individual.

Other concerning and serious adverse side effects seen have included injury to the liver and liver failure, Stevens Johnson Syndrome (SJS) or toxic epidermal necrosis (TEN). The latter two are very serious skin reactions to drugs in which the immune system attacks the skin and leaves it looking burnt or eaten away.

Prior to this voluntary market pull from Biogen and Abbvie, adverse effects since Zinbryta’s commercial approval led to a high-level black box warning being put on the label. The warning indicated the potential for liver and skin effects but didn’t mention the connection to witnessed types of encephalopathy.

What are the Different Types of Encephalopathy?

According to Healthline, there are approximately 10 types of encephalopathy. Among these types are chronic traumatic, glycine, Hashimoto’s, hepatic, hypertensive, hypoxic ischemic, toxic-metabolic, infectious, uremic and Wernicke.

The first type is related to physical blows to the head, and the second type is a familial condition where one inherits the tendency to produce too much glycine—an amino acid—in the brain.

Hashimoto’s is an autoimmune issue where the thyroid gland is under attack, and hepatic encephalopathy is due to liver malfunction and failure. Hypertensive encephalopathy is produced by high blood pressure, and hypoxic encephalopathy is brought on by a lack of oxygen to the brain.

Toxic encephalopathy can come on because of organ system failure or chemical or hormonal imbalances.

Infectious encephalopathy is caused by prion proteins that, in excess, mutate and bring on disease. Uremic encephalopathy may be caused by kidney damage or failure where metabolic waste products are not getting flushed from the body. Finally, Wernicke encephalopathy is related to a vitamin B-1 deficiency coming from poor intake of nutritionally-dense food.

It is likely that certain types of encephalopathy (hepatic, toxic-metabolic, and uremic) could be related to the use of Zinbryta. Regardless of which type of encephalopathy, this condition comes with symptoms that can be confused with the flu.

In addition to muscle and joint pain, fever, and overall weakness, there will likely be evidence of mental confusion, indecision and disorientation.