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New Effective Combination Treatment (Rituximab With Intravenous Immune Globulin) for Pemphigus Vulgaris

Pemphigus vulgaris is an autoimmune blistering disease, which basically means that an individual's immune system starts reacting against his or her own tissue, most commonly inside the mouth. The building block cells of the epidermis are called keratinocytes. These cells are cemented together at special sticky spots called desmosomes. In pemphigus vulgaris immunoglobulin type G (IgG) autoantibodies bind to a protein called desmoglein 3, which is found in desmosomes in the keratinocytes near the bottom of the epidermis. The result is the keratinocytes separate from each other, and are replaced by fluid, the blister.It is the most common subtype of pemphigus, accounting for 70% of all pemphigus cases worldwide although it is extremely rare in New Zealand (about one case per million). The other two main subtypes of pemphigus are pemphigus foliaceus and paraneoplastic pemphigus.

The primary aim of treatment is to decrease blister formation, prevent infections and promote healing of blisters and erosions. Oral corticosteroids are the mainstay of medical treatment for controlling the disease. Since their use, many deaths from pemphigus vulgaris have been prevented (mortality rate dropped from 99% to 5-15%). They are not a cure for the disease but improve the patient's quality of life by reducing disease activity. Unfortunately higher doses of corticosteroids may result in serious side effects and risks.

Most recently, a new combination treatment offers hope to people who have the blistering, potentially fatal skin disease known as pemphigus vulgaris.

By combining the cancer-fighting drug rituximab with intravenous immune globulin, Harvard doctors have discovered a therapy that can effectively treat people with cases of pemphigus vulgaris that haven't responded to other treatments.

"We got a home run with this combination," said study co-author Dr. Marshall Posner, medical director of the head and neck oncology program at the Dana-Farber Cancer Institute and Harvard Medical School.

"These patients were extremely ill and on multiple medications," he said. "This therapy resulted in complete eradication of the disease for nine patients." The remaining two patients in the study required additional doses of the treatment before they, too, went into remission. All of those involved in the study had sustained remissions, some as long as 37 months, by the end of the study.

Pemphigus vulgaris is a rare autoimmune disease that causes the skin cells to stop adhering to one another. Blisters and lesions form, usually beginning in the mouth and then spreading to the skin.

"Before the discovery of corticosteroids, it was fatal within five years. People lost the surface of their skin, and died horrible deaths," explained Dr. John Stanley, chairman of the department of dermatology at the University of Pennsylvania School of Medicine. "This is an instructive disease about the power of the immune system. While it's usually used for good, it can actually destroy you."

Stanley co-authored a review article in the same issue of the journal about pemphigus and other dermatological diseases.

Currently, the first line of treatment for this devastating skin condition is prednisone, a corticosteroid. While it's often an effective treatment, it has numerous side effects that can be serious, so people generally can't stay on high doses for a long time. Other medications used are immune-suppressing agents that also carry the risk of serious side effects, such as infection.

Posner said most deaths from pemphigus occur as a result of immune-system suppression. But without suppressing the immune system, people with pemphigus would continue to develop blisters and erosions in their skin, giving bacteria an easy entry into the body.

Another treatment option is intravenous immune globulin. This option is usually reserved for those who don't respond to the other treatment options. Stanley said scientists aren't sure how this therapy works, but it may be that it replaces the immune-system antibodies that are attacking the skin cells with healthy antibodies.

For most people, these treatments options have proved lifesaving, and people with the disease often do well, said Stanley.

However, there are people who don't respond to any of the currently available treatments. And, the 11 people treated in the new Harvard study fell into that category. None of the available treatments had worked for them, and the disease was covering more than 30 percent of their body's surface area.

Each study volunteer received two cycles of rituximab weekly for three weeks. During the fourth week, they received a dose of intravenous immune globulin. Then, they received monthly infusions of both rituximab and IV immune globulin for four months.

During the initial treatment, nine of the 11 study participants went into remission for an average of 32 months. The remaining two required additional treatments about six months after treatment, but subsequently went back into remission.

While previous research on rituximab has sometimes found serious side effects, such as allergic reaction, Posner said there were virtually no side effects seen in this trial.

He said he thinks this drug combination would likely be helpful in less severe cases of pemphigus vulgaris, and he added that it could potentially be useful for treating other autoimmune diseases, such as rheumatoid arthritis, systemic lupus and type 1 diabetes.

"This therapy offers hope for this disease, and it could lead the way to treatment for other diseases that have a big impact on people's lives -- it needs to be investigated in other diseases so we can see how it works in other situations," Posner said.

Stanley said he doubted that rituximab would become a first-line treatment for pemphigus vulgaris anytime soon because the medication is quite costly and insurance companies would likely balk at paying for an expensive drug that isn't FDA approved specifically for treating pemphigus. The problem, he added, is that because pemphigus is so rare, it would be difficult to conduct a large enough trial to get such approval.

But, Posner suggested that while the rituximab/immune globulin combination treatment is more expensive initially, a cost analysis comparing all of the costs, including hospitalizations, might find the combination treatment is the cheaper alternative in the long run.