Hepatitis C: Treatment Side Effects

by Food and Drug Administration (FDA)

(Page 2 of 4)

The goal of treatment is sustained response — meaning that the virus is not measurable in the blood after drug therapy is completed. Those who continue to have measurable levels of the virus after treatment are considered non-responders. Relapsers "clear" the virus during therapy or shortly thereafter, but the virus returns after therapy ends.

About half of the people who initially respond to monotherapy (interferon alone) relapse.

There is no absolute way to know who will or won't respond to therapy. But health-care providers try to predict responsiveness using research tests to determine genotype and concentration of HCV in the blood, says John Ticehurst, M.D., a microbiologist and clinical laboratory faculty member at the Johns Hopkins Medical Institutions. HCV concentration in the blood is often referred to as "viral load."

An HCV genotype, which is also determined by a blood test, reflects the variation in the genetic makeup of the virus. At least six different genotypes and many more subtypes of HCV exist. In the United States, genotypes 1, 2 and 3 are most common.

People with genotypes 2 and 3 are almost three times more likely to respond to therapy than those with genotype 1, according to NIDDK researchers. Unfortunately, about 70 percent of HCV-infected people in the United States have genotype 1.

Genotyping also can be used to determine the duration of treatment for many people. For those with genotype 2 or 3, a 24-week course of combination therapy is usually sufficient. Patients with genotype 1 who have responded at the end of 24 weeks of treatment may benefit from an additional 24 weeks of treatment.

Historically, only 10 to 20 percent of those treated with conventional interferon alone had sustained responses, depending on the interferon product used. Combination therapy (conventional interferon plus ribavirin) showed better results, with 35 percent to 45 percent of those treated sustaining the response, depending on genotype.

Studies have shown that PEG-Intron used with Rebetol is slightly more effective than the conventional interferon Intron A with Rebetol. PEG-Intron with Rebetol caused the same types of side effects as Intron A with Rebetol, but some occurred more often. (See "Treatment Side Effects.")

Ken Gamache, of Middletown, Md., was diagnosed with hepatitis C in 1995, but believes that he became infected over 30 years ago after an operation. Gamache has genotype 1 HCV. He was treated initially with monotherapy, and when that failed, he tried combination therapy, again without success.

When first told he needed a liver transplant, Gamache thought it was a death sentence. Now, after more than five years on a waiting list for a liver, he has more hope. "I caught it early in the cirrhosis process and am doing whatever I can to prevent further damage," he says. Gamache still gets tired and run down, but has learned to pace himself. "I exercise regularly, but don't overextend myself. I'm careful to get enough sleep, eat right, and take vitamins, and I don't drink or smoke."

Treatment Side Effects

"Side effects are variable," says Adrian Di Bisceglie, M.D., medical director of the American Liver Foundation and professor of internal medicine at St. Louis University. "About 10 percent of patients have virtually no side effects. Approximately 10 percent have very severe, almost disabling side effects and have to stop work or stop the drug. The remaining 80 percent have side effects — but they are tolerable."

For some people, the side effects decrease after the first few weeks of treatment. But many individuals have severe side effects through the duration of treatment; these side effects may persist for months after the treatment ends.

Patricia Buchanan of Brooklyn Park, Minn., suffered severe side effects throughout the 19 months she was in treatment — first in a 24-week clinical trial with monotherapy, and then in a 52-week treatment course with combination therapy after the monotherapy didn't work.

Buchanan clearly remembers the completion of her therapy on Nov. 6, 1999. "When you do chemotherapy for over a year, you remember the date of your last injection," she says. "I lived on my couch because of the extreme fatigue. I lost two-thirds of my hair and I had nausea, fever, chills, body aches and terrible depression. I went from having diarrhea to being constipated."

Because of interferon's potentially serious side effects, the products come with an FDA-approved medication guide written for patients. Under regulations that became effective in 1999, pharmacists must distribute a medication guide with products that the FDA has determined pose a serious risk and for which patient guidelines can help prevent that risk.

The guide for interferon products lists both the common, less serious side effects, and the rarer but potentially life-threatening ones. The common side effects include "flu-like" symptoms, extreme fatigue, nausea and loss of appetite, thyroid problems, high blood sugar, hair loss, and skin reactions (such as redness and itching at the injection site). Possible serious side effects are psychoses or suicidal behavior, heart problems (low blood pressure, heart attack), other internal organ damage, blood problems (blood counts falling dangerously low), and new or worsening autoimmune disease (such as rheumatoid arthritis).

Side effects of ribavirin, the oral part of the combination therapy, include anemia, fatigue, irritability, skin rash, nasal stuffiness, sinusitis, and cough. Ribavirin can also cause birth defects, so pregnancy in female patients and female partners of male patients must be avoided during treatment and for six months afterward.

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