Much of the following
information has been gathered from various sites about the internet as well
as various newsgroup articles, emails, and personal documents. As such,
I am unable to verify the accuracy of all of the information so be wary
of what one takes from these pages. Please consult with a professional health
care provider before doing anything suggested or implied.
This is still one of the most commonly used treatments
for chronic HBV carriers.
Interferon is a protein naturally produced by many cells in the body.
Interferons help the body fight disease through a cellular pathway known
aptly as the interferon pathway. During the course of an infection, the
interferon pathway is often upregulated. This upregulation usually coincides
with a downregulation of viral replication. Interferons also appear to
signal other, uninfected cells, making them more resistent to viral intection.
Interferons are also thought to modulate immune system activity. However,
some people have deficient interferon levels or have low interferon response.
Thus, the need for interferon treatment.
The most commonly used interferon
for chronic HBV treatment is Interferon Alpha-2B (Intron-A).
For HBV infection, about 20-25% appear to be cured of their infection
while 25% - 45% convert from active to persistent/subclinical HBV infection.
Success rates are lower in cases of long term infection or if co-infected
with HIV or HCV. Relapse rates are also higher if HIV positive, so an
HIV test may be appropriate.
Typical Interferon Dosing
The typical duration of treatment is four to six months. Recommended
dosing of Intron-A is 2.5 to 5 Million Units (MU) per meter square (/MSq)
of body surface area three times a week. Higher doses (up to 10MU/MSq)
of interferon may used and some studies indicate that higher doses have
an improved response rate. However, higher doses also come with higher
chances of unwanted side-effects. If you decide to take interferon, discuss
dosage with your doctor .(Interferon is expensive and cost may be relevant,
depending on your medical insurance or heath care system.) An alternate
schedule is 5 million units daily which may ensure a more consistent level
of interferon in the body.
Many individuals experience a flu like illness characterized by fever,
chills, headache, muscle aches, and nausea within four to eight hours
following the first administration of interferon. These symptoms can be
reduced by giving acetaminophen thirty minutes to one hour before the
time of injection.
Long-term therapy is accompanied
by other side effects such as fatigue, muscle aches, poor appetite, weight
loss, alopecia, bone marrow suppression, autoimmune phenomena, bacterial
infections (which can be severe or life-threatening, particularly in patients
with established cirrhosis), and psychological side effects (for example,
anxiety, depression, irritability, and moodiness). The side effects are
dose-related and generally reversible. Less than 10% to 20% of patients
require interruption of therapy. Treatment with interferon is contraindicated
in patients with psychosis, autoimmune disease, renal, or heart failure.
It is extremely important that
patients be carefully evaluated, including a psychological evaluation,
before initiating treatment with interferon. Appropriately selected patients
often can tolerate very high doses while others are intolerant of even
the smallest doses.
Narcotics, hypnotics, or sedatives should be taken with caution when
under interferon treatment. Xanthine derivatives should also be administered
with caution and if so serum theophyline levels should be measured. (Note:
Xanthine derivatives are frequently found in cough mixtures). It is highly
recommended that one discusses any other medicines (prescription or over
the counter) with both your doctor and the pharmacist before mixing them
with your interferon treatment.
Typical Response Profile:
The severity of side-effects will be felt usually within the first
week upon commencing interferon treatment. Blood tests to measure the
success of treatment are typically taken at 1,2, 4, 8, 12 and 16 weeks
after first injection.
Patients who respond to interferon
may have fluctuating ALT levels. Detectable DNA will disappear within
four to six months, followed by HBeAg. Finally, HBeAb will be found in
the serum indicating a successful seroconversion.
Relapse After Treatment:
A small number of individuals (~5%) who initially respond to interferon
treatment may relapse some months or years later. (Elevation of ALT immediately
after therapy is not considered a relapse, but rather treatment failure.)
The definition of relapse requires that after completion of therapy the
patient has a prolonged period of HBV DNA negativity with normal ALT and
seroconversion to an anti-HBe-positive state. Patients who relapse after
therapy usually respond to a second course of treatment. HBeAg-positive
HBV carriers who relapse after treatment can be retreated.
When It Fails:
Patients who have undergone a full course of interferon therapy but
have failed to normalize ALT or lose HBeAg are considered non-responders.
Retreatment of such patients is usually futile except in certain circumstances
such as if the HBV DNA levels fall spontaneously. Retreatment of initial
treatment failures with interferon is not recommended. Patients should
be referred to an expert for consideration of other options.