Who should take the Enfuvirtide?

Who should take the Enfuvirtide?
Naturally, one should take the advice from one's doctor. The doctor and the patient should consider the patient's T-cell count, viral load, any symptoms the patient is having, and the patient's attitude about taking HIV medications.

T-cells are a type of lymphocyte (white blood cell). They are an important part of the immune system. There are two main types of T-cells. T-4 cells, also called CD4+, "helper" cells. They lead the attack against infections. T-8 cells, (CD8+), are "suppressor" cells that end the immune response. CD8+ cells can also be "killer" cells that kill cancer cells and cells infected with a virus. Researchers can tell the T-cells apart by specific proteins on the cell surface. A T-4 cell is a T-cell with CD4 molecules on its surface. This is why that this type of T-cell is called "CD4 positive", or CD4+.

The viral load test measures the amount of HIV virus in your blood. There are different techniques for doing this:
# The PCR (polymerase chain reaction) test uses an enzyme to multiply the HIV in the blood sample. Then a chemical reaction marks the virus. The markers are measured and used to calculate the amount of virus. Roche produces this test.
# The bDNA (branched DNA) test combines a material that gives off light with the sample. This material connects with the HIV particles. The amount of light is measured and converted to a viral count. Chiron produces this test.

Viral loads are usually reported as copies of HIV in one milliliter of blood. The tests count up to about 1.5 million copies, and are always being improved to be more sensitive. (see sensitivity definition below) The first bDNA test measured down to 10,000 copies. The second generation could detect as few as 500 copies. Now there are ultra sensitive tests that can detect less than 5 copies. Be aware of that the PCR test results are often different from the bDNA results for the same sample.

The best viral load test result is "undetectable". This does not mean that there is no virus in your blood; it just means that there is not enough for the test to find a count. With the first generation test, "undetectable" could mean 9,999 copies. "Undetectable" depends on the sensitivity of the test used on your blood sample.

How is the drug administered?
If Enfuvirtide is swallowed, it is destroyed by stomach acids. This means that it cannot be taken in pill form. Enfuvirtide is injected just under the skin. This is called a "subcutaneous" injection. Enfuvirtide is injected twice a day. It will most likely be used by people who have run out of choices to use antiviral medications in pill form. The adult dosage of Enfuvirtide is 90 mg per injection, twice a day. The dosage for children is based on their body weight. If one's doctor prescribes Enfuvirtide, one should be shown how to prepare such injection, and how and where to inject it.

What does drug-resistance mean?
Enfuvirtide is a new class of antiviral drug. This means that it is active against HIV that has developed resistance to any other antiviral drug. However, it cannot be used by itself. It must be combined with other antiviral drugs.

If you take Enfuvirtide with other antiviral drugs, you can reduce your viral load and increase your T-cell counts. This means possibilities of staying healthier longer.

HIV is "resistant" to a drug if it keeps multiplying rapidly while you are taking the drug. Changes (mutations) in the virus cause resistance. The HIV virus is tricky when it makes copies of its genetic code (RNA). Many new copies of HIV are mutations: they are slightly different from the original virus. Some mutations can continue to multiply even when you are taking an antiviral drug. When this happens, the drug will stop working. This is called "developing resistance" to the drug. Not every mutation causes resistance. The "wild type" virus is the most common form of HIV. Anything different from the wild type is considered a mutation.

Resistance to Enfuvirtide can develop quickly if it is taken by itself. With combination therapy (taking more than one antiviral drug at the same time), HIV mutates much more slowly. Resistance takes longer to develop. It is very important to take antiviral medications according to instructions, on schedule, and not to skip or reduce doses.

Sometimes, if one developed resistance to one drug, one would also have resistance to other antiviral drugs. This is called "cross-resistance". Enfuvirtide has been tested and there is no known interaction with other anti-HIV medication. However, as for any new drugs, there is no complete test with all medicines, especially over-the-counter drugs or vitamins or herbal supplements. Always be sure to let one's doctor know about all medications and supplements that one is taking..

Is there any side-effects with Enfuvirtide?
A detailed discussion on side effects with anti-viral drugs can be found in the reference below. The most common side effects of Enfuvirtide are skin reactions where the drug is injected. Almost everybody who uses Enfuvirtide gets these reactions. They can be very mild, such as slight redness. They can include itching, swelling, pain, hardened skin, or hard lumps. Each reaction might last up to a week. With two injections each day, people using enfuvirtide might have reactions at several spots on their body at the same time. The most common other side effects of Enfuvirtide are headache, pain and numbness in feet or legs, dizziness, and loss of sleep.