Other names: Fuzeon^®, T-20 is approved for use in treatment of HIV incombination with other antiretrovirals.

Description: T-20 IS A FUSION INHIBITOR and prevents HIV from fusing to a host cell. During infection, the HIV binds to the CD4 cell. T-20 interferes with this process. There is no oral formulation of T-20; the current delivery method is by subcutaneous injection.

Dose: 100 mg in 1 mL carbonate solution, injected under the skin (subcutaneously) twice daily (each injection delivers 90 mg of drug). It is injected into the upper arm, front of the thogh or abdomen. Not recommended in people over 65 years.

Enfuvirtide must be prepared for subcutaneous injection. This is done by adding liquid (sterile water) to powder by syringe. This mixture normally takes about 45 minutes to dissolve before it can be administered. Once mixed the drug can be stored for up to 24 hours at below 25⁰ C. This allows doses to be made up before they are needed. 

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.

Toxicity and side effects: In studies  98% of volunteers experienced injection site reactions (ISRs) after using T-20. These reactions include swelling and hardening, pain, redness, and itching at the spot where T-20 was deposited under the skin. Most patients (86%) had the first ISR after the first week. The average duration of the reaction was 7 days and it did not generally worsen over time. The most common symptoms of ISRs were pain and discomfort (95%), hardening of the skin (89%), redness (89%), and nodules or cysts (76%). During trials, 3% of participants stopped using the drug because of ISRs (Delfraissy). In severe cases, resolving a knot formed at a T-20 injection site can take several days to 2 weeks.

Other adverse events specific to treatment with T-20 included bacterial pneumonia and eosinophilia. Eosinophilia is characterized by elevated levels of eosinophils in the blood (>700 cells/mm3).

Resistance: Two T-20 resistance mutations, G36S and V38M in gp41, have been found in vitro.

Drug interactions: Three studies were performed to look at drug interactions with ritonavir, boosted saquinavir, and rifampin. Because T-20 is a synthetic peptide, drug interactions were not anticipated, and none were documented in studies with these drugs (Boyd).

THE BOTTOM LINE

  Subcutaneous administration of T20

Client's Comments/Advice after 94 weeks of use

Using T20 is fairly easy. Once you have injected yourself for the first time, any fears you may have about injecting the drug will disappear. It does not hurt much at all. The timing is fairly flexible. Just make sure that - at some point in the morning and some point in the evening - you inject. Thats all there is to it. Twice a day. Remember: there is a FOUR hour window period either side of the twelve hour routine - a total window of EIGHT hours. Just make sure you do it twice a day. My routine is quite interesting actually: I get up, eat and take my other pills and inject at some point before about 3pm. Then in the evening I do it all again at about midnight. It sound quite hectic, but it really doesn't interfere in my lifestyle at all. I have been on the course for 94 weeks now, and have got a CD4 of 750 and an undetectable viral load. I think these particularly good results can really only be explained by one thing only: my mental attitude. If you can be strong, and positive about your future and relaxed about your regime then you will succeed.