What Is Enfuvirtide?
Enfuvirtide is a medicine doctors use to help treat HIV. It can be given to adults and to children who are six years or older and weigh at least 24 pounds.
It is used when other HIV medicines are not working well. Enfuvirtide is always taken together with other HIV medicines.
Although Enfuvirtide is not a long-acting injectable HIV medication, it plays an important role in treatment-experienced patients and supports them by helping maintain viral suppression.
How Does Enfuvirtide Work?
Enfuvirtide works by stopping the HIV virus from entering healthy cells. It does this by blocking the virus from fusing (joining) with the cell’s outer layer. Scientists tested Enfuvirtide by adding HIV-1 to CD4+ cells (helper immune cells) and found that it helped stop the virus from infecting these cells.
Indications and usage:
Enfuvirtide, along with other HIV medicines, is used to treat HIV-1 in people who have already tried other treatments but still have signs that the virus is growing.
Enfuvirtide may be used together with other antiretroviral medicines and HIV prevention methods to support viral suppression and reduce transmission risk.
Dosing:
Adults
The usual dose of Enfuvirtide is 90 mg twice a day.
It is given as a shot under the skin on the upper arm, front of the thigh, or belly.
Do not inject in the same spot each time. Use a different area for every dose.
Only inject where there is no swelling or reaction from a previous shot.
Do not inject near big nerves, such as the elbow, knee, or groin.
Avoid injecting into moles, scars, near the belly button, over blood vessels, or on burned or damaged skin.
Pediatric patients
There is not enough information to recommend a dose of Enfuvirtide for children younger than six years.
For children ages six to 16, the usual dose is 2 mg per kilogram of body weight, twice a day, up to a maximum of 90 mg twice daily.
For Subcutaneous Administration
How to Mix (Reconstitute) Enfuvirtide?
Use only 1 mL of sterile water that comes in the kit.
Add the water to the vial.
Gently tap or swirl the vial for about 10 seconds.
Roll the vial slowly between your hands so it does not make foam. This helps the powder mix with the water.
Let the vial sit until all the powder is fully dissolved. This can take up to 45 minutes.
You can speed up mixing by continuing to roll the vial slowly.
Before using the solution:
Check that the liquid is clear, fully dissolved, and has no particles.
If the liquid looks foamy, let it sit longer.
If you see particles, do not use the vial; return it to the pharmacy.
Storage and use:
Enfuvirtide has no preservatives.
After mixing, use it right away or keep it in the refrigerator for up to 24 hours.
Before injecting, let the vial come back to room temperature.
Check the solution again to make sure it is clear, colorless, and without bubbles.
The next dose can also be mixed ahead of time and stored in the refrigerator, but it must be used within 24 hours.
Contraindications:
Enfuvirtide is contraindicated in cases with known hypersensitivity (severe allergy) to Enfuvirtide or any of its elements.
Warnings And Precautions
Local injection site reactions
Most people who receive Enfuvirtide injections have at least one reaction at the injection site. Common symptoms include:
Pain.
Hardening of the skin.
Redness.
Small lumps.
Itching.
Bruising.
These reactions can happen in more than one spot where the medicine is injected. Patients should be properly trained on how to inject Enfuvirtide and should watch for signs of infection, such as redness that spreads, warmth, or pus, which could mean cellulitis (skin infection) or a local infection.
Pneumonia
More cases of bacterial pneumonia were seen in people taking Enfuvirtide compared to those not taking it.
It is not clear if Enfuvirtide is the direct cause of this increase.
People with HIV-1 should be watched closely for signs of pneumonia.
Extra care is needed for people who already have conditions that increase their risk.
Risk factors for pneumonia include:
Low CD4 cell count at the start of treatment.
High viral load.
Injection (IV) drug use.
Smoking.
Previous lung problems.
Hypersensitivity reactions
Serious allergic (hypersensitivity) reactions have been reported with Enfuvirtide and can happen again if the medicine is restarted.
These reactions may include:
Rash.
Fever.
Nausea or vomiting.
Shaking or chills.
Low blood pressure.
Increased liver enzymes.
Other possible immune-related problems include:
Immune complex reactions.
Trouble breathing.
If someone shows signs of a serious allergic reaction, they should stop taking Enfuvirtide and get medical help immediately. Do not restart Enfuvirtide after a systemic allergic reaction. There are no known factors that clearly predict who is at risk for hypersensitivity to Enfuvirtide.
Non-HIV Infected Individuals - There is a hypothetical risk that Enfuvirtide usage may direct the production of anti-enfuvirtide antibodies, which cross-react with HIV gp41.
This may cause a false positive HIV examination with an ELISA assay; a confirmatory Western blot examination would be expected to be negative. Enfuvirtide has not been examined in non-HIV-infected people.
Immune reconstitution syndrome:
Immune reconstitution syndrome has been noted in cases managed with combination antiretroviral treatment, including Enfuvirtide.
During the initial stage of combination antiretroviral therapy, cases whose immune systems react may create an inflammatory reaction to residual opportunistic infections, which might increase the need for additional assessment and therapy.
For Patients
How Is Enfuvirtide Supplied, Stored, and Handled?
Enfuvirtide comes as a white or off-white powder in a single-use glass vial.
Each vial contains 108 mg of Enfuvirtide, which gives about 90 mg in 1 mL after mixing with 1 mL of sterile water.
Enfuvirtide is sold in a convenience kit that includes:
60 single-use vials of Enfuvirtide (90 mg each).
60 vials of sterile water (two cartons of 30 each).
60 syringes for mixing.
60 syringes for injection.
Storage:
Store the powder at 25°C, with allowed temperature changes between 15 to 30°C.
After mixing, keep the solution in the same vial in the refrigerator at 2 to 8°C.
Use the mixed solution within 24 hours.
How Should This Medicine Be Used?
General use:
Enfuvirtide is a powder mixed with sterile water and given as a shot under the skin.
It is usually injected twice a day.
Follow the prescription instructions exactly.
Enfuvirtide controls HIV but does not cure it.
Keep taking it even if you feel well, and do not stop without talking to your doctor.
Missing doses or stopping can make HIV harder to treat.
When you are running low, get more from your doctor or pharmacist.
Training and injecting:
The first dose is usually given in the doctor’s office.
After that, you or a caregiver can give the injections at home.
The doctor will teach you how to inject properly.
Read and understand the patient instructions from the manufacturer before using Enfuvirtide at home.
Where to inject:
Inject into the front of the thighs, stomach, or upper arms.
Do not inject:
Near the belly button.
Under a belt or waistband.
Around the elbow, knee, groin, or buttocks.
Over a blood vessel.
Use a different spot every time to reduce soreness. Keep a record of injection sites and do not inject in the same place twice in a row.
Safety:
Never reuse needles, syringes, or vials.
Throw used needles and syringes in a puncture-proof container.
Follow the manufacturer’s instructions for preparing and injecting each dose.
If you have any questions, ask your doctor or pharmacist.
What Are the Side Effects of Enfuvirtide?
Enfuvirtide may induce side effects.
Inform the doctor if any of these manifestations are extreme. Enfuvirtide may cause a range of side effects, including:
Itching (skin feels scratchy).
Inflammation (swelling and redness).
Ache (dull pain).
Tingling (pins-and-needles feeling).
Distress (discomfort or irritation).
Bruising (purple or blue skin mark).
Bumps (small raised areas on the skin).
Hardship in falling asleep (trouble sleeping).
Depression (feeling very sad or hopeless).
Nervousness (feeling anxious or worried).
Tiredness.
Muscle aches (pain in muscles).
Nausea (feeling like vomiting).
Appetite loss (not feeling hungry).
Changes in the ability to taste food (food tastes different).
Weight loss (losing body weight).
Diarrhea (loose stools).
Constipation (difficulty passing stools).
Flu-like manifestations (fever, chills, and body pain).
Runny nose (nasal discharge).
Sinus aches (pain around the nose and forehead).
Warts (small skin bumps).
Cold sores (small sores on the lips).
Swollen glands (enlarged lymph nodes).
Painful eyes (eye irritation).
Red eyes (eye inflammation).
Teary eyes (watery eyes).
Some side effects can be severe and demand immediate medical attention, such as:
Severe aches (strong pain at the site of injection).
Oozing (fluid coming from the injection area).
Warmth (area feels hot to the touch).
Redness at the injection area (skin looks red).
Rash (red, itchy skin patches).
Fever .
Vomiting.
Chills (shaking or shivering).
Fainting.
Dizziness (feeling light-headed).
Blurred vision (unable to see clearly).
Cough (irritation of the throat causing coughing).
Difficulty breathing (trouble getting enough air).
Blood in urine (reddish or pink urine).
Inflamed feet (swollen or painful feet).
Quick breathing (rapid breaths).
Shortness of breath (feeling you cannot breathe deeply).
Burning (painful, hot sensation).
Numbness in the feet (loss of sensation in feet).
Pale stools (light-colored bowel movements).
Yellowing of the skin or eyes (may indicate jaundice).
For Doctors
Clinical pharmacology:
Mechanism of Action - Enfuvirtide is an antiretroviral medicine.
Pharmacokinetics - The pharmacokinetic effects of Enfuvirtide were assessed in HIV-1-infected adults and pediatric cases.
Enfuvirtide works by stopping HIV-1 from entering healthy cells. It does this by blocking a step where the virus normally joins and fuses with the cell. The medicine attaches to a specific part of the virus (called gp41) and prevents the virus from changing shape, which it needs to enter the cell.
Nonclinical toxicology:
Carcinogenesis, Mutagenesis, and Impairment of Fertility:
Carcinogenesis and mutagenesis: Studies to check if Enfuvirtide can cause cancer have not been done. However, tests done in the laboratory and in animals showed that Enfuvirtide did not cause genetic changes or mutations.
Impairment of fertility: Studies in rats showed that Enfuvirtide did not affect the ability of males or females to have babies, even at doses up to 1.6 times higher than the dose used in humans.
Use in specific populations:
Pregnancy - In animal reproduction examinations, no adverse developmental outcomes were seen with subcutaneous administration of Enfuvirtide at exposures more significant than or equal to around two times higher than human exposure at the recommended human dose, found on the surface area.
Lactation - No human data is known about the presence of Enfuvirtide or its metabolites in human milk, the consequences on the breastfed baby, or the results on milk production. When Enfuvirtide was distributed to lactating rats, Enfuvirtide was probably present in the milk because of both the potential for HIV-1 transmission in HIV-negative infants, generating viral resistance in HIV-positive infants, and adverse responses in breastfed infants compared to those seen in grown-ups. Mothers should stop breastfeeding if they are taking Enfuvirtide.
Pediatric use - The use of Enfuvirtide in pediatric cases weighing at least 24 pounds is supported by proof from acceptable and well-controlled analyses of Enfuvirtide in adults and two pediatric examinations assessing the safety, pharmacokinetics, and efficacy of Enfuvirtide in subjects six years of age and older.
Hepatic and renal impairment - No dosage alteration of Enfuvirtide is required in cases with hepatic impairment.
