March 13, 2003
FDA's approval of Fuzeon is the first, worldwide, of a new class of drugs known as "fusion inhibitors." Fusion inhibitors interfere with the entry of HIV-1 into cells by inhibiting the merging of the virus with the cellular membrane, the first step in viral infiltration. This inhibition blocks HIV before it enters the human immune cell.
Combination therapy using multiple medications is used to effectively treat HIV infection. However, a significant percentage of patients with chronic HIV have developed infection resistant to many existing medications. Because of its unique mode of action, Fuzeon may be active against HIV that is resistant to currently available classes of anti-HIV drugs.
Fuzeon, administered twice daily as a subcutaneous injection (under the skin), can be used as part of a treatment regimen in patients for whom there are limited options. It should only be used in patients who have used other anti-HIV medications and show evidence of ongoing viral replication.
FDA based its approval on an analysis of six months of data from two ongoing clinical studies of Fuzeon involving approximately 1,000 patients. The data from this analysis showed that the addition of Fuzeon to a combination of other antiretroviral medications reduced viral load in the blood, a measure of HIV infection, more than the use of the combination of medications alone.
Fuzeon was studied in 35 pediatric patients from the age of 6 years to 16 with pharmacokinetic data from 18 of these patients.
The long-term effects of Fuzeon are not known at this time, but are being evaluated by ongoing clinical studies.
The approved labeling for Fuzeon warns physicians to carefully monitor patients for signs and symptoms of pneumonia. Although bacterial pneumonia was not common in clinical study participants, more patients treated with Fuzeon developed bacterial pneumonia than did patients who did not receive Fuzeon. Patients receiving Fuzeon are advised to seek medical evaluation immediately if they develop signs or symptoms suggestive of pneumonia, such as cough with fever, rapid breathing and shortness of breath.
In addition, Fuzeon can cause serious allergic reactions, and local skin reactions at the site of injection.
Symptoms of a serious allergic reaction with Fuzeon can include: trouble breathing, fever with vomiting and a skin rash, blood in urine, and swelling of the feet. Patients taking Fuzeon should contact their healthcare provider right away if they experience any of these symptoms.
Local skin reactions from Fuzeon injections are common, occurring in almost all patients, and may be painful. Patients must be careful that their skin does not become infected at the site of injection. It is important to follow the injection Instructions that come with the medication to lower the chances of getting an injection site infection.
Patients should call their health care provider if there are signs of infection at the injection site such as drainage, increasing heat, swelling, redness or pain.
Because of the molecular complexity, and difficulty of manufacture, it is possible that demand for Fuzeon may exceed supply at launch. The sponsor is working with HIV physician and patient groups to develop a progressive launch plan, and will carefully manage allocation of Fuzeon.
Roche Pharmaceuticals of Nutley, N.J., has licensed the product from Trimeris Inc. of Durham, N.C., and will distribute Fuzeon.