Simple FactSheet: fosamprenavir (Lexiva)

fosamprenavir (Lexiva)
a Simple FactSheet from the AIDS Treatment Data Network

||||| Lexiva is a Protease Inhibitor:

Lexiva, also known as fosamprenavir, is an anti-HIV treatment in the class of drugs called Protease Inhibitors (PIs). Protease inhibitors work by blocking, or inhibiting, a part of HIV called protease. HIV needs protease to make new copies of itself. When protease is blocked, the copies that HIV makes of itself cannot infect new cells. Lexiva is one of eight approved protease inhibitors used to treat HIV.

||||| Taking the drug:

Lexiva is taken as part of a carefully chosen combination of anti-HIV drugs. In order to get the most benefit, Lexiva must be taken with two other anti-HIV drugs known as Nucleoside Reverse Transcriptase Inhibitors (NRTIs). Combination HIV treatment (also known as HAART) helps people live longer and develop less opportunistic infections. Lexiva should not be taken as your only anti-HIV drug or the virus very quickly becomes resistant to it. Drug resistance tests (genotypic or phenotypic) have been shown to be useful in choosing the optimal anti-HIV treatment regimen specific to an individual. See the FactSheets Combination Therapy & Understanding Drug Resistance for more information.
The Public Health Service HIV treatment guidelines list Lexiva as an alternative for an initial HIV treatment regimen using a protease inhibitor in combination with two NRTIs. According to the guidelines panel, Lexiva's advantages over amprenavir include the need to take fewer pills, and the option of once-daily dosing if taken with ritonavir (Norvir). One disadvantage is the high frequency of rashes in people taking Lexiva.
||||| Trial results:

Lexiva was approved based on three clinical trials involving over 1,200 people.
In one study (APV30001, NEAT), volunteers who had never taken HIV treatment before received Epivir (3TC; lamivudine) and Ziagen (abacavir) with either Lexiva or nelfinavir (Viracept). After 48 weeks of treatment, 66% of volunteers receiving Lexiva had viral loads below 400, compared to 52% of volunteers taking Viracept.
In another study (APV30002, SOLO), volunteers who had never taken HIV treatment before received Epivir and Ziagen with either Lexiva plus Norvir or Viracept. After 48 weeks of treatment, 69% of volunteers receiving Lexiva and Norvir had viral loads below 400, compared to 68% of volunteers taking Viracept.
A third study (APV30003, CONTEXT) enrolled volunteers who had previously taken HIV treatment with a protease inhibitor but could not supress HIV. All volunteers received two NRTIs. They were randomly assigned to also receive either Lexiva and Norvir once daily, Lexiva and Norvir twice daily, or Kaletra (lopinavir and ritonavir). After 48 weeks of treatment, 58% of volunteers receiving twice daily Lexiva and Norvir had viral loads below 400, compared to 61% of volunteers taking Kaletra. The study was not large enough to determine whether twice daily Lexiva and Norvir works as well as Kaletra. Only 50% of volunteers taking once daily Lexiva and Norvir had viral loads below 400 after 48 weeks.

||||| Dosage:

Lexiva comes in 700 mg capsules. It can be stored at room temperature.
The approved dosage of Lexiva is 1,400 mg twice a day (two 700 mg capsules in the morning and two 700 mg capsules in the evening). Lexiva can be taken with or without food.
Lexiva can also be taken with small doses of Norvir. Norvir boosts the blood levels of Lexiva. The Lexiva/ Norvir combination is taken either once or twice a day. The combination doses are 1,400 mg of Lexiva with 200 mg of ritonavir, taken either together once a day or split into morning and evening doses (700 mg of Lexiva with 100 mg of Norvir, each time).
People who already have some drug resistance to other protease inhibitors should take the twice a day Lexiva with Norvir combination.
If you take Lexiva with ddI (Videx) or ddI EC (Videx EC), Lexiva should be taken either an hour before or an hour after you take Videx.
Lexiva has not been approved for children.
||||| Side effects:

Lexiva causes rashes in about one out of five people who take it. If you develop a rash, contact your doctor immediately. Lexiva contains sulfa, and should be used with caution in people with sulfa allergies.
Lexiva may also cause diarrhea, nausea and vomiting, or headaches.
Lexiva can increase liver enzymes levels and blood sugars (hyperglycemia). People with hepatitis B or C should be monitored for liver function when taking Lexiva. Like other protease inhibitors, Lexiva can increase blood levels of fats (cholesterol and triglycerides) and cause changes in body fat (see Lipodystrophy FactSheet).

||||| Warnings:

Efavirenz (Sustiva) lowers the blood levels of Lexiva. If using these drugs together, take Lexiva in combination with ritonavir (for twice a day: 700 mg Lexiva with 100 mg ritonavir; for once a day: 1,400 mg Lexiva with 300 mg ritonavir).
Other drugs can interact with Lexiva, changing the blood levels or one or both medications. Lexiva should not be taken with simvastatin (Zocor) or lovastatin (Mevacor), rifampin or rifapentine (Priftin), pimozide (Orap), midazolam (Versed) or triazolam (Halcion), astemizole (Hismanal) or terfenadine (Seldane), St. John's wort, cisapride (Propulsid) and proton pump inhibitors, bepridil (Vascor), irinotecan (Camptosar), or ergot alkoloid migraine drugs such as dihydroergotamine (Migranal) and ergotamine.
Lexiva may reduce the blood levels of methadone. You might need your dose increased. Lexiva can also decrease the blood levels of oral contraceptives (the pill), so women taking Lexiva should use other methods (i.e. condoms) if they want to avoid pregnancy.
Lexiva may also interact with other drugs for the treatment of erectile dysfunction, including sildenafil (Viagra), vardenafil (Levitra), and tadalafil (Cialis). Lexiva increase the levels of these drugs in the blood. This can lead to high blood pressure and other effects. Tell your doctor about all of the drugs that you take, including non-prescription medicine and herbs.

GlaxoSmithKline, the maker of fosamprenavir (Lexiva), has a patient assistance program for people having problems getting the drug. The number to call is (866) 728-4368.

Recent Updates • Home • Hepatitis Co-infection • About The Network • The Access Project • Simple Fact Sheets
Last modified: 8/15/2006
copyright © 2006 The Network
Contact The Network

\|\|\|\|\| Lexiva is a Protease Inhibitor:
Lexiva, also known as fosamprenavir, is an anti-HIV treatment in the class of drugs called Protease Inhibitors (PIs). Protease inhibitors work by blocking, or inhibiting, a part of HIV called protease. HIV needs protease to make new copies of itself. When protease is blocked, the copies that HIV makes of itself cannot infect new cells. Lexiva is one of eight approved protease inhibitors used to treat HIV.
\|\|\|\|\| Taking the drug:
Lexiva is taken as part of a carefully chosen combination of anti-HIV drugs. In order to get the most benefit, Lexiva must be taken with two other anti-HIV drugs known as Nucleoside Reverse Transcriptase Inhibitors (NRTIs). Combination HIV treatment (also known as HAART) helps people live longer and develop less opportunistic infections. Lexiva should not be taken as your only anti-HIV drug or the virus very quickly becomes resistant to it. Drug resistance tests (genotypic or phenotypic) have been shown to be useful in choosing the optimal anti-HIV treatment regimen specific to an individual. See the FactSheets Combination Therapy & Understanding Drug Resistance for more information. The Public Health Service HIV treatment guidelines list Lexiva as an alternative for an initial HIV treatment regimen using a protease inhibitor in combination with two NRTIs. According to the guidelines panel, Lexiva's advantages over amprenavir include the need to take fewer pills, and the option of once-daily dosing if taken with ritonavir (Norvir). One disadvantage is the high frequency of rashes in people taking Lexiva.
\|\|\|\|\| Trial results:
Lexiva was approved based on three clinical trials involving over 1,200 people. In one study (APV30001, NEAT), volunteers who had never taken HIV treatment before received Epivir (3TC; lamivudine) and Ziagen (abacavir) with either Lexiva or nelfinavir (Viracept). After 48 weeks of treatment, 66% of volunteers receiving Lexiva had viral loads below 400, compared to 52% of volunteers taking Viracept. In another study (APV30002, SOLO), volunteers who had never taken HIV treatment before received Epivir and Ziagen with either Lexiva plus Norvir or Viracept. After 48 weeks of treatment, 69% of volunteers receiving Lexiva and Norvir had viral loads below 400, compared to 68% of volunteers taking Viracept. A third study (APV30003, CONTEXT) enrolled volunteers who had previously taken HIV treatment with a protease inhibitor but could not supress HIV. All volunteers received two NRTIs. They were randomly assigned to also receive either Lexiva and Norvir once daily, Lexiva and Norvir twice daily, or Kaletra (lopinavir and ritonavir). After 48 weeks of treatment, 58% of volunteers receiving twice daily Lexiva and Norvir had viral loads below 400, compared to 61% of volunteers taking Kaletra. The study was not large enough to determine whether twice daily Lexiva and Norvir works as well as Kaletra. Only 50% of volunteers taking once daily Lexiva and Norvir had viral loads below 400 after 48 weeks.
\|\|\|\|\| Dosage:
Lexiva comes in 700 mg capsules. It can be stored at room temperature. The approved dosage of Lexiva is 1,400 mg twice a day (two 700 mg capsules in the morning and two 700 mg capsules in the evening). Lexiva can be taken with or without food. Lexiva can also be taken with small doses of Norvir. Norvir boosts the blood levels of Lexiva. The Lexiva/ Norvir combination is taken either once or twice a day. The combination doses are 1,400 mg of Lexiva with 200 mg of ritonavir, taken either together once a day or split into morning and evening doses (700 mg of Lexiva with 100 mg of Norvir, each time). People who already have some drug resistance to other protease inhibitors should take the twice a day Lexiva with Norvir combination. If you take Lexiva with ddI (Videx) or ddI EC (Videx EC), Lexiva should be taken either an hour before or an hour after you take Videx. Lexiva has not been approved for children.
\|\|\|\|\| Side effects:
Lexiva causes rashes in about one out of five people who take it. If you develop a rash, contact your doctor immediately. Lexiva contains sulfa, and should be used with caution in people with sulfa allergies. Lexiva may also cause diarrhea, nausea and vomiting, or headaches. Lexiva can increase liver enzymes levels and blood sugars (hyperglycemia). People with hepatitis B or C should be monitored for liver function when taking Lexiva. Like other protease inhibitors, Lexiva can increase blood levels of fats (cholesterol and triglycerides) and cause changes in body fat (see Lipodystrophy FactSheet).
\|\|\|\|\| Warnings:
Efavirenz (Sustiva) lowers the blood levels of Lexiva. If using these drugs together, take Lexiva in combination with ritonavir (for twice a day: 700 mg Lexiva with 100 mg ritonavir; for once a day: 1,400 mg Lexiva with 300 mg ritonavir). Other drugs can interact with Lexiva, changing the blood levels or one or both medications. Lexiva should not be taken with simvastatin (Zocor) or lovastatin (Mevacor), rifampin or rifapentine (Priftin), pimozide (Orap), midazolam (Versed) or triazolam (Halcion), astemizole (Hismanal) or terfenadine (Seldane), St. John's wort, cisapride (Propulsid) and proton pump inhibitors, bepridil (Vascor), irinotecan (Camptosar), or ergot alkoloid migraine drugs such as dihydroergotamine (Migranal) and ergotamine. Lexiva may reduce the blood levels of methadone. You might need your dose increased. Lexiva can also decrease the blood levels of oral contraceptives (the pill), so women taking Lexiva should use other methods (i.e. condoms) if they want to avoid pregnancy. Lexiva may also interact with other drugs for the treatment of erectile dysfunction, including sildenafil (Viagra), vardenafil (Levitra), and tadalafil (Cialis). Lexiva increase the levels of these drugs in the blood. This can lead to high blood pressure and other effects. Tell your doctor about all of the drugs that you take, including non-prescription medicine and herbs. GlaxoSmithKline, the maker of fosamprenavir (Lexiva), has a patient assistance program* for people having problems getting the drug. The number to call is (866) 728-4368.*