What is Isentress?
Isentress is a medicine that contains the active substance raltegravir, available as pink oval tablets (400 mg).
What is Isentress used for?
Isentress is an antiviral drug. It is used in combination with other antiviral medicines to treat adults infected with human immunodeficiency virus (HIV-1), a virus that causes acquired immune deficiency syndrome (AIDS).
The medicine can only be obtained with a prescription.
How is Isentress used?
Isentress therapy should be started by a doctor who has experience in the treatment of HIV infection.
One tablet is given twice a day, with or without food.
How does Isentress work?
The active substance in Isentress, raltegravir, is an integrase inhibitor. This substance blocks an enzyme called integrase, which is involved in a phase of HIV reproduction. When the enzyme is blocked, the virus fails to reproduce normally, consequently slowing down the spread of infection. Isentress, taken in combination with other antiviral medicines, reduces the amount of HIV in the blood and keeps it at a low level. Isentress does not cure HIV infection or AIDS, but it may delay the damage to the immune system and the development of infections and diseases associated with AIDS.
How has Isentress been studied?
Isentress has been analyzed in three main studies:
- two studies conducted on a total of 699 of "experienced" patients (already treated) whose ongoing treatment against the HIV virus was ineffective. The studies compared Isentress with a placebo (a dummy treatment), in addition to the "optimized basic therapy" (a combination of other antiviral drugs selected for each patient as it was most likely to reduce HIV levels in the blood). The main measure of effectiveness was the reduction of HIV levels in the blood (viral load) after 16 weeks;
- the third study involved 566 adults who had never been treated for HIV before and compared Isentress with efavirenz (another antiviral drug). All patients also took tenofovir and emtricitabine (other antiviral drugs). The main measure of effectiveness was the number of patients who had "undetectable" viral loads (below 50 copies per milliliter of blood) after 48 weeks.
What benefit has Isentress shown during the studies?
In "experienced" patients, Isentress was more effective than placebo: after 16 weeks, viral loads below 400 copies / ml were observed in 77% of patients taking Isentress, compared to 42% of placebo-treated patients. The response was maintained for at least 48 weeks.
In patients never treated for HIV previously, Isentress was as effective as efavirenz. After 48 weeks, 86% of patients taking Isentress had viral loads below 50 copies / ml (241 out of 281), compared to 82% of subjects treated with efavirenz (230 out of 282).
What is the risk associated with Isentress?
The most common side effects seen with Isentress (1-10 patients in 100) are abnormal dreams, insomnia (sleep disorders), dizziness, headache, dizziness, abdominal distention (swelling), abdominal pain, diarrhea, flatulence (gas), nausea, vomiting, rash, asthenia (weakness), exhaustion (fatigue), atypical lymphocytes (presence of abnormal white blood cells) and increased levels of liver enzymes in the blood (alanine aminotransferase and aspartate aminotransferase) and triglycerides (a type of fat). For the full list of all side effects reported with Isentress, see the Package Leaflet.
Isentress should not be used in people who may be hypersensitive (allergic) to raltegravir or any of the other components.
As with other anti-HIV medicines, patients taking Isentress may be at risk of osteonecrosis (death of bone tissue) or immune reactivation syndrome (symptoms of infection caused by reactivation of the immune system).
Why has Isentress been approved?
The Committee for Medicinal Products for Human Use (CHMP) has determined that the benefits of Isentress, taken in combination with other antiretroviral medicines, are greater than its risks for the treatment of HIV-1 infection in adult patients. The Committee recommended that Isentress be given marketing authorization.
Pending further data, Isentress initially received "conditional approval". Since the company provided the necessary additional information, the authorization was changed from conditional to regular on July 14, 2009.
Other information about Isentress:
On 20 December 2007, the European Commission granted a marketing authorization valid for Isentress, valid throughout the European Union, to Merck Sharp & Dohme Limited.
The full EPAR for Isentress can be found here.
Last update of this summary: 08-2009.
