What is Prezista?
Prezista is a medicine that contains the active substance darunavir. It is available as tablets (white coated capsules: 75 mg; white and oval: 150 mg; orange and oval: 300 and 600 mg; light orange and oval: 400 mg).
What is Prezista used for?
Prezista is an antiviral drug. It is given in combination with a small dose of ritonavir (another antiviral medicine) and other antiviral medicines to treat patients aged six years or over with human immunodeficiency virus (HIV-1) infection, a virus that causes acquired immune deficiency syndrome (AIDS). Prezista can be used in adults (over the age of 18), whether previously treated or not. In children and adolescents aged between six and 18 years, it can only be used if they have been previously treated and weigh at least 20 kg.
Doctors should prescribe Prezista to patients who have been treated previously only once the patient's previous antiviral treatments have been examined and the likelihood of the virus responding to the drug being considered.
The medicine can only be obtained with a prescription.
How is Prezista used?
Treatment with Prezista should be started by a doctor experienced in treating HIV infection.
For adults who have not been treated before, the recommended dose is 800 mg once a day, while for previously treated adults it is 600 mg twice a day. The doses to be administered to children and adolescents depend on their body weight and range from 375 to 600 mg twice a day. Each dose of Prezista should be taken together with ritonavir and food.
How does Prezista work?
The active substance in Prezista, darunavir, is a protease inhibitor. It blocks an enzyme called protease that is involved in the reproduction of HIV. If the enzyme is blocked, the virus is unable to reproduce normally and the multiplication rate is slowed down.
Ritonavir is another protease inhibitor that is used as a "booster" (ie to increase the potency of another drug). Slow down the speed at which darunavir is assimilated, increasing it
so concentration in the blood. Using a booster allows a lower dosage of darunavir to be used to achieve the same antiviral effect.
Prezista does not cure HIV infection or AIDS, but it may delay or reverse the damage to the immune system and reduce the risk of developing diseases associated with HIV or AIDS.
What studies have been carried out on Prezista?
In adults, Prezista has been studied in four main studies .
One study compared ritonavir-boosted Prezista with ritonavir-boosted lopinavir (another protease inhibitor) in 691 adults who had never before been treated for HIV .
The other three studies involved adults who had previously undergone treatment . One study compared ritonavir-boosted Prezista with ritonavir-boosted lopinavir in 604 patients who had taken some anti-HIV medicines in the past. The other two studies compared ritonavir-boosted Prezista with other protease inhibitors chosen on the basis of previous patient treatments and the expected response, out of a total of 628 patients who had previously taken several anti-HIV drugs.
Prezista boosted with ritonavir has also been studied in 80 children and adolescents aged between six and 18 years. All these patients had been treated previously and weighed at least 20 kg.
In all the studies, patients also took other anti-HIV drugs . The main measures of effectiveness were the change in HIV levels in the blood (viral load) .
What benefit has Prezista shown during the studies?
In adults who had not been treated previously, Prezista was as effective as lopinavir. After 48 weeks, 84% of patients taking ritonavir-boosted Prezista had viral loads below 50 copies / ml (287 of 343) compared with 78% of those taking lonatin-enhanced ritonavir (271 out of 346).
In adults who had been treated previously, those taking Prezista had lower viral loads than those taking comparator protease inhibitors. In patients who had taken some anti-HIV drugs in the past, 77% of those taking ritonavir-boosted Prezista had viral loads below 400 copies / ml after 48 weeks, compared to 68% of those who took ritonavir-boosted lopinavir . In adults who had taken several anti-HIV drugs in the past, 70% of those taking the approved dose of Prezista boosted with ritonavir (92 out of 131) had a reduction of at least 90% in the viral load after 24 weeks, compared to 21 % of those taking comparator protease inhibitors (26 out of 124).
Similar results were found in children and adolescents: 74% (59 out of 80) showed a reduction of at least 90% in viral loads after 24 weeks of treatment.
What is the risk associated with Prezista?
In adults, the most common side effect of Prezista (seen in more than 1 patient in 10) is diarrhea. Side effects are similar in children and adolescents. For the full list of all side effects reported with Prezista, see the Package Leaflet.
As with other anti-HIV drugs, patients being treated with Prezista may be at risk of lipodystrophy (changes in body fat distribution), osteonecrosis (death of bone tissue) or immune reactivation syndrome (symptoms of infections caused by system recovery immune). Patients with liver problems (including hepatitis B or C infection) may be at a higher risk of developing liver damage when treated with anti-HIV drugs such as Prezista.
Prezista should not be used in patients who may be hypersensitive (allergic) to darunavir or any of the other substances. It must also not be given to patients with severe liver problems or to patients being treated with the following drugs:
- rifampicin (for the treatment of tuberculosis);
- lopinavir boosted with ritonavir;
- St. John's wort (a herbal preparation used in the treatment of depression);
drugs that are metabolized in the same way as Prezista and that are dangerous if they reach high concentrations in the blood. For the full list of these medicines, see the package leaflet.
The 300 and 600 mg tablets contain a coloring substance called sunset yellow (E110), which can cause allergies. For patients allergic to this substance it may be necessary to take tablets with lower dosage, which do not contain sunset yellow.
Why was Prezista approved?
The Committee for Medicinal Products for Human Use (CHMP) has determined that Prezista's benefits, taken in combination with ritonavir and other antiretroviral medicinal products, are greater than its risks for the treatment of HIV-1 infection. The committee recommended that Prezista be given marketing authorization.
Prezista was originally granted "conditional approval". This means that further data is expected, in particular regarding the safety of the medicine. Since the manufacturer provided the necessary additional information, on December 16th 2008 the approval was changed from "conditional" to "final".
Further information on Prezista:
On 12 February 2007, the European Commission granted a marketing authorization for Prezista, valid throughout the European Union, to Janssen-Cilag International NV.
For the full EPAR Prezista click here.
Last update of this summary: 05-2009.
