Tibotec Therapeutics today announced the availability of a new 600 mg tablet strength for PREZISTA (darunavir), a protease inhibitor (PI). The new dosage strength was approved by the U.S. Food and Drug Administration (FDA) on February 25, 2008. The recommended oral dose of PREZISTA for treatment-experienced adult patients with HIV-1 is 600 mg (one 600 mg tablet or two 300 mg tablets ) taken twice daily with ritonavir 100 mg, in combination with other antiretroviral agents, and with food.

The 300mg tablet will remain available as long as there is sufficient demand for it.

PREZISTA, co-administered with 100 mg ritonavir and with other antiretroviral agents, is currently indicated for the treatment of human immunodeficiency virus (HIV) infection in antiretroviral treatment-experienced adult patients, such as those with HIV-1 strains resistant to more than one protease inhibitor.

This indication is based on Week 24 analyses of plasma HIV RNA levels and CD4+ cell counts from two controlled trials of PREZISTA/ritonavir (PREZISTA/r) in combination with other antiretroviral drugs. Both studies were conducted in clinically advanced, treatment-experienced (NRTIs, NNRTIs, and PIs) adult patients with evidence of HIV-1 replication despite ongoing antiretroviral therapy.

The following points should be considered when initiating therapy with PREZISTA/r:

• Treatment history and, when available, genotypic or phenotypic testing should guide the use of PREZISTA/r.

• The use of other active agents with PREZISTA/r is associated with a greater likelihood of treatment response.

• The risks and benefits of PREZISTA/r have not been established in treatment-naïve adult patients or pediatric patients.

PREZISTA/r is not recommended for use in patients with severe hepatic impairment.

Important Safety Information

• PREZISTA does not cure HIV infection or AIDS, and does not prevent passing HIV to others.

• PREZISTA is contraindicated in patients with known hypersensitivity to any of its ingredients.

PREZISTA must be co-administered with 100 mg ritonavir and food to exert its therapeutic effect. Failure to correctly administer PREZISTA with ritonavir and food will result in reduced plasma concentration of darunavir that will be insufficient to achieve the desired antiviral effect. Please refer to ritonavir prescribing information for additional information on precautionary measures.

Coadministration of PREZISTA/r is contraindicated with drugs that are highly dependent on CYP3A for clearance and have a narrow therapeutic index (e.g., astemizole, terfenadine, dihydroergotamine, ergonovine, ergotamine, methylergonovine, cisapride, pimozide, midazolam, or triazolam) and for which elevated plasma concentrations are associated with serious and/or life-threatening events.

Coadministration is not recommended with carbamazepine, phenobarbital, phenytoin, rifampin, lopinavir/ritonavir, saquinavir, lovastatin, pravastatin, simvastatin, or products containing St. John's wort (Hypericum perforatum).

Caution should be used when prescribing agents such as sildenafil, vardenafil, tadalafil, or other substrates, inhibitors, or inducers of CYP3A in patients receiving PREZISTA/r. This list of potential drug interactions is not complete.