Roche's new Invirase 500 mg formulation has received US Food and Drug Administration (FDA) marketing approval following a six-month priority review process. The new 500 mg formulation will significantly reduce Invirase's pill count by more than half, from 5 to 2 pills twice a day. With less tablets per day, Invirase now becomes an excellent choice for HIV-patients who require treatment with an HIV-protease inhibitor.

"With the new Invirase 500 mg tablet now available, pill burden is considerably reduced and we anticipate that this improved convenience together with boosted Invirase's record of convincing data will result in an expansion of its use in the earlier stages of HIV therapy" said William M Burns, head of the Roche Pharmaceutical Division.

Invirase (saquinavir mesylate) is an HIV protease inhibitor approved for use in combination with a small dose of ritonavir ('boosting') and other anti-HIV medicines for the treatment of HIV infection. Boosted Invirase has been shown to be highly efficacious, with an excellent safety and tolerability profile and is recommended as first choice boosted protease inhibitor in the International AIDS Society (IAS) guidelines.

"The FDA approval of Invirase 500 mg together with the recently reported results of the Staccato trial is good news for patients as they now have access to a more convenient dosing regimen of a potent and well tolerated HIV drug" said Michael S. Saag, MD, Professor of Medicine and Director, UAB AIDS Outpatient Clinic, Birmingham, Alabama, USA. "In the Staccato trial patients treated with saquinavir/ritonavir showed one of the highest response rates in a clinical trial; after 24 weeks of treatment the HIV-virus was undetectable in around 90 per cent of patients1."

Invirase, originally approved by the FDA in 1995, was the first HIV protease inhibitor on the market. Its introduction represented a major milestone in the treatment of HIV/AIDS. In December 2003, the FDA approved Invirase for use in boosted dosing regimens with ritonavir (1000 mg Invirase/100 mg ritonavir bid). Co-administering Invirase with ritonavir enhances therapeutic blood levels of the drug and enables simplified dosing.

Data from the Staccato clinical study show reductions in patients' HIV RNA recorded in the first 24 weeks on therapy that are the best ever seen in a large cohort of patients given HAART. Some 96 per cent of patients achieved viral load reductions to <400 HIV RNA copies/ml and 91 per cent were shown to have undetectable levels (<50 HIV RNA copies/ml). Over the 24 week induction phase of the study, these reductions in patient viral load were accompanied by a median increase of CD4 cells of 109 cells/mm3.