Tibotec's Prezista granted further US approval
This article was originally published in Scrip
Tibotec (Johnson & Johnson) has received expanded US FDAapproval for its HIV protease inhibitor Prezista (darunavir) to include its use once-daily as part of an HIV combination regimen in treatment-naive adult patients.
Prezista also received a traditional (full) approval for its original indication for use in treatment-experienced adults, including those with resistance to protease inhibitors, in combination with other antiretrovirals. Prezista was previously granted conditional approval by the FDA in 2006 for this indication, and the change in status to full approval signifies that Tibotec has fully complied with the FDA's request for postmarketing studies that verify the clinical benefits of darunavir.
The treatment-naive indication of Prezista was based on a 48-week randomised, controlled, open-label Phase III study, known as ARTEMIS, which compared Prezista, co-administered with ritonavir (800mg/100mg once daily), with Abbott's Kaletra (lopinavir co-administered with ritonavir (400mg/10 mg twice daily or 800mg/200mg once daily)) in treatment-naive patients, with a viral load <5,000>5,000>
The primary endpoint was to demonstrate non-inferiority of Prezista compared with lopinavir in virologic response (confirmed HIV-1 viral load <50>50>
The results showed that 84% of patients in the Prezista arm and 78% of patients in the lopinavir arm achieved this.
The full approval for treatment-experienced patients was based on data from the TITAN Phase III non-inferiority and the 96-week safety and efficacy Phase IIb POWER studies.
TITAN, a randomised, controlled, open-label trial that enrolled 595 patients, compared twice daily doses of Prezista/ritonavir of 600mg/100mg with lopinavir/ritonavir, and demonstrated non-inferiority of Prezista compared with lopinavir in virologic response (HIV-1 viral load <400>400><0.0001)>0.0001)>
Recommended dosing in treatment-naive patients is 800mg (two 400mg tablets) and 600mg per day in treatment-experienced patients, to be taken with 100mg ritonavir each day. Tibotec launched a 600mg tablet earlier this year and plans to launch a 400mg tablet in November (Scrip Online, May 23rd, 2008).
On October 23rd, the EU's CHMP recommended an expansion of Prezista's marketing authorisation. This extension of indication broadened the patient population to include those who have been pre-treated with other antiviral medications, whereas the previous indication was only for persons who have failed under previous treatment with a protease inhibitor.
Earlier this year, the FDA called for Tibotec to strengthen warnings on hepatotoxicity on the drug's label after postmarketing cases of liver injury, including fatalities, were reported (Scrip Online, March 19th, 2008).