Tibotec Therapeutics, a division of Centocor Ortho Biotech Products, L.P., announced the availability of a lower-dose (75 mg) formulation of Prezista (darunavir) for paediatric patients with HIV. The announcement follows the FDA approval of Prezista, co-administered with ritonavir (Prezista/r) and with other antiretroviral agents, for the treatment of HIV infection in paediatric patients six years of age and older, granted December 18, 2008. Prezista was developed by Tibotec Pharmaceuticals, Ltd. and is marketed in the US by Tibotec Therapeutics.

According to the most recent reports from the Centers for Disease Control (CDC), there were 2,587 children under 13 years of age living with HIV and 1,116 children under 13 years of age living with AIDS in the US at the end of 2006. The CDC estimates that 56,500 young people between the ages of 13 and 24 years were living with HIV in 2006.

"The HIV epidemic continues to affect thousands of children in the US, and these patients have fewer treatment options than adults," said Ram Yogev, M.D., director of paediatric, adolescent and maternal HIV infection at Children's Memorial Hospital in Chicago. "The availability of Prezista in a formulation designed especially for children over the age of six provides an important new option for these patients."

In October 2008, Prezista received traditional (full) approval for treatment-naïve and treatment-experienced adult patients as part of combination therapy.

The paediatric indication for Prezista is based on 24-week analyses of pharmacokinetics, safety, tolerability and antiviral activity from DELPHI (TMC114-C212), an open-label Phase 2 trial in which antiretroviral treatment-experienced HIV-1 infected paediatric patients (6 to <18 years of age and weighing at least 44 lbs [20 kg]) received twice-daily Prezista/r in combination with other antiretroviral agents.

DELPHI (TMC114-C212) is an open-label, phase 2 trial evaluating the pharmacokinetics, safety, tolerability, and efficacy of Prezista/r in combination with other antiretrovirals in 80 antiretroviral treatment-experienced HIV-1-infected paediatric subjects 6 to <18 years of age and weighing at least 44 lbs (20 kg). Virologic response rate was evaluated at week 24.

Virologic response was defined as a decrease in plasma HIV-1 RNA viral load of at least 1 log10 versus baseline. The mean baseline plasma HIV-1 RNA was 4.64 log10 copies/mL, and the median baseline CD4+ cell count was 330 cells/mm3 (range: 6 to 1505 cells/mm3). Most paediatric subjects (79 per cent) had previous use of at least one NNRTI and 96 percent of paediatric subjects had previously used at least one protease inhibitor PI.

Paediatric subjects who were at risk of discontinuing therapy due to intolerance of the ritonavir oral solution (e.g., taste aversion) were allowed to switch to the capsule formulation. Of the 44 paediatric subjects taking ritonavir oral solution, 23 subjects switched to the 100 mg capsule formulation and exceeded the weight-based ritonavir dose without changes in observed safety.