In the new study of treatment-experienced HIV-1-infected adults with no Prezista resistance-associated mutations (RAMs), 72% of patients in the Prezista/ritonavir (800/100 mg) once-daily arm achieved undetectable viral loads (<50 copies/ml) compared with 71% of patients in the Prezista/r (600/100 mg) twice-daily arm.
Once-daily Prezista/r is an investigational regimen for treatment-experienced adult patients. The current FDA-approved dosing recommendation is Prezista/r 800/100 mg once daily for treatment-naive adults (patients starting treatment for the first time) and Prezista/r 600/100 twice daily for treatment-experienced adults (patients who have taken HIV medications in the past), in combination with other antiretrovirals and with food.
Tibotec plans to file data supporting the use of once-daily dosing for treatment-experienced adults from the ODIN (Once-daily Darunavir In treatment-experieNced patients) study with the US FDA, the European Medicines Agency (EMEA) and other national regulatory agencies for approval.
In the ODIN study, 590 patients were randomized to receive treatment with either Prezista/r 800/100mg once daily or Prezista/r 600/100 mg twice daily. For both treatment arms, Prezista/r was used in combination with an optimized background regimen (OBR) of at least two nucleoside reverse transcriptase inhibitors (NRTIs).
Overall, 46% of patients were protease inhibitor (PI)-naive and 13% were non-nucleoside reverse transcriptase inhibitor (NNRTI)-naive; 8% were susceptible to eight PIs (excluding ritonavir) and 60% were susceptible to at least two NRTIs in their OBR. At 48 weeks, a similar proportion of patients in both treatment arms achieved an undetectable viral load of <50 copies/mL (72% once-daily vs. 71% twice-daily). The study met its primary objective of non-inferiority.
Ron Falcon, vice president of Tibotec Therapeutics Clinical Affairs, said: “It is our hope that with FDA approval, Prezista once-daily dosing will provide an important option for treatment-experienced patients with no Prezista resistance-associated mutations, which represents a large percentage of age of the treatment-experienced population.”