Effect of adherence on virological response to once-daily (qd) versus twice-daily (bid) darunavir/ritonavir (DRV/r) in treatment-experienced, HIV-1-infected patients with no DRV resistance-associated mutations (RAMs): ODIN 48-week data
C. Workman1, P. Benson2, J. Valdez Madruga3, A. Rieger4, T. Van de Casteele5, L. Lavreys5, S. Spinosa-Guzman5
1AIDS Research Initiative, Darlinghurst, Australia, 2Well Medical Center, Berkley, United States, 3Centro de Referência e Treinamento DST/AIDS, São Paulo, Brazil, 4Medical University of Vienna, Vienna, Austria, 5Tibotec BVBA, Mechelen, Belgium
Background: ODIN is a Phase IIIb, randomised, open-label study comparing DRV/r 800/100mg qd vs DRV/r 600/100mg bid at Week 48 in treatment-experienced, HIV-1-infected adult patients. Patients were included if they had no DRV RAMs at screening. In this analysis, adherence and its association with virological response to Week 48 were examined.
Methods: Mean adherence (Week 4-48) was assessed during the last 30 days prior to study visits over 48 weeks using (1) the Modified-Medication Adherence Self-Report Inventory (M-MASRI) questionnaire. Rates were transformed into binary variables of >95% (adherence) and ≤95% (suboptimal adherence). Adherence was also assessed by (2) DRV plasma concentrations (being above or below the detection limit of 10ng/mL), and (3) pill count (actual amount taken/amount to be taken).
Results: Across the three methods used, the percentage of patients who were adherent over the whole treatment period ranged from 57% to 83% (DRV/r qd) and 54% to 88% (DRV/r bid). Overall, adherent patients in both the DRV/r qd and bid groups achieved greater virological responses (HIV-1 RNA < 50 copies/mL intent-to-treat/time-to-loss of virological response) than suboptimally adherent patients (Table). In adherent patients, virological response to DRV/r qd was similar to that for DRV/r bid for each of the three adherence methods used.
[Virological response at W48 by adherence measure]
600/100mg bid||DRV/r qd - DRV/r bid|
|Parameter||N||Number of responders,
n (%)||N||Number of responders,
n (%)||Difference in response (%)||95% CI of difference in response (%)|
|Adherence measured by
|Adherence based on DRV plasma concentrations
|Adherence measured by pill count
Conclusions: Regardless of the adherence methodology used, virological response was greater in adherent than suboptimally adherent patients in both DRV/r 800/100mg qd and 600/100mg bid arms. Adherent patients had comparable virological responses with DRV/r qd and DRV/r bid for each of the three adherence methods used.
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