Sabrina Spinosa-Guzman

Efficacy and safety of darunavir-ritonavir at week 48 in treatment-experienced patients with HIV-1 infection in POWER 1 and 2: a pooled subgroup analysis of data from two randomised trials.

BACKGROUND The continuing, randomised, multinational, phase IIB POWER 1 and 2 studies aim to evaluate efficacy and safety of darunavir in combination with low-dose ritonavir in treatment-experienced HIV-1-infected patients. We did a pooled subgroup analysis to update results at week 48 for patients receiving the recommended dose of darunavir-ritonavir compared with those receiving other protease inhibitors (PIs). METHODS After 24-week dose-finding phases and primary efficacy analyses, patients randomised to receive darunavir-ritonavir were given 600/100 mg twice daily, and patients receiving control PIs continued on assigned treatment into the longer-term, open-label phase; all patients continued on optimised background regimen. We assessed patients who had reached week 48 or discontinued earlier at the time of analysis; for the darunavir-ritonavir group, only patients who received 600/100 mg twice daily from baseline were included. Analyses were intention-to-treat. The POWER 2 study (TMC114-C202) is registered with ClinicalTrials.gov (NCT00071097). FINDINGS At week 48, 67 of 110 (61%) darunavir-ritonavir patients compared with 18 of 120 (15%) of control PI patients had viral load reductions of 1 log10 copies per mL or greater from baseline (primary endpoint; difference in response rates 46%, 95% CI 35%-57%, p<0.0001). Based on a logistic regression model including stratification factors (baseline number of primary PI mutations, use of enfuvirtide, baseline viral load) and study as covariates, the difference in response was 50% (odds ratio 11.72, 95% CI 5.75-23.89). In the darunavir-ritonavir group, rates of adverse events were mostly lower than or similar to those in the control group when corrected for treatment exposure. No unexpected safety concerns were identified. INTERPRETATION Efficacy responses with darunavir-ritonavir 600/100 mg twice daily plus optimised background regimen were greater than those with control PI and were sustained to at least week 48, with favourable safety and tolerability in treatment-experienced patients. This regimen could expand the treatment options available for such patients.

Efficacy and safety of once-daily darunavir/ritonavir versus lopinavir/ritonavir in treatment-naive HIV-1-infected patients at week 48

Background:The present primary analysis of AntiRetroviral Therapy with TMC114 ExaMined In naive Subjects (ARTEMIS) compares the efficacy and safety of once-daily darunavir/ritonavir (DRV/r) with that of lopinavir/ritonavir (LPV/r) in treatment-naive patients. Methods:Patients with HIV-1 RNA at least 5000 copies/ml were stratified by HIV-1 RNA and CD4 cell count in a phase III, open-label trial, and randomized to receive DRV/r 800/100 mg qd or LPV/r 800/200 mg total daily dose (bid or qd) plus fixed-dose tenofovir and emtricitabine for 192 weeks. The primary objective was to demonstrate non-inferiority of DRV/r as compared with LPV/r in HIV-1 RNA less than 50 copies/ml per-protocol time-to-loss of virologic response at 48 weeks. Results:Six hundred and eighty-nine patients were randomized and treated; mean baseline HIV-1 RNA: 4.85 log10 copies/ml and median CD4 count: 225 cells/μl. At 48 weeks, 84% of DRV/r and 78% of LPV/r patients achieved HIV-1 RNA less than 50 copies/ml (estimated difference = 5.6 [95% confidence interval −0.1–11]%), demonstrating non-inferiority of DRV/r as compared with LPV/r (P < 0.001; per-protocol time-to-loss of virologic response). Patients with HIV-1 RNA at least 100 000 copies/ml had a significantly higher response rate with DRV/r (79%) versus LPV/r (67%; P < 0.05). Median CD4 cell count increases (non-completer = failure; cells/μl) were 137 for DRV/r and 141 for LPV/r. DRV/r had a lower incidence of possibly treatment-related grade 2–4 gastrointestinal-related adverse events (7 versus 14%) and treatment-related moderate-to-severe diarrhea (4 versus 10%) than LPV/r. Adverse events leading to discontinuation were DRV/r: 3% and LPV/r: 7%. Conclusion:DRV/r 800/100 mg qd was non-inferior to LPV/r 800/200 mg at 48 weeks, with a more favorable safety profile. Significantly higher response rates were observed with DRV/r in patients with HIV-1 RNA at least 100 000 copies/ml. DRV/r 800/100 mg offers a new effective and well tolerated once-daily, first-line treatment option for treatment-naive patients.

Efficacy and safety of darunavir-ritonavir compared with that of lopinavir-ritonavir at 48 weeks in treatment-experienced, HIV-infected patients in TITAN: a randomised controlled phase III trial

BACKGROUND The protease inhibitor darunavir has been shown to be efficacious in highly treatment-experienced patients with HIV infection, but needs to be assessed in patients with a broader range of treatment experience. We did a randomised, controlled, phase III trial (TITAN) to compare 48-week efficacy and safety of darunavir-ritonavir with that of lopinavir-ritonavir in treatment-experienced, lopinavir-naive patients. METHODS Patients received optimised background regimen plus non-blinded treatment with darunavir-ritonavir 600/100 mg twice daily or lopinavir-ritonavir 400/100 mg twice daily. The primary endpoint was non-inferiority (95% CI lower limit for the difference in treatment response -12% or greater) for HIV RNA of less than 400 copies per mL in plasma at week 48 (per-protocol analysis). TITAN (TMC114-C214) is registered with ClinicalTrials.gov, number NCT00110877. FINDINGS Of 595 patients randomised and treated, 187 (31%) were protease inhibitor naive; 476 of 582 (82%) were susceptible to four or more protease inhibitors. At week 48, significantly more darunavir-ritonavir than lopinavir-ritonavir patients had HIV RNA of less than 400 copies per mL (77% [220 of 286] vs 68% [199 of 293]; estimated difference 9%, 95% CI 2-16). Fewer virological failures treated with darunavir-ritonavir than with lopinavir-ritonavir developed primary protease inhibitor mutations (21% [n=6] vs 36% [n=20]) and nucleoside analogue-associated mutations (14% [n=4] vs 27% [n=15]). Safety data were generally similar between the groups; grade 3 or 4 adverse events occurred in 80 (27%) darunavir-ritonavir and 89 (30%) lopinavir-ritonavir patients. INTERPRETATION In lopinavir-naive, treatment-experienced patients, darunavir-ritonavir was non-inferior to lopinavir-ritonavir treatment in terms of our virological endpoint, and should therefore be considered as a treatment option for this population.

The Effect of Different Meal Types on the Pharmacokinetics of Darunavir (TMC114)/Ritonavir in HIV‐Negative Healthy Volunteers

This open‐label, randomized, crossover study investigated the bioavailability, short‐term safety, and tolerability of darunavir (TMC114) coadministered with low‐dose ritonavir under fasted conditions and after different meal types in HIV‐negative healthy volunteers. All volunteers received ritonavir 100 mg twice daily on days 1 to 5, with a single darunavir 400‐mg tablet given on day 3 (darunavir/rtv). Pharmacokinetic parameters for darunavir and ritonavir were determined under fasted conditions and following a standard breakfast, a high‐fat breakfast, a nutritional protein‐rich drink, or a croissant with coffee. Administration of darunavir/rtv in a fasting state resulted in a decrease in darunavir Cmax and AUClast of approximately 30% compared with administration after a standard meal. No significant differences in darunavir plasma concentrations were observed between different fed states. Darunavir/rtv should therefore be administered with food, but exposure to darunavir is not affected by the type of meal.

Pharmacokinetics, safety and efficacy of darunavir/ ritonavir in treatment-experienced children and adolescents

Objective:To assess pharmacokinetics, safety and efficacy of darunavir/ritonavir (DRV/r) and optimized background regimen in treatment-experienced patients (6–17 years). Design:Forty-eight-week, open-label, two-part, phase II study. Methods:In part I, 44 patients were randomized (1: 1 ratio) to receive a body weight-adjusted, adult-equivalent dose (group A) or a 20–33% higher DRV/r twice daily (b.i.d.) dose (group B). Pharmacokinetics, safety and efficacy were assessed following 2-week dosing (part I), which determined dosing for part II (evaluated 48-week safety and efficacy). Results:In part I, both groups met the protocol-specified criteria for pharmacokinetics and showed favorable tolerability and efficacy. The following body-weight doses were selected: DRV/r 375/50 mg b.i.d. (20–<30 kg), 450/60 mg b.i.d. (30–<40 kg) and 600/100 mg b.i.d. (≥40 kg); these gave an AUC24h, C0h and Cmax of 102, 114 and 112%, respectively, versus the corresponding mean adult pharmacokinetic parameter. In part II, 80 patients received DRV/r (median age: 14 years, mean baseline HIV-1 RNA: 4.64 log10copies/ml). One patient (1%) discontinued (treatment-unrelated grade 3 anxiety). An abnormal mean baseline triglyceride level was normalized at 48 weeks (P < 0.01). At week 48, 65% had at least 1.0 log10HIV-1 RNA reduction; 59 and 48% achieved HIV-1 RNA less than 400 and less than 50 copies/ml, respectively (time-to-loss-of-virologic response). Mean age-adjusted weight z-score increased by 0.2 (P = 0.003). Conclusion:In treatment-experienced children and adolescents, DRV/r showed comparable exposure to adults with appropriate dose selection, favorable safety and tolerability, improved body weight and significant virologic response. DRV/r is a valuable therapeutic option for this population.

Characterization of virologic failure patients on darunavir/ritonavir in treatment-experienced patients.

Objective:Characterization of resistance development in virologic failure patients on the protease inhibitor darunavir administered with low-dose ritonavir (DRV/r) in the 48-week analysis of TMC114/r In Treatment-experienced pAtients Naive to lopinavir (TITAN). Design:TITAN is a randomized, controlled, open-label, phase III, noninferiority trial comparing the efficacy and safety of DRV/r with that of lopinavir/ritonavir (LPV/r) in HIV-1-infected, treatment-experienced, LPV-naive patients. The primary endpoint was the proportion of patients with HIV-1 RNA less than 400 copies/ml at week 48. Methods:Patients received DRV/r 600/100 mg twice daily (n = 298) or LPV/r 400/100 mg twice daily (n = 297), and an optimized background regimen. Patients who lost or never achieved HIV-1 RNA less than 400 copies/ml after week 16 were considered virologic failure patients. Genotyping and phenotyping were performed. Results:The virologic failure rate in the DRV/r arm (10%, n = 31) was lower than in the LPV/r arm (22%, n = 65). Furthermore, fewer virologic failure patients in the DRV/r arm than in the LPV/r arm developed primary protease inhibitor mutations (6 vs. 20) or nucleoside reverse transcriptase inhibitor resistance-associated mutations (4 vs. 15). In addition, fewer virologic failure patients on DRV/r than on LPV/r lost susceptibility to the protease inhibitor (3 vs. 13) or nucleoside reverse transcriptase inhibitor(s) (3 vs. 14) used in the treatment regimen or to other protease inhibitors. Most DRV/r-treated virologic failure patients retained susceptibility to all protease inhibitors. Conclusion:In treatment-experienced, LPV-naive patients, the overall virologic failure rate in the DRV/r arm was low and was associated with limited resistance development. These findings showed that the use of DRV/r in earlier lines of treatment was less likely to lead to cross-resistance to other protease inhibitors compared with LPV/r.

Pharmacokinetics of darunavir/ritonavir and rifabutin coadministered in HIV-negative healthy volunteers.

ABSTRACT The drug-drug interaction between rifabutin (RFB) and darunavir/ritonavir (DRV/r) was examined in a randomized, three-way crossover study of HIV-negative healthy volunteers who received DRV/r 600/100 mg twice a day (BID) (treatment A), RFB 300 mg once a day (QD) (treatment B), and DRV/r 600/100 mg BID plus RFB 150 mg every other day (QOD) (treatment C). The sequence of treatments was randomized, and each treatment period lasted 12 days. Full pharmacokinetic profiles were determined for DRV, ritonavir, and RFB and its active metabolite, 25-O-desacetylrifabutin (desRFB), on day 13. The DRV and ritonavir areas under the plasma concentration-time curve from zero to 12 h (AUC12h) increased by 57% and 66%, respectively, in the presence of RFB. The RFB exposure was comparable between treatment with RFB QD alone (treatment B) and treatment with DRV/r plus RFB QOD (treatment C); however, based on least-square means ratios, the minimum plasma concentration (Cmin) increased by 64% and the maximum plasma concentration (Cmax) decreased by 28%, respectively. The exposure (AUC within the dosage interval and at steady state [AUCτ]) to desRFB was considerably increased (by 881%) following treatment with DRV/r/RFB. The exposure to the parent drug plus the metabolite increased 1.6-fold in the presence of DRV/r. Adverse events (AEs) were more commonly reported during combined treatment (83% versus 44% for RFB and 28% for DRV/r); similarly, grade 3-4 AEs occurred in 17% versus 11% and 0%, respectively, of volunteers. Eighteen of 27 volunteers (66.7%) prematurely discontinued the trial; all volunteers discontinuing for safety reasons (n = 9) did so during RFB treatment phases. These results suggest that DRV/r may be coadministered with RFB with a dose adjustment of RFB to 150 mg QOD and increased monitoring for RFB-related AEs. Based on the overall safety profile of DRV/r, no dose adjustment of DRV/r is considered to be warranted. Given the safety profile seen with the combination of RFB with a boosted protease inhibitor in this and other studies, it is not recommended to conduct further studies with this combination in healthy volunteers.

Efficacy of once-daily darunavir/ritonavir 800/100 mg in HIV-infected, treatment-experienced patients with no baseline resistance-associated mutations to darunavir.

Objective:The objective of this study was to examine the potential of once-daily dosing with darunavir/ritonavir 800/100 mg in a HIV-infected, treatment-experienced patient population with no baseline darunavir resistance-associated mutations (RAMs). Methods:Patients in the randomized controlled POWER 1 and 2 trials were treatment experienced, with ≥1 International AIDS Society-USA primary protease inhibitor (PI) mutation. The virological and immunological responses in patients with no baseline darunavir RAMs receiving darunavir/r 800/100 mg once daily (n = 23), darunavir/r 600/100 mg twice daily (n = 29), or currently available PI(s) (n = 28) plus an optimized background regimen were compared. Results:The proportion of patients achieving HIV RNA <50 copies per milliliter at week 24 was 67% for the group receiving darunavir/r 800/100 mg once daily and 62% for the group receiving darunavir/r 600/100 mg twice daily (P = 0.774); both were superior to control PI(s) (11%; P < 0.0001). Mean HIV RNA change from baseline was 22.39 and 22.35 log10 copies per milliliter for the group receiving darunavir/r 800/100 mg once daily and for the group receiving 600/100 mg twice daily, respectively (P = 0.895); mean CD4 increases were 88 and 111 cells per milliliter, respectively (P = 0.526). Conclusions:Treatment-experienced, HIV-infected patients with no baseline darunavir RAMs achieved similar high responses with darunavir/r 800/100 mg once daily and 600/100 mg twice daily. This suggests that once-daily darunavir/r 800/100 mg therapy, which has been shown effective in treatment-naive patients and is currently being studied in treatment-experienced patients, shows potential in patients with no darunavir RAMs.

Pharmacokinetics of Darunavir (TMC114) and Atazanavir during Coadministration in HIV-Negative, Healthy Volunteers

AbstractBackground and objective: To investigate the potential for pharmacokinetic interactions between the protease inhibitors darunavir (DRV, TMC114) coadministered with low-dose ritonavir (darunavir/r), and atazanavir in HIVnegative, healthy volunteers. Methods: This was an open-label, randomised, three-period, crossover study. Darunavir/r (400/100mg twice daily), atazanavir/r (300/100mg once daily) or darunavir/r (400/100mg twice daily) plus atazanavir (300mg once daily) were administered in three separate sessions, with a washout period of at least 7 days between regimens. The follow-up lasted 30 days. Twenty-three healthy volunteers participated. Pharmacokinetic assessments were performed at steady-state on day 7. Plasma drug concentrations were determined by liquid chromatography-tandem mass spectrometry and pharmacokinetic parameters were compared between treatments. The safety and tolerability of the study medications were monitored throughout. Results: Darunavir pharmacokinetics were unaffected by atazanavir. No change in overall exposure to atazanavir was observed during coadministration with darunavir/r. However, there was a 52% increase in minimum atazanavir plasma concentration (least squares mean ratio [90% CI 0.99, 2.34]). Mean systemic exposure to ritonavir was increased by 65% and 106%, respectively, with the combination treatment compared with darunavir/r alone or atazanavir/r alone. There were no apparent differences in mean changes in lipids between the darunavir/r, atazanavir/r or darunavir/r plus atazanavir regimens. Hyperbilirubinaemia and ocular icterus were reported with atazanavir-containing regimens. Conclusion: Atazanavir at a dose of 300mg once daily can be coadministered with a darunavir/r twice-daily regimen without any dose adjustment if there is a clinical need to combine darunavir/r and atazanavir in HIV-1-infected patients.

In vitro susceptibility and virological outcome to darunavir and lopinavir are independent of HIV type-1 subtype in treatment-naive patients.

BACKGROUND The effect of HIV type-1 (HIV-1) subtype on in vitro susceptibility and virological response to darunavir (DRV) and lopinavir (LPV) was studied using a broad panel of primary isolates, and in recombinant clinical isolates from treatment-naive, HIV-1-infected patients in the Phase III trial, AntiRetroviral Therapy with TMC114 ExaMined In naive Subjects (ARTEMIS). METHODS Patients received DRV/ritonavir (DRV/r) 800/100 mg once daily (n=343) or LPV/ritonavir (LPV/r) 800/200 mg total daily dose (n=346), plus a fixed daily dose of emtricitabine and tenofovir disoproxil fumarate. RESULTS DRV demonstrated high antiviral activity against a broad panel of HIV-1 major group (M) and outlier group (O) primary isolates in peripheral blood mononuclear cells, with a median 50% effective concentration (EC(50)) of 0.52 nM. Most (61%) patients in ARTEMIS harboured HIV-1 subtype B; other prevalent subtypes were C (13%) and CRF01_AE (17%); 9% harboured other subtypes. Median EC(50) values (interquartile range) for DRV were 1.79 nM (1.3-2.6) for subtype B, 1.12 nM (0.8-1.4) for C and 1.27 nM (1.0-1.7) for CRF01_AE. Virological response to DRV/r (HIV-1 RNA<50 copies/ml [intent-to-treat, time-to-loss of virological response algorithm]) was 81%, 87% and 85% for patients with subtype B, C and CRF01_AE infections, respectively. Similar results were observed in the LPV/r treatment group. CONCLUSIONS In vitro susceptibility to DRV was comparable across HIV-1 subtypes in a broad panel of primary isolates and in recombinant clinical isolates. Once daily DRV/r 800/100 mg and LPV/r 800/200 mg were highly effective in ARTEMIS irrespective of the HIV-1 subtype studied, confirming their broad anti-HIV-1 activity.