Once- versus twice-daily lopinavir/ritonavir tablets in virologically suppressed, HIV-infected, treatment-experienced children: comparative pharmacokinetics and virological outcome after switching to once-daily lopinavir/ritonavir

Sustained Viral Suppression in HIV-infected Children on Once-daily Lopinavir/Ritonavir in Clinical Practice

BACKGROUND

The use of lopinavir/ritonavir once-daily (LPV/r QD) has not been approved for children. Good short-term clinical, virologic and immunologic outcomes have been observed in children on LPV/r QD.

METHODS

We evaluated the long-term effectiveness of a LPV/r QD containing regimen in HIV-1-infected children in clinical practice. Selected children (0-18 years of age) with an undetectable HIV-1 RNA viral load (<50 copies/mL) for at least 6 months on a twice-daily LPV/r-containing regimen switched to LPV/r QD. The main outcome measures were the percentage of patients with an undetectable HIV-1 viral load each subsequent year after switch to LPV/r QD (on treatment and last observation carried forward), and virologic failure during follow-up (>400 copies/mL twice within 6 months). Also, the exposure to LPV on the initial once-daily dosing regimen was determined.

RESULTS

Forty children (median age: 6.5 years; range: 1.0-17) were included. Median follow-up was 6.3 years (range: 1.0-10.3). During yearly follow-up, the percentage of children with an undetectable viral load varied between 82% and 100% (on treatment) and 83% and 93% (last observation carried forward). Five children (12.5%) met the criteria for failure. CD4+ and CD8+ counts remained stable at normal values. Geometric mean LPV area under the plasma concentration-time curve (linear up-log down method) over a dosing interval from time 0 to 24 hours after dosing was 169.3 mg x h/L, and last observed drug concentration was 1.35 mg/L. Adverse events were encountered in 8 patients, were mainly gastrointestinal, and in these cases, no reason to stop treatment.

CONCLUSION

A once-daily LPV/r-containing regimen in HIV-1-infected children with intensive clinical and therapeutic drug monitoring is well tolerated and has good long-term clinical, virologic and immunologic outcomes.

Novel in situ self-assembly nanoparticles for formulating a poorly water-soluble drug in oral solid granules, improving stability, palatability, and bioavailability

PURPOSE

The purpose of this study was to develop a novel lipid-based nanotechnology to formulate poorly water-soluble drugs in oral solid granules to improve stability, palatability, and bioavailability.

MATERIALS AND METHODS

In one method, we prepared ritonavir (RTV) nanoparticles (NPs) by a microemulsion-precursor method and then converted the RTV NPs to solid granules by wet granulation to produce RTV NP-containing granules. In the other innovative method, we did not use water in the formulation preparation, and discovered novel in situ self-assembly nanoparticles (ISNPs). We prepared RTV ISNP granules that did not initially contain NPs, but spontaneously produced RTV ISNPs when the granules were introduced to water with gentle agitation. We fully characterized these RTV nanoformulations. We also used rats to test the bioavailability of RTV ISNP granules. Finally, an Astree electronic tongue was used to assess the taste of the RTV ISNP granules.

RESULTS

RTV NP-containing granules only had about 1% drug loading of RTV in the solid granules. In contrast, RTV ISNP granules achieved over 16% drug loading and were stable at room temperature over 24 weeks. RTV ISNPs had particle size between 160 nm and 300 nm with narrow size distribution. RTV ISNPs were stable in simulated gastric fluid for 2 hours and in simulated intestinal fluid for another 6 hours. The data from the electronic tongue showed that the RTV ISNP granules were similar in taste to blank ISNP granules, but were much different from RTV solution. RTV ISNP granules increased RTV bioavailability over 2.5-fold compared to RTV solution.

CONCLUSION

We successfully discovered and developed novel ISNPs to manufacture RTV ISNP granules that were reconstitutable, stable, and palatable, and improved RTV bioavailability. The novel ISNP nanotechnology is a platform to manufacture oral solid dosage forms for poorly water-soluble drugs, especially for pediatric formulation development.

Once vs. twice-daily lopinavir/ritonavir in HIV-1-infected children

OBJECTIVE

To evaluate whether once daily (q.d.) lopinavir/ritonavir is noninferior to twice daily (b.i.d.) dosing in children.

DESIGN

International, multicentre, phase II/III, randomized, open-label, noninferiority trial (KONCERT/PENTA18/ANRS150).

SETTING

Clinical centres participating in the PENTA, HIV-NAT and PHPT networks.

PARTICIPANTS

Children/adolescents with HIV-1 RNA viral load less than 50 copies/ml for at least 24 weeks on lopinavir/ritonavir-containing antiretroviral therapy.

INTERVENTION

Children were randomized to continue lopinavir/ritonavir b.i.d. or change to q.d.

MAIN OUTCOME MEASURE

Confirmed viral load ≥50 copies/ml by 48 weeks (12% noninferiority margin).

RESULTS

One hundred seventy-three children were randomized in the KONCERT trial (86 q.d., 87 b.i.d.); 46% men, median (IQR) age 11 (9-14) years, CD4% 33 (27-38)%. By week 48, 97 and 98% of time was spent on q.d. and b.i.d., respectively (one q.d. child lost at week 4). Twelve q.d. vs. seven b.i.d. children had confirmed viral load ≥50 copies/ml within 48 weeks; estimated difference in percentage with viral load rebound 6% [90% CI (-2, 14)]. Numbers of children with grade 3/4 adverse events (11 vs. 7) or major resistance mutations (3 vs. 2) were similar, q.d. vs. b.i.d. (both P > 0.3). Among 26 children in an intrasubject lopinavir/ritonavir pharmacokinetic substudy, lower daily exposure (AUC0-24 161 h.mg/l vs. 224 h.mg/l) and lower Clast (1.03 mg/l vs. 5.69 mg/l) were observed with q.d. vs. b.i.d. dosing.

CONCLUSION

Noninferiority for viral load suppression on q.d. vs. b.i.d. lopinavir/ritonavir was not demonstrated. Although results, therefore, do not support routine use of q.d. lopinavir/ritonavir, lack of safety concerns or resistance suggest that q.d. dosing remains an option in selected, adherent children, with close viral load monitoring.