Pharmacokinetic Interaction Study of Ritonavir-Boosted Saquinavir in Combination with Rifabutin in Healthy Subjects▿

The effect of multiple doses of rifabutin (150 mg) on the pharmacokinetics of saquinavir-ritonavir (1,000 mg of saquinavir and 100 mg of ritonavir [1,000/100 mg]) twice daily (BID) was assessed in 25 healthy subjects. Rifabutin reduced the area under the plasma drug concentration-time curve from 0 to 12 h postdose (AUC0-12), maximum observed concentration of drug in plasma (Cmax), and minimum observed concentration of drug in plasma at the end of the dosing interval (Cmin) for saquinavir by 13%, 15%, and 9%, respectively, for subjects receiving rifabutin (150 mg) every 3 days with saquinavir-ritonavir BID. No effects of rifabutin on ritonavir AUC0-12, Cmax, and Cmin were observed. No adjustment of the saquinavir-ritonavir dose (1,000/100 mg) BID is required when the drugs are administered in combination with rifabutin. The effect of multiple doses of saquinavir-ritonavir on rifabutin pharmacokinetics was evaluated in two groups of healthy subjects. In group 1 (n = 14), rifabutin (150 mg) was coadministered every 3 days with saquinavir-ritonavir BID. The AUC0-72 and Cmax of the active moiety (rifabutin plus 25-O-desacetyl-rifabutin) increased by 134% and 130%, respectively, compared with administration of rifabutin (150 mg) once daily alone. Rifabutin exposure increased by 53% for AUC0-72 and by 86% for Cmax. In group 3 (n = 13), rifabutin was coadministered every 4 days with saquinavir-ritonavir BID. The AUC0-96 and Cmax of the active moiety increased by 60% and 111%, respectively, compared to administration of 150 mg of rifabutin once daily alone. The AUC0-96 of rifabutin was not affected, and Cmax increased by 68%. Monitoring of neutropenia and liver enzyme levels is recommended for patients receiving rifabutin with saquinavir-ritonavir BID

Drug-Drug Interaction Study of Ketoconazole and Ritonavir-Boosted Saquinavir▿

Saquinavir, a potent human immunodeficiency virus protease inhibitor, is extensively metabolized by CYP3A4. Saquinavir is coadministered with ritonavir, a strong CYP3A4 inhibitor, to boost its exposure. Ketoconazole is a potent CYP3A inhibitor. The objectives of this study were to investigate the effect of ketoconazole on the pharmacokinetics of saquinavir/ritonavir and vice versa using the approved dosage regimens of saquinavir/ritonavir at 1,000/100 mg twice daily and ketoconazole at 200 mg once daily. This was an open-label, randomized two-arm, one-sequence, two-period crossover study in healthy subjects. In study arm 1, 20 subjects received saquinavir/ritonavir treatment alone for 14 days, followed in combination with ketoconazole treatment for 14 days. In arm 2, 12 subjects received ketoconazole treatment for 6 days, followed in combination with saquinavir/ritonavir treatment for 14 days. The pharmacokinetics were assessed on the last day of each treatment (days 14 and 28 in arm 1 and days 6 and 20 in arm 2). The exposures Cmax and the area under the concentration-time curve from 0 to 12 h (AUC0-12) of saquinavir and ritonavir with or without ketoconazole were not substantially altered after 2 weeks of concomitant dosing with ketoconazole. The Cmax and AUC0-12 of ketoconazole, dosed at 200 mg once daily, were increased by 45% (90% confidence interval = 32 to 59%) and 168% (90% confidence interval = 146 to 193%), respectively, after 2 weeks of concomitant dosing with ritonavir-boosted saquinavir (1,000 mg of saquinavir/100 mg of ritonavir given twice daily). The greater exposure to ketoconazole when given in combination with saquinavir/ritonavir was not associated with unacceptable safety or tolerability. No dose adjustment for saquinavir/ritonavir (1,000/100 mg twice daily) is required when coadministered with 200 mg of ketoconazole once daily, and high doses of ketoconazole (>200 mg/day) are not recommended

Safety and Pharmacokinetic Characterization of Nacubactam, a Novel β-Lactamase Inhibitor, Alone and in Combination with Meropenem, in Healthy Volunteers

Nacubactam is a novel, β-lactamase inhibitor with dual mechanism of action as an inhibitor of serine β-lactamases (classes A, C, and some class D) and an inhibitor of penicillin binding protein 2 in Enterobacteriaceae The safety, tolerability, and pharmacokinetics of intravenous nacubactam were evaluated in single and multiple ascending dose, placebo-controlled studies. Healthy participants received single ascending doses of nacubactam 50 to 8,000 mg, multiple ascending doses of nacubactam 1,000 to 4,000 mg every 8 hours (q8h) for up to 7 days, or nacubactam 2,000 mg plus meropenem 2,000 mg q8h for 6 days after a 3-day lead-in period. Nacubactam was generally well tolerated, with the most frequently reported adverse events (AEs) being mild-to-moderate complications associated with intravenous access and headache. There was no apparent relationship between drug dose and the pattern, incidence, or severity of AEs. No clinically relevant dose-related trends were observed in laboratory safety test results. No serious AEs, dose-limiting AEs, or deaths were reported. After single or multiple doses, nacubactam pharmacokinetics appeared linear, and exposure increased in an approximately dose-proportional manner across the dose range investigated. Nacubactam was excreted largely unchanged into urine. Co-administration of nacubactam with meropenem did not significantly alter the pharmacokinetics of either drug. These findings support the continued clinical development of nacubactam and demonstrate the suitability of meropenem as a potential β-lactam partner for nacubactam.ClinicalTrials.gov NCT02134834 (single ascending dose study); ClinicalTrials.gov NCT02972255 (multiple ascending dose study)