Pharmacokinetics of Omadacycline in Adults with Cystic Fibrosis

Omadacycline offers a potential advancement in the management of infections in people with cystic fibrosis (CF) because of its spectrum of activity, intrapulmonary penetration, and oral bioavailability. A prospective single-dose, single-arm study was conducted to characterize the pharmacokinetic (PK) profile of omadacycline in people with CF, considering the known alterations in PK observed in this population (NCT04460586, 2020-07-01).

Plasma samples were obtained from nine adults with CF who received a single dose of intravenous omadacycline 100 mg over 0.5 h followed by a 1-week washout and an oral dose of omadacycline 300 mg. The data were analyzed using noncompartmental PK.

The maximum plasma concentration (C_max) and area under the curve extrapolated to infinity (AUC_0-∞) after intravenous administration of omadacycline were similar between healthy volunteers and people with CF. The absorption kinetics of oral omadacycline, encompassing both the rate (C_max and time to C_max [t_max]) and the extent (AUC_0-∞), also showed consistency between healthy volunteers and people with CF. The absolute bioavailability of the oral tablet formulation of omadacycline in people with CF (31.2%) was also consistent with that observed in healthy volunteers (34.5%). In comparing the two routes of administration, intravenous omadacycline 100 mg provided plasma exposures equivalent to those with oral omadacycline 300 mg in people with CF, as evidenced by geometric mean ratios for both AUC_0-∞ (0.9381; 90% confidence intervals [CI] 0.6783-1.2975) and C_max (0.7746; 90% CI 0.5478-1.0951).

Overall, the similarity in plasma PK observed in this study when comparing healthy volunteers and infected patients indicates that no dosing alterations are necessary when using omadacycline in people with CF.