Pharmacokinetics and Bioequivalence of Isavuconazole Administered as Isavuconazonium Sulfate Intravenous Solution via Nasogastric Tube or Orally in Healthy Subjects

For critically ill patients with invasive fungal infections, a nasogastric (NG) tube can be an alternative route for administration of isavuconazonium sulfate (ISAVUSULF). This was a randomized, open-label, 2-period, 2-sequence single-dose crossover study comparing single doses of 372 mg ISAVUSULF intravenous (i.v.) solution via NG tube (test formulation) to 372-mg ISAVUSULF capsules for oral administration (reference formulation) in healthy male and female subjects. A single dose of ISAVUSULF was administered under fasting conditions on day 1 of each period, with a washout of 30 days between periods. Pharmacokinetic (PK) samples were collected predose through day 21. Standard safety and tolerability assessments were conducted in each period. The analysis of variance estimate of the study population demonstrates that the isavuconazole i.v. NG tube administration geometric least-squares (LS) mean values of the observed maximum concentration (C(max)), area under the plasma concentration-time curve (AUC) to the last measurable concentration (AUC(last)), AUC to time infinity (AUC(inf)), and AUC from start of dosing to 72 h (AUC(72)) were 105.3%, 97.6%, 99.3%, and 97.8%, respectively, of the corresponding oral-administration values. The geometric LS mean ratio and 90% confidence intervals for the PK parameters were completely contained within the prespecified limits of 80% to 125%. There were no deaths or serious adverse events that led to the withdrawal of treatment during the study. The study met its primary endpoint of bioequivalence between the two routes of administration. Both routes of administration were well tolerated.