1557. Population Pharmacokinetics of Suvratoxumab (MEDI4893), an Extended Half-life Staphylococcus aureus Alpha Toxin-Neutralizing Human Monoclonal Antibody, in Healthy Adults and Patients on Mechanical Ventilation in Intensive Care Units

BACKGROUND: Suvratoxumab (suvra), an extended half-life (~80 days), Staphylococcus aureus (SA) alpha toxin-neutralizing IgG monoclonal antibody, is under investigation for prevention of SA pneumonia in patients on mechanical ventilation (MV). We characterized the serum PK of suvra using population pharmacokinetics (popPK) in both healthy volunteers and MV patients and quantified the proportion of patients reaching the serum target of 211 μg/mL at 30 days post-dose. METHODS: The popPK analysis included 1,368 serum samples from two early phase studies (NCT02296320; EudraCT 2014-001097-34): (1) Phase 1 study in 26 healthy adults receiving single IV suvra doses ranging from 0.225g to 5g, with PK sampled up to 360 days; and (2) Phase 2 study in MV patients with PCR-confirmed SA colonization of lower respiratory tract receiving one suvra IV dose of 2g (n = 15) or 5g (n = 96), with PK sampled up to 100 days. RESULTS: A two-compartment linear model with weight-based scaling of the PK parameters adequately described the serum PK data (Figure 1). MV status, number of days on MV, and age impacted the PK of suvra. A moderate between-subject variability (<45% CV) was estimated for key PK parameters. An estimated two-fold increase in MV patients’ volume of distribution parameters compared with healthy volunteers explained the observed C(max) differences between the two groups (1145±369 μg/mL vs. 1783±396 μg/mL) (Figures 2 and 3). Although age, MV status and days on MV post-dose appeared to be associated with higher systemic clearance (CL) in the model, this estimate could be biased due to limited PK data available for only one half-life (~90 days) of the drug in MV patients (Figure 2). More patients achieved suvra levels above the PK target following the 5 g (73.5%; 50/68) vs. 2 g dose (7.6%; 1/13) at 30 days post-dose. CONCLUSION: MV status, post-dose duration on MV, body weight, and age were identified as statistically significant covariates influencing the PK of suvra. Serum PK and popPK analyses support the 5g dose for future studies with suvra in MV patients. [Image: see text] [Image: see text] [Image: see text] DISCLOSURES: All authors: No reported disclosures.