Pharmacokinetics and safety of aztreonam/avibactam for the treatment of complicated intra-abdominal infections in hospitalized adults: results from the REJUVENATE study.

OBJECTIVES: To investigate pharmacokinetics (PK) and safety (primary objectives) and efficacy (secondary objective) of the investigational monobactam/ß-lactamase inhibitor combination aztreonam/avibactam in patients with complicated intra-abdominal infection (cIAI). METHODS: This Phase 2a open-label, multicentre study (NCT02655419; EudraCT 2015-002726-39) enrolled adults with cIAI into sequential cohorts for 5-14 days treatment. Cohort 1 patients received an aztreonam/avibactam loading dose of 500/137 mg (30 min infusion), followed by maintenance doses of 1500/410 mg (3 h infusions) q6h; Cohort 2 received 500/167 mg (30 min infusion), followed by 1500/500 mg (3 h infusions) q6h. Cohort 3 was an extension of exposure at the higher dose regimen. Doses were adjusted for creatinine clearance of 31-50 mL/min (Cohorts 2 + 3). All patients received IV metronidazole 500 mg q8h. PK, safety and efficacy were assessed. RESULTS: Thirty-four patients (Cohort 1, n = 16; Cohorts 2 + 3, n = 18) comprised the modified ITT (MITT) population. Mean exposures of aztreonam and avibactam in Cohorts 2 + 3 were consistent with those predicted to achieve joint PK/pharmacodynamic target attainment in >90% patients. Adverse events (AEs) were similar between cohorts. The most common AEs were hepatic enzyme increases [n = 9 (26.5%)] and diarrhoea [n = 5 (14.7%)]. Clinical cure rates at the test-of-cure visit overall were 20/34 (58.8%) (MITT) and 14/23 (60.9%) (microbiological-MITT population). CONCLUSIONS: Observed AEs were consistent with the known safety profile of aztreonam monotherapy, with no new safety concerns identified. These data support selection of the aztreonam/avibactam 500/167 mg (30 min infusion) loading dose and 1500/500 mg (3 h infusions) maintenance dose q6h regimen, in patients with creatinine clearance >50 mL/min, for the Phase 3 development programme.

A Phase 1, open-label, multicentre study to compare the capsule and tablet formulations of AZD5363 and explore the effect of food on the pharmacokinetic exposure, safety and tolerability of AZD5363 in patients with advanced solid malignancies: OAK.

PURPOSE: AZD5363 is a potent pan-AKT inhibitor originally formulated as a capsule; a tablet was developed for patient convenience and manufacturing ease. This study assessed the PK comparability of both formulations (Part A) and the effect of food (Part B) on the PK/safety of the tablet. METHODS: Adults with advanced solid tumours received AZD5363 480 mg bid in a partially fasted state by tablet (Week 1) and capsule (Week 2) in a '4-days-on/3-days-off' schedule (Part A). PK parameters were evaluated using pre-defined 90% CIs for AUCτ and Cmax ratios of 0.75-1.33 to assess comparability. In Part B, AZD5363 tablet was given to a new cohort of patients under the same conditions as Part A, except on the morning of PK assessment days, when it was administered after an overnight fast (Week 1) and standard meal (Week 2). RESULTS: In evaluable patients (N = 11), the geometric least-squares mean ratios (tablet:capsule) for AUCτ and Cmax were 0.90 (0.77-1.06) and 1.02 (0.86-1.20), respectively, demonstrating comparable PK in the partially fasted state. Tablet and capsule safety data were also comparable. Tablet PK profiles indicated later tmax and lower Cmax after food versus overnight fast. Fed and fasted AUCτ and Cmax ratios were 0.89 (0.76-1.05) and 0.67 (0.55-0.82), respectively (N = 9). The safety/tolerability profile of the tablet was comparable between fed and fasted states. CONCLUSIONS: PK and safety/tolerability of AZD5363 tablet and capsule were comparable. Food did not affect the bioavailability of AZD5363, but reduced the absorption rate without discernibly affecting safety/tolerability.