Complicated Urinary Tract Infections (cUTI), Including Pyelonephritis
A total of 545 adults with cUTI, including pyelonephritis were randomized into a double-blind, double dummy, multi-center trial comparing VABOMERE™ (meropenem 2 grams and vaborbactam 2 grams) to piperacillin/tazobactam (piperacillin 4 grams/tazobactam
0.5 grams) intravenously every 8 hours. Switch to an oral antibacterial drug, such as levofloxacin was allowed after a minimum of 15 doses of IV therapy.
The microbiologically modified intent to treat population (m-MITT) included all randomized patients who received any study drug and had at least 1 baseline uropathogen. Clinical and microbiological response at the end of IV treatment (EOIVT) required both a clinical outcome of cure or improvement and a microbiologic outcome of eradication (all baseline uropathogens at >105 CFU/mL are to be reduced to <104 CFU/mL). Clinical and microbiological response was also assessed at the Test of Cure (TOC) visit (approximately 7 days after completion of treatment) in the m-MITT population and required both a clinical outcome of cure and a microbiological outcome of eradication.
Patient demographic and baseline characteristics were balanced between treatment groups in the m-MITT population. Approximately 93% of patients were Caucasian and 66% were females in both treatment groups. The mean age was 54 years with 32% and 42% patients greater than 65 years of age in VABOMERE and piperacillin/tazobactam treatment groups, respectively. Mean body mass index was approximately 26.5 kg/m2 in both treatment groups. Concomitant bacteremia was identified in 12 (6%) and 15 (8%) patients at baseline in VABOMERE and piperacillin/tazobactam treatment groups respectively. The proportion of patients with diabetes mellitus at baseline was 17% and 19% in VABOMERE and piperacillin/tazobactam treatment groups, respectively. The majority of patients (approximately 90%) were enrolled from Europe, and approximately 2% of patients were enrolled from North America. Overall, in both treatment groups, 59% of patients had pyelonephritis and 40% had cUTI, with 21% and 19% of patients having a non-removable and removable source of infection, respectively.
Mean duration of IV treatment in both treatment groups was 8 days and mean total treatment duration (IV and oral) was 10 days; patients with baseline bacteremia could receive up to 14 days of therapy. Approximately 10% of patients in each treatment group in the m-MITT population had a levofloxacin-resistant pathogen at baseline and received levofloxacin as the oral switch therapy. This protocol violation may have impacted the assessment of the outcomes at the TOC visit. These patients were not excluded from the analysis presented in Table 6, as the decision to switch to oral levofloxacin was based on post-randomization factors.
VABOMERE demonstrated efficacy with regard to clinical and microbiological response at the EOIVT visit and TOC visits in the m-MITT population as shown below.
Table 6: Clinical and Microbiological Response Rates in a Phase 3 Trial of cUTI Including Pyelonephritis (m-MITT Population)
Tazobactam n/N (%)
|Clinical cure or improvement AND microbiological eradication at the End of
IV Treatment Visit*
|Clinical cure AND microbiological eradication at the Test of Cure visit aproximately
7 days after completetion of treatment†
CI = confidence interval; EOIVT = End of Intravenous Treatment; TOC = Test of Cure
*End of IV Treatment visit includes patients with organisms resistant to piperacillin/tazobactam at baseline.
†Test of Cure visit excludes patients with organisms resistant to piperacillin/tazobactam at baseline.
In the m-MITT population, the rate of clinical and microbiological response in VABOMERE-treated patients with concurrent bacteremia at baseline was 10/12 (83.3%).
In a subset of the E. coli and K. pneumoniae isolates, genotypic testing identified certain ESBL groups (eg, TEM, CTX-M, SHV and OXA) in both treatment groups of the Phase 3 cUTI trial. The rates of clinical and microbiological response were similar in the ESBL-positive and ESBL-negative subset at EOIVT; at TOC, clinical and microbiological response was lower in the ESBL-positive as compared with ESBL-negative subset in both treatment groups.
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Reference: 1. Vabomere [package insert]. Lincolnshire, IL: Melinta Therapeutics, Inc.; 2018.