1573. Efficacy of Ceftolozane/tazobactam Versus Levofloxacin in the Treatment of Complicated Pyelonephritis: Results from the Phase 3 ASPECT-cUTI Trial
Session: Poster Abstract Session: Clinical Infectious Diseases: UTIs
Saturday, October 10, 2015
Room: Poster Hall
  • 101102101_Efficacy_cUTI_L2c.pdf (378.9 kB)
  • Background : Complicated pyelonephritis can be life-threatening. The objective of this post hoc analysis was to evaluate the efficacy of ceftolozane/tazobactam (C/T) vs levofloxacin (LVX) in the subset of patients with complicated pyelonephritis in a global phase 3 program.

    Methods: Hospitalized patients ≥18 years with complicated lower urinary tract infections or pyelonephritis were randomized to IV C/T 1.5 g q8h or IV LVX 750 mg/d for 7 days. Patients with complicated (ie, infection in the presence of an indwelling catheter or structural or functional urinary tract abnormality) or uncomplicated pyelonephritis were eligible. Primary outcome was composite cure (microbiological eradication and clinical cure) at the test-of‐cure (TOC) visit 5‐9 days post‑therapy in the microbiological modified intent‐to‐treat (mMITT) and microbiologically evaluable (ME) populations.

    Results : 656 of 800 (82%) patients in the mMITT population had pyelonephritis; 115 of 656 (17.5%) occurred in the presence of a complicating factor.  Median age of patients with complicated pyelonephritis was 60 y (range 18-86), 39% were aged ≥65 y and 41% had renal impairment. LVX-resistant baseline uropathogens were isolated in 17/58 (29.3%) and 20/57 (35.1%) patients in the C/T and LVX treatment arms, respectively. C/T demonstrated comparable composite cure rates to LVX in the mMITT and ME populations (Table). Clinical cure rates were high in both treatment groups at the TOC visit.  Microbiological eradication rates were lower than clinical cure rates, suggesting that the microbiological failures were cases of asymptomatic bacteriuria and/or colonization.

    Conclusion: These data demonstrate that C/T has comparable outcomes to LVX, offering a new treatment option for patients with complicated pyelonephritis.


    Outcomes at

    TOC in patients with complicated pyelonephritis



    % (n/N)


    % (n/N)

    % Difference


    Clinical cure


    87.9 (51/58)

    89.5 (51/57)

    -1.5 (-13.7 to 10.7)


    93.6 (44/47)

    93.9 (46/49)

    -0.3 (-11.8 to 11.0)

    Microbiological eradication


    65.5 (38/58)

    61.4 (35/57)

    4.1 (-13.2 to 21.1)


    70.2 (33/47)

    67.3 (33/49)

    2.9 (-15.4 to 20.7)

    Composite cure


    58.6 (34/58)

    57.9 (33/57)

    0.7 (-16.8 to 18.2)


    63.8 (30/47)

    65.3 (32/49)

    -1.5 (-20.0 to 17.1)

    Daniel Cloutier, PharmD1, Loren Miller, MD, MPH2, Jennifer Huntington, PharmD1, Brian Yu, PharmD1, Calib Bliss, PhD1, Eliana Armstrong, PhD1, Judith Steenbergen, PhD1 and Florian Wagenlehner, MD3, (1)Merck and Co., Inc., Kenilworth, NJ, (2)Division of Infectious Diseases, Harbor-UCLA Medical Center, Torrance, CA, (3)Clinic for Urology, Pediatric Urology and Andrology, Giessen, Germany


    D. Cloutier, Merck and Co., Inc.: Employee , Salary

    L. Miller, Merck and Co., Inc.: Consultant , Consulting fee

    J. Huntington, Merck and Co, Inc.: Employee , Salary

    B. Yu, Merck and Co., Inc.: Employee , Salary

    C. Bliss, Merck and Co., Inc.: Employee , Salary

    E. Armstrong, Merck and Co., Inc.: Consultant , Consulting fee

    J. Steenbergen, Merck and Co., Inc.: Employee , Salary

    F. Wagenlehner, Merck and Co., Inc.: Speaker's Bureau , Speaker honorarium

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 7th with the exception of research findings presented at the IDWeek press conferences.