Structured patient interview to assess clinical outcomes in complicated urinary tract infections in the APEKS-cUTI study: pilot investigation

Background

The APEKS-cUTI study demonstrated the non-inferiority of cefiderocol to imipenem-cilastatin in the primary endpoint of the composite of clinical and microbiological outcome in patients with complicated urinary tract infections (cUTIs). We piloted a structured patient interview (SPI) to evaluate clinical outcomes based on patient-reported symptoms while conducting this pivotal randomized, double-blind, phase-2 study. The objectives were to assess the value of the SPI, using its performance relative to physician assessment, and also to strengthen the value of patient-reported measures in conducting clinical trials for cUTI treatment.

Methods

In addition to the protocol-defined clinical and microbiological outcomes, patients randomized in the APEKS-cUTI study were interviewed by the investigator or qualified study personnel at screening/baseline, early assessment (EA), end of treatment (EOT), test of cure (TOC), and follow-up (FUP). The 14-element questionnaire graded cUTI symptoms as absent or present, and if present, as mild, moderate, or severe. Changes in post-baseline symptoms based on patients' responses were rated by the interviewer. The overall clinical outcome was evaluated based on the responses provided by patients at each time point.

Results

Among the 371 patients in the modified intention-to-treat population, the rate of SPI completion in each treatment arm exceeded 90% at each time point. SPI-assessed clinical cure rates were 89.7% in the cefiderocol arm and 84.9% in the imipenem-cilastatin arm. There was substantial agreement between SPI evaluation and investigator global assessment of clinical outcome at TOC and FUP, with lower agreement at EA and EOT.

Conclusion

This analysis suggests that patient-reported symptoms can be effectively captured in hospitalized patients with cUTI in a clinical trial setting. Development of a validated patient-reported outcome for use in such a setting is warranted.

Registration

NCT02321800 (registered on 22 December 2014).

1292. Safety Profile of the Novel Siderophore Cephalosporin Cefiderocol in Randomized Phase 2 and Phase 3 Clinical Studies of Serious Gram-Negative Infections

Background

Cefiderocol (CFDC), the first siderophore cephalosporin, is approved in the United States (complicated urinary tract infections [cUTI]) and Europe for the treatment of patients with Gram-negative (GN) infections with limited treatment options.

Methods

This analysis investigated the safety profile of CFDC across three prospective, multicenter, randomized clinical studies: APEKS-cUTI (double-blind, non-inferiority Phase 2 study in patients with cUTI) vs imipenem-cilastatin (1 g/1 g, three-times daily); APEKS-NP (double-blind, non-inferiority Phase 3 study in patients with nosocomial pneumonia [NP]) vs meropenem (2 g, q8h); CREDIBLE-CR (open-label, descriptive Phase 3 study in patients with cUTI, NP, bloodstream infections/sepsis [BSI/sepsis]) caused by carbapenem-resistant GN bacteria; patients in the control arm received best available therapy (BAT; up to 3 agents, dosing based on local label). CFDC was given at 2 g, q8h, infused over 1 (APEKS-cUTI) or 3 (APEKS-NP, CREDIBLE-CR) hours. One adjunctive agent with CFDC was only allowed in CREDIBLE-CR.

Results

549 patients were treated with CFDC, 347 control treated (Table 1). More than 50% of patients were aged ≥65 years, except BAT arm in CREDIBLE-CR. The majority of patients were admitted to the ICU in APEKS-NP and CREDIBLE-CR. The median treatment duration with CFDC was similar (9–11 days) across studies. The rates of TEAEs and serious AEs (SAEs) between CDFC and comparators were similar in each study (Table 2). The rates of adverse drug reactions were lower with CFDC than with comparators in each study, with a greater difference in CREDIBLE-CR than in APEKS-cUTI and APEKS-NP. TEAEs leading to death rates are shown in Table 2. Eight CFDC-related Clostridioides difficile infections occurred across studies (APEKS-cUTI: n=1; APEKS-NP: n=4; CREDIBLE-CR: n=3 [ie, C. difficile colitis; pseudomembranous colitis]). In total, eight experienced seizures (APEKS-cUTI: CFDC n=1; APEKS-NP: CFDC n=3, meropenem n=2; CREDIBLE-CR: CFDC n=1, BAT n=1), none of which were related to study drugs. Parameters of iron homeostasis showed no differences between CFDC and comparators.

Table 1. Baseline characteristics and treatment duration (safety populations)

Table 2. Overall safety parameters (safety populations)

Conclusion

CFDC demonstrated a comparable safety profile to carbapenems or other cephalosporins and was generally well tolerated in critically ill patients.

Disclosures

Yuko Matsunaga, MD, Shionogi Inc. (Employee) Takuhiro Sonoyama, MD, Shionogi & Co., Ltd. (Employee) Luis Casanova, PharmD, Shionogi B.V. (Employee) Tsutae Den Nagata, MD, Shionogi & Co., Ltd. (Employee) Roger Echols, MD, Shionogi Inc. (Consultant) Fabio De Gregorio, MD, Shionogi B.V. (Employee) Eriko Ogura, MD, Shionogi & Co., Ltd. (Employee) Simon Portsmouth, MD, Shionogi Inc. (Employee)

165. Cefiderocol Treatment for Serious Infections Caused by Carbapenem-resistant Bacteria: Post-hoc Analysis of Outcomes by Pathogen in the CREDIBLE-CR Study

Background

The efficacy and safety of cefiderocol (CFDC), a novel siderophore cephalosporin, for the treatment of serious infections due to carbapenem-resistant (CR) Gram-negative pathogens was assessed in the CREDIBLE-CR study. The current analysis evaluated clinical and microbiological outcomes by baseline CR pathogen.

Methods

An open-label, prospective, randomised 2:1, Phase 3 study (CREDIBLE-CR; NCT02714595) was conducted in adult patients with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia, bloodstream infections or sepsis, and complicated urinary tract infections caused by CR Gram-negative pathogens. Patients received either intravenous (IV) CFDC 2g, q8h, 3-h infusion, or IV best available therapy (BAT: up to 3 drugs in combination), for 7–14 days (extendable to 21 days). Clinical and microbiological outcomes were assessed in the CR microbiological intent-to-treat (CR-MITT) population by CR pathogen, baseline MIC and by mechanism of carbapenem resistance at test of cure (TOC). Only summary statistics were collected.

Results

In the CR-MITT population (CFDC N=80; BAT N=38), Acinetobacter baumannii (46.3% and 44.7%), Klebsiella pneumoniae (33.8% and 31.5%), and Pseudomonas aeruginosa (15% and 26%) were the most frequent pathogens in CFDC and BAT arms, respectively. For all CR pathogens, clinical cure rates were achieved in 52.5% in the CFDC arm and 50.0% in the BAT arm at TOC; rates were similar between treatment arms by baseline CR pathogen (Table 1). Numerically higher clinical cure and microbiological outcomes were observed with CFDC for Enterobacterales (Table 1), especially against NDM-producing bacteria or those with porin-channel mutations (Table 1). CFDC MIC values ranged between ≤0.03 and 4 μg/mL, except for one pathogen (Table 2). Microbiological outcomes for CR A. baumannii, CR K. pneumoniae, and CR P. aeruginosa at TOC by baseline MICs of ≤4 μg/mL ranged between 0–40%, 0–100%, and 0–100%, respectively; at MIC ≤4 μg/mL, clinical and microbiological outcomes were equal (Table 2).

Conclusion

CFDC, via a novel mechanism of entry and its stability against β-lactamases, was effective against serious infections caused by CR pathogens with various resistance mechanisms or baseline MIC values.

Disclosures

Yuko Matsunaga, MD, Shionogi Inc. (Employee) Mari Ariyasu, BPharm, Shionogi & Co., Ltd. (Employee) Miki Takemura, MSc, Shionogi & Co., Ltd. (Employee) Yoshinori Yamano, PhD, Shionogi & Co., Ltd. (Employee) Kiichiro Toyoizumi, PhD, Shionogi & Co., Ltd. (Employee) Masahiro Kinoshita, MPharm, Shionogi & Co., Ltd. (Employee) Roger Echols, MD, Shionogi Inc. (Consultant) Tsutae Den Nagata, MD, Shionogi & Co., Ltd. (Employee)

1271. Efficacy and Safety of Cefiderocol and Best Available Therapy in Patients with Serious Infections Caused by Carbapenem-Resistant Gram-Negative Infections: Results of the Pathogen-Focused Phase 3 CREDIBLE-CR Study

Background

The CREDIBLE-CR study assessed the efficacy and safety of cefiderocol (CFDC), a novel siderophore cephalosporin, in the treatment of serious infections due to carbapenem-resistant (CR) Gram-negative (GN) bacteria.

Methods

CREDIBLE-CR was an open-label, prospective, randomized 2:1, Phase 3 study (NCT02714595) in patients with nosocomial pneumonia (NP), bloodstream infections/sepsis (BSI/Sepsis), or complicated urinary tract infections (cUTI) with evidence of CR GN pathogens. Adults received intravenous CFDC 2 g, q8h, 3-h infusion or best available therapy (BAT; up to 3 drugs) for 7–14 days (extendable to 21 days). The primary endpoint at test of cure in the CR microbiological intent-to-treat (CR-MITT) population was clinical cure (NP, BSI/Sepsis) or microbiological eradication (cUTI). Secondary endpoints were clinical and microbiological outcomes, all-cause mortality (ACM) and safety. Only descriptive statistics were pre-specified.

Results

A total of 101 patients received CFDC and 49 received BAT (CR-MITT: CFDC n=80, BAT n=38): 50% had pneumonia, 31.4% BSI/Sepsis, and 18.6% cUTI (Table 1). Most frequent CR pathogens were Acinetobacter baumannii (45.8%), Klebsiella pneumoniae (37.3%), and Pseudomonas aeruginosa (23.7%). CFDC monotherapy was given to 83% of patients, while BAT monotherapy to 29% of patients. Primary outcome in the CFDC and BAT arms was achieved in 50.0% and 52.6% in NP, 43.5% and 42.9% in BSI/Sepsis, and 52.9% and 20.0% in cUTI patients (Figure). CFDC was highly efficacious vs CREs and NDM-producing pathogens. Day 28 ACM was 24.8% (25/101) with CFDC and 18.4% (9/49) with BAT. Rescue therapy was given more frequently in the BAT than CFDC arm. Mortality results by pathogen showed an imbalance in Acinetobacter spp. infections (Table 2) with a higher rate in the CFDC arm than BAT arm. ICU and shock at randomization were more frequent in the CFDC arm than in the BAT arm in Acinetobacter spp. infections (Table 2). No safety concerns related to CFDC emerged.

Table 1. Baseline demographics and characteristics (CR-MITT population)

Conclusion

Efficacy of CFDC was demonstrated in this descriptive pathogen-focused study, including CREs, metallo-NDM producers and CR non-fermenters. Baseline imbalances of ICU and shock in the subset of infections with Acinetobacter spp. may have contributed to the mortality difference between CFDC and BAT arms.

Disclosures

Matteo Bassetti, MD, Shionogi Inc. (Advisor or Review Panel member) Roger Echols, MD, Shionogi Inc. (Consultant) Yuko Matsunaga, MD, Shionogi Inc. (Employee) Simon Portsmouth, MD, Shionogi Inc. (Employee) Mari Ariyasu, BPharm, Shionogi & Co., Ltd. (Employee) Kiichiro Toyoizumi, PhD, Shionogi & Co., Ltd. (Employee) Tsutae Den Nagata, MD, Shionogi & Co., Ltd. (Employee)

1266. Characterization of Shifts in Minimum Inhibitory Concentrations During Treatment with Cefiderocol or Comparators in the Phase 3 CREDIBLE-CR and APEKS-NP Studies

Background

Cefiderocol (CFDC) is a novel siderophore cephalosporin developed to treat serious carbapenem-resistant (CR) Gram-negative (GN) infections.

Methods

In CREDIBLE-CR (NCT02714595), adults with serious infections caused by CR GN pathogens received CFDC 2 g, q8h, 3-h infusion, or best available therapy (BAT). In APEKS-NP (NCT03032380), adults with nosocomial pneumonia received CFDC or high-dose, extended-infusion meropenem (each 2 g, q8h, 3-h infusion). All treatments were given for 7‒14 days (extendable to 21 days). Biospecimens were collected before the first dose of study drug and at subsequent visits for assessments, and minimum inhibitory concentrations (MIC) to various antibiotics, including CFDC and carbapenems, were determined. Isolates with an increased MIC were evaluated by RT-PCR or whole genome sequencing (WGS) for CFDC resistance-related genes or mutations. Results for genetically related isolates with an elevated MIC during therapy are shown.

Results

On-therapy ≥4-fold CFDC MIC increase was found in 12 out of 106 (CREDIBLE-CR; Table 1) and 7 out of 159 (APEKS-NP; Table 2) isolates, respectively. For most isolates, CFDC MIC increased by 4–8-fold but remained ≤4 µg/mL. Specific mutations which could explain CFDC MIC increases were found in only 3 isolates. Mutations in iron-transport related genes were not identified. Mutation in CFDC target gene PBP-3 was identified in 1 A. baumannii isolate. Class-C enzyme mutation was observed in 2 isolates (CREDIBLE-CR: PDC-30 in P. aeruginosa; APEKS-NP: ACT-17 in E. cloacae), although the contribution to CFDC MIC increase has not been confirmed. In the BAT arm in CREDIBLE-CR, 6 out of 46 isolates had ≥4-fold MIC increase; all post-treatment isolates were resistant to BAT agents (Table 1), although WGS was not conducted for these isolates. In the meropenem arm in APEKS-NP, 5 out of 164 isolates had ≥4-fold MIC increase (Table 2).

Table 1. MIC changes in CREDIBLE-CR

Conclusion

Among isolates with ≥4-fold MIC increase during CFDC treatment, actual CFDC MIC values remained relatively low for most isolates. Frequency of MIC increase in BAT or meropenem arms was similar to that of CFDC, but the magnitude was greater. Acquisition of contributory mechanism has not been identified except for the mutation in PBP 3 and some β-lactamases.

Disclosures

Miki Takemura, MSc, Shionogi & Co., Ltd. (Employee) Yoshinori Yamano, PhD, Shionogi & Co., Ltd. (Employee) Yuko Matsunaga, MD, Shionogi Inc. (Employee) Mari Ariyasu, BPharm, Shionogi & Co., Ltd. (Employee) Roger Echols, MD, Shionogi Inc. (Consultant) Tsutae Den Nagata, MD, Shionogi & Co., Ltd. (Employee)

1316. Pharmacokinetic/Pharmacodynamic Analyses of Cefiderocol in Critically Ill Patients

Background

Cefiderocol (CFDC), a novel siderophore cephalosporin, has demonstrated potent antibacterial activity against a wide range of Gram-negative bacteria including carbapenem-resistant strains. We aimed to evaluate relationships between drug exposure and outcomes in critically ill patients.

Methods

Sparse pharmacokinetic (PK) samples at steady state from critically ill patients with pneumonia, bloodstream infection/sepsis, or complicated urinary tract infection receiving CFDC in two Phase 3 studies were analyzed. Percent time of dosing interval of free drug concentration exceeding the minimum inhibitory concentration (MIC) in plasma and epithelial lining fluid (ELF) (%fT>MIC and %fT>MIC,ELF, respectively) were determined for 60 (CREDIBLE-CR; NCT02714595) and 97 patients (APEKS-NP; NCT03032380), using a 3-compartment population PK model. The %fT>MIC,ELF was calculated for 125 pneumonia patients based on an intrapulmonary PK model. Relationships between %fT>MIC, %fT>MIC,ELF and clinical and microbiological outcomes at test of cure (TOC), or mortality at Day 28 were assessed.

Results

The median (90th percentile) MICs of Gram-negative pathogens in the PK/pharmacodynamic (PD) analyses were 0.25 (4) µg/mL (CREDIBLE-CR) and 0.25 (2) µg/mL (APEKS-NP), respectively. Individual plasma %fT>MIC was 100% in ≥95% of patients in each study, and estimated %fT>MIC,ELF was 100% in 89.3% (25/28 pneumonia patients; CREDIBLE-CR) and 97.9% (95/97 pneumonia patients; APEKS-NP). Clinical cure rates and survival rates in patients with 100% fT>MIC or %fT>MIC,ELF were similar between the two studies (Table). No PK/PD relationships between %fT>MIC, %fT>MIC,ELF and clinical cure, microbiological eradication, or survival were identified in either study because high %fT>MIC or %fT>MIC,ELF was achieved in all patients.

Table. Clinical cure and survival rates in patients with 100% fT>MIC or %fT>MIC,ELF in CREDIBLE-CR and APEKS-NP studies

Conclusion

PK/PD relationship was not identified between CFDC plasma or ELF exposure and clinical or microbiological outcomes, or mortality as high %fT>MIC and %fT>MIC,ELF were achieved, suggesting the recommended dosing regimen of 2 g q8h or renally adjusted dosage (including augmented renal clearance), infused over 3 hours, provides sufficient exposure to CFDC in critically ill patients.

Disclosures

Takayuki Katsube, PhD, Shionogi & Co., Ltd. (Employee) Nao Kawaguchi, BPharm, Shionogi & Co., Ltd. (Employee) Yuko Matsunaga, MD, Shionogi Inc. (Employee) Mari Ariyasu, BPharm, Shionogi & Co., Ltd. (Employee) Tsutae Den Nagata, MD, Shionogi & Co., Ltd. (Employee) Simon Portsmouth, MD, Shionogi Inc. (Employee) David Paterson, Accelerate (Speaker’s Bureau)BioMerieux (Speaker’s Bureau)BioMerieux (Advisor or Review Panel member)Entasis (Advisor or Review Panel member)Merck (Advisor or Review Panel member)Merck (Grant/Research Support)Merck (Speaker’s Bureau)Pfizer (Speaker’s Bureau)Shionogi & Co., Ltd. (Grant/Research Support)VenatoRx (Advisor or Review Panel member) Michael J. Satlin, MD, MS, Achaogen (Consultant)Allergan (Grant/Research Support)Merck (Grant/Research Support)Shionogi Inc. (Consultant) Roger Echols, MD, Shionogi Inc. (Consultant) Toshihiro Wajima, PhD, Shionogi & Co., Ltd. (Employee)

Designing A Pathogen-Focused Study To Address The High Unmet Medical Need Represented By Carbapenem-Resistant Gram-Negative Pathogens - The International, Multicenter, Randomized, Open-Label, Phase 3 CREDIBLE-CR Study

Carbapenem-resistant (CR) Gram-negative infections, including those caused by Enterobacteriaceae and the non-fermenters, represent the greatest unmet need for new effective treatments. The clinical development of new antibiotics for the treatment of CR infections is challenging and should focus on the individual pathogens irrespective of the infection site. However, the drug approval pathway is generally infection-site specific and rarely includes such drug-resistant pathogens. To overcome this limitation, a streamlined clinical development program may include a pathogen-focused clinical study, such as the CREDIBLE-CR study, to meet the expectations of some health authorities (ie, the European Medicines Agency [EMA]) and the medical community. Cefiderocol is a novel siderophore cephalosporin designed to target CR pathogens, including CR strains of Enterobacteriaceae (CRE), Pseudomonas aeruginosa, Acinetobacter baumannii, and also Stenotrophomonas maltophilia, which is intrinsically CR. The CREDIBLE-CR study was planned to evaluate cefiderocol in patients with CR Gram-negative infections regardless of species or infection-site source. Rapid diagnostic testing and/or selective media were provided to facilitate detection of CR pathogens to rapidly enroll patients with nosocomial pneumonia, bloodstream infection/sepsis, or complicated urinary tract infection. Patients were randomized 2:1 to receive cefiderocol or best available therapy. There were no pre-specified statistical hypotheses for this study, as the sample size was driven by enrollment feasibility and not based on statistical power calculations. The objective of the CREDIBLE-CR study was to provide descriptive evidence of the efficacy and safety of cefiderocol for the target population of patients with CR infections, including the non-fermenters. The CREDIBLE-CR study is currently the largest pathogen-focused, randomized, open-label, prospective, Phase 3 clinical study to investigate a new antibiotic in patients with CR Gram-negative infections. Here we describe the design of this pathogen-focused study and steps taken to aid patient enrollment into the study within an evolving regulatory environment.

Pathogen-focused Clinical Development to Address Unmet Medical Need: Cefiderocol Targeting Carbapenem Resistance

Historically, the regulatory requirements of the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for developing new antibiotics have not addressed pathogen-focused indications for drug approval. The design of the necessary randomized controlled trials traditionally involves the enrollment of patients with site-specific infections caused by susceptible as well as resistant pathogens. Cefiderocol has undergone a streamlined clinical development program to address serious carbapenem-resistant infections. The regulatory approach, and the pivotal clinical trials, differed between the FDA and EMA. In the United States, the APEKS-cUTI (Acinetobacter, Pseudomonas, Escherichia coli, Klebsiella, Stenotrophomonas-complicated urinary tract infection) study was conducted to provide the basis for FDA approval of a site-specific cUTI indication. The EMA, however, preferred the CREDIBLE-CR (A MultiCenter, RandomizED, Open-label ClInical Study of S-649266 or Best AvailabLE Therapy for the Treatment of Severe Infections Caused by Carbapenem-Resistant Gram-negative Pathogens) study, in which patients with nosocomial pneumonia, bloodstream infections, or cUTIs were enrolled if they had a carbapenem-resistant pathogen. The resulting European label will be pathogen focused rather than infection site specific (ie, treatment of gram-negative infection in patients with limited treatment options). The implications and limitations of these different regulatory processes are discussed.

LB4. Efficacy and Safety of Cefiderocol vs. High-Dose Meropenem in Patients with Nosocomial Pneumonia—Results of a Phase 3, Randomized, Multicenter, Double-Blind, Non-Inferiority Study

Background

Cefiderocol (CFDC) is a novel siderophore cephalosporin with activity against a broad range of Gram-negative bacteria. In this study, Day 14 all-cause mortality (ACM) rates were compared between CFDC and meropenem (MEM) in patients with nosocomial Gram-negative pneumonia.

Methods

The study (NCT03032380) was a Phase 3, international, double-blind, randomized, non-inferiority study in hospitalized patients with ventilator-associated, hospital-acquired, or healthcare-associated pneumonia caused by suspected Gram-negative bacteria. Patients were treated with CFDC (2 g, q8h) or MEM (2 g, q8h), both infused for 3 hours, for 7–14 days. Adjunctive linezolid (600 mg, q12h, ≥5 days) was given in both arms to cover Gram-positive bacteria. The primary endpoint was non-inferiority of CFDC to MEM for Day 14 ACM rate in the modified intent-to-treat population (mITT; non-inferiority margin: –12.5%). Key secondary endpoints were clinical and microbiological outcomes at test of cure (TOC), and Day 28 mortality. Safety was investigated up to 28 days after the end of treatment.

Results

In the ITT population, 148 patients were randomized to CFDC and 150 to MEM: 59.7% were ventilated, 32.6% had failure of prior therapy, the median APACHE II score was 15, and 6.0% had concomitant Gram-negative bacteremia at baseline. In the mITT population, non-inferiority of CFDC to MEM for Day 14 ACM was demonstrated; CFDC: 12.4% (18 out of 145 patients) vs. MEM: 11.6% (17 out of 146 patients); treatment difference: 0.8; 95% confidence interval: –6.6; 8.2. Comparable Day 28 ACM (CFDC: 21.0% vs. MEM: 20.5%), clinical cure (CFDC: 64.8% vs. MEM: 66.7%), and microbiological eradication (CFDC: 47.6% vs. MEM: 48.0%) rates were demonstrated in the mITT population at TOC. Clinical cure rates for major target pathogens at TOC were similar between CFDC and MEM arms (figure). The rates of treatment-emergent adverse events (TEAEs), drug-related TEAEs, serious AEs, discontinuation due to TEAEs, and deaths were similar between treatment arms (table).

Conclusion

This study demonstrated the non-inferiority of CFDC to high-dose MEM for the pre-specified endpoint of Day 14 ACM. No unexpected safety signals were observed in the study.

Disclosures

Richard G. Wunderink, MD, Merck (Consultant, Grant/Research Support), Shionogi Inc. (Consultant), Yuko Matsunaga, MD, Shionogi Inc. (Employee), Mari Ariyasu, BPharm, Shionogi & Co., Ltd. (Employee), Roger Echols, MD, Shionogi Inc. (Consultant), Anju Menon, PhD, Shionogi Inc. (Employee), Tsutae Den Nagata, MD, Shionogi & Co., Ltd. (Employee).

1473. Structured Patient Interview in Complicated Urinary Tract Infections to Assess Clinical Outcomes vs. Investigator’s Evaluation in the APEKS-cUTI Study

Background

Based on the 2009 US FDA guidance, patient-reported outcome (PRO) measures are recommended in clinical study designs for certain indications to evaluate response to therapy from the patient’s perspective, and a PRO was recommended in the final complicated urinary tract infection (cUTI) guidance in 2014. Several PRO tools have been rigorously validated, but currently, no tool exists for evaluating cUTI. We included a “structured patient interview (SPI)“ while conducting a randomized, double-blind, study (NCT02321800) investigating cefiderocol (CFDC) vs. imipenem–cilastatin (IPM/CS) in cUTI patients to support the physician’s assessment of clinical response.

Methods

Patients, who were fully alert and oriented, were interviewed at randomization, end of treatment, test of cure (TOC), and follow-up (FUP) by the same interviewer. The questionnaire identified the presence or absence of relevant symptoms pertinent to cUTI. Responses were graded as none, or if present, mild, moderate, or severe. Investigator assessment included objective measures of clinical outcome(s) and was performed independently from the patient-reported symptoms collected in the SPI. Changes in the patient’s responses were compared with the investigator’s assessment at randomization and at each study visit. A kappa correlation coefficient comparing the SPI and physician’s clinical assessment was calculated at each evaluation time point.

Results

Based on investigator assessment, 89.7% (226 out of 252 patients) in the CFDC arm and 87.4% (104 out of 119 patients) in the IPM/CS arm achieved clinical cure (adjusted treatment difference: 2.39%; 95% CI: –4.66; 9.44) at TOC. Based on the SPI responses, 89.7% (226 out of 252 patients) in the CFDC arm and 84.9% (101 out of 119 patients) in the IPM/CS arm achieved clinical cure (adjusted treatment difference: 4.96%; 95% CI: –2.48; 12.39) in favor of CFDC. The correlation between SPI evaluation and physician’s assessment of clinical outcomes was very high at TOC and FUP visits (Kappa coefficients: 0.820 and 0.766, respectively).

Conclusion

The strong correlation between patients’ reported symptoms collected in the SPI and investigator assessment showed that SPI responses could be a useful alternative measure of clinical outcomes in cUTI studies.

Disclosures

All authors: No reported disclosures.

666. Efficacy and Safety of Cefiderocol According to Renal Impairment in Patients With Complicated Urinary Tract Infection (cUTI) in a Phase 2 Study

Background

Cefiderocol, a novel siderophore cephalosporin with broad activity against Gram-negative bacteria, requires dose adjustment in patients with renal impairment or augmented renal clearance, similarly to other β-lactams. The efficacy and safety of cefiderocol were assessed according to degree of renal impairment as part of a pivotal study vs. imipenem–cilastatin (IPM/CS) in patients with cUTI (NCT02321800).

Methods

A total of 448 randomized adults with cUTI received cefiderocol (2 g) or IPM/CS (1 g / 1 g), IV, q8h, for 7–14 days (safety population), with 371 patients in the microbiological intent-to-treat (Micro-ITT) population. Dose adjustments were made based on body weight (to enable IPM/CS blinding) and creatinine clearance (CrCL). The composite (clinical and microbiological) outcome at a test of cure (TOC; 7 days after treatment cessation) was analyzed by CrCL subgroup. Adverse events (AEs) according to renal subgroup were monitored throughout the study.

Results

A treatment difference in the composite outcome at TOC in favor of cefiderocol vs. IPM/CS was observed across renal subgroups (table), with greater differences in moderate and severe groups, consistent with that observed in the overall population (n = 371; 18.0%, 95% confidence interval: 7.5; 28.5). The incidence of AEs in the cefiderocol group was comparable across all renal subgroups. Conversely, AE incidence increased with the degree of impairment in the IPM/CS group (table).

Conclusion

In contrast to IPM/CS, the efficacy of cefiderocol was maintained across all renal function subgroups with no increase in the rate of AEs. These findings underscore the efficacy and safety of cefiderocol in patients with renal impairment and support the adequacy of the dose adjustment.

Disclosures

All authors: No reported disclosures.

Effect of Cefiderocol, a Siderophore Cephalosporin, on QT/QTc Interval in Healthy Adult Subjects

PURPOSE

Cefiderocol is a novel siderophore cephalosporin with potent activity against gram-negative bacteria, including multidrug-resistant strains. This Phase I study was conducted to assess the tolerability of single-ascending doses of cefiderocol (part 1) and the effect of cefiderocol on cardiac repolarization, assessed using the electrocardiographic corrected QT interval (QTcF) and other ECG parameters (part 2), in healthy adult subjects.

METHODS

Part 1 was a randomized, double-blind, placebo-controlled, single-ascending dose study in healthy adult male and female subjects. Part 2 was a 4-period crossover study in which subjects received a single 2-g dose of cefiderocol (therapeutic dose), a single 4-g dose of cefiderocol (supratherapeutic dose), or saline (placebo), each infused over 3 hours, and a single oral 400-mg dose of moxifloxacin. In each treatment period, continuous cardiac monitoring was used to assess the effects of cefiderocol on ECG parameters. The QT interval corrected using the Fridericia formula (QTcF) was the primary ECG parameter; the time-matched placebo- and baseline-adjusted (dd)-QTcF interval was the primary end point. The plasma pharmacokinetic properties of cefiderocol were calculated on the basis of concentration-time profiles in all evaluable subjects.

FINDINGS

All point estimates for the ddQTcF interval were <5 ms and the upper bound of the 90% CIs were <10 ms at each timepoint after the initiation of the cefiderocol 3-hour infusion. Concentration-effect modeling showed a slightly negative slope and predicted modestly negative values of the ddQTcF interval at the Cmax of cefiderocol. Both doses of cefiderocol were well tolerated. All adverse events were mild in severity, with no deaths or serious adverse events reported.

IMPLICATIONS

Overall, therapeutic and supratherapeutic doses of cefiderocol had no apparent clinically significant effect on the QTcF.

Compassionate Use of Cefiderocol as Adjunctive Treatment of Native Aortic Valve Endocarditis Due to Extremely Drug-resistant Pseudomonas aeruginosa

Serious infections such as endocarditis due to extremely drug-resistance gram-negative bacteria are an increasing challenge. Here, we present successful adjunctive use of cefiderocol for a patient with persistently bacteremic healthcare-associated native aortic valve endocarditis due to an extended-spectrum beta-lactamase-positive Pseudomonas aeruginosa susceptible in vitro only to colistin, following failure of conventional therapeutic options.

Cefiderocol versus imipenem-cilastatin for the treatment of complicated urinary tract infections caused by Gram-negative uropathogens: a phase 2, randomised, double-blind, non-inferiority trial

BACKGROUND

Carbapenem-resistant Gram-negative bacteria represent the highest priority for addressing global antibiotic resistance. Cefiderocol (S-649266), a new siderophore cephalosporin, has broad activity against Enterobacteriaceae and non-fermenting bacteria, such as Pseudomonas aeruginosa and Acinetobacter baumannii, including carbapenem-resistant strains. We assessed the efficacy and safety of cefiderocol versus imipenem-cilastatin for the treatment of complicated urinary tract infection in patients at risk of multidrug-resistant Gram-negative infections.

METHODS

We did a phase 2, multicentre, double-blind, parallel-group non-inferiority trial at 67 hospitals in 15 countries. Adults (≥18 years) admitted to hospital with a clinical diagnosis of complicated urinary tract infection with or without pyelonephritis or those with acute uncomplicated pyelonephritis were randomly assigned (2:1) by an interactive web or voice response system to receive 1 h intravenous infusions of cefiderocol (2 g) or imipenem-cilastatin (1 g each) three times daily, every 8 h for 7-14 days. Patients were excluded if they had a baseline urine culture with more than two uropathogens, a fungal urinary tract infection, or pathogens known to be carbapenem resistant. The primary endpoint was the composite of clinical and microbiological outcomes at test of cure (ie, 7 days after treatment cessation), which was used to establish non-inferiority (15% and 20% margins) of cefiderocol versus imipenem-cilastatin. The primary efficacy analysis was done on a modified intention-to-treat population, which included all randomly assigned individuals who received at least one dose of study drug and had a qualifying Gram-negative uropathogen (≥1 × 105 colony-forming units [CFU]/mL). Safety was assessed in all randomly assigned individuals who received at least one dose of study drug, according to the treatment they received. This study is registered with ClinicalTrials.gov, number NCT02321800.

FINDINGS

Between Feb 5, 2015, and Aug 16, 2016, 452 patients were randomly assigned to cefiderocol (n=303) or imipenem-cilastatin (n=149), of whom 448 patients (n=300 in the cefiderocol group; n=148 in the imipenem-cilastatin group) received treatment. 371 patients (n=252 patients in the cefiderocol group; n=119 patients in the imipenem-cilastatin group) had qualifying Gram-negative uropathogen (≥1 × 105 CFU/mL) and were included in the primary efficacy analysis. At test of cure, the primary efficacy endpoint was achieved by 183 (73%) of 252 patients in the cefiderocol group and 65 (55%) of 119 patients in the imipenem-cilastatin group, with an adjusted treatment difference of 18·58% (95% CI 8·23-28·92; p=0·0004), establishing the non-inferiority of cefiderocol. Cefiderocol was well tolerated. Adverse events occurred in 122 (41%) of 300 patients in the cefiderocol group and 76 (51%) of 148 patients in the imipenem-cilastatin group, with gastrointestinal disorders (ie, diarrhoea, constipation, nausea, vomiting, and abdominal pain) the most common adverse events for both treatment groups (35 [12%] patients in the cefiderocol group and 27 [18%] patients in the imipenem-cilastatin group).

INTERPRETATION

Intravenous infusion of cefiderocol (2 g) three times daily was non-inferior compared with imipenem-cilastatin (1 g each) for the treatment of complicated urinary tract infection in people with multidrug-resistant Gram-negative infections. The results of this study will provide the basis for submission of a New Drug Application to the US Food and Drug Administration. Clinical trials of hospital-acquired pneumonia and carbapenem-resistant infections are ongoing.

FUNDING

Shionogi & Co Ltd, Shionogi Inc.

Prevalence of Carbapenem-Resistant Gram-Negative Infections in the United States Predominated by Acinetobacter baumannii and Pseudomonas aeruginosa

Background

Carbapenem-resistant (CR) Gram-negative pathogens are recognized as a major health concern. This study examined the prevalence of infections due to 4 CR Gram-negative species (Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli) in the United States and assessed their impact on hospital stays and mortality.

Methods

Hospitalized patients with laboratory-confirmed infection due to any of the 4 Gram-negative pathogens were identified from the Premier Healthcare Database. Proportions of CR were calculated by pathogen and infection site (blood, respiratory, urinary, or other) for the United States as whole and by census regions. Crude and adjusted odds ratios for in-hospital mortality were produced using logistic regression.

Results

From 2009 to 2013, 13 262 (4.5%) of 292 742 infections due to these 4 Gram-negative pathogens were CR. Of these CR infections, 82.3% were caused by A. baumannii (22%) or P. aeruginosa (60.3%), while 17.7% were caused by K. pneumoniae or E. coli. CR patients had longer hospital stays than carbapenem-susceptible (CS) patients in all pathogen-infection site cohorts, except in the A. baumannii-respiratory cohort. The crude all cause in-hospital mortality was greater for most pathogen-infection site cohorts of the CR group compared with the CS group, especially for A. baumannii infection in the blood (crude odds ratio [OR], 3.91; 95% confidence interval [CI], 2.69–5.70). This difference for the A. baumannii-blood cohort remained after adjusting for the relevant covariates (adjusted OR, 2.46; 95% CI, 1.43–4.22).

Conclusion

The majority of CR infections and disease burden in the United States was caused by nonfermenters A. baumannii and P. aeruginosa. Patients with CR infections had longer hospital stays and higher crude in-hospital mortality.