IDWEEK 2016 Activity of Dalbavancin Tested against Gram-positive Clinical Isolates Causing Skin For more information, please contact: 1835 Rodrigo E. Mendes, PhD and Skin Structure Infections in Pediatric Patients from USA Hospitals (2014 - 2015) JMI Laboratories [email protected] RE Mendes, HS Sader, MA Pfaller, M Castanheira, RK Flamm JMI Laboratories, North Liberty, IA, USA ABSTRACT INTRODUCTION RESULTS Table 2. Antimicrobial activity of dalbavancin and comparator agents against contemporary Gram-positive isolates causing SSSIs in children in the USA. CONCLUSIONS Background Dalbavancin was approved in the United States (USA; 2014) and Europe (2015) • Dalbavancin had MIC50/90 values of 0.03/0.06 μg/mL against S. aureus and CoNS, including the Organism/Groupa (no.) MIC (μg/mL): • Approved agents available for treatment of ABSSSI in children for the treatment of adults with acute bacterial skin and skin structure infections MRSA and MSSA subsets (Table 1). When tested against MRSA, dalbavancin MIC results were 8- to %Susceptible/%Intermediate/%Resistantc: Dalbavancin is approved for the treatment of acute bacterial skin Antimicrobial agentb MIC50 MIC90 Range are limited. Staphylococcal isolates comprised the majority of (ABSSSI) caused by susceptible isolates of Staphylococcus aureus, including 32-fold lower than those of daptomycin (MIC50/90, 0.25/0.5 μg/mL), vancomycin (MIC50/90, 0.5/1 μg/mL) and skin structure infections (ABSSSI) in adults. Current trials will MSSA (455) pathogens responsible for SSSI in children in the USA and a methicillin-susceptible (MSSA) and -resistant (MRSA) S. aureus, Streptococcus and linezolid (MIC50/90, 1/1 μg/mL; Table 2). Dalbavancin 0.03 0.06 0.008 — 0.12 100.0 - - further define dalbavancin therapeutic use, including for the Clindamycin ≤0.25 ≤0.25 ≤0.25 — >2 97.4 0.0 2.6 great proportion of these organisms were oxacillin-resistant pyogenes, Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus All tested agents showed in vitro activity against MSSA and MRSA (92.7 - 100.0% susceptible), Daptomycin 0.25 0.5 ≤0.12 — 1 100.0 - - treatment of ABSSSI in pediatric patients. This study provides an • (41.7%). anginosus group and vancomycin-susceptible Enterococcus faecalis. except for erythromycin (72.9% susceptible) against MSSA, and erythromycin (17.1% susceptible) Erythromycin 0.25 >8 ≤0.12 — >8 72.9 5.1 22.0 in vitro analysis of dalbavancin activity against isolates causing Levofloxacin ≤0.12 0.25 ≤0.12 — >4 94.7 0.0 5.3 Dalbavancin allows for very convenient administrations, which can be a single and levofloxacin (46.7% susceptible) against MRSA (Table 2). Linezolid 1 1 0.25 — 2 100.0 - 0.0 SSSI in children. • Dalbavancin demonstrated potent in vitro activity against these dose of 1500 mg or a dose of 1000 mg followed by 500 mg a week later. Tetracycline ≤0.5 ≤0.5 ≤0.5 — >8 94.7 0.2 5.1 • A total of 42.9% of CoNS isolates were oxacillin-resistant (Table 2). Dalbavancin MIC results were 8- TMP-SMX ≤0.5 ≤0.5 ≤0.5 — >4 99.6 - 0.4 Gram-positive isolates causing SSSI in children, and all Methods Moreover, current trials will further define dalbavancin therapeutic use, including Vancomycin 0.5 1 ≤0.12 — 1 100.0 0.0 0.0 to 16-fold lower than those of daptomycin (MIC50/90, 0.25/0.5 μg/mL), levofloxacin (MIC50/90, 0.25/1 MRSA (315) indicated species were susceptible to dalbavancin when for the treatment of ABSSSI in pediatric patients. Dalbavancin 0.03 0.06 0.008 — 0.06 100.0 - - 770 S. aureus, 167 β-hemolytic streptococci (BHS), 42 coagulase- μg/mL) and linezolid (MIC50/90, 0.5/1 μg/mL) against CoNS. Moreover, dalbavancin was 32-fold more applying the FDA breakpoints. Clindamycin ≤0.25 ≤0.25 ≤0.25 — >2 92.7 0.3 7.0 negative staphylococci (CoNS), 25 E. faecalis and 13 viridans active than vancomycin (MIC50/90, 1/2 μg/mL; Table 2). During pre-clinical development, dalbavancin has demonstrated potent in vitro Daptomycin 0.25 0.5 ≤0.12 — 1 100.0 - - group streptococci (VGS) causing SSSI were collected from Erythromycin >8 >8 ≤0.12 — >8 17.1 2.5 80.3 • These data warrant further development of dalbavancin for All E. faecalis isolates were inhibited by dalbavancin (MIC , 0.03/0.06 μg/mL) at ≤0.06 μg/mL, Levofloxacin 4 >4 ≤0.12 — >4 46.7 1.3 52.1 activity against S. aureus (including MRSA), streptococci and vancomycin– • 50/90 treatment of SSSI in children, provided safety and tolerability are children (<18 years old) in the USA (2014 - 2015). Bacteria were except for one vancomycin-resistant isolate (Table 1). Other tested agents (92.0 – 100.0% Linezolid 1 1 0.25 — 1 100.0 - 0.0 susceptible enterococci. In vitro activity has also been demonstrated against Tetracycline ≤0.5 1 ≤0.5 — >8 93.0 1.6 5.4 satisfactory. identified by standard algorithms and MALDI-TOF-MS. susceptible) were also active against E. faecalis, with the exception of tetracycline (24.0% TMP-SMX ≤0.5 ≤0.5 ≤0.5 — >4 97.8 - 2.2 heterogeneous vancomycin–intermediate (hVISA; MIC range, 0.12 – 0. 5 μg/mL) Susceptibility testing was performed by CLSI methods (M07-A10); susceptible; Table 2). Vancomycin 0.5 1 ≤0.12 — 1 100.0 0.0 0.0 and vancomycin–intermediate S. aureus (VISA; 0.5 – 2 μg/mL), and other Gram– CoNS (42)d interpretation of MICs used CLSI criteria. Dalbavancin 0.03 0.06 0.008 — >0.25 - - - positive isolates less often recovered from human clinical specimens. This report • Dalbavancin was up to 32-fold more active than ampicillin (MIC50/90, ≤0.5/1 μg/mL), daptomycin Oxacillin 0.5 >2 ≤0.25 — >2 57.1 - 42.9 REFERENCES Clindamycin ≤0.25 >2 ≤0.25 — >2 78.6 2.4 19.0 1. Boucher HW, Wilcox M, Talbot GH, Puttagunta S, Das AF, Dunne MW (2014). Once-weekly Results describes dalbavancin in vitro activity and potency when tested against a (MIC50/90, 1/1 μg/mL), linezolid (MIC50/90, 1/2 μg/mL), levofloxacin (MIC50/90, 1/2 μg/mL) and vancomycin (MIC , 1/2 μg/mL) against the E. faecalis population (Table 2). Daptomycin 0.25 0.5 ≤0.12 — 1 100.0 - - dalbavancin versus daily conventional therapy for skin infection. N Engl J Med 370: 2169-2179. contemporary (2014 – 2015) collection of Gram–positive isolates responsible for 50/90 Erythromycin 0.25 >8 ≤0.12 — >8 50.0 0.0 50.0 2. Citron DM, Tyrrell KL, Goldstein EJ (2014). Comparative in vitro activities of dalbavancin and Dalbavancin had MIC50/90 values of 0.03/0.06 μg/mL against S. SSSI recovered from a pediatric patient population in USA medical centers. Levofloxacin 0.25 1 ≤0.12 — >4 90.5 0.0 9.5 seven comparator agents against 41 Staphylococcus species cultured from osteomyelitis aureus and CoNS, including methicillin-resistant (MRSA) and • Dalbavancin was very active against BHS (MIC50/90, 0.008/0.03 μg/mL) and VGS (MIC50/90, Linezolid 0.5 1 ≤0.12 — 1 100.0 - 0.0 infections and 18 VISA and hVISA strains. Diagn Microbiol Infect Dis 79: 438-440. Tetracycline ≤0.5 1 ≤0.5 — >8 92.9 0.0 7.1 0.008/0.015 μg/mL), inhibiting 100% of these isolates at ≤0.06 and ≤0.03 μg/mL, respectively (Tables 3. Clinical and Laboratory Standards Institute (2015). M07-A10. Methods for dilution antimicrobial -susceptible (MSSA) S. aureus subsets. When tested against TMP-SMX ≤0.5 ≤0.5 ≤0.5 — 4 95.2 - 4.8 susceptibility tests for bacteria that grow aerobically; Approved Standard - Tenth edition. Wayne, 1 and 2). Vancomycin 1 2 ≤0.12 — 2 100.0 0.0 0.0 MRSA, dalbavancin MICs were 8- to 32-fold lower than those of PA, USA. METHODS E. faecalis (25) daptomycin (MIC , 0.25/0.5 μg/mL), vancomycin (MIC , 0.5/1 • Dalbavancin (MIC , 0.008/0.03 μg/mL), ceftriaxone (MIC , ≤0.06/≤0.06 μg/mL) and penicillin Dalbavancin 0.03 0.06 ≤0.015 — >2 96.0e - - 4. Clinical and Laboratory Standards Institute (2016). M100-S26. Performance standards for 50/90 50/90 50/90 50/90 antimicrobial susceptibility testing: 26th Informational Supplement. Wayne, PA, USA. Bacterial isolates (MIC , ≤0.06/≤0.06 μg/mL) were the most active agents against BHS, although other tested agents Ampicillin ≤0.5 1 ≤0.5 — 1 100.0 - 0.0 μg/mL) and linezolid (MIC50/90, 1/1 μg/mL). These agents showed 50/90 Daptomycin 1 1 0.5 — 2 100.0 - - 5. DalvanceTM Package Insert (2016). Available at http://www.allergan.com/assets/pdf/dalvance_pi. 100.0% susceptibility against MRSA, and clindamycin also had a A total of 770 S. aureus, 167 β-hemolytic streptococci (BHS), 42 coagulase- also showed susceptibility rates >90.0%, except for tetracycline (84.4%; Table 2). Levofloxacin 1 2 ≤0.5 — >4 92.0 0.0 8.0 Accessed February 2016. Linezolid 1 2 0.5 — 2 100.0 0.0 0.0 6. Dunne MW, Puttagunta S, Giordano P, Krievins D, Zelasky M, Baldassarre J (2016). A high (92.7%) susceptibility rate. Dalbavancin (MIC , 0.03/0.06 negative staphylococci (CoNS), 25 E. faecalis and 13 viridans group streptococci Tetracycline >8 >8 ≤1 — >8 24.0 0.0 76.0 randomized clinical trial of single-dose versus weekly dalbavancin for treatment of acute bacterial 50/90 • All VGS isolates were susceptible to dalbavancin (MIC100, 0.03 μg/mL) with MIC results 32- to 64-fold (VGS) causing SSSI were collected from children (<18 years old) in the USA Vancomycin 1 2 ≤0.5 — >16 96.0 0.0 4.0 skin and skin structure infection.