New Antibiotics

Will Roland, MD

FDA Approvals

• 2010 - ceftaroline

• 2011 - fidaxomicin, telaprevir, boceprevir, spinosad

• 2012 – bedaquiline, raxibacumab, Stribild,

• 2013 – sofosbuvir, simeprevir, dolutegravir

• 2014 – peramivir, ceftolozane/tazobactam, Viekira Pak, Harvoni, oritavancin, tedizolid, dalbavancin, miltefosine, Jublia, Kerydin

• 2015 – daclatasvir, ceftazidime-avibactam

• 2016 – obiltoxaximab, elbasvir and grazoprevir, sofosbuvir and velpatasvir

Ceftaroline(Teflaro)

• ABSSSIs and CABP

• Binds to PBPs inhibiting cell wall synthesis

– High affinity for PBP2a - associated w/ methicillin resistance

• Consistently active against MDR Strep. pneumoniae and S. aureus

– Methicillin-resistant, vancomycin-intermediate, linezolid-resistant, daptomycin-nonsusceptible strains

• Variable activity against Enterobacteriaceae

Ceftaroline

• Good activity against oral anaerobes

• IV 600 mg every 12 h

• Excreted by kidneys - dose adjust in renal failure

• Noninferiority compared w/ vancomycin in ABSSSIs

• Noninferiority compared w/ ceftriaxone in CABP

• Safety profile similar to that of comparator drugs in clinical trials

Ceftaroline

• Well tolerated - adverse effect profile similar to other cephalosporins

• Can be given IM w/o causing significant pain

• No controlled trials in pregnancy – animal studies did not find adverse effects on offspring

– Category B designation for use in pregnancy

• Not known if it is excreted in breast milk

– Manufacturer recommends that caution administering ceftaroline to nursing women

Ceftaroline

• Acquisition cost ∼$80/day - favorable comparisons to other newer agents for the treatment of ABSSSI and CABP

• More costly than other IV cephalosporins, fluoroquinolones and vancomycin

– Less expensive than single-drug or combination-drug therapy utilizing newer agents to treat MRSA - linezolid, daptomycin, or tigecycline

Fidaxomicin(Dificid)

• Nonabsorbed macrocyclic compound

• 1st antimicrobial agent approved by FDA for Rx of C. difficile in last 25 years

• Bactericidal - mechanism of action: inhibition of a RNA polymerase

• 200 mg po BID not inferior to vancomycin for Rx of CDI as determined by clinical response after 10 days of Rx

Fidaxomicin

• Superior to vancomycin for sustained response w/o recurrence 25 days after Rx completion

• Relatively spares the indigenous fecal microbiota

• AEs not observed in animal reproduction studies

– Limited systemic absorption - exposure to fetus expected to be low

• Not known if it is excreted in breast milk

– Manufacturer recommends that caution when administering to nursing women

Louie , T. J., et al. (2011). "Fidaxomicin versus Vancomycin for Clostridium difficile Infection." New England Journal of Medicine 364(5): 422-431.

FidaxomicinVA Restrictions

• One of the following:

• Pts w/ severe CDI w/ 2nd recurrence (previously received appropriate therapy i.e., vanc 125mg po QID for initial and 1st recurrence)– Alternatively option to prescribe vanc taper for 2nd

recurrence

• OR

• Pts w/ mild-moderate CDI with 3rd recurrence (who previously received appropriate therapy, i.e., metronidazole 500mg po TID for initial and 1st

recurrence and then vanc taper for 2nd recurrence)

Oritavancin(Orbactiv)

• Lipoglycopeptide abx with multiple mechanisms of action – Inhibiting peptidoglycan cell wall synthesis – Disrupting bacterial cell membrane

• Highly active against common gram-positive pathogens –MRSA, VISA, VRSA, VRE

• Single IV dose of 1200 mg over 3 hours in adult patients– Terminal half-life of 393 hours, repeat dosing not required for

ABSSIs– Very slow elimination from tissue sites– No dosing adjustments required for renal, hepatic insufficiency

Oritavancin

• 2 clinical trials demonstrated noninferioritycompared w/ vancomycin in the treatment of ABSSSIs

• AEs similar to vanc in f/u for up to 60 days– Liver enzyme elevation – Occurrence of osteomyelitis

• Pregnancy Risk Factor C - AEs not observed in animal reproduction studies

• Not known if it is excreted into breast milk– Manufacturer recommends caution when

administered to a nursing woman

Oritavancin

• Pts should be monitored for osteomyelitis and alternate Rx given in case of confirmed or suspected osteomyelitis

• Attractive antibiotic to consider in the outpatient area

• Efficacy and safety in Rx of other sites of infection yet to be established

Oritavancin

• Can reduce outpatient infusion services and home care - improve patient satisfaction

• Acquisition cost ($2900) may ultimately limit its use – Costs in healthcare frequently limited by acquisition costs -

many other associated costs are fixed or not easily reduced

• Occurrence of MSSA - 30-60% of isolates of S. aureus– β-lactam after a short inpatient course of vancomycin,

telavancin, daptomycin may be a more acceptable cost-effective strategy

Oritavancin

• Has not been assessed in bacteremia or bone and joint infections

• Resolution of reimbursement, co-pay issues along w/ cost-benefit analyses of oritavancin vs other abx used for OPAT of ABSSSIs are needed

• Additional clinical experience w/ response to transition therapy from other regimens needed to further assess oritavancin's role in treatment of ABSSSIs

Dalbavancin(Dalvance)

• Lipoglycopeptide w/ broad spectrum against virtually all important gram-positive pathogens

– Exception of vanA – expressing VRE

• Potent bactericidal agent against drug-resistant staphylococci

• Animal models and clinical trials - demonstrated efficacy in Rx of SSTIs

• Prolonged half-life of 181 h - allows for convenient once-weekly dosing

Dalbavancin

• No data to suggest clinical superiority over β -lactam abx or linezolid for infections due to susceptible organisms

• No sufficient data on Rx of pneumonia or bone and joint infections to draw conclusions about it‘s clinical usefulness for these indications

• Noninvolvement w/ cytochrome p450 system makes drug-drug interactions unlikely

Dalbavancin

• No serious AEs in early clinical trials– Prolonged half-life - unique challenge should AEs

occur

• Pregnancy Implications – AEs have been observed in animal reproduction studies

• Long half-life should be considered when evaluating potential exposure to the fetus.

• Not known if it is excreted into breast milk– Manufacturer recommends caution when

administered to a nursing woman

Tedizolid(Sivextro)

• 2nd commercially available oxazolidinone abx– 1st in class that is dosed qD

• Activity against wide range of gram-positive pathogens• Approved to treat ABSSSIs• 2 randomized controlled phase 3 trials: 6 days of

tedizolid (200 mg once daily) - noninferior to 10 days of linezolid (600 mg twice daily)

• Differs from linezolid in incidence of GI and hematologic side fx– Lacks drug interactions w/ SSRIs

• Conditions other than ABSSSI currently being evaluated

Tedizolid

• PO and IV tedizolid costs $235 per day.

• Branded IV linezolid (Zyvox) is currently $288 per day, oral $246 per day

• Generic intravenous linezolid relatively cheap

• The apparent lack of interactions with SSRIs can be a significant benefit

Tedizolid

• Pregnancy Risk Factor C – AEs observed in animal reproduction studies

• Not known if it is excreted into breast milk

– Manufacturer recommends caution when administered to a nursing woman

Tedizolid

• Lack of an interaction between tedizolid and SSRIs are currently lacking clinical confirmation, as no patients in ESTABLISH-1 and -2 were on concomitant SSRIs due to the black-box warning with the comparator, linezolid

• Postmarketing data will need to be collected to clarify this clinical entity, as serotonin syndrome is rare and could not be studied prospectively

Tedizolid

• Linezolid does maintain certain advantages over tedizolid to date in FDA indications for: – Pneumonia (nosocomial and community acquired)

– Complicated skin and skin structure infections (including diabetic foot infections without concomitant osteomyelitis)

– Uncomplicated skin and skin structure infections

– VRE

• Some physicians comfortable w/ prolonged courses of linezolid w/ close clinical monitoring– Longest use of tedizolid to date is 21 days in healthy

subjects

Telavancin(Vibativ)

• Approved (2009) for treatment of adults w/ HABP/VABP caused by susceptible isolates of S. aureus when alternative treatments are not suitable

• 05/09/16 – FDA approval to expand the product's label to include data describing the treatment of pts w/ concurrent S. aureus bacteremia in HABP/VABP

• Approved for the treatment of adult pts w/ complicated skin & skin structure infections caused by susceptible isolates of Gram-positive bacteria

TelavancinCaveats

• Pts w/CrCl ≤50 mL/min treated w/ Telavancinfor HABP/VABP - increased mortality observed versus vancomycin

• Need to monitor renal fnx thruout therapy

• IV unfractionated heparin is contraindicated w/ Telavancin administration due to artificially prolonged aPTT test results for up to 18 hrsafter Telavancin administration

TelavancinCaveats

• Avoid in pregnancy – AEs in animal developmental outcomes have been observed– Women of childbearing age should have serum

pregnancy test

• Not recommended during pregnancy unless potential benefit to mother outweighs possible risk to fetus

• Not known if it is excreted into breast milk– Manufacturer recommends caution when

administered to a nursing woman

Clinical decision tree to predict a bacteremic patient's likelihood of infection with an

extended-spectrum β-lactamase (ESBL)–producing organism at the time of organism genus

and species identification.

Katherine E. Goodman et al. Clin Infect Dis.

2016;cid.ciw425

© The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of

America. All rights reserved.

Ceftolozane/tazobactam (Zerbaxa)Ceftazidime/avibactam (Avicaz)

• 2 novel β-lactam/β-lactamase combination abx

• Active against MDR gram-negatives including P. aeruginosa

• Ceftazidime/avibactam - active against carbapenem-resistant Enterobacteriaceae that produce Klebsiella pneumoniae carbapenemases

– Avibactam does not inactivate metallo-β-lactamases such as New Delhi metallo-β-lactamases

Ceftolozane/tazobactam (Zerbaxa)Ceftazidime/avibactam (Avicaz)

• Both only available as IV - dosed TID in pts w/ normal renal function

• Clinical trials - noninferiority to comparators of both agents when used in Rx of cUTIs and complicated IAIs (w/ metronidazole)

• Results from pneumonia studies - not yet been reported

• Antimicrobial stewardship - essential to preserve activity

Ceftolozane sulfate and Tazobactamsodium (Zerbaxa)

• Novel cephalosporin, w/ activity against P. aeruginosa, w/ extended spectrum beta-lactamase inhibitor

• cUTIs caused by E. coli, K. pneumoniae, P. mirabilis, P. aeruginosa

• Combo w/ metronidazole for cIAI caused by E. cloacae, E. coli, K. oxytoca, K. pneumoniae, P. mirabilis, P. aeruginosa, B. fragilis, Strep anginosus, Strep constellatus, Strep salivarius

Metallo-β-lactamases

• Diverse set of enzymes that catalyze the hydrolysis of a broad range of β-lactam drugs including carbapenems

– Exception - monobactams

• Not inhibited by mechanism-based inhibitors such as clavulanate, sulbactam, or tazobactam

New Delhi Metallo-beta-lactamase-1 (NDM-1)

• 1st found in K. pneumoniae isolate from Swedish pt in India in 2008

– Died despite colistin

• EID Volume 19, Number 6—June 2013

– 9 NDM-producing isolates - resistant to all β-lactams, aztreonam, aminoglycosides and fluoroquinolones

Ceftolozane sulfate and Tazobactamsodium

• Pregnancy Risk Factor B - AEs observed in some animal reproduction studies

• Tazobactam crosses the placenta

• Not known if ceftolozane or tazobactam are excreted into breast milk

– Manufacturer recommends caution if administered to a nursing woman

Ceftazidime/avibactam(Avicaz)

• Avibactam - novel, non–β-lactam β-lactamase inhibitor that restores the in vitro activity of the established extended-spectrum antipseudomonal cephalosporin, ceftazidime, against Ambler class A, class C, and some class D β-lactamase–producing pathogens

Ceftazidime/avibactam

• In phase 2 trials - effective and well tolerated in pts w/ cIAI (in combo w/ metronidazole) and cUTIs

• Based on these data - approved by FDA for Rx of cIAI (in combo w/ metronidazole) and cUTIs(including pyelonephritis) in adults w/ limited or no alternative Rx options

Ceftazidime/avibactam

• Pregnancy Implications – AEs not been observed in animal reproduction studies conducted with ceftazidime– AEs observed in some animal reproduction studies

conducted with avibactam.

• Ceftazidime is excreted in breast milk

• Not known if avibactam is excreted in breast milk

• Manufacturer recommends caution when administering ceftazidime and avibactam to breast-feeding women

Difference in clinical cure rates at test-of-cure (TOC) visit by renal function.

John E. Mazuski et al. Clin Infect Dis. 2016;62:1380-1389

© The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of

America.

van Duin D, Bonomo RA. Ceftazidime/Avibactam and Ceftolozane/Tazobactam: Second-generation β-Lactam/β-Lactamase Combinations. Clin Infect Dis. 2016;63(2):234-241

No commercial sensitivity testing for the top 6 below

• Research use only disk

• Surrogate

• Pharma-Supported Research lab

Peramivir2009 Emergency Use

• ~ 1274 hospitalized pts Rxed w/ IV peramivirthru the EUA program during the pandemic

• Mostly critically ill, white adults w/ underlying medical conditions who had been treated initially w/ oral oseltamivir and subsequently treated late in the clinical course with peramivir for ~ 1 wk

• Hard to interpret results

PeramivirPotential Indications

• N/V/D, or other GI sensitivity

• Requiring IV for rehydration or other meds

• Pts preferring a single-dose Rx administered by a healthcare provider

• Pts who otherwise cannot be prescribed oral or inhaled, multi-dose therapies

Peramivir

• Pregnancy Risk Factor C – AEs observed in some animal reproduction studies

• Information related to the use of peramivir in pregnancy is limited

• Based on information from one case, the pharmacokinetics of peramivir may be changed with pregnancy

Peramivir

• Untreated influenza - associated with increased risk of AEs to the fetus and increased risk of complications or death to the mother

• Neuraminidase inhibitors are currently recommended for the treatment or prophylaxis of influenza in pregnant women and women up to 2 weeks postpartum

• Not known if peramivir is excreted into breast milk

• Manufacturer - decision to breast-feed during therapy should take into account the risk of exposure to the infant and the benefits of treatment to the mother

Isavuconazole(Cresemba)

• Extended spectrum triazole with activity against yeasts, molds, dimorphic fungi

• Approved for treatment of invasive aspergillosis and mucormycosis

• Advantages

– Availability of a water-soluble IV formulation

– Excellent bioavailability of the oral formulation

– Predictable pharmacokinetics in adults

IsavuconazoleMechanism of Action

• Inhibits cytochrome P450–dependent 14α-lanosteroldemethylation– Essential for fungal cell membrane ergosterol synthesis

• This blockade produces methylated sterols in the fungal membrane - accumulation of ergosterol toxic precursors in the cytoplasm, which leads to cell death

• Side arm of the active isavuconazole molecule allows greater avidity for the binding pocket in the fungal CYP51 protein, conferring broader antifungal spectrum even to pathogens resistant to other azoles

IsavuconazoleDrug-Drug Interactions

• Substrate for CYP3A4 - inhibitors of this enzyme lead to increased levels of isavuconazole– Rifampin, carbamazepine, long-acting barbituates

• Should not be used with this antifungal

• Moderate inhibitor of CYP3A4– Higher levels of sirolimus, tacrolimus, cyclosporine

• Serum levels need to be monitored

• Minimal effect on CYP2C9 and CYP2C19,– No dosage adjustment of warfarin and omeprazole

• Overall compared with voriconazole and posaconazole– Isavuconazole seems to have fewer drug-drug interactions

IsavuconazoleSide Effects

• Relatively safe and well tolerated

• Most common – N/V/D, rarely have led to discontinuation

• <15% - HA, rash, peripheral edema

• No voriconazole side effects - visual disturbances, hallucinations, photosensitivity

Isavuconazole

• Liver enzymes should be monitored

• Infusion reactions in a few pts - acute respiratory distress, chills, dyspnea, hypotension

– Recommend in-line filter be used for infusion

• Pregnancy Risk Factor C – AEs observed in animal reproduction studies

• Not known if it is excreted into breast milk

– Breast-feeding not recommended by manufacturer

Restricting Fluoroquinolone UseFDA

• Serious side f/x ass. w/ fluoroquinolones generally outweigh benefits for pts w/ acute sinusitis, acute bronchitis, uncomplicated UTIs who have other Rx options

– Tendons, muscles, joints, nerves, CNS

• Fluoroquinolones should be reserved for those who do not have alternative Rx options

On The Verge

• Solithromycin - next-generation IV/po fluoroketolide in Phase 3 studies for Rx of moderate to moderately-severe CABP and urethritis

• Fusidic acid – bacteriostatic protein synthesis inhibitor used topically being investigated for IV/oral use

• Delafloxacin – fluoroquinolone more active (lower MIC90) than other quinolones against MRSA– In contrast to other fluoroquinolones, which are

zwitterionic, delafloxacin has an anionic character, which results in a 10-fold increase in delafloxacin accumulation in both bacteria and cells at acidic pH

On The Verge

• Lefamulin – pleuromutilin in Phase 2 studies– Inhibits bacterial growth by binding to specific site

on the bacterial ribosome

• Brilacidin - novel defensin mimetic in Phase 2 studies

• Omadacycline – aminomethylcycline derived from tetracyclines in Phase 3– IV/po qD w/activity against Gram-positive, Gram-

negative, atypical and anaerobic bacteria

References

• Burdette SD, Trotman R. Tedizolid: The First Once-Daily OxazolidinoneClass Antibiotic. Clin Infect Dis. 2015 Oct 15;61(8):1315-21

• Saravolatz LD, Stein GE. Oritavancin: A Long-Half-Life Lipoglycopeptide.Clin Infect Dis. 2015 Aug 15;61(4):627-32.

• Billeter M, Zervos MJ, Chen AY, Dalovisio JR, Kurukularatne C. Dalbavancin: a novel once-weekly lipoglycopeptide antibiotic. Clin Infect Dis. 2008 Feb 15;46(4):577-83

• van Duin D, Bonomo RA. Ceftazidime/Avibactam and Ceftolozane/Tazobactam: Second-generation β-Lactam/β-Lactamase Combinations. Clin Infect Dis. 2016 Apr 20.epub

• Center for Disease Dynamics, Economics & Policy. 2015. State of the World’s Antibiotics, 2015. CDDEP: Washington, DC.

• Deak, D., et al. (2016). "Progress in the Fight Against Multidrug-Resistant Bacteria? A Review of U.S. Food and Drug Administration–Approved Antibiotics, 2010–2015FDA-Approved Antibiotics, 2010-2015." Annals of Internal Medicine Online May 31,2016.

References

• Saravolatz LD, Stein GE, Johnson LB. Ceftaroline: a novel cephalosporin with activity against methicillin-resistant Staphylococcus aureus. Clin Infect Dis. 2011 May;52(9):1156-63.

• Louie , T. J., et al. (2011). "Fidaxomicin versus Vancomycin for Clostridium difficile Infection." New England Journal of Medicine 364(5): 422-431.

• Moran, Gregory J et al. Tedizolid for 6 days versus linezolid for 10 days for acute bacterial skin and skin-structure infections (ESTABLISH-2): a randomised, double-blind, phase 3, non-inferiority trial. The Lancet Infectious Diseases, Volume 14 , Issue 8 , 696 – 705

• Rubinstein, E., et al. (2011). "Telavancin versus vancomycin for hospital-acquired pneumonia due to gram-positive pathogens." Clin Infect Dis 52(1): 31-40.

• Maertens, Johan A et al. Isavuconazole versus voriconazole for primary treatment of invasive mould disease caused by Aspergillus and other filamentous fungi (SECURE): a phase 3, randomised-controlled, non-inferiority trial. The Lancet , Volume 387, Issue 10020 , 760-769

• Humphries, R. M. and J. A. Hindler (2016). "Emerging Resistance, New Antimicrobial Agents  …  but No Tests! The Challenge of Antimicrobial Susceptibility Testing in the Current US Regulatory Landscape." Clinical Infectious Diseases 63(1): 83-88.