CENTER FOR DRUG EVALUATION AND. RESEARCH
`
`APPROVAL PACKAGE FOR:
`
`APPLICATION NUMBER
`
`21-572
`
`Pharmacology. Review(s)
`
`

`

`Reviewer: W. Schmidt
`
`NDA No. 21572
`
`Note:
`
`This will be the Standard CDER Coversheet
`
`_,’—..
`
`H. H \I
`
`

`

`Reviewer:
`
`\V. Schmidt
`
`.
`
`NDA No. 21572
`
`TABLE OF CONTENTS
`
`EXECUTIVE SUNIMARY .............................................................................................. 3
`
`PHARMACOLOGY/TOXICOLOGY REVIEW .............................. 5
`
`3.1
`
`INTRODUCTION AND DRUG HISTORY ................................................................... 5
`
`3.2
`3.2.]
`3.2.4
`
`PHARMACOLOGY ......................................................................................................... 6
`Briefsummary ........................................................................................................................ 6
`Safety pharmacology .............................................................................................................. 6
`
`3.3
`3.3.1
`
`PHARMACOKINETICS/TOXI COKINETICS ............................................................ 8
`Briefsummary ........................................................................................................................ 8
`
`3.4
`3.4.]
`3.4.3
`3.4.4.
`3.4.5.
`3.4.6.
`3.4.7
`
`TOXICOLOGY ............................................................................................................... 10 "
`Overall toxicology summary ................................................................................................ 10
`Repeat-dose toxicity ............................................................................................................. 12
`Genetic toxicology ................................................................................................................ 15
`Carcinogenicity ..................................................................................................................... 15
`Reproductive and developmental toxicology ................................... . .................................... 15
`Local tolerance ..................................................................................................................... 16
`
`3.4.8
`
`Special toxicology studies .................................................................................................... 16
`
`_"
`
`3.6
`
`OVERALL CONCLUSIONS AND RECOMMENDATIONS ................................... 27
`
`3.7.
`
`APPENDIX/ATTACHMENTS ..................................................................................... 27
`
`

`

`Reviewer: W. Schmidt
`
`NDA No. 21572
`
`EXECUTIVE SUMMARY
`
`I.
`
`Recommendations
`
`1.]
`
`Recommendation on approvability: Approval with appropriate warnings and
`caveats in the label.
`
`1.2
`
`1.3
`
`Recommendation for nonclinical studies: None
`
`‘
`Recommendations on labeling:
`An insertion to the precautions section on the non-clinical findings of muscular
`and neurologic toxicity is recommended. Minor changes to the distribution,
`pregnancy and animal toxicology sections are also requested.
`-
`
`2. Summary of nonclinical findings
`
`2.]
`
`Brief overview of nonclinical findings:
`The major target organs of toxicity in rat, dog and monkey were muscle and
`peripheral nerves. Muscle damage consisted of muscle degeneration/regeneration
`and usually resolved within 1 month of cessation of treatment. Muscle changes
`were sometime accompanied by increases in CPK. Peripheral nerve damage
`occurred at higher doses and included loss of patellar/gag reflexes, loss of pain
`perception, decreases in nerve conduction velocity, and axonal degeneration.
`Recovery was dependent on close, and was incomplete after a 3 month period. In
`the rat, renal toxicity was also observed. The NOEL levels from the animal
`toxicity studies, when expressed as either AUC or doses on a body surface area
`basis, were less than those at the proposed human dose of4 mg/kg. Similar
`toxicities were noted in the l, 3 and 6 month toxicity studies.
`
`Daptomycin was negative in the Segment I, II and III reproductive toxicity
`studies. Daptomycin was neither mutagenic nor clastogenic in a series of in vitro
`and in vivo genotoxicity tests.
`
`Phannacologic activity:
`The proposed mechanism of action is through interaction with the bacterial
`membrane via the fatty acid chain. A calcium dependent insertion occurs, the
`membrane potential decreases, and the cell dies.
`
`2.3
`
`Nonclinical safety issues relevant to clinical use:
`Muscle and peripheral nerve damage were seen in all species tested as shown by
`changes in clinical signs and microscopic changes. In human trials, muscle
`weakness was observed. In animals, the no—observed effect levels (NOELs) were
`at or below those in the proposed human doses on both an AUC and body surface
`area basis. Muscle damage occurred at lower doses than neurologic changes, and
`~ “u.
`
`

`

`Reviewer: W. Schmidt
`
`NDA No. 21572
`
`resolved within several weeks of the cessation of dosing. At higher doses,
`peripheral nerve damage was still present 3 months after the recovery period.
`Both muscle and nerve damage could occur after a single dose of daptomycin.
`While severe muscle and neurologic damage was accompanied by >10 fold
`elevations in CPK, lesser damage did not correlate well with elevations in CPK
`either in frequency or magnitude.
`
`

`

`Reviewer: W. Schmidt
`
`NDA No. 21572
`
`PHARMA COLOGY/TOXICOLOGYREVIEW
`
`3.1
`
`INTRODUCTION AND DRUG HISTORY
`
`NDA number: 21572
`Review number:
`1
`
`Sequence number/date/type of submission: December 19, 2002
`Information to sponsor: Yes ( ) No ()
`Sponsor and/or agent:
`
`Cubist Pharmaceuticals, Inc.
`65 Hayden Avenue
`Lexington, MA 02421
`
`Manufacturer for drug substance:
`
`/
`/
`/
`
`Reviewer name: Wendelyn J. Schmidt, PhD.
`Division name: Anti-Infective Drug Products
`HFD #: 520
`
`Review completion date: 7/22/03
`
`_/"'\
`
`Drug:
`
`-
`
`/
`
`/
`/
`
`Trade name: Cidecin
`. Code name: LY146032
`Generic name: Daptomycin for injection
`Chemical name: N-[N-[N-[N-[N-[N-[N-[N-[N~
`[N—[N-[N—[N-( 1 -oxodecyl)-L-tryptophyl]-L-
`asparaginyl]-L~aspartyl]-I.—threonyl]-glycyl]-L-
`omithyl]-aspartyl]-D-alanyl]-L-aspartyl]glycyl]-D-
`seryl]threo-3-methyl-L-a-glutamy1]-L-kynurenine e, Lactone.
`CAS registry number: 103060-53-3
`Molecular formula/molecular weight: C72H101N17026,mw=1620.67
`Structure:
`
`
`
`Relevant 1NDs/NDAs/DMFS: Original E. Lilly: IND 27627, Cubist 1ND 57693
`
`Drug class: Cyclic lipopeptide antibiotic
`
`Indication: Treatment of complicated skin and skin structure infections including those
`complicating diabetic foot and decubitus ulcers caused by susceptible strains of the
`following Gram-positive microorganisms: Staphylococcus aureus (including methicillin-
`resistant strains), Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus
`dysgalactiae subsp. equisimilis, Enterococcusfaecalis (vancomycin-susceptible strains
`only)
`_ «1
`
`it
`
`

`

`Reviewer: w. Schmidt
`
`'
`
`NDA No. 21572
`
`Clinical formulation: 250 or 500 mg sterile lyophilized powder for reconstitution with
`0.9% NaCl.
`
`Route of administration: Intravenous
`
`Disclaimer: Tabular and graphical information are constructed by the reviewer unless
`cited otherwise.
`
`Studies reviewed within this submission:
`
`Safety Pharmacology
`1. Effects of daptomycin on cloned hERG channels expressed in human embryonic
`kidney (HEK) cells. Tox055, electronic NDA.
`Pharmacokinetics:
`'
`
`1.' Study of daptomycin pharmacokinetics in rats with renal impairment.
`Pk\admel 5.pdf.
`'
`Toxicology
`l. 28 day toxicity study ofdaptomycin in juvenile beagle dogs. Tox\tox51.pdf.
`Special Toxicity
`1.
`In vitro studies of daptomycin in the male Sprague Dawley rat phrenjc
`nerve/diaphragm preparation. Tox O38, electronic NBA.
`2. Repeated intravenous dose study of daptomycin to assess skeletal muscle fiber type
`affected in rats. Tox\tox49.pdf.
`3. Chronic dosing of rat with daptomycin and morphological alterations in peripheral
`nerve. Tox\tox35.pdf.
`4. A 10 day exploratory nephrotoxicity interaction study of intravenous daptomycin in
`combination with intramuscular gentarnicin in dogs. Tox\tox47.pdf.
`5. A 14 day repeated dose toxicity study of daptomycin in dogs: evaluations of skeletal
`muscle and peripheral nerve effects. Tox\tox52.pdf.
`in vitro investigation of daptomycin-related skeletal muscle effects: development and
`mechanistic investigations tier 1 studies. Tox\tox53.pdf.
`7. A 14-day repeated dose toxicity study of daptomycin in dogs: comparison of
`intravenous infusion versus bolus injection. Tox\tox54.pdf.
`.
`8. Development of an in vitro model of myotoxicity. Tox\tox56.pdf.
`9. A series of exploratory innamuscular toxicity studies of daptomycin in rats and mice.
`Tox\tox57.pdf.
`10. A Study of the irnmunogenicity of daptomycin. Tox\tox58.pdf.
`
`6.
`
`Studies not reviewed within this submission: None
`
`3.2 PHARMACOLOGY
`
`3.2.1 Brief Summary
`Daptomycin is cyclic lipopeptide antibiotic with activity against Gram-positive
`bacteria including methicillin resistant Staphylococcus aureus (MRSA). The proposed
`mechanism of action is through interaction with the bacterial membrane via the fatty acid
`chain. A calcium dependent insertion occurs, the membrane potential decreases, and the
`cell dies.
`a“-
`
`wrw
`
`

`

`Reviewer: W. Schmidt
`
`NDA No. 21572
`
`3.2.4 SAFETY PHARMACOLOGY
`
`Brief Summary:
`A standard battery of safety pharmacology studies were conducted. To
`investigate the cardiac effects of daptomycin, both the in vitro hERG assay and an
`anesthetized dog study were conducted. There was no suggestion of inhibition of the
`Ether-a-go-go channel with daptomycin. Similarly, with the anesthetized dog with
`cumulative doses of 50 mg/kg, there were no changes in QT interval, mean arterial
`pressure, heart rate or stroke volume. EKGs were not measured in any of the subchronic
`or chronic dose toxicology studies. Cardiac parameters were not disturbed by
`daptomycin in clinical trials. However,
`there was a 35-40% decrease in pulmonary
`vascular resistance and pulmonary pressure by 30 minutes post—dose at doses of 2 20
`mg/kg.
`‘
`CNS and neuromuscular changes were investigated in mice and dogs. Single
`doses of 50 mg/kg in mice resulted in irritability, decreased motor activity, leg weakness,
`grasping loss, decreased abdominal tone and catalepsy progressing to ataxia and tremors
`at 200 mg/kg and convulsions at 400 mg/kg. Apomorphine induced hypothermia was
`reduced at 200 mg/kg. Acetic acid induced writhing was decreased at 200 mg/kg in
`mice. Hexobarbital sleep time was increased at 50 and 200 mg/kg in mice. No
`toxicologically relevant changes, in convulsion induced by electric shock or
`pentyienetetrazole were noted.
`.
`Other mechanistic. studies included investigations of isolated smooth and cardiac
`muscles (in vitro) where only uterine response to oxytocin and serotonin responses were
`affected. This was postulated to be a calcium effect. Further experiments with calcium
`loaded sarcoplasmic reticulum vesicles showed no change in release or uptake with the
`addition of extra-vesicular calcium or calcium ionophores. Diaphragm twitch response in
`vitro was also unaffected by daptomycin.
`The general pharmacology screen showed no effect on respiratory-cardiovascular
`systems, GI motility or intestinal transit time, hemolysis, or cellular osmolan'ty, but did
`result in CNS changes as discussed above. Urinary excretion of electrolytes was
`unaffected, as was antibody production in the mouse at doses up to 10 mg/kg for 10 days.
`
`1. Effects of daptomycin on cloned hERG channels expressed in human embrvonic
`kidney (HEK) cells. ToxOSS. electronic NDA.
`
`Conducting laboratory and location:
`Date of study initiation: Aug. 27, 2001
`GLP compliance: Yes
`QA report: Yes (X ) No ()
`Drug, lot #, and % purity: Daptomycin, lot # 680403A. 96.7% pure
`Formulation/vehicle: Glucose-free Tyrode’solution
`
`Methods (unique aspects): Either 3 or more measurements on the same cell or 3 separate
`cells were measured to determine if the current was decreased. Cells were tested
`
`with a single concentration of daptomycin. Each cell served as its own control.
`
`Dosing:
`Cell line: Human embryonic kidney (HEK-293 transfected with human hERG
`(the human ether-a-gg-go channel) cDNA.
`
`

`

`Reviewer: W. Schmidt
`
`NDA No. 21572
`
`Doses in administered units: 0, 3, 30, 100, 300 uM daptomycin
`Positive controls: Terfenadine (60 nM) dissolved in DMSO, diluted in Tyrode’s
`solution
`
`Observations, Times, and Results:
`The actual concentration of daptomycin in solution ranged from 57.6% to 95.7%
`of the targeted concentration. The lowest concentrations were in the putative 3 uM (57.6-
`69.7% of the theoretical values). The 300 uM solution ranged from 76.3% to 90.1% of
`the theoretical.
`.
`The mean fraction of current did not significantly change between control and
`daptomycin concentrations of 300 uM (range - Terfenidine at concentrations
`of 60 nM resulted in between a 52% and 64% reduction in current.
`
`Comments and conclusions: The positive control was active in the historical range. The
`study was adequate and valid. Daptornycin did not affect the hERG channel at
`concentrations of approximately 300 uM.
`
`3.3
`
`PHARMACOKJNETICS/TOXICOKINETICS
`
`3.3.1 Brief Summary:
`All of the studies with the exception of “Study of daptomycin pharmacokinetics in
`rats with renal impairment, tox15.pdf’ were previously reviewed by Dr. Terry Peters.
`Single dose pharmacokinetics have been explored in mice, rats, and dogs. Most of the
`studies were done in males only. In the dog where both genders were used, the AUC and
`half-life were slightly longer in males than in females, although not to a toxicologically
`relevant extent. The toxicokinetic parameters did not show any gender influence.
`lntravenous, oral and subcutaneous dosing were investigated in the rat. Metabolism was
`investigated using TLC in the rat un'ne. Finally, excretion was investigated in the mouse,
`rat, Rhesus monkey and dog. Protein binding was discussed in a series of literature
`articles.
`
`The single dose pharmacokinetics are summarized in the following table. Most of
`these studies used radiolabeled daptomycin to determine the pharmacokinetics. By
`comparing AUCs by — and radiolabel in the rat, the first study showed good
`similarity, su gesting a lack of metabolism. However, comparing the renal impairment
`study to the ' C studies shows that the plasma AUCs and Cmax by —~ ‘ are much
`lower, suggesting metabolism (or just a lack of agreement between studies). AUC values
`across species showed better agreement on a body surface area basis (mouse being the
`outlier). Renal damage to the tubules (cortex) by uranyl nitrate resulted in- increases in
`Cmax, AUC and half~life as the clearance is decreased to approximately 70% (AUC
`increased 2-3 fold vs. normal rats). The half life of daptomycin in mouse, rat and dog
`was around 2 hours. Oral bioavailability in the rat was <1%.
`
`

`

`Reviewer: W. Schmidt
`
`NDA No. 21572
`
`T 1/2 (hr)
`
`_I
`
`!-
`
`I_
`II—
`I_
`
`Cmax
`(u _/mL
`
`N \l
`
`E-
`
`wwwewOO\Ut\lN
`
`_
`
`2.9 M, 2.4 F
`
`' R1 = renally impaired
`*indicates analysis by ’-
`Oral bioavailability was low in the rat (approximately 1%). Gastrointestinal
`uptake of daptomycin was minimal.
`Metabolism and tissue distribution were investigated primarily in the rat. One
`method involved comparison of elimination of either I4C label in the decanoic acid side
`chain (DEC) versus that with the MC label in the tryptophan moiety (TRP). Although
`there was a difference in the amount of radioactivity released in the urine (85.2 i 2.0%
`with the TR? and 76.8 i 0.8%), the total radioactivity recovered did not differ to a
`statistically significant extent and the sponsor concluded that there were no differences in
`metabolism; In a study measuring MC label in respired air, decanoic acid labeled
`daptomycin yielded 1-2% of the dose as MC-COz, while TRP labeled daptomycin had no
`appreciable label in respired air. This suggests a small amount of metabolism on the side
`chain.
`_ --
`_
`_
`analysis ofthe rat urine also showed primarily
`a single peak of radioactivity which co-eluted with daptomycin standard and was
`bioactive. Tissue distribution studies showed that after 4 hours, radioactivity levels Were
`higher in kidney than in plasma and remained detectable for as long as 6 weeks.
`Daptomycin did not cross the blood brain barrier to an appreciable extent (<1% of the
`dose administered). At 96 hours post-dose, levels in brachial and sciatic nerve were
`higher than those in plasma. Most tissue distribution studies did not measure daptomycin
`levels in peripheral nerves.
`Protein binding was investigated in a series of literature papers (Antimicrobial
`Agents and Chemotherapy, volumes 45(3): 845-851, 2001; 34(11): 2081-2085, 1990; and
`35(12):2505-2508, 1991). Concentrations ofup to 100 ug/mL were investigated using
`n-a—u-
`-
`
`

`

`Reviewer: W. Schmidt
`
`NDA No. 21572
`
`ultracentrifugation and a bioassay in mouse, rabbit and human plasma. Protein binding in
`all 3 species ranged from 90 to 96% and was independent ofconcentration.
`Mass balance studies were conducted in multiples species, as shown in the table
`below. Mouse, rat, dog and monkey all excreted daptomycin primarily in the urine
`(approximately 70-90% of the administered dose). Anywhere from 3-15% of the dose
`was recovered in the feces, and the total recovery was usually around 95% of the
`administered dose based on radiolabel.
`
`Cumulative Excretion
`
`°/o dose in urine
`
`0
`l/
`I
`0 dose in feces % dose in carcass
`.4
`79.2
`7
`rat—m—
`7.5
`—
`
`'
`
`Mouse (lCR
`.l Rat (Wistar
`
`10 DX7
`
`
`
`A drug interaction study was conducted in dogs on daptomycin and tobramycin.
`No effect on the pharmacokinetics of either drug was seen.
`
`]. Studv of da tomvcin harmacokinetics in rats m'th renal im airment.
`
`Pk\adme]5.pdf.
`Animals: Male Sprague Dawley rats, 3/group, 12 weeks old, 250 g, one group treated 4
`days prior to study with 0.2 mg/kg iv. uranyl nitrate (results in 79% decrease in
`creatinine clearance).
`Drug: 25 mg/kg daptomycin (lot 6701 13A) in saline, single sc. bolus
`Sampling times: 0.08, 0.5, l, 4, 6, 24 h
`. Analysis method: ""
`
`Results:
`
`No individual animal data was presented. The pharmacokinetic parameters are
`shown below.
`
`
`
`Clearance (mL/h
`
`Comments and conclusions: This is an adequate exploratory study. The conclusion
`drawn, that close alteration may be necessary in renally impaired patients, is valid.
`
`3.4
`
`TOXICOLOGY
`
`3.4.] Overall toxicology summary
`General toxicology:
`One of the major issues with daptomycin is whether recovery from nerve and
`muscle damage occurs, and, if so, when does it occur. The data from the rat toxicology
`:— -m-y
`
`10
`
`

`

`Reviewer: W. Schmidt
`
`NDA No. 21572
`
`studies are not as helpful as that from the dog for the following reasons: 1) no clinical
`signs related to neuro/muscular toxicity were seen, 2) no consistent changes in CPK were
`observed, and 3) histopathology was only obtained at the end ofthe dosing period. Only
`the 6 month rat study included a recovery period. Rat also did not show the nerve
`damage that was seen in dogs and monkeys. 1n the 6 month study, the only skeletal
`muscle damage (degeneration/regeneration) was seen at the end ofthe dosing period in
`high dose rats (50 mg/kg). No changes in incidence or severity between treated and
`controls were noted at the end of the 8 week recovery period in the rats. Whether this is a
`matter ofdose, or ofa species effect is not clear. The rat also shows a renal toxicity
`which is not seen in the dog, monkey or human.
`In the dogs, the evidence ofnerve and muscular toxicity was more easily seen.
`The changes in clinical signs, CPK, and histopathology in the dogs are shown in the
`following table. Muscle myopathy was observed at lower doses than the peripheral nerve
`axonal degeneration. Axonal degeneration (primarily seen in the 1 month and 6 month
`dog studies), was generally manifested functionally as loss ofpatellar reflex, and at the
`75 mg/kg dose, crouched hind limb position, skeletal muscle atrophy, as well as
`decreased perception of pain, depressed postural motor responses, flexor responses, and
`gag reflex. With a 3 month recovery period after dosing for 1 month with daptomycin,.
`these signs were still present in 6/8 of the dogs and patellar reflex was absent in all dogs.
`At 40 mg/kg for 6 months, patellar reflex was diminished in 6/ 12 dogs; but 2/4 dogs with
`patellar deficits during treatment in the recovery group regained the reflex within 2 weeks
`of cessation of dosing. The histopathology in the dogs was described as axonal
`degeneration without demyelination and at 40 mg/kg, was minimal to slight (and still
`resulted in deficits in patellar reflex), while neuronal damage with 75 mg/kg for 1 month
`was minimal to severe. The AUC levels in dogs at 40 and 75 mg/kg respectively were
`1446-1731 ugh/ml. and 3144-3669 ug.h/mL. Cmax levels were 730-1115 ug/mL at 40
`mg/kg and 1277-1864 at 75 mg/kg.
`In humans at the proposed clinical dose (4 mg/kg)
`the Cmax as approximately 55 ug/mL while the AUC was 425 ug.hr/mL. Based on these
`figures, the exposure levels where neurotoxicity-occurs are roughly 3.4 fold higher than
`the human exposure (Cmax is about 13 fold higher).
`In the monkey, a single dose study showed leg weakness and axonal degeneration
`ofthe sciatic nerve at 200 mg/kg. With daily dosing for 1 month at 1, 5 and 10 mg/kg, no
`muscular toxicity or nerve damage was observed above the incidence in controls. It
`should be noted that theses doses are quite low compared to the dog.
`
`11
`
`

`

`Reviewer: W. Schmidt
`
`NDA No. 21572
`
`1 month
`
`
`
`.
`
`1, 5, 20
`
`6 months
`
`2, 10, 40
`
`end of Recoverv
`timeoints
`
`HD: minimal to severe axonal
`10, 25, 75-
`HD: 13/15 wo/
`HD; T>2X by
`
`
`
`degeneration; 6/8 dogs with
`patellar reflex
`day 2
`
`
`wk 2, No
`LD/MD: T 2x
`severe myoneuronal disease
`
`
`
`
`
`
`sporadically in Muscular
`recovery by 6
`
`
`
`
`degeneration/regeneration at all
`weeks
`week 2-3; all
`
`
`
`doses, recovery @ LD, lvfl) by 3
`recovery by
`
`
`
`
`months
`D30
`
`
`
`
`3 months
`No signs
`Mild muscular
`HD: T by D7,
`
`
`degeneration/regeneration in 2/8
`normal >290
`
`
`
`M, 7/8 H at 3 mos. No
`
`muscular pathology @ 1 1 weeks
`post-dose.
`
`
`No nerve damage or change in
`
`
`"
`conduction
`
`HD: CPK T2-
`HD: 6/8 at end ofo with
`HD: 6/12
`
`
`minimal axonal degeneration in
`wo/patellar
`>10X day 7-
`
`
`
`
`reflex in 1’l 5
`183 (not all
`sciatic and radial nerves (2/6 of
`
`
`
`weeks of
`
`these with normal patellar
`dogs, sporadic)
`
`
`
`treatment
`reflex)
`'
`
`
`End of 3 month recovery 1/4
`HD: l (non-
`
`
`HD with minimal axonal
`stat sig) in
`
`
`nerve
`
`degeneration
`conduction at
`' muscle degeneration/
`
`
`3, 6 months
`regeneration seen in 6/40 sites
`
`
`@ MD, 20/40 sites @ HD (5
`sites/dog X 8 dogs); all normal
`at 3 months recove
`
`
`
`
`
`
`
`
`
`
`
`
`REPEAT-DOSE TOXICllTY
`1. Multi
`1e dose toxicity studv in 'uvenile bea 1e do 5. Tox 051 electronic NDA.
`
`Conducting laboratory and location:
`Date of study initiation: December 22, 2000
`GLP compliance: YES
`QA report: Yes (X ) No ( )
`Drug, lot #, and % purity: Daptomycin, lot # 680313A, 95.6% pure
`Formulation/vehicle: 0.9% saline
`
`A —-
`
`
`
`Dosing:
`Species/strain: Beagle dogs
`#lsex/group or time point (main study): 4/sex/dose
`#/sex/group for recovery: 2/sex/dose at control, HD
`Age: 7 weeks at study initiation
`Weight: 1.39-3.34 kg
`Doses in administered units: 0, 20, 50, 150 mg/kg/day once daily for 28
`consecutive days; recovery group observed for an additional 28 days.
`Route, form, volume, and infusion rate: Intravenous, 2 mL/kg,
`
`12
`
`

`

`Reviewer: W. Schmidt
`
`,
`
`NDA No. 21572
`
`Observations, Times, and Results:
`-
`Clinical signs (twice daily): One HD female was sacrificed at day 17 with
`severe muscle weakness, inability to move, lateral recumbency, vocalization, and
`inappetence. All remaining puppies survived to scheduled sacrifice. Muscular weakness
`in all 4 limbs was observed in 5/6 ofthe HD males and females beginning on day 9-18
`and persisting through day 15—43. The remaining HD female had muscle weakness only
`in the hindlimbs. Additionally one each HD male and female were thin with decreased
`appetite, and one HD female hyper-extended her feet to stand.
`Body weights (daily during dosing, weekly during recovery): There were neither
`statistically significant differences in body weight gain nor body weights over the 28 days
`of treatment. However, in the last week of treatment, body weight gains were less (by
`approximately half) in the HD animals.
`.
`Hematology (day 29, 57): There were no remarkable changes associated with
`treatment.
`
`Clinical chemistry (day 29, 57; CPK on day 14 as well): There were no
`remarkable changes as compared to controls with treatment. CPK levels did not correlate
`well with muscle damage as in both controls and HD animals, 3/6 males and 4/6 females
`had CPK levels above 400 U/L. Moreover, animals without any observations of muscle
`weakness had higher CPK levels than those with observed muscle weakness in all 4
`limbs.
`
`Urinalysis (day 29, 57): There were no remarkable changes in urine parameters
`_
`with treatment or dose. Males showed a slight increase in excretion of proteins and
`hippuric acid crystals at the HD. Daptomycin recovery inlthe urine ranged between 20%
`and 60%.
`
`Ophthalmoscopy: There were no remarkable changes with treatment.
`Gross Pathology: Foci in the intestines, hemorrhages near the injection site were
`common to both control and treated dogs; and, as such, are considered incidental. The
`early sacrifice HD female had interstitial inflannnation/consolidation in the lung.
`Organ weights: There were no statistically significant differences between organ
`weights in treated and control animals.
`Histopathology (all tissues in control, HD; skeletal muscle, peripheral nerve,
`kidney and gross lesions in LD, MD; skeletal muscle, peripheral nerve and gross lesions
`at recovery): The microscopic changes seen at the end of the treatment period were all
`grade 1-2 (minimal to slight). At the end ofthe recovery period, all findings were 61.
`The greatest damage (frequency, severity) was in nerves (sciatic, ulnar, spinal cord) and
`muscle.
`‘
`
`13
`
`

`

`
`Reviewer: W. Schmidt
`NDA No. 21572
`
`Incidence of microsco sic findin_s
`Males
`
`all minimal to sliht in severi
`Females
`
`'
`
`Early death
`
`N=l H
`
`Treatment
`n=4 H=3
`
`Recovery
`n= 2
`
`3H
`
`_ Treatment Recovery
`
`nfl
`
`5
`
`l
`—
`
`N
`
`I Brain—cranial nerve
`degeneration
`
`Spinal cord (cervical)—
`degeneration
`
`Spinal cord (thoracic)—
`de - eneration
`
`3 M, 4 H
`
`2 H
`
`] M, 4 H
`
`2 H
`
`---
`
`Spinal cord (thoracic)—nerve
`root degeneration
`
`Spinal cord (lumbar)——
`
`deeeneration
`
`
`Spinal cord (lumbar)—dorsal
`nerve root degeneration _
`
`
`
`Sciatic nerve—nerve fiber
`deceneration
`
`4 M, 4 H
`
`] H
`
`Sciatic nerve—blood vessel,
`fibrinoid necrosis
`Ulnar nerve—mixed inflam
`infiltr
`Ulnar nerve—nerve fiber
`degeneration
`
`Tongue—skeletal muscle
`degeneration
`
`Tongue—glossal nerve
`degeneration
`
`
`
`
`Skeletal muscle (biceps)—
`
`
`muscle de - eneration/atroh
`
`Skeletal muscle
`
`(semimembranosus)—
`degeneration/atroh
`Skeletal muscle
`
`
`(semimembranosus)—nerve
`
`fiber degeneration
`
`Skeletal muscle (quadriceps)—_
`
`deeeneration/atroh
`Skeletal muscle (quadriceps)—
`nerve fiber degeneration
`
`
`
`2H
`
`2
`
`H
`
`O
`
`#‘x‘
`
`"\
`
`Toxicokjnetics (half of dogs/group at 0, 5, 15, 30 minutes, 1, 3, 5, 24 hours on day
`1,27): Plasma samples were analyzed using -— method with a limit of
`quantitation of—ug/mL. There were no differences in toxicokjnetic parameters with
`‘ gender and minimal increases (probably within experimental error) between day 0 and
`day 27 values. The toxicokinetic parameters are summarized in the following table.
`
`l4
`
`2H
`
`1H
`
`2 :1:
`
`2H
`
`lM,3H
`
`1M,2H
`
`2M,3H
`
`u—INn—an—Iup)I—I
`
`
`
`:11:111$Ill::1:
`
`

`

`Reviewer: W. Schmidt
`
`NDA No. 21572
`
`647
`306
`104 II_ 251
`II-
`77.2—
`74 1
`65.4
`cr, mL/hr/k_
`-__188 _ -
`_
`06 .
`638 ‘
`740
`367
`
`{)1 Oa
`Males
`Females
`549
`647
`
`553
`
`269
`
`77.3
`
`.
`
`_ 5 .
`655
`
`782
`
`
`
`
`
`
`
`2
`—II_
`
`
`
`379 _lm_
`
`.2
`_l_
`
`mu—
`
`7
`
`
`
`0‘\I Ch
` I 177
`76
`
`
`
`
`
`
`
`
`
`
`AUC0.5_u.hr/mL
`
`251
`
`AUCO...u_.hr/mL
`
`- 1
`
`- AUCo¢.u.hr/ml.
`--_140
`-— 2.0
`-—__m_
`182
`
`
`303
`
`.’*\ .
`
`Comments and conclusions: Based on the numbers of animals studied and the toxicities
`
`observed, the study was adequate. The NOEL for this juvenile dog study is the low dose,
`20 mg/kg (the MD is a LOAEL). In the 1 month adult dog study, the NOEL was not
`determined and was less than l0 mg/kg/day. The Cmax at the lowest dose in the adult
`study was 260 ug/mL, which is in the range seen at the LOAEL. Although the
`microscopic damage was considered minimal to slight, the clustering in nerve and
`muscle, where lesions are seldom seen, makes these findings noteworthy.
`
`3.4.4 Genetic toxicology
`The ICH standard battery of tests for genotoxicity were conducted. In the Ames
`test, daptomycin in the presence and absence of metabolic enzymes (S9 fraction) did not
`increase the number of revertants. Similarly, in mouse lymphoma cells, daptomycin was
`negative for mutation. Daptomycin was not clastogenic in that no chromosomal
`aberrations were detected in Chinese Hamster ovary cells with/without metabolic
`activation. In vivo, daptomycin was negative in the mouse micronucleus assay. Two
`other assays of genotoxicity, unscheduled DNA synthesis in rat hepatocytes and sister
`chromosomal exchange in Chinese hamster cells were also negative. Adequate positive
`and negative controls as well as sufficiently high concentrations of drug were studied.
`Daptomycin was negative for mutagenicity and clastogenicity in all assays conducted.
`
`3.4.5 Carcinogenicity :
`No carcinogenicity studies were submitted to this NDA.
`
`3.4.6 Reproductive and developmental toxicology
`_
`Fertility (Segment 1), deveIOpmental (Segment II), and multi-generational
`(Segment Ill) reproductive studies have been conducted with daptomycin.
`In assays of
`fertility where male rats were treated for 10 weeks and females for 2 weeks prior to
`mating at doses up to 150 mg/kg/day i.v., no effects on fertility or offspring were seen.
`However, the parental rats showed significant signs of skeletal muscle toxicity at doses
`“nun-w
`
`15
`
`

`

`,4“
`
`Reviewer: W. Schmidt
`
`.
`
`NDA No. 21572
`
`225 mg/kg with sciatic nerve damage seen at 75 mg/kg. A Segment Ill rat toxicity study
`also showed no daptomycin effects in the offspring at doses up to 75 mg/kg/day, the
`highest dose tested.
`In developmental toxicity studies in rats and rabbits, the fetal NOELs were the
`highest dose tested (75 mg/kg/day i.v. in both species). Dams showed decrements in
`body weight gain at this dose in each study. The studies used adequate numbers of
`animals at sufficient doses and appeared well-conducted. Thus, daptomycin had no
`effects on fertility or fetal development in rats and rabbits.
`The sponsor did not conduct TK measurements in conjunction with the
`developmental toxicity studies. Thus, direct exposure comparisons to human levels are
`not possible. On a body surface area basis, the NOEL for developmental toxicity in the
`rat and rabbit, 3 and 6 fold margins between the animal and human models were
`observed. For fertility, a 6 fold margin of safety was seen between the rat NOEL and the
`proposed human dose on a body surface area basis. The sponsor calculated this on the
`basis of an extrapolated AUC and arrived at a 10 fold margin (actually 9 fold).
`
`3.4.7 Local tolerance
`
`3.4.8 Special Toxicology Studies
`The sponsor has conducted a series of studies to investigate special areas of
`toxicity (local reactions, immunogenicity, interactions with blood, ototoxicity),
`combination toxicity, as well as further investigations into the nerve and muscle toxicities
`seen in the standard toxicity studies. Screening methods for detecting damage to muscle
`and nerve were also explored.
`Daptomycin did not cause hemolysis or flocculation in dog or rat serum.
`Daptomycin was not a corneal or dermal irritant. No immunotoxicity, as demonstrated
`by hemagglutination or by antibody production following daptomycin challenge was
`seen. No ototoxicity was observed in guinea pig models. Combinations of daptomycin
`with gentamicin, tobramycin and simvastatin were investigated with minimal effects on
`renal, muscular and ototoxicity and no significant changes in pharmacokinetics.
`The screening methods for myelotoxicity included in vitro or single muscle in
`vivo preparations. CPK release, muscle cell viability were tried as endpoints. None of
`the tests resulted in a positive, dose dependent or specific signal.
`Finally, a series of studies further examined the muscle damage seen in rats and
`dogs, but did not further elucidate the nature/timecourse of the neurologic damage. Rat
`was a better model for muscle damage than dog as muscle damage was seen in the
`absence of neurologic microscopic changes. However, rats were used in a study on nerve
`fibers where casts were made of the nerves or nerves were teased apart. Here, there was
`a slight decrease in nerve fibers after daily dosing for 28 days at 100 mg/kyday (600
`mg/mz/day). Muscular damage was easily seen in the rat at 150 mg/kg (900