1.
`
`Introduction
`
`SCIENTIFIC DISCUSSION
`
`The majority of skin and soft tissues infections (SSTIs) are caused by usually Staphylococcus aureus
`or β-haemolytic streptococci. SSTIs are considered complicated when they involve deeper skin
`structures, such as fascia or muscle layers, require significant surgical intervention or arise in the
`presence of significant co-morbidity.
`
`The inexorable increase in the prevalence of bacterial resistance since the 1940s now threatens the
`utility of some antibiotics for treating certain species. Infections due to Gram-positive bacterial species
`are now the foremost problems in many specialised units and institutions. Methicillin-resistant S.
`aureus (MRSA), glycopeptide-insusceptible S. aureus (GISA) and glycopeptide-resistant enterococci
`(VRE or GRE), particularly E. faecium, are of particular concern. For example, the European
`Antimicrobial Resistance Surveillance System (EARSS) study of 2002 reported that 22% of S. aureus
`isolates were methicillin-resistant overall, with the highest rates recorded in participating centres in
`Greece (44%), Ireland (42%), Malta (43%) and the UK (44%). The highest rates of vancomycin-
`resistant E. faecium were reported from Greece (19%), Italy (21%) and Croatia (22%). Bulgaria,
`Greece and Hungary reported the highest prevalence of high-level aminoglycoside-resistant E.
`faecalis. Other gram-positive species, such as coagulase-negative staphylococci and Corynebacteria
`spp., have also caused problems due to acquisition of multiple resistance determinants.
`
`Therefore, there is a need for additional agents that might be clinically active against these difficult to
`treat pathogens to the existing antibiotic armamentarium.
`
`The present application for marketing authorisation of CUBICIN (350 or 500 mg powder for
`concentrate for solution for infusion) is made under Article 8.3 (i) and concerns a new active
`substance, daptomycin.
`
`Daptomycin is a novel cyclic lipopeptide derived from a natural product of Streptomyces roseosporus.
`
`The approved indication at the recommended dose of 4 mg/kg administered as a single daily dose for
`7-14 days or until the infection is resolved is: CUBICIN is indicated for the treatment of complicated
`skin and soft-tissue infections in adults (see sections 4.4 and 5.1 of the Summary of Product
`Characteristics).
`Daptomycin is active against Gram-positive bacteria only (see section 5.1 of the Summary of Product
`Characteristics). In mixed infections where Gram-negative and/or certain types of anaerobic bacteria
`are suspected, CUBICIN should be co-administered with appropriate antibacterial agent(s).
`
`2.
`
`Quality aspects
`
`Introduction
`
`CUBICIN is formulated as a single use powder for concentrate for solution for infusion containing
`350 mg or 500 mg of daptomycin, as active substance. Following reconstitution with 9 mg/ml (0.9%)
`sodium chloride for injection or water for injections (7 ml for the 350 mg strength and 10 ml for the
`500 mg strength) to yield to a 50 mg/ml solution, the product is administered by intravenous infusion
`after dilution in sodium chloride 9 mg/ml (0.9%).
`
`The other ingredients include sodium hydroxide.
`
`It is presented in 10 ml glass vials closed with a rubber stopper, an aluminium seal and a plastic flip-
`off cap.
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`Drug Substance
`
`Daptomycin is a novel macrocyclic peptide, with a decanoyl side chain linked to the N-terminus
`Tryptophan, produced by fermentation of Streptomyces roseosporus.It was selected based on a
`superior relative therapeutic index in mice from a 6-lipopeptide antibiotic complex in which each
`peptide has the same inactive 13 amino acid nucleus with various fatty acid acyl groups on the N-
`terminus. Detailed information on quality/control of materials used in the fermentation process and
`subsequent purification steps, has been provided by the way of an active substance master file.
`
`
`
`The frozen active substance yields a clear, dark yellow to light brown solution upon thawing. X-ray
`diffraction studies indicated that daptomycin powder is amorphous. It is highly soluble in water..
`Stress stability studies showed that it degradates when exposed to direct light, heat, oxygen and to
`extreme pHs in solution.
`
` •
`
`
`
`Manufacture
`
`
`Daptomycin is produced by 2 different manufacturers. The manufacturing process includes the
`following steps: fermentation (inoculum preparation, fermentation and harvest), purification by
`chromatography and ultrafiltration, and filling in low-density polyethylene (LDPE) bioprocess
`container. Critical process parameters have been identified and respective process ranges and/or set
`points have been satisfactorily established.
`Characterisation of impurities has been conducted based on detailed evaluation of daptomycin
`impurity profile. The main impurities include 3 fermentation process related impurities and three
`degradation products namely anhydro-daptomycin, ß-aspartyl isomer and lactone hydrolysis product
`of daptomycin. The only solvent used during synthesis is a class 3 solvent.
`
`During development, the active substance was obtained from 3 different manufacturers. Changes were
`made to the purification steps and to the final presentation of daptomycin (frozen concentrate instead
`of lyophilised powder). Comparative analytical results demonstrate that daptomycin batches used in
`pre-clinical and clinical studies produced according to the current and the earlier processes are
`physicochemically equivalent.
`
` •
`
`
`
`Specification
`
`
`The active substance specification includes tests for appearance, identity (UV and FTIR), assay
`(HPLC), impurity content (HPLC), residual solvents (GC), pH, bacterial endotoxins, microbial limits,
`specific rotation, heavy metals and residue on ignition.
`The impurity limits have been satisfactorily justified based on toxicology studies.
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`Batch analysis data provided for 5 consecutive commercial batches manufactured at one site and for 3
`consecutive batches manufactured at the other site confirm satisfactory compliance and uniformity
`with the proposed specifications.
`
` •
`
`
`
`Stability
`
`
`Stability data have been provided for 3 batches manufactured by both manufacturers. 6-month data are
`available under accelerated conditions (5ºC±3ºC – scale down commercial packaging) and up to
`2-year data are available under long-term conditions (-20ºC±5ºC – scale down commercial
`packaging). Samples were tested for appearance, assay, pH, and impurities.
`Data in support of the stability of the active substance when raised briefly to higher temperatures, as
`might be experienced during transit, were also satisfactory. Stress testing included photostability, pH
`stability profile, thermal degradation and oxidative degradation. 2 batches have been satisfactory
`studied for potential extractables and leachables following storage at -20ºC for up to 20 months.
`The proposed retest period is supported by the presented data when daptomycin is stored in a LDPE
`bioprocess container stored in a sealed plastic bag placed in a foil outer bag.
`
`Drug Product
`
` •
`
`
`
`Pharmaceutical Development
`
`
`The degradation profile of daptomycin was the main parameter to take into account during the
`pharmaceutical development (see active substance).
`
`The target in-process pH range (4.5-5.0) was selected based on the sensitivity of the active to extreme
`pHs. Given the high solubility of the active, the only excipients considered necessary were the vehicle,
`sodium hydroxide to achieve the target pH and nitrogen as process aid during lyophilisation. Sodium
`citrate and mannitol used as bulking agents for the formulation of early batches became unnecessary as
`the dose for clinical use increased. All the excipients are of PhEur quality. Regarding the TSE risk,
`CUBICIN does not contain any component of ruminant origin.
`The 5% daptomycin overfill is suitable to allow the label claim volume to be withdrawn from the vial
`after reconstitution.
`
`The container closure system, consisting of a type I glass vial closed by a rubber stopper capped with
`an aluminium seal and a flip-off plastic cap, meet the PhEur requirements. Integrity of the closure to
`microbiological and thermal challenges has been demonstrated.
`
`The reconstituted and diluted finished product has been shown to be physically and chemically
`compatible with sodium chloride for injection 9 mg/ml (0.9%), water for injections used as diluents
`and with some of the commonly intravenously administered medications (see section 6.6 of the SPC).
`Possible sorption of daptomycin on tubes and bags used during intravenous infusion has been
`satisfactorily investigated.
`
`In order to minimise potential daptomycin degradation during the manufacturing process, refrigerating
`conditions are used, lyophilisation is performed under nitrogen atmosphere and a prefiltration step was
`introduced prior to pooling of the bulk substance in order to reduce the processing time during sterile
`filtration process. The choice of sterilisation by filtration is justified by the peptidic nature of
`daptomycin and its sensitivity to heat.
`
`Slightly different formulations (including sodium citrate or mannitol used as bulking agents) and
`diluents have been used in early clinical studies. This is not expected to have any impact on the
`product performance based on the type of molecule and the mode of administration.
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` •
`
`
`
` •
`
`
`
`Manufacture of the Product
`
`
`CUBICIN is produced at two different sites. The method of manufacture involves the following
`operations designed to minimize any potential degradation of the active (see pharmaceutical
`development): thawing of the active substance, pre-filtration, pooling, pH and concentration
`adjustment, sterile filtration, filling, lyophilisation and packaging.
`Satisfactory operating parameters and in-process controls have been defined at each stage of
`manufacture. Holding times and conditions for the pooled active substance before dilution and for the
`formulated product before filling have been adequately justified based on validation data.
`Satisfactory validation data have been provided on production scale batches for the relevant strengths
`at both manufacturing sites.
`
`Product Specification
`
`
`The finished product specification include tests for appearance, identification (UV and FTIR), pH,
`assay (HPLC), powder fill weight, degradation products, uniformity of content (PhEur), water content
`(PhEur), bacterial endotoxins (PhEur), particulate contamination (PhEur), sterility (PhEur), container
`closure integrity and reconstitution time.
`The degradation products limits have been satisfactorily justified based on toxicology studies.
`Satisfactory batch analysis data have been provided for full-scale batches manufactured at both sites.
`
`Stability of the Product
`
`Before reconstitution and dilution
`
` •
`
`
`
`
`
` -
`
`
`Stability data are presented for 3 batches of each strength (250 mg/vial and 500 mg/vial). 3-year data
`under long term conditions (5ºC - proposed packaging) and under accelerated conditions
`(25ºC/60%RH - proposed packaging) have been provided.
`The parameters tested included appearance, assay, related substances, pH of reconstituted solution,
`water content, particulate contamination and container closure integrity. Photostability investigated in
`line with ICH recommendations showed that the product is not sensitive to light when stored in its
`original packaging.
`
`
`
`After reconstitution
`
` -
`
`
`Chemical and physical in-use stability of finished product has been examined after reconstitution with
`9 mg/ml (0.9%) sodium chloride for injection or water for injections. The reconstitution time is
`typically 15 minutes, which is rather long. This is specified in the Summary of Product Characteristics.
`
`
`- After reconstitution and dilution
`
`
`Chemical and physical in-use stability of the reconstituted finished product diluted in normal saline
`infusion bags has been studied.
`
`The results presented support the proposed shelf life and storage conditions defined in the Summary of
`Product Characteristics for the finished product before reconstitution and dilution, after reconstitution,
`and after reconstitution and dilution.
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`
`3. Non-clinical aspects
`
`Introduction
`
`The development of daptomycin began in the early 1980s but was terminated due to observations of
`adverse skeletal muscle effects in animals, and in a low number of subjects, during Phase 1 clinical
`trials. In the late 90’s Cubist licensed daptomycin from Lilly in 1997, the non-clinical and clinical
`development of daptomycin resumed.
`The development programme spans some 20 years, some studies were conducted prior to the issuance
`of CHMP/ICH guidelines. Nonetheless, the non-clinical studies were appropriately and adequately
`conducted for the state of the science of the day. Although the bulk of the toxicological assessment of
`daptomycin was performed in rats and dogs, primates were used in a single and a repeat dose study.
`All the pivotal in vivo toxicity studies (with the exception of genotoxicity) were conducted using the iv
`route of administration, the intended route of clinical administration. All of the pivotal repeat dose
`toxicity studies were conducted in compliance with Good Laboratory Practices (GLP) regulations. The
`lack of GLP compliance for selected acute toxicity and investigative studies as well as some
`toxicokinetic studies is not considered to have invalidated them.
`
`Pharmacology
`
`The primary pharmacology studies focused on in vitro microbiological profiling, animal models of
`infection, and pharmacodynamic studies correlating efficacy with pharmacokinetic parameters.
`Secondary and safety pharmacology studies were also performed.
`
` •
`
`
`
`Primary pharmacodynamics
`
`
`Daptomycin is a novel cyclic lipopeptide antibiotic derived from the fermentation of a strain of
`Streptomyces roseosporus.
`
`Daptomycin inserts directly into the cytoplasmic membrane of Gram-positive cells (aerobes and
`anaerobes). This action is calcium-dependent and results in a rapid depolarisation of the membrane,
`thus giving rise to the efflux of potassium ions. Bacterial DNA, RNA and protein synthesis is rapidly
`stopped with subsequent cell death that does not depend upon lysis. The antibacterial activity of
`daptomycin requires the presence of free calcium. The exact mechanism of action of daptomycin
`remains to be determined.
`
`Due to its different mechanism of action, the antibacterial activity of daptomycin is not affected by
`mechanisms that confer specific resistance to beta-lactam agents (including methicillin), glycopeptides
`(such as vancomycin), quinupristin/dalfopristin, linezolid or other agents potentially useful against
`Gram-positive bacterial species.
`
`In both in vitro and in vivo studies, the action of daptomycin was bactericidal against a number of
`clinically important antibiotic-resistant Gram-positive bacteria including Staphylococcus spp.
`(including both methicillin- and vancomycin-resistant isolates), Enterococcus spp. (including
`vancomycin-resistant isolates), and Streptococcus spp. (including penicillin-resistant isolates).
`Further information can be found in the clinical part under the pharmacodynamics section.
`
`Daptomycin had poor in vitro activity against both aerobic and anaerobic Gram-negative organisms.
`
` •
`
`
`
`Safety pharmacology
`
`
`Safety pharmacology was primarily investigated in rodents, dogs, and in vitro models. No adverse
`effects on the cardiovascular, respiratory, renal, gastrointestinal or immune systems were observed in
`vivo at clinically relevant doses.
`
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`Daptomycin’s effects on the central nervous system as well as the neuromuscular system were
`assessed in a series of in vivo and in vitro studies. Effects on the nervous and/or muscular system were
`evident at high dose iv levels in rodents (≥ 50 mg/kg). Depressive clinical signs included abnormal
`gait and/or posture, and decreased motor activity and motor coordination.
`Marked effects on the central nervous system in animals were observed only at iv dose levels of
`≥ 150 mg/kg. At doses ≥ 200 mg/kg in mice, tremors and clonic convulsions were observed; with
`death occurring at ≥ 1000 mg/kg. No corresponding effects were observed in rats at 150 mg/kg.
`
`No effect on EEG or neuromuscular conduction was noted in dogs after acute administration of
`daptomycin at iv dose levels of 50 and 30 mg/kg, respectively.
`
`Daptomycin appears to have no clinically relevant pharmacological activity in cardiac or smooth
`muscle. In vitro, at high concentrations (up to 25-fold peak plasma concentration observed in patients
`at intended clinical dose of 4 mg/kg/day), no effects were seen in cardiac (atria) or smooth muscle
`preparations (ileum, jejunum, or aorta). Effects were limited to selective antagonism of rat uterus and
`vas deferens smooth muscle preparations. However, the concentration at which these effects were
`observed (160 µg/ml free drug) is 30-fold greater than the maximal concentration of free drug in
`patients at the intended clinical dose of 4 mg/kg/day.
`
`There was no potential for prolongation of QT interval based on exposure of the hERG channel up to
`100 times the clinical plasma concentrations.
`
` •
`
`
`
`Pharmacodynamic drug interactions
`
`
`Use of daptomycin in combination therapy was investigated in a number of animal models of
`infection. These studies showed synergistic increases in efficacy with amikacin, tobramycin,
`gentamicin and rifampicin.
`
`Pharmacokinetics
`
`Single and multiple dose pharmacokinetics studies were conducted in mice, rats, beagle dogs, and
`rhesus monkeys using both unlabelled and radiolabelled daptomycin. As the intended clinical route is
`intravenous, the majority of the studies used this route of administration. Toxicokinetic studies were
`included in the 6-month rat study (Day 1 only) and in all repeat-dose studies in dogs (up to 6-months)
`and in monkeys (1-month).
`information on
`Published
`literature on daptomycin provided supportive data, as well as
`pharmacokinetics in other species, such as rabbits and guinea pigs, and information on serum protein
`binding. Methods of analysis were adequate.
`
` •
`
`
`
`Absorption- Bioavailability
`
`
`Overall, the pharmacokinetic characteristics were generally comparable across the 4 species tested.
`
`Studies in rats showed that daptomycin was poorly absorbed orally and exhibited slow passage
`through the gastrointestinal tract with > 90% excreted in the faeces.
`
`Limited data indicated a relatively high bioavailability after s.c. or i.p. administration. Daptomycin
`plasma profile following iv injection was consistent with a 2-compartement model with a rapid
`distribution phase and slower elimination phase.
`Daptomycin exhibited linear kinetics following intravenous injection across a dose range of 1 to
`50 mg/kg in the rat, 1 to 200 mg/kg in the dog, and 1 to 25 mg/kg in the monkey.
`
`For all species, plasma clearance, volume of distribution, and terminal half-life were dose-independent
`over the linear range. Within the linear range, terminal half life of daptomycin was 1 – 3 hours in
`rodents and 2 – 4 hours in non-rodents. The pharmacokinetic profile of daptomycin was similar
`between strain and gender and was not altered upon repeated daily administration for up to 6 months.
`
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`Distribution
`
`•
`
`In the rat, the only species in which tissue distribution was studied, daptomycin distributes rapidly
`from the plasma to the tissues with a distribution phase half-life (t½ α) of approximately 7 minutes.
`The volume of distribution was essentially the same (approximately 60 to 160 ml/kg) in mice, rats,
`dogs, monkeys and humans, and clearance scales to body size. Daptomycin appears to distribute
`preferentially to the kidneys, reflecting the vascularisation of the tissue as well as renal concentration
`of the drug during excretion. Daptomycin is shown cross the placenta in pregnant rats and to enter the
`CNS, but data suggest that no extensive penetration across the blood-brain or placental barriers appear
`to occur. .
`
`In general, the half-life in tissues was slightly greater than that in plasma and tissue levels were higher
`after repeated dosing than after a single dose. No accumulation was observed in plasma upon repeated
`administration in rats, dogs, or monkeys.
`
`There is no data on the excretion of daptomycin into milk. Therefore,
`breastfeeding should be discontinued during treatment as indicated in the Summary of Product
`Characteristics.
`
`Published data indicated that the extent of protein binding was the same in mice, rabbits and humans
`(approximately 90%). Although direct measurements were lacking in rats, dogs and monkeys,
`pharmacokinetic data suggested that the extent of protein binding was consistent among species.
`
` •
`
`
`
`Metabolism (in vitro/in vivo)
`
`
`In vivo metabolism studies performed in mice, rats, dogs and monkeys showed that daptomycin
`exhibited limited metabolism. Although the studies were not up to the current standard,
`pharmacokinetics data showed that daptomycin was primarily eliminated in animals as intact in the
`urine confirming that it undergoes little or no systemic metabolism. PK studies indicated that it did not
`appear to inhibit or induce any of the key cytochrome P450 isoenzymes. Therefore, the potential for
`metabolic drug-drug interactions should be limited and the potential for pharmacokinetic drug
`interactions with daptomycin is probably low.
`
` •
`
`
`
`Excretion
`
`
`Daptomycin was excreted primarily via the kidney largely as unchanged. In mice, rats, dogs, monkeys
`most of the compound (≥ 70 %) was recovered in the urinary within 48 hours post-dose. Faecal
`excretion accounted for approximately 3 to 10 % of the administered radioactivity in these species.
`This is comparable to the human data. In rats less than 2 % of the administered radioactivity was
`recovered in the expired air.
`
` A
`
` study in juvenile dogs showed that total systemic clearance appears to be faster in juvenile dogs as
`compared to adults, resulting in shorter terminal half-life and lower AUC0-24, at the same dose level.
`
`In rats with renal impairment, the systemic clearance was reduced by ~70 % compared to that of
`normal rats. This resulted in a ~1.5 to 2-fold increase in peak plasma concentration (Tmax), a 2 to 3-
`fold increase in the AUC, and increased half-life. Volume of distribution was decreased by 53 %.
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`Toxicology
`
` •
`
`
`
`Single dose toxicity
`
`
`After single dose iv bolus injection of daptomycin, clinical signs suggestive of toxicity to the skeletal
`muscle and/or nervous systems (CNS and peripheral nerves) were evident in all 4 species (mouse, rat,
`dog and monkey) and were accompanied by decreases in body weight and/or body weight gain in
`rodents and dogs. Mortality occurred across animal species at dose levels 25 to >100 fold higher than
`the clinical dose of 4 mg/kg. In mice, there were no significant toxicity signs after single oral
`administration up to 2000 mg/kg. Sc administration of daptomycin to rats was less toxic than iv
`injection. The peak plasma levels of daptomycin in animals at the minimal lethal dose ranged from
`approximately 30 to 100 times that at the intended clinical dose. Primates appeared to be the most
`sensitive animal species.
`
` •
`
`
`
`Repeat dose toxicity (with toxicokinetics)
`
`
`The repeat dose toxicity has been studied in rats and dogs up to 6 months, and monkeys up to 1 month.
`Daptomycin was administered by bolus iv injection in all studies, with one study also investigating
`administration via 30 minute iv infusion. For most studies, daptomycin was administered once daily,
`except for select investigative studies in which it was also administered every 8 hours. The main
`finding are displayed in Table 1.
`
`Table 1:
`Species/strain
`
`Signs of toxicity identified
`
`Study
`duration
`1 month
`Rat Fischer
`1 month
`Rat Fischer
`3 months
`Rat Fischer
`3 months
`Rat Fischer
`6 months
`Rat Fischer
`2 weeks
`Dog Beagle
`1 month
`Dog Beagle
`6 months
`Dog Beagle
`Monkey Rhesus 1 month
`
`Dose range
`(mg/kg/day)
`25-150
`10-20
`1-20
`5-80
`2-50
`25-100
`10-75
`2-40
`1-10
`
`Skeletal myopathy, renal effects, peripheral neuropathy (high dose)
`Skeletal myopathy, renal effects.
`Skeletal myopathy.
`Skeletal myopathy, renal effects, bone marrow.
`Skeletal myopathy, bone marrow.
`Skeletal myopathy, nerve.
`Skeletal myopathy, peripheral neuropathy (high dose), bone marrow.
`Skeletal myopathy, nerve, bone marrow.
`No evidence of skeletal myopathy, peripheral neuropathy or renal
`changes
`
`
`The results of the repeat dose and investigative studies consistently demonstrated daptomycin’s
`primary target organ to be skeletal muscle in rats and dogs, with effects observed in peripheral nerve at
`higher dose levels in both species.
`
`Skeletal muscle
`
`Daptomycin-induced myopathy was specific to the skeletal muscle in the rat and dog, which occurred
`at exposure levels below human therapeutic levels. No functional or pathological changes were
`observed in cardiac or smooth muscle.
`Microscopic changes to skeletal muscles were typically characterised by minimal to mild degeneration
`with regeneration. Degeneration was confined to a few (single, randomly distributed) myofibres.
`Under light microscopy, degeneration was generally characterised by myofibre swelling, sarcoplasmic
`hyalinization or vacuolation, fragmentation and/or loss of cross striations, accompanied by
`inflammatory infiltrates. Electron microscopic examination of slightly degenerative fibres revealed
`streaming of the Z-band and, in more affected fibres, disorganisation and loss of myofilaments and
`minimal myofibril lysis, occasionally associated with mitochondria swelling and aggregation. In the
`degenerative fibres, there was no evidence of disruption of cristae or calcium deposits in the
`mitochondria. All muscle effects, including microscopic changes, were reversible within 3 months
`following cessation of dosing.
`No evidence of rhabdomyolysis was observed even at the highest dose levels tested in non-clinical
`studies.
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`
`The degrees of skeletal myopathy appeared to be related to the dosing frequency and AUC, and were
`usually accompanied by elevations in creatinine phosphokinase (CPK). It was hypothesised that once-
`daily administration reduced the potential for skeletal myopathy because this dose regimen results in
`more time at low plasma concentrations and, consequently, greater time between doses for repair of
`the affected myofibres. Dog studies have demonstrated that serum daptomycin levels below 10 µg/ml
`were not associated with cumulative skeletal muscle damage.
`
`Although the precise mechanism of daptomycin’s effect on skeletal muscle has not been completely
`elucidated several possible mechanisms were ruled out based on comparisons with other myotoxic
`drugs. Daptomycin-induced myopathy did not appear to share the characteristics associated with
`inflammatory myopathy or rhabdomyolysis, and the muscle damage is unlikely to be mediated through
`a direct effect on calcium flux and/or channels. Daptomycin probably causes a direct effect on skeletal
`muscle rather than an indirect effect through alterations in associated tissue(s). Daptomycin had no
`effect on the contractility of vascular tissue, which could lead to ischemia-reperfusion of the muscle
`fibres. Daptomycin-related myopathy was observed at dose levels that are not associated with
`peripheral neuropathy, indicating that the mechanism of muscle toxicity is not related to a change in
`muscle fibre innervation or secondary to the nerve effects.
`
`Peripheral nerves
`
`Daptomycin treatment was also associated with effects on peripheral nerves in adult rats and dogs at
`doses higher than those associated with skeletal myopathy. Dog was the most sensitive species. In
`juvenile dogs, degenerative effects in the peripheral nerve and spinal cord were evident at a dose of 50
`mg/kg/day, which was a lower dose than those producing muscle lesions (see “Other toxicity
`studies”). The peripheral neuropathy was characterised by axonal degeneration in the absence of
`effects on the neuronal cell body; these microscopic lesions were associated with clinical signs (e.g.
`abnormal posture and gait, as well as impaired coordination, inability to stand, and sternal
`recumbency) and electrophysiological evidence (e.g. reduction in nerve conduction velocities for both
`motor and sensory nerves).
`Peripheral neuropathy appears to be related to Cmax. Across the repeat dose studies, the severity of
`morphologic lesions in the nerve increased with dose but not duration of dose administration.
`Peripheral nerve effects appeared to be reversible during a 6-months recovery period, consistent with
`the absence of a microscopic effect on the neuron. The rate of recovery from daptomycin-related nerve
`effects appears to be dependent upon severity of the effects and, therefore, dose. Assessment of
`reversibility was, however, limited to studies in dogs. No mechanistic studies have been conducted on
`the peripheral neuropathy. Non-clinical studies have shown nonetheless that skeletal muscle and
`peripheral nerves effects are independent (i.e. myopathy not secondary to neuropathy).
`
`Other effects
`
`Mild renal and gastrointestinal effects were observed in rats, but appeared to be species-specific as
`they were not evident in either dogs or monkeys.
`The localisation of daptomycin in the kidney of rats may explain the mild nephrotoxic effects
`observed in this species. No indication of kidney toxicity was observed in either the dog or the
`monkey after repeat dose injection, suggesting that renal accumulation of daptomycin either did not
`occur or was non-toxic in these species.
`Signs of bone marrow toxicity (decreased myeloid to erythroid ratio, decreased erythrocyte,
`reticulocyte, total leukocyte and neutrophil, thrombocyte and monocyte numbers) were observed in
`both rats and dogs. These changes, although not consistent in pattern, were treatment-related and
`occurred at low doses (2 mg/kg/day in the rat). The re-examination of these findings suggested that
`any apparent haematological/bone marrow effects were adaptive as opposed to treatment-related bone
`marrow toxicity.
`
`Adverse effects of daptomycin on circulating immune cells were occasionally observed in rats and
`dogs. Nonetheless, considering its antibiotic activity, it was considered possible that administration of
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`daptomycin to normal healthy rats and dogs could be associated with slight effects on immune-system
`related parameters because of a decrease in normal bacterial flora.
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`Genotoxicity in vitro and in vivo (with toxicokinetics)
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`Testing of daptomycin for genotoxicity with a battery of tests in bacteria, mammalian cells, and in
`vivo, did not reveal genotoxic effects of daptomycin in different concentrations and dose levels.
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` Carcinogenicity (with toxicokinetics)
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`No carcinogenicity studies have been conducted with daptomycin in view of the expected short
`duration of treatment (less than 6 months). This is consistent with the current international guidelines
`on carcinogenicity testing.
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`Reproductive and developmental studies
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`Daptomycin administered by iv bolus injection had no effect on fertility parameters in male and female
`rats. NOAEL for reproductive effects was 150 mg/kg/day and for parental toxicity < 25 mg/kg/day.
`Effects on offspring were limited to a transient decrease in body weight at 150 mg/kg/day. This effect
`which was attributed to maternal toxicity was reversible 14 days postpartum.
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`Two teratology studies were conducted in rats and rabbits with doses up to 75 mg/kg/day during
`organogenesis. Daptomycin was not teratogenic in either species. The NOAEL for maternal toxicity
`was 20 mg/kg/day and for teratogenic effects 75 mg/kg/day.
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`The effects of daptomycin on peri and post-natal development were evaluated in rats receiving daily
`intravenous bolus injection of daptomycin with dose level up to 75 mg/kg/day. Reproduction was not
`affected in the F0 animals, and no treatment-related developmental toxicity was noted in the offspring.
`No treatment-related effect