Australian Public Assessment Report
`for Dimethyl Fumarate
`
`Proprietary Product Name: Tecfidera
`
`Sponsor: Biogen Idec Australia Pty Ltd
`
`October 2013
`
`Page 1 of 87
`
`Biogen Exhibit 2004
`Mylan v. Biogen
`IPR2018-01403
`
`

`

`About the Therapeutic Goods Administration (TGA)
`
`Therapeutic Goods Administration
`• The Therapeutic Goods Administration (TGA) is part of the Australian Government
`Department of Health and is responsible for regulating medicines and medical devices.
`• The TGA administers the Therapeutic Goods Act 1989 (the Act), applying a risk
`management approach designed to ensure therapeutic goods supplied in Australia
`meet acceptable standards of quality, safety and efficacy (performance), when
`necessary.
`• The work of the TGA is based on applying scientific and clinical expertise to decision-
`making, to ensure that the benefits to consumers outweigh any risks associated with
`the use of medicines and medical devices.
`• The TGA relies on the public, healthcare professionals and industry to report problems
`with medicines or medical devices. TGA investigates reports received by it to
`determine any necessary regulatory action.
`• To report a problem with a medicine or medical device, please see the information on
`the TGA website <http://www.tga.gov.au>.
`• An Australian Public Assessment Record (AusPAR) provides information about the
`evaluation of a prescription medicine and the considerations that led the TGA to
`approve or not approve a prescription medicine submission.
`• AusPARs are prepared and published by the TGA.
`• An AusPAR is prepared for submissions that relate to new chemical entities, generic
`medicines, major variations, and extensions of indications.
`• An AusPAR is a static document, in that it will provide information that relates to a
`submission at a particular point in time.
`• A new AusPAR will be developed to reflect changes to indications and/or major
`variations to a prescription medicine subject to evaluation by the TGA.
`
`About AusPARs
`
`Copyright
`
`© Commonwealth of Australia 2013
`This work is copyright. You may reproduce the whole or part of this work in unaltered form for your own personal
`use or, if you are part of an organisation, for internal use within your organisation, but only if you or your
`organisation do not use the reproduction for any commercial purpose and retain this copyright notice and all
`disclaimer notices as part of that reproduction. Apart from rights to use as permitted by the Copyright Act 1968 or
`allowed by this copyright notice, all other rights are reserved and you are not allowed to reproduce the whole or any
`part of this work in any way (electronic or otherwise) without first being given specific written permission from the
`Commonwealth to do so. Requests and inquiries concerning reproduction and rights are to be sent to the TGA
`Copyright Officer, Therapeutic Goods Administration, PO Box 100, Woden ACT 2606 or emailed to
`<tga.copyright@tga.gov.au>.
`AusPAR Tecfidera Dimethyl Fumarate Biogen Idec Australia Pty LtdPM-2012-00808-3-1
`Final 22 October 2013
`
`
`Page 2 of 87
`
`Page 2 of 87
`
`

`

`Therapeutic Goods Administration
`Contents
`List of abbreviations __________________________________________________________ 4
`I. Introduction to product submission _____________________________________ 7
`Submission details ____________________________________________________________________ 7
`Product background __________________________________________________________________ 7
`Regulatory status _____________________________________________________________________ 9
`Product Information__________________________________________________________________ 9
`II. Quality findings _____________________________________________________________ 9
`Drug substance (active ingredient) _________________________________________________ 9
`Drug product _________________________________________________________________________ 10
`Biopharmaceutics ___________________________________________________________________ 11
`Advisory committee considerations _______________________________________________ 13
`Quality summary and conclusions _________________________________________________ 13
`III. Nonclinical findings _____________________________________________________ 13
`Introduction __________________________________________________________________________ 13
`Pharmacology ________________________________________________________________________ 13
`Pharmacokinetics ____________________________________________________________________ 17
`Toxicology ____________________________________________________________________________ 21
`Nonclinical summary ________________________________________________________________ 38
`Conclusions and recommendation _________________________________________________ 40
`IV. Clinical findings __________________________________________________________ 41
`Introduction __________________________________________________________________________ 41
`Contents of the clinical dossier _____________________________________________________ 42
`Pharmacokinetics ____________________________________________________________________ 43
`Pharmacodynamics__________________________________________________________________ 45
`Efficacy _______________________________________________________________________________ 45
`Safety _________________________________________________________________________________ 48
`Evaluator’s overall conclusions on clinical safety _________________________________ 53
`List of questions _____________________________________________________________________ 53
`Clinical summary and conclusions _________________________________________________ 54
`Second round evaluation of clinical data submitted in response to questions _ 55
`Pregnancy category _________________________________________________________________ 64
`Revision to the PI ____________________________________________________________________ 65
`Second round benefit-risk assessment ____________________________________________ 65
`Second round recommendation regarding authorisation ________________________ 65
`V. Pharmacovigilance findings ____________________________________________ 65
`AusPAR Tecfidera Dimethyl Fumarate Biogen Idec Australia Pty LtdPM-2012-00808-3-1
`Page 3 of 87
`Final 22 October 2013
`
`
`Page 3 of 87
`
`

`

`Therapeutic Goods Administration
`Risk management plan ______________________________________________________________ 65
`VI. Overall conclusion and risk/benefit assessment __________________ 72
`Quality ________________________________________________________________________________ 73
`Nonclinical ___________________________________________________________________________ 73
`Clinical ________________________________________________________________________________ 74
`Risk management plan ______________________________________________________________ 79
`Risk-benefit analysis ________________________________________________________________ 80
`Outcome ______________________________________________________________________________ 86
`Attachment 1. Product Information ____________________________________ 86
`Attachment 2. Extract from the Clinical Evaluation Report __________ 86
`
`
`
`List of abbreviations
`Abbreviation
`Meaning
`
`Nine-Hole Peg Test
`9HPT
`adverse event
`AE
`analysis of covariance
`ANCOVA
`area under the curve
`AUC
`Tecfidera (dimethyl fumarate)
`BG00012
`twice daily
`BID
`confidence interval
`CI
`maximum plasma concentration
`Cmax
`central nervous system
`CNS
`case report form
`CRF
`clinical study report
`CSR
`dimethyl fumarate
`DMF
`disease modifying therapy
`DMT
`Expanded Disability Status Scale
`EDSS
`European Quality of Life-5 Dimensions Health Survey
`EQ-5D
`GA
`glatiramer acetate
`AusPAR Tecfidera Dimethyl Fumarate Biogen Idec Australia Pty LtdPM-2012-00808-3-1
`Final 22 October 2013
`
`
`Page 4 of 87
`
`Page 4 of 87
`
`

`

`Therapeutic Goods Administration
`
`Abbreviation
`
`Meaning
`
`gadolinium
`Gd
`interferon beta
`IFN β
`intramuscular
`IM
`Independent Neurology Evaluation Committee
`INEC
`Intent-to-treat
`ITT
`intravenous
`IV
`Intravenous methylprednisolone
`IVMP
`Mental Component Summary
`MCS
`monomethyl fumarate
`MMF
`magnetic resonance imaging
`MRI
`multiple sclerosis
`MS
`Multiple Sclerosis Functional Composite
`MSFC
`magnetization transfer ratio
`MTR
`nuclear factor (erythroid-derived 2) related factor 2
`Nrf2
`3-Second Paced Auditory Serial Addition Test
`PASAT-3
`percent brain volume change
`PBVC
`Physical Component Summary
`PCS
`pharmacodynamics
`PD
`pharmacokinetics
`PK
`primary progressive multiple sclerosis
`PPMS
`progressive-relapsing multiple sclerosis
`PRMS
`once daily
`QD
`relapsing-remitting multiple sclerosis
`RRMS
`serious adverse event
`SAE
`Short Form-36® Health Survey
`SF-36
`SC
`subcutaneous
`SIENA
`Structural Image Evaluation of Normalized Atrophy
`AusPAR Tecfidera Dimethyl Fumarate Biogen Idec Australia Pty LtdPM-2012-00808-3-1
`Final 22 October 2013
`
`
`Page 5 of 87
`
`Page 5 of 87
`
`

`

`Therapeutic Goods Administration
`
`Abbreviation
`
`SPMS
`T25FW
`TID
`VAS
`
`Meaning
`
`secondary progressive multiple sclerosis
`Timed 25-Foot Walk
`3 times daily
`Visual Analogue Scale
`
`AusPAR Tecfidera Dimethyl Fumarate Biogen Idec Australia Pty LtdPM-2012-00808-3-1
`Final 22 October 2013
`
`
`Page 6 of 87
`
`Page 6 of 87
`
`

`

`I. Introduction to product submission
`
`Therapeutic Goods Administration
`
`Submission details
`Type of submission
`
`Approved therapeutic use:
`
`Route of administration:
`
`Dosage:
`
`ARTG numbers:
`
`Product background
`
`Tecfidera is indicated in patients with relapsing multiple sclerosis to reduce the
`frequency of relapses and to delay the progression of disability.
`
`Decision:
`
`Date of decision:
`
`Active ingredient:
`
`Product name:
`
`Dose form:
`
`Strengths:
`
`Container:
`
`Pack sizes:
`
`New Chemical Entity
`Approved
`3 July 2013
`Dimethyl Fumarate
`Tecfidera1
`Sponsor’s name and address: Biogen Idec Australia Pty Ltd
`PO Box 380, North Ryde BC NSW 1670
`Modified release capsules
`120 mg and 240 mg
`Blister pack
`14 and 112 capsules (120 mg)
`14 and 56 capsules (240 mg)
`Tecfidera is indicated in patients with relapsing multiple
`sclerosis to reduce the frequency of relapses and to delay the
`progression of disability.
`Oral (PO)
`The starting dose for Tecfidera is 120 mg twice a day orally.
`After 7 days, increase to the recommended dose of 240 mg twice
`a day orally
`197119 and 197118
`This AusPAR describes and application by the sponsor Biogen Idec Australia Pty Ltd to
`register encapsulated enteric coated microtablets containing the new chemical entity
`dimethyl fumerate under the trade name Tecfidera.
`The sponsor proposed the following indication in their application letter:
`The maximum recommended dose was proposed as 240 mg twice daily orally. A maximum
`duration of dosing was not specified.
`1 The tradename was amended during evaluation, from Neutrinza to Tecfidera. The tradename was amended in
`the USA as it was considered too similar to Neurontin. The new tradename was subsequently accepted by the
`TGA.
`AusPAR Tecfidera Dimethyl Fumarate Biogen Idec Australia Pty LtdPM-2012-00808-3-1
`Page 7 of 87
`Final 22 October 2013
`
`
`Page 7 of 87
`
`

`

`Therapeutic Goods Administration
`MS is characterised by the development of inflammatory plaques in the central nervous
`system including the brain, spinal cord and optic nerves. The primary process is
`inflammatory damage to the myelin of the central nervous system which may be
`reversible but axonal damage may also occur and leads to increasing permanent disability.
`MS also has a degenerative component and is associated with progressive brain atrophy.
`The mechanism of action of dimethyl fumarate (abbreviated to DMF) addresses MS
`pathogenesis on multiple levels demonstrating anti-inflammatory and immunomodulatory
`properties. Both DMF and its primary metabolite monomethyl fumarate (MMF)
`significantly reduce immune cell activation and subsequent release of pro-inflammatory
`cytokines in response to inflammatory stimuli and also affect lymphocyte phenotypes
`through a down-regulation of pro-inflammatory cytokine profiles (TH1, TH17) and biases
`towards anti-inflammatory production (TH2). DMF also appears to promote improvement
`in blood brain barrier integrity.
`Other oral agents approved for treatment of relapsing forms of MS are fingolimod
`(Gilenya) and teriflunomide (Aubagio). Another oral immunomodifier, cladribine
`(Movectro) was approved in August 2010 for Relapsing Remitting Multiple Sclerosis
`(RRMS) only and only for up to 2 years but was subsequently withdrawn from the market
`by the sponsor. Other immunomodifier agents for MS include: interferon beta-1a,
`interferon beta-1b, glatiramer and natalizumab. Fampridine, is an orally administered
`non-disease modifying medication for MS. It was approved in Australia in May 2011 for
`the symptomatic improvement of walking ability in adult patients with MS who have
`shown improvement after 8 weeks of treatment.
`The interferons and glatiramer have indications that include treatment after a single
`demyelinating event with associated brain magnetic resonance imaging (MRI)
`abnormalities characteristic of MS. Natalizumab is indicated only for treatment of RRMS.
`Interferon β-1b and natalizumab have indications which include delaying progression of
`disease/disability and reduction in frequency of relapse.
`The precise mechanism of action of dimethyl fumarate (DMF) in MS is unclear. The
`sponsor claims that pharmacodynamic effects appear to be predominately mediated
`through activation of the nuclear factor (erythroid-derived 2)-related factor 2 (Nrf2)
`antioxidant response pathway, which is the primary cellular defence system for
`responding to a variety of potentially toxic stimuli. It may also have an
`immunomodulatory or anti-inflammatory action. In a variety of animal models, including
`collagen-induced arthritis and experimental autoimmune encephalitis, DMF was observed
`to reduce cytokine production and inflammation. Experimental autoimmune encephalitis
`is an animal model of antigen-induced central nervous system (CNS) inflammation that
`has many parallels with MS. Efficacy in that setting suggested that a similar benefit might
`be achieved in humans with MS.
`The sponsor initially requested an indication for all forms of relapsing MS. As noted in
`discussions of recent submissions concerning MS, the McDonald’s criteria for diagnosis of
`MS were amended in 2010. Patients with a single clinical episode and evidence of past
`demylination on MRI are now regarded as having clinically definite MS.
`The Guideline on clinical investigation of Medicinal Products for the Treatment of Multiple
`Sclerosis provides the following advice on primary efficacy parameters in clinical trials for
`RRMS:
`• The most relevant parameter in MS, the accumulation of disability, usually takes place
`over many years.
`• Changes in progression of disability in a few years, which can be shown in clinical
`trials, could be accepted as a proof of efficacy, although it would be highly desirable to
`evaluate if the effect is maintained on a long-term basis.
`AusPAR Tecfidera Dimethyl Fumarate Biogen Idec Australia Pty LtdPM-2012-00808-3-1
`Page 8 of 87
`Final 22 October 2013
`
`
`Page 8 of 87
`
`

`

`•
`
`•
`
`•
`
`Regulatory status
`
`Therapeutic Goods Administration
`Changes in progression of disability should be distinguished between accumulation of
`disability in relation to relapses in Relapsing Remitting Multiple Sclerosis (RRMS) and
`progression of disability in Secondary Progressive Multiple Sclerosis (SPMS) or in
`Primary Progressive Multiple Sclerosis (PPMS).
`In patients with RRMS or SPMS with superimposed relapses (RMS), the primary
`efficacy parameter may also be the relapse rate although the number, duration or
`severity of relapses cannot be taken as a surrogate for disease progression and this
`would be expressed accordingly in the EU Summary of Product Characteristics (SmPC)
`(Product information in Australia).
`Progression of disability should be evaluated and worsening of disability should be
`reasonably excluded by means of adequately powered long-term studies.
`At the time of submission dimethyl fumarate (DMF) did not have marketing approval in
`any country but similar applications had been lodged in the European Union under the
`Centralised Procedure, the USA, Switzerland and Canada. DMF has subsequently been
`approved for marketing in Canada with an indication for RRMS and the USA with an
`indication for relapsing forms of MS (see Table 1 below).
`
`Table 1. International regulatory status
`
`Product Information
`
`The approved Product Information (PI) current at the time this AusPAR was prepared can
`be found as Attachment 1.
`
`II. Quality findings
`
`Drug substance (active ingredient)
`
`Both DMF and Monomethyl Fumarate (MMF) (structures reproduced below) are achiral.
`The substance proposed for registration is the (E)-isomer, and is manufactured by
`chemical synthesis.
`
`AusPAR Tecfidera Dimethyl Fumarate Biogen Idec Australia Pty LtdPM-2012-00808-3-1
`Final 22 October 2013
`
`
`Page 9 of 87
`
`Page 9 of 87
`
`

`

`Figure 1. Chemical structures of DMF and MMF
`
`Therapeutic Goods Administration
`
`Drug product
`
`Monomethyl Fumarate (CAS No 2756-87-8)
`Dimethyl Fumarate (CAS No 624-49-7)
`Only a single polymorph or pseudopolymorph has been described in the literature. The
`applicant has claimed that the drug is BCS Class 1.2 Technically, this is not the case;
`although “highly soluble” across the pH range 4.0 – 8.0, dimethyl fumarate is acid labile.
`Further, no evidence was provided to support the implicit claim that the substance is also
`“highly permeable”; however, the literature3 reports that of a series of homologous
`fumarates DMF showed the highest permeability in the Caco-2 cell model. However, in
`permeation experiments with intestinal mucosa in Ussing-type chambers, no undegraded
`DMF was found on the receiver side, indicating complete metabolism in the intestinal
`tissue.
`Dimethyl fumarate does not have any ionisable group; therefore, no pKa was determined.
`Only two impurities have been found in the drug substance: MMF and fumaric acid. Both
`are human metabolites and are adequately controlled in the active pharmaceutical
`ingredient (API) specification.
`The drug products are enteric coated microtablets encapsulated in hard gelatin capsule,
`and containing dimethyl fumarate 120 mg or 240 mg. A gastro resistant dosage form was
`necessary due to the acid lability of DMF.
`The 120 mg capsule has a white body and green cap whereas the 240 mg capsule has a
`green body and green cap.
`The formulation of the 240 mg product (which was developed after the 120 mg capsule) is
`different to that of the 120 mg product.
`The US FDA Office of Generic Drugs4 has not recommended any specific dissolution test
`method conditions for this product. The chosen method closely resembles Method B for
`delayed release dosage forms as described in USP <711>.
`A shelf life of 36 months stored below 30°C has been allocated to the 120 mg capsule on a
`risk management basis; however, the limited data only support a shelf life of 9 months
`stored below 30°C for the 240 mg capsule. Although a tighter lower Assay limit has not
`been applied at batch release to accommodate decreases in active content observed
`during stability trials of the capsules, the 36 months shelf life has allocated on the grounds
`that:
`2 The Biopharmaceutics Classification System (BCS) is a guidance for predicting the intestinal drug absorption
`provided by the U.S. Food and Drug Administration. According to the BCS, drug substances are classified as
`follows: Class I: high permeability, high solubility; Class II: high permeability, low solubility; Class III: low
`permeability, high solubility; Class IV: low permeability, low solubility.
`3 Werenberg, D R et al; Biopharm Drug Dispos. 24(6), (2003), pp 259 - 273
`4 US FDA Office of Generic Drugs; Dissolution Methods Database at <http://www.fda.gov/cder/ogd/index.htm>
`AusPAR Tecfidera Dimethyl Fumarate Biogen Idec Australia Pty LtdPM-2012-00808-3-1
`Page 10 of 87
`Final 22 October 2013
`
`
`Page 10 of 87
`
`

`

`Therapeutic Goods Administration
`• The company could have applied expiry limits of 92.5 – 107.5% label claim (LC) in line
`with TGO 785 instead of the proposed (common release and expiry limits of) 95.0–
`105.0% LC, and these would have been accepted.
`• The only degradants formed (fumaric acid and MMF) are human metabolites.
` It follows that an active content of 92.5% LC would pose no safety concern to the patient,
`leaving all risk with the company in the event of the capsules being tested for regulatory
`purposes at some future time.
`1. Acceptable release and expiry specifications have not been submitted for the finished
`products; instead, “has been revised to ensure that it is clear that all acceptance criteria
`be met throughout the shelf life of the product, even if only tested at release”, with the
`“formal” specifications to be submitted after approval of the changes proposed in the
`revised Module 3.2.P.5.1. This was accepted as an interim measure.
`The limits proposed for the 2 identified impurities controlled in the finished product
`specifications have also been accepted on the grounds that each is a human metabolite.
`DMF is rapidly hydrolysed to the active monomethyl fumarate (MMF). As the parent drug
`is undetectable in human blood or plasma, the outcomes of all supportive
`bioavailability/bioequivalence studies have been determined on the basis of MMF
`concentrations.
`Study 109-HV-105 determined the pharmacokinetics of dimethyl fumarate and assessed
`the relative bioavailability of MMF from 2 of the 120 mg dimethyl fumarate capsules in
`comparison with a single dose of 240 mg of dimethyl fumarate API encapsulated in a hard
`gelatin capsule. As anticipated, the encapsulated active pharmaceutical ingredient (API)
`had a shorter lag time (Tlag), shorter time to peak plasma concentration (Tmax) and a lower
`peak plasma concentration (Cmax) compared to the encapsulated microtablets, which was
`attributed to the enteric coating. However, the PK profiles from both Treatments displayed
`high variability.
`The following outcomes were obtained:
`
`Table 2. Pharmacokinetic analysis for study 109HV105
`
`Biopharmaceutics
`
`5 Therapeutic Goods Order 78: This Order supersedes Therapeutic Goods Order No. 56 - General standard for
`tablets, pills and capsules, made on 19 September 1996 to introduce changes sought by the industry sectors to
`modernise requirements relating to the quality of tablets (but not including pills) and capsules, and is largely
`consistent with international standards, where such exist.
`AusPAR Tecfidera Dimethyl Fumarate Biogen Idec Australia Pty LtdPM-2012-00808-3-1
`Page 11 of 87
`Final 22 October 2013
`
`
`Page 11 of 87
`
`

`

`Therapeutic Goods Administration
`Study 109-HV-107 assessed the relative bioavailability of MMF from 2 of the 120 mg
`dimethyl fumarate capsules in comparison with a single 240 mg capsule under fasted
`conditions, and determined that exposure from both Treatments (results reproduced
`below) was similar in terms of Cmax and AUC.
`
`Table 3. Summary of bioequivalence analysis for plasma pharmacokinetic (PK) parameters.
`PK population. Study 109HV107.
`
`
`
`Tmax (h)
`
`Cmax
`(ng/mL)
`
`AUC(0-∞)
`(ng.h/mL)
`
`Table 4. Monomethyl fumarate - treatment A versus B (fasting versus fed)
`
`
`Two studies were conducted to assess the effect of food: Study FAG-201-FGPK-02/02 was
`a preliminary investigation that appeared to not follow the FDA recommended design for
`food interaction studies in relation to subject numbers and meal design, whilst Study C-
`1903 was the definitive food effect study that assessed the effects of a high fat meal on
`drug bioavailability relative to the fasted state following administration of 2x120 mg of the
`proposed commercial formulation for Australia.
`The following outcomes were reported:
`3.93
`2.26
`A: Fasting
`2.00
`3.82
`1.45
`B: Fed
`5.50
`102.9
`161.5
`A versus B Estimate
`3.50
`(96 – 110)
`(141 – 182)
`90% Confidence
`-
`interval
`Thus, for dimethyl fumarate and its metabolite, the extent of exposure (area under the
`plasma concentration time curve from time 0 to infinity (AUC0-∞)), but not the peak
`exposure (Cmax), was equivalent in the fed state compared to the fasted state. Consumption
`of a high-fat meal led to a delayed Tmax of 3.5 h and a 36% reduction in Cmax, with respect to
`the MMF metabolite. No mention of these results is made in the draft Product Information
`leaflet.
`AusPAR Tecfidera Dimethyl Fumarate Biogen Idec Australia Pty LtdPM-2012-00808-3-1
`Final 22 October 2013
`
`
`Statistical
`analysis:
`
`median diff
`
`ratio (%)
`
`ratio (%)
`
`Page 12 of 87
`
`Page 12 of 87
`
`

`

`Advisory committee considerations
`
`Therapeutic Goods Administration
`
`Pharmaceutical sub-committee to the Advisory Committee on Prescription
`Medicines (ACPM)
`Recommendation number 2315
`
`The PSC endorsed all the questions raised by the TGA in relation to the quality and
`1.
`pharmaceutic aspects of the submission by Biogen Idec Australia Pty Ltd to register
`Tecfidera modified release capsule containing 120 mg and 240 mg of dimethyl
`fumarate.
`The PSC agreed that the sponsor should address the issues relating to reprocessing of
`2.
`non-compliant batches to the satisfaction of the TGA.
`The PSC advised that the sponsor should ensure that the drug substance
`3.
`manufactured at all nominated manufacturing sites are included in the batch analyses
`and stability trial protocols for the drug product.
`In the Product Information (PI) the “Description” section should be amended to
`include the partition coefficient and solubility of the drug substance at relevant
`physiological pH.
`There was no requirement for this submission to be reviewed again by the PSC before
`consideration by the ACPM.
`A number of questions have been raised with the sponsor concerning the
`quality/biopharmaceutical data, to which satisfactory responses were provided.
`Approval was recommended from a quality/biopharmaceutic perspective.
`
`Quality summary and conclusions
`
`III. Nonclinical findings
`
`Introduction
`
`An adequate set of nonclinical studies was submitted, with relevant studies being Good
`Laboratory practice (GLP) compliant, with the exception of the in vivo
`cardiovascular/respiratory safety pharmacology study in dogs.
`
`Pharmacology
`
`Primary pharmacology
`Mode of action
`
`Multiple sclerosis (MS) is a chronic autoimmune and neurodegenerative disorder of the
`central nervous system (CNS) that is characterised by inflammation, demyelination, and
`oligodendrocyte and neuronal loss. Oxidative stress associated with reactive oxygen and
`nitrogen species is implicated as a significant factor in the pathology of MS.6 The post-
`6 Gilgun-Sherki, Y., Melamed, E. and Offen. D. (2004) The role of oxidative stress in the pathogenesis of multiple
`sclerosis: the need for effective antioxidant therapy. J. Neurol. 251, 261-268.
`AusPAR Tecfidera Dimethyl Fumarate Biogen Idec Australia Pty LtdPM-2012-00808-3-1
`Page 13 of 87
`Final 22 October 2013
`
`
`Page 13 of 87
`
`

`

`Therapeutic Goods Administration
`mitotic cells in the CNS have a low capacity for mitigating oxidative stress and are
`susceptible to its damaging effects.7
`Primary pharmacology studies revealed that dimethyl fumarate (DMF) has anti-
`inflammatory and neuroprotective activity (see below). Evidence was provided that DMF
`activates the Nrf2 antioxidant response pathway and may exert its effects, at least in part,
`via this mechanism. Nrf2 is a transcription factor that controls the expression of various
`genes, including those whose protein products are involved in the detoxification and
`elimination of reactive oxidants, thus allowing cells to respond to various forms of
`oxidative stress.8 It is well established that Nrf2 activity is controlled, in part, by the
`cytosolic protein, kelch-like ECH-associated protein 1 (Keap1). Under basal conditions,
`Nrf2 is anchored in the cytoplasm through binding with Keap1 which results in its
`ubiquination and subsequent proteosomal degradation. Mass spectrophotometric analysis
`revealed that both DMF and its primary metabolite, monomethyl fumarate (MMF), cause
`molecular changes to rat Keap1 within a peptide fragment including the critical Cys-151,
`indicating that they can both alkylate the reactive thiol. This would be expected to result in
`a reduction in binding of Keap1 to Nrf2 and an increase in steady-state Nrf2 protein levels,
`and the latter was demonstrated in cell lysates/extracts from various cell types, including
`human astrocytes (the CNS cells that regulate the myelinating activity of oligodendrocytes,
`amongst other functions), treated with DMF and/or MMF, and the effect was
`concentration dependent.
`To have an effect on gene expression, Nrf2 needs to be translocated from the cytoplasm to
`the nucleus, and such translocation was demonstrated in DLD-1 cells (a colonic epithelial
`cell line) treated with DMF, and human astrocytes treated with DMF and MMF. In the
`nucleus, Nrf2 binds to a specific promoter sequence known as the Antioxidant Response
`Element (ARE). The ARE regulates expression of antioxidant and stress response-
`associated genes, with transcription of these genes initiated when Nrf2 binds to it. DMF
`and MMF treatment of an ARE reporter cell line resulted in up-regulated transcription
`(luminescence). DMF and/or MMF were also demonstrated to up-regulate transcription of
`several endogenous Nrf2 target genes in various cell types, including human and rat
`astrocytes and oligodendrocyte precursor cells and human hippocampal neurons.
`Through experiments using siRNA constructs in DLD-1 cells, the up-regulation of target
`genes was shown to be at least partially dependent on Nrf2.
`Up-regulation of NAD(P)H dehydrogenase (quinone 1)(NQO1) and aldo-keto reductase
`1B8 (AKR1B8) (marker genes) was demonstrated in mice in vivo in response to DMF.
`Different organs showed quantitative differences in the up-regulation of the two genes,
`suggesting some tissue specificity of response. Rats showed a similar pharmacological
`response to mice and MMF had similar activity to DMF. An essential role of Nrf2 in the up-
`regulation was confirmed using Nfr2 knockout (KO) mice (Nrf2-/-).
`Up-regulation of NQO1 and AKR1B8 genes in tissues from the CNS was quantitatively
`small (see Table 5 below). At a dose of 200 mg/kg that was required to see even a small
`effect on target gene up-regulation in the brain, the animal: human exposure ratio (ER)
`was about 4 in mice and 3 in rats (ER values were from the repeat dose toxicity studies,
`although the strains of rats used were different).
`
`7 Scannevin, R.H., Chollate, S., Jung, M., Patel, H., Bista, P., Zeng, W., Ryan, S., Yamamoto, M., Lukashev, M. and
`Rhodes, K.J. (2012) Fumarates promote cytoprotection of central nervous system cells against oxidative stress
`via the nuclear factor (erythroid-derived 2)-like 2 pathway. J. Pharmacol. & Exp. Therap. 341, 274-284.
`8Lau, A., Villeneuve, N.F., Sun, Z., Wong, P.K. and Zhang, D.D. (2008) Dual roles of Nrf2 in cancer. Pharmacol. Res.
`58, 262-270.
`AusPAR Tecfidera Dimethyl Fumarate Biogen Idec Australia Pty LtdPM-2012-00808-3-1
`Page 14 of 87
`Final 22 October 2013
`
`
`Page 14 of 87
`
`

`

`Table 5. Up-regulation of NQO1 and AKR1B8 genes in tissues from the CNS.
`
`Therapeutic Goods Administration
`
`Study Species
`(strain)
`
`Tissue
`
`RSCH-2011-
`025
`
`RSCH-2011-
`028
`RSCH-2011-
`030
`
`Mice
`(C57BL6
`)
`Rats
`(Brown
`Norway)
`Mice
`(C57BL6
`)
`Rats
`(Brown
`Norway)
`with EAE
`
`Anti-inflammatory effects
`
`Fold
`upregulatio
`n of NQO1
`
`Fold
`upregulatio
`n of AKR1B8
`
`Dose
`(mg/kg
`)
`
`Single
`dose/repea
`t dose
`
`Single
`
`Single
`Repeat
`
`- -
`1.6
`200
`Forebrain
`-
`Cerebellu
`m
`- -
`- -
`50
`Forebrain
`Cerebellu
`m
`-
`-
`200
`Cerebellu
`m
`NE
`1.6
`200
`Brain
`(significant)
`NE
`-
`50
`- 3
`- -
`200
`Spinal
`cord
`Cerebellu
`m
`- -
`- -
`100
`Spinal
`cord
`Cerebellu
`m
`- = no or minimal up-regulation observed (< ~1.5 fold); NE = not examined; again, the essential role of
`Nrf2 in the up-regulation was confirmed using KO mice which showed no up-regulation of NQO1 (in
`either brain or spleen)
`The anti-inflammatory activity of DMF was demonstrated both in vitro and in vivo. In vitro,
`pretreatment with DMF reduced expression of pro-inflammatory cytokines in LPS-
`stimulated RAW264.7 and J774A.1 macrophages, in primary cultures