Friday, 30 September 2016

ClinicSpeak: not so NICE - alemtuzumab vs. cladribine

NICE is not so NICE; alemtuzumab is too expensive to use properly. #ClinicSpeak #MSBlog #MSResearch

Could oral cladribine steal alemtuzumab's thunder? #ClinicSpeak #MSBlog #MSResearch

"I naively discovered yesterday that NHS England will only be allowing us to use two courses of alemtuzumb in our patients with active relapsing MS. If these patients breakthrough and need a third, fourth or additional course of alemtuzumab we will have to apply for additional funding via an IFR (individual funding request). The problem with the latter is that as soon as there are more than 5 patients in England requiring IFRs this will require a business case. Making a business cases stack-up for additional courses will be difficult outside of a formal NICE guidance. At present ~40-50% of patients treated with alemtuzumab will require additional courses. Based on my previous experience with NHS England, and their dire financial predicament, I suspect getting a green-light for additional courses is going to be an uphill battle. In short with have been truly NICED. The question is whether or not Genzyme-Sanofi will come to table with additional courses and a lowered price? If not we are going to need a plan B. What DMT will we use in patients who breakthrough post-alemtuzumab?"

"I am going to have to take this information into account when counselling patients. I suspect that this may turn-off many patients off alemtuzumab. Does this also mean we should be routinely be offering our patients, who want an induction therapy, off-label cladribine? This new information also means that if oral cladribine gets a license it is going to be massively disruptive to alemtuzumab's market. The following is my ECTRIMS poster showing you the durable effect of oral cladribine. The difference with oral cladribine is that we have access to the much cheaper oncology version that could be used for subsequent courses if NICE and NHS England say no to additional course. It looks like we don't have this option with alemtuzumab."

CoI: multiple

Location, location, location: MS pathology preferentially affects the edges of the brain

The Paper

Objective To assess the association between proximity to the inner (ventricular and aqueductal) and outer (pial) surfaces of the brain and the distribution of normal appearing white matter (NAWM) and grey matter (GM) abnormalities, and white matter (WM) lesions, in multiple sclerosis (MS).

Methods 67 people with relapse-onset MS and 30 healthy controls were included in the study. Volumetric T1 images and high-resolution (1 mm3) magnetisation transfer ratio (MTR) images were acquired and segmented into 12 bands between the inner and outer surfaces of the brain. The first and last bands were discarded to limit partial volume effects with cerebrospinal fluid. MTR values were computed for all bands in supratentorial NAWM, cerebellar NAWM and brainstem NA tissue, and deep and cortical GM. Band WM lesion volumes were also measured.

Results Proximity to the ventricular surfaces was associated with progressively lower MTR values in the MS group but not in controls in supratentorial and cerebellar NAWM, brainstem NA and in deep and cortical GM. The density of WM lesions was associated with proximity to the ventricles only in the supratentorial compartment, and no link was found with distance from the pial surfaces.

Conclusions In MS, MTR abnormalities in NAWM and GM are related to distance from the inner and outer surfaces of the brain, and this suggests that there is a common factor underlying their spatial distribution. A similar pattern was not found for WM lesions, raising the possibility that different factors promote their formation.

The Interpretation

In Multiple Sclerosis (MS), there are two broad kinds of damage done to the brain. There are focal lesions – inflammatory scars - which accumulate over time and are associated with relapses, and there is a diffuse neurodegenerative process which is more associated with the progression of disability. Lesions in MS affect both the grey matter – where nerve cell bodies reside – and the white matter, which consists of nerve cell projections (axons) to distant brain regions.

Interestingly, lesions in MS are more likely to appear in some parts of the brain than others. Post-mortem studies have demonstrated that white matter lesions have a predilection for the outer and inner surfaces of the brain. This predilection for particular sites is important because, amongst other reasons, it sheds light on the processes that initiate and perpetuate MS. For instance, it has been proposed that as MS lesions are most likely to occur in places close to cerebrospinal fluid (CSF) – the fluid that bathes and encases the brain – there may be a ‘toxic’ factor of some description that is involved in triggering and/or perpetuating MS.

It is therefore important that we understand exactly where in the brain is most vulnerable to developing lesions and non-lesional pathology in MS. This nice new paper from Declan Chard and pals uses a funky imaging method to find out the spatial distribution of grey and white matter pathology in people with MS.
The authors used Magnetisation Transfer Ratio (MTR) – a variant of MRI which can show subtle disturbances of brain tissue integrity quite well. MTR is used frequently in studies of MS because it is particularly good at detecting non-lesional pathology. We don’t know exactly what features of brain tissue affect MTR, but we do know that demyelination and axonal loss – which are both common in MS – do affect the MTR image.

This study recruited 30 healthy controls and 67 people with MS, of whom 41 had relapsing-remitting (RRMS) disease, and 26 had secondary progressive MS (SPMS). The authors used MTR to image these participants’ brains. They then took the images and divided each one into 12 bands based on the distance from the edge of the brain.

In normal-appearing white matter of both the cerebellum and the cerebral cortex, MTR values were reduced in MS, with the bands nearest the ventricles – the inside of the brain – most affected. This was also the case for the deep grey matter. The amount of lesioned white matter was also highest nearest the ventricles, and showed a clear relationship with distance from the ventricles. In addition there was a small, if slightly less convincing, reduction in MTR in MS related to distance from the outside edge of the brain (the pia).

These findings are cool but need to be interpreted with a bit of caution. For one, as mentioned, we do not fully understand what MTR imaging is actually measuring, and so some of the imaging abnormalities noted in this paper may not reflect pathological changes that are relevant to MS. Another problem is that some people with MS have slightly smaller brains than control subjects due to atrophy (i.e. degenerative changes) over time – this means that each ‘band’ on their brain images is smaller, and so there is more space for random variability to affect their results. Furthermore, MTR is bad at detecting grey matter lesions, and so it is tricky to say whether the grey matter abnormalities they describe are due to lesions, effects around lesions, or unrelated to lesions altogether. This is important because, as I’ve said, the processes driving lesions and the processes driving neurodegeneration are not the same – if we are trying to use studies like this to discover more about these processes then it is important to be able to distinguish lesional from non-lesional areas. A final gripe is that the control participants weren’t that well matched – the people with MS were mainly women, while the controls were split 50:50 between men and women.

But putting these concerns to one side, this paper does definitely add to our understanding of ‘selective vulnerability’ in MS – it shows that distance from the ventricles – the CSF-filled spaces which abut the inner face of the brain – and to some extent from the pia, is a key determinant of MS grey matter and white matter pathology. We will obviously need further work to determine exactly what MTR is measuring, whether these gradients in MS pathology hold up in bigger studies and to clarify what these gradients actually tell us about the disease processes in MS. Further work will also need to clarify the relationship between MS pathology and proximity to the pia, as this was not entirely clear from this study in my opinion.

In short, this work adds to previous imaging and post-mortem studies by showing that MS pathology selectively affects regions nearest the outer and inner surfaces of the brain.

Thursday, 29 September 2016

How does laquinimod block attacks

Kaye J, Piryatinsky V, Birnberg T, Hingaly T, Raymond E, Kashi R, Amit-Romach E, Caballero IS, Towfic F, Ator MA, Rubinstein E, Laifenfeld D, Orbach A, Shinar D, Marantz Y, Grossman I, Knappertz V, Hayden MR, Laufer R. Laquinimod arrests experimental autoimmune encephalomyelitis by activating the aryl hydrocarbon receptor. Proc Natl Acad Sci U S A. 2016. pii: 201607843. [Epub ahead of print].

Laquinimod is an oral drug currently being evaluated for the treatment of relapsing, remitting, and primary progressive multiple sclerosis and Huntington's disease. Laquinimod exerts beneficial activities on both the peripheral immune system and the CNS with distinctive changes in CNS resident cell populations, especially astrocytes and microglia. Analysis of genome-wide expression data revealed activation of the aryl hydrocarbon receptor (AhR) pathway in laquinimod-treated mice. The AhR pathway modulates the differentiation and function of several cell populations, many of which play an important role in neuroinflammation. We therefore tested the consequences of AhR activation in myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE) using AhR knockout mice. We demonstrate that the pronounced effect of laquinimod on clinical score, CNS inflammation, and demyelination in EAE was abolished in AhR-/- mice. Furthermore, using bone marrow chimeras we show that deletion of AhR in the immune system fully abrogates, whereas deletion within the CNS partially abrogates the effect of laquinimod in EAE. These data strongly support the idea that AhR is necessary for the efficacy of laquinimod in EAE and that laquinimod may represent a first-in-class drug targeting AhR for the treatment of multiple sclerosis and other neurodegenerative diseases.

Laquinimod is a pretty rubbish DMT when you look at its effect on inhibiting relapse, but when you looked at MRI, the results looked more promising a slowing nerve damage suggesting that it may be neuroprotective.

How does it work?

In this current paper, it is reported that Laquinimod acts via the aryl hydrocarbon receptor (AHR). The aryl hydrocarbon receptor is a ligand-activated transcription factor involved in the regulation of biological responses to planar aromatic (aryl) hydrocarbons. This receptor has been shown to regulate xenobiotic-metabolizing enzymes such as cytochrome P450.

The aryl hydrocarbon receptor is a member of the family of basic helix-loop-helix transcription factors. AHR binds several exogenous ligands such as natural plant flavonoids, polyphenolics and indoles, as well as synthetic polycyclic aromatic hydrocarbons and dioxin-like compounds. AhR is a cytosolic transcription factor that is normally inactive, bound to several co-chaperones. Upon ligand binding to chemicals, the chaperones dissociate resulting in AhR translocating into the nucleus and dimerizing with ARNT (AhR nuclear translocator), leading to changes in gene transcription.

In this study they report that if they removed the AhR from mice and it stops laquinimod from blocking the immune attack which was shown earlier by Berg J, Mahmoudjanlou Y, Duscha A, Massa MG, Thöne J, Esser C, Gold R, Haghikia A. The immunomodulatory effect of laquinimod in CNS autoimmunity is mediated by the aryl hydrocarbon receptor. J Neuroimmunol. 2016 Sep 15;298:9-15. They reported that  the AhR pathway is crucial for the immunomodulatory, but not neuroprotective, efficacy of laquinimod in EAE.

Likewise in the current study, they show that it when removed from white blood cells it blocks the action of laquinimod in EAE but if you remove it from the brain then it doesn't do much to EAE.

So the interestering question remains how is the potential neuroprotective effect mediated. The other question is. Is there a neuroprotective effect? Will Laquinimod be developed?

The 1.2mg dosing was stopped because of heart issues but will people believe that the 0.6mg dose is safe.

Wednesday, 28 September 2016

#GuestPost #ThinkHand, #ECTRIMS2016: Professor Coyle's motion at the "Burning Debate"

Last week I posted my slides in favour of the motion that pwMS in wheelchairs should be included in DMT trials. You were asking to learn more about the motion against, and my opponent during the 'burning debate' at ECTRIMS 2016, Patricia Coyle, kindly agreed to share her slides and some key points of her argument for this Guestpost.

Patricia K. Coyle, MD, FAAN, FANA, is Professor and Vice Chair (Clinical Affairs) of Neurology, and Director of the Multiple Sclerosis Comprehensive Care Center at Stony Brook University Medical Center, Stony Brook, New York.  She received a BS degree with highest honors from Fordham University, Bronx, New York, and an MD degree from the Johns Hopkins School of Medicine, where she was elected to Alpha Omega Alpha.  While at the Johns Hopkins School of Medicine, she completed a residency and chief residency in neurology, followed by a two-year fellowship in neuroimmunology and neurovirology.  She then went on to establish a successful research laboratory in addition to building a busy clinical practice at the Stony Brook University Medical Center.  Dr. Coyle is the author of numerous articles on clinical and basic research aspects of multiple sclerosis (MS) and neurologic infections and she is recognized as a leading expert on MS and neurologic infections.  Her areas of expertise include Lyme disease and neurologic infections, cerebrospinal fluid, therapeutics, and neuroimmunology.  Her research has been supported by the National Institutes of Health and other organizations.  She is currently involved in a number of therapeutic trials testing new immunotherapies for MS, as well as studies addressing neurologic aspects of Lyme disease.  In addition to her busy clinical and research careers, she has held active leadership positions in a number of national and international organizations and academic societies, including the American Academy of Neurology, American Neurological Association, National MS Society, and the American Board of Psychiatry and Neurology, and has been a member of the FDA CNS and PNS Drugs Advisory Panel. She lectures widely on MS and neurologic infections to national and international audiences.

Professor Coyle's key points:
  • People with MS in wheelchairs can and should participate in many types of clinical trials (testing CNS repair strategies, symptom management, rehabilitation techniques, national history studies) 
  • People with MS in wheelchairs have been and are currently routinely excluded from pivotal trials testing progressive MS DMTs
  • This exclusion is not based on discrimination; it is done to give the pivotal trial the best chance to be successful
  • In such pivotal trials you typically enter much more restricted “idealized” populations to avoid bias of failing to see a treatment effect
  • The primary outcome in such trials remains a clinical one, which documents that a drug can slow progression over a short (typically two year) period
  • People with MS in wheelchairs are not ideal to show such a time-related change for multiple reasons:
  • They typically have had bad MS for a long time, have accumulated a lot of CNS damage, and have the least CNS reserve
  • They do not have EDSS in the walking part of the scale, which is where changes are most commonly seen quickly; they are in the EDSS ≥7 range, where EDSS changes slowly if at all
  • They have more confounding comorbidities, more symptoms that are not as well managed, less physical exercise tolerance, all of which can interfere with their evaluation
  • The two current successful phase III PPMS and SPMS progressive trials both excluded people with MS in wheelchairs
  • Once approved, progressive MS DMTs should and in fact must be made available to people with MS in wheelchairs
  • Bottom line: for the ultimate higher good, to provide the best chance for critical pivotal progressive treatment trials to be positive, people with MS in wheelchairs must continue to be excluded (but not from the right to be treated)
What do you think?

CoI: PKC has served in a consultancy capacity for Accordant, Bayer, Biogen, Genentech/Roche, Mallinckrodt, Novartis, Sanofi Genzyme, Merck Serono and Teva, and has received research support  from Actelion, Genentech/Roche, Novartis and Opexa.

Making Microglia

Muffat J, Li Y, Yuan B, Mitalipova M, Omer A, Corcoran S, Bakiasi G, Tsai LH, Aubourg P, Ransohoff RM, Jaenisch R. Efficient derivation of microglia-like cells from human pluripotent stem cells. Nat Med. 2016. doi: 10.1038/nm.4189. [Epub ahead of print]

Microglia, the only lifelong resident immune cells of the central nervous system (CNS), are highly specialized macrophages that have been recognized to have a crucial role in neurodegenerative diseases such as Alzheimer's, Parkinson's and adrenoleukodystrophy (ALD). However, in contrast to other cell types of the human CNS, bona fide microglia have not yet been derived from cultured human pluripotent stem cells. Here we establish a robust and efficient protocol for the rapid production of microglia-like cells from human (h) embryonic stem (ES) and induced pluripotent stem (iPS) cells that uses defined serum-free culture conditions. These in vitro pluripotent stem cell-derived microglia-like cells (termed pMGLs) faithfully recapitulate the expected ontogeny and characteristics of their in vivo counterparts, and they resemble primary foetal human and mouse microglia. We generated these cells from multiple disease-specific cell lines . We further describe a platform to study the integration and live behaviour of pMGLs in organotypic 3D cultures. This modular differentiation system allows for the study of microglia in highly defined conditions as they mature in response to developmentally relevant cues, and it provides a framework in which to study the long-term interactions of microglia residing in a tissue-like environment.

Anyone that works on living animals in the UK has to have ethical approval to justify their work and each year they have to supply numbers of animals used as part of the national statistic.

The UK Government have wanted to get the number of animals used down, but their was a problem with the development of transgenic animals, as this caused the number of animals used to increase.

Many of the transgenic animals do not develop any harms as consequence to their genetic modification, but they are recorded because they are genetically modified, yet one can get a so called "normal" mouse and not record it yet some of the bog standard lab mice have mutations that affect function such as vision and hearing loss that go un-noticed. 

It seems that a fudge is being created to limit the problem of normal transgenic mice and rather that being reported as "mild", "moderate" or "severe" they are being reported as being "sub threshold", which sounds like something below the need to report:-(

However, worst fudges that have been around to that mask the number of animals actually used and this is the use of normal animals, that are killed and tissues used to make cell cultures.

These typically don't count in the statistics and so probably thousands upon thousands of animals don't show up on the records.

I believe they should and likewise people who use animals to kill them for tissues should have to go through the same hoops that people who use living animals. I would suspect that if they had to have the same level of ethical scrutiny and licences required then some of the animal work done may not get done. 

Most notably how do you justify the use of animal cells when you can use human cells instead? 

I think it is more and more difficult to use this argument because it is becoming easier and easier to make human cells and one of these ways is via use and diffentiation of  stem cells. One of the stem cells approach is called induced pluripotent stem cells (iPS cells) 

Here you take a cell like a skin cell and give it growth factors so that it becomes a stem cell capable of growing into any other cell type if you know how to give the right differentiation clues.

In this current study they have found a way to make human microglial-like cells from iPS cells, so you should not need to use rodent cells to study microglia. So a way forward to save our furry friends

Microglia are thought by many to be central to the generation of progressive disease and so the capacity to make human microglia is going to be of value in the search for treatments of progressive MS.