Prof G are we being lulled into a false sense of security by being told that we have no evident disease activity (NEDA)?
A patient of mine, who I have been looking after now for over 11 years, asked me in clinic a few weeks ago why despite being NEDA for 6 years, on a highly effective maintenance DMT (fingolimod), has she gone from being able to run 5-10 km to needing a stick and barely managing to walk from the Whitechapel Underground Station to my clinic (~200m), without having to stop and rest?
What this patient doesn’t know, despite no new visible T2 lesions, is that she has developed obvious, to the naked eye, progressive brain atrophy. This particular patient prompted me to write a few blog posts to try and explain what is happening to her brain. Before reading the remainder of this post you may want to read the following posts:
An important question in relation to this patient is why do some DMTs have such a profound impact on end-organ damage markers, in particular, brain volume loss and others do not? Not all DMTs are made equal when it comes to preventing, or slowing down, brain volume loss.
At the top of the league table are alemtuzumab and HSCT (~0.2-0.25% loss per annum). Both these treatments are NIRTs (non-selective immune reconstitution therapies). Natalizumab is next with an annual brain volume loss in region of 0.25-0.30% per annum. Ocrelizumab (anti-CD20) comes fourth with a rate of brain volume loss of ~0.30-0.35% per annum. Fingolimod 5th at ~0.4% per annum. Cladribine has a rate of loss of brain volume of ~0.55% per annum with the other runs after that.
For me, the disappointment are the anti-B cell therapies, ocrelizumab and cladribine. Despite these DMTs being very effective at switching off new focal inflammatory lesions (relapses and new T2 and Gd-enhancing lesions) their impact on end-organ damage is only moderate. These observations have convinced me more than ever that focal inflammation is not MS, but simply the immune system’s response to what is causing MS. The latter hypothesis is what I have been presenting as part of my ‘Field Hypothesis’ for several years on this blog.
What these observations are telling me is that peripheral B-cells are a very important part of the immune response to the cause of MS, but they are not necessarily involved in driving the true pathology, which is causing the progressive brain volume loss. The caveat to this is that anti-CD20 therapies and cladribine may not be eliminating the B-cells and plasma cells within the CNS, which is why we need add-on treatments to try and scrub the brain free of these cells to see if the brain atrophy rate ‘normalises’. This is why we are starting a safety study this year of an add-on myeloma drug to target the CNS B-cell and plasma cell response to test this hypothesis.
What does this mean for the average person with MS? Firstly, you may not want to dismiss alemtuzumab and HSCT as a treatment option. These NIRTS differ from anti-CD20 therapies and cladribine in that they target both B and T cells. We may need to target both these cells types to really get on top of MS. I am aware of the appeal of anti-CD20 therapies and cladribine; they are safer and easier to use because of less monitoring, however, this may come at a cost in the long-term. The SIRTs (selective IRTs) may not be as good as the NEDA data suggests. Please remember that once you have lost brain you can’t get it back.
The tradeoff with alemtuzumab and HSCT is the frontloading of risk to get the greatest efficacy over time. Choosing a DMT on a rung or two down on the therapeutic ladder gives you better short-term safety and makes the lives of your MS team easier, because of less monitoring, but at a potential long-term cost to your brain and spinal cord. This is why to make an informed decision about which DMT you choose is a very complicated process and subject to subtle and often hidden effects of cognitive biases. The one bias I am very aware of is the ‘Gambler’s Dilemma’, be careful not to be lulled into a false sense of security by your beliefs; most gamblers lose.
Over the last few years you may have seen a theme developing in my thinking as we move the goalposts in terms of our treatment target beyond NEDA-3 to target end-organ damage, i.e. brain volume loss, T1 black holes, the slowly expanding lesions (SELs), neurofilament levels, cognition, sickness behaviour, OCBs, etc. Our treatment aim should be to ‘Maximise Brain Health’ across your life and not just the next decade. Please stop and think!
When I was preparing this post I dropped Prof. Doug Arnold an email about the impact of alemtuzumab and HSCT on the slowly expanding lesion or SEL. Unfortunately, these analyses have not been done despite good trial data sets being available for analysis. He said it was a resource issue; i.e. a euphemism for money and permission to do the analyses. For me, these questions are the most important ones to answer in 2019. Wouldn’t you want to know if alemtuzumab and HSCT were able to switch off those destructive SELs in your brain? Knowing this may impact your decision to go for the most effective DMTs; frontloading risk to maximise outcomes in the long term.
What should I advise my patient; to stay on fingolimod or to escalate to a more effective DMT?
The following articles are the important ones for you to read or at least be aware of:
Lee et al. Brain atrophy after bone marrow transplantation for treatment of multiple sclerosis. Mult Scler. 2017 Mar;23(3):420-431.
BACKGROUND: A cohort of patients with poor-prognosis multiple sclerosis (MS) underwent chemotherapy-based immune ablation followed by immune reconstitution with an autologous hematopoietic stem cell transplant (IA/aHSCT). This eliminated new focal inflammatory activity, but resulted in early acceleration of brain atrophy.
OBJECTIVE: We modeled the time course of whole-brain volume in 19 patients to identify the baseline predictors of atrophy and to estimate the average rate of atrophy after IA/aHSCT.
METHODS: Percentage whole-brain volume changes were calculated between the baseline and follow-up magnetic resonance imaging (MRI; mean duration: 5 years). A mixed-effects model was applied using two predictors: total busulfan dose and baseline volume of T1-weighted white-matter lesions.
RESULTS: Treatment was followed by accelerated whole-brain volume loss averaging 3.3%. Both the busulfan dose and the baseline lesion volume were significant predictors. The atrophy slowed progressively over approximately 2.5 years. There was no evidence that resolution of edema contributed to volume loss. The mean rate of long-term atrophy was -0.23% per year, consistent with the rate expected from normal aging.
CONCLUSION: Following IA/aHSCT, MS patients showed accelerated whole-brain atrophy that was likely associated with treatment-related toxicity and degeneration of “committed” tissues. Atrophy eventually slowed to that expected from normal aging, suggesting that stopping inflammatory activity in MS can reduce secondary degeneration and atrophy.
Arnold et al. Superior MRI outcomes with alemtuzumab compared with subcutaneous interferon β-1a in MS. Neurology. 2016 Oct 4;87(14):1464-1472.Neurology. 2016 Oct 4;87(14):1464-1472.
OBJECTIVE: To describe detailed MRI results from 2 head-to-head phase III trials, Comparison of Alemtuzumab and Rebif Efficacy in Multiple Sclerosis Study I (CARE-MS I; NCT00530348) and Study II (CARE-MS II; NCT00548405), of alemtuzumab vs subcutaneous interferon β-1a (SC IFN-β-1a) in patients with active relapsing-remitting multiple sclerosis (RRMS).
METHODS: The impact of alemtuzumab 12 mg vs SC IFN-β-1a 44 μg on MRI measures was evaluated in patients with RRMS who were treatment-naive (CARE-MS I) or who had an inadequate response, defined as at least one relapse, to prior therapy (CARE-MS II).
RESULTS: Both treatments prevented T2-hyperintense lesion volume increases from baseline. Alemtuzumab was more effective than SC IFN-β-1a on most lesion-based endpoints in both studies (p < 0.05), including decreased risk of new/enlarging T2 lesions over 2 years and gadolinium-enhancing lesions at year 2. Reduced risk of new T1 lesions (p < 0.0001) and gadolinium-enhancing lesion conversion to T1-hypointense black holes (p = 0.0078) were observed with alemtuzumab vs SC IFN-β-1a in CARE-MS II. Alemtuzumab slowed brain volume loss over 2 years in CARE-MS I (p < 0.0001) and II (p = 0.012) vs SC IFN-β-1a.
CONCLUSIONS: Alemtuzumab demonstrated greater efficacy than SC IFN-β-1a on MRI endpoints in active RRMS. The superiority of alemtuzumab was more prominent during the second year of both studies. These findings complement the superior clinical efficacy of alemtuzumab over SC IFN-β-1a in RRMS.
CLASSIFICATION OF EVIDENCE: The results reported here provide Class I evidence that, for patients with active RRMS, alemtuzumab is superior to SC IFN-β-1a on multiple MRI endpoints.
Vavasour et al. A 24-month advanced magnetic resonance imaging study of multiple sclerosis patients treated with alemtuzumab. Mult Scler. 2018 Apr 1:1352458518770085. doi: 10.1177/1352458518770085.
BACKGROUND: Tissue damage in both multiple sclerosis (MS) lesions and normal-appearing white matter (NAWM) are important contributors to disability and progression. Specific aspects of MS pathology can be measured using advanced imaging. Alemtuzumab is a humanised monoclonal antibody targeting CD52 developed for MS treatment.
OBJECTIVE: To investigate changes over 2 years of advanced magnetic resonance (MR) metrics in lesions and NAWM of MS patients treated with alemtuzumab.
METHODS: A total of 42 relapsing-remitting alemtuzumab-treated MS subjects were scanned for 2 years at 3 T. T1 relaxation, T2relaxation, diffusion tensor, MR spectroscopy and volumetric sequences were performed. Mean T1 and myelin water fraction (MWF) were determined for stable lesions, new lesions and NAWM. Fractional anisotropy was calculated for the corpus callosum (CC) and N-acetylaspartate (NAA) concentration was determined from a large NAWM voxel. Brain parenchymal fraction (BPF), cortical thickness and CC area were also calculated.
RESULTS: No change in any MR measurement was found in lesions or NAWM over 24 months. BPF, cortical thickness and CC area all showed decreases in the first year followed by stability in the second year.
CONCLUSION: Advanced MR biomarkers of myelin (MWF) and neuron/axons (NAA) show no change in NAWM over 24 months in alemtuzumab-treated MS participants.