Barts-MS rose-tinted-odometer: ★★★★★
What should be our therapeutic target in MS? Reducing relapses and MRI activity, NEDA (no evident disease activity) or saving the end-organ (brain volume loss)?
I have been pushing the for the latter, i.e. the most important treatment target must be protecting the end-organ and saving or protecting as many neurons, axons and synapses as possible in people with MS (pwMS) so that can age normally and live as near normal life as possible. To achieve this we need to diagnose and treat MS as effectively as possible (Time is Brain) and to promote a brain-healthy lifestyle and to treat MS holistically (minimal gains hypothesis).
This principle of protecting the end-organ is not new and was probably first promulgated by the kidney doctors in relation to loss of kidney function in chronic kidney disease; every nephron (the kidney’s equivalent of a neuron) is sacred. Every neuron is sacred! The difference between kidney doctors and neurologists is that they can always put their patients on dialysis and offer them kidney transplants. We, neurologists, don’t have that luxury and what awaits our patients with progressive loss of end-organ (brain atrophy) is unemployment, worsening cognitive impairment and physical disabilities and the consequences (bladder, bowel, falls, walking aids, wheelchairs, dementia, etc).
What is interesting is that not all DMTs are made equal when it comes to protecting the end-organ. At the top of the rankings are HSCT and alemtuzumab followed by natalizumab and then there are the also-rans. What is interesting is the impact on brain volume loss is not necessarily linked to the DMTs ability to switch of focal lesions (relapses and MRI activity). A good example of this is teriflunomide, which has only a modest effect on relapses (~35% reduction in relapse rate) compared to say anti-CD20 therapies, which after 6 months of treatment almost completely stop relapses and MRI activity, but these two classes of therapy have a similar impact on slowing down brain volume loss.
Teriflunomide is clearly doing something at the level of the end-organ that anti-CD20 therapies are not. This study below in subjects with CIS shows that teriflunomide works very well, on the end-organ, even early on in the disease, but not all subjects are responders. This begs the question; what is it about teriflunomide’s mode of action that explains its remarkable effects on brain atrophy? I have hypothesised in the past about teriflunomide’s broad-spectrum anti-viral effects and have proposed doing the iTeri study, i.e. using an anti-CD20 or other depleting DMT as true induction therapy and then using teriflunomide (or another DHODH inhibitor) as the maintenance therapy. The hypothesis is to allow peripheral B-cell reconstitution or recovery to occur in the presence of anti-EBV agents, which will prevent EBV-infected autoreactive (MS causing) B-cells returning. The problem we are having with the iTeri study is trial design; i.e. how do you design a trial that will convince the regulators of its efficacy and get the drug licensed as a maintenance therapy? Would the regulators accept non-inferiority or safety design? Another reason for this study design is to derisk anti-CD20 therapies. The doubting Thomas in me is saying there is no way someone with MS can stay on an anti-CD20 therapy indefinitely.
Maybe I am wrong, but let’s not stick our heads in the sand. Relapses and focal MRI activity are not MS. The real MS is smouldering MS and all the processes that cause accelerated brain volume loss. Let’s focus on smouldering MS and ask questions about what needs to be done to tackle these processes. What is ot about HSCT, alemtuzumab, natalizumab and possible teriflunomide that differentiates the DMTs into two classes. For example, could it be the T-cell?
Zivadinov et al. Slowing of brain atrophy with teriflunomide and delayed conversion to clinically definite MS. Ther Adv Neurol Disord. 2020 Nov 11;13:1756286420970754.
Background: We explored the effect of teriflunomide on cortical gray matter (CGM) and whole brain (WB) atrophy in patients with clinically isolated syndrome (CIS) from the phase III TOPIC study and assessed the relationship between atrophy and risk of conversion to clinically definite MS (CDMS).
Methods: Patients (per McDonald 2005 criteria) were randomized 1:1:1 to placebo, teriflunomide 7 mg, or teriflunomide 14 mg for ⩽108 weeks (core study). In the extension, teriflunomide-treated patients maintained their original dose; placebo-treated patients were re-randomized 1:1 to teriflunomide 7 mg or 14 mg. Brain volume was assessed during years 1-2.
Results: Teriflunomide 14 mg significantly slowed annualized CGM and WB atrophy versus placebo during years 1-2 [percent reduction: month 12, 61.4% (CGM; p = 0.0359) and 28.6% (WB; p = 0.0286); month 24, 40.2% (CGM; p = 0.0416) and 43.0% (WB; p < 0.0001)]. For every 1% decrease in CGM or WB volume during years 1-2, risk of CDMS conversion increased by 14.5% (p = 0.0004) and 47.3% (p < 0.0001) during years 1-2, respectively, and 6.6% (p = 0.0570) and 35.9% (p = 0.0250) during years 1-5. In patients with the least (bottom quartile) versus most (top quartile) atrophy during years 1-2, risk of CDMS conversion was reduced by 58% (CGM; p = 0.0024) and 58% (WB; p = 0.0028) during years 1-2, and 42% (CGM; p = 0.0138) and 29% (WB; p = 0.1912) during years 1-5.
Conclusion: These findings support the clinical relevance of CGM and WB atrophy and early intervention with teriflunomide in CIS.
If you enjoy reading this blog you may want to support Prof G’s challenge
After his recent accident in which he sustained a broken pelvis and cervical spine, he has set himself a rehab challenge to walk 5 km unsupported by the end of the year (‘Prof G’s bed to 5km Challenge’). He is raising money for Queen Mary University of London to support Dr Ruth Dobson and Dr Angray Kang’s COVID-19 MS Antibody Study. So please donate if you can, every little helps and will get this study completed on time.