Saturday, 15 June 2013

Cognitive reserve: MRI and Alemtuzumab

Alemtuzumab reduces the rate of brain atrophy compared to interferon-beta and protects brain tissue integrity. #MSBlog #MSResearch

"As you can see from the 4 studies below Alemtuzumab (aka Campath or Campath-1h) has a positive effect on brain atrophy, when compared to interferon-beta. It slows the rate of brain shrinkage. In addition it has a positive effect on an MRI metric called MTR that is a measure of tissue integrity."

"The fact that Alemtuzumab does not stop brain atrophy is not surprising; all of us lose brain volume. Brain volume loss in MS is probably a delayed phenomenon from previous damage years earlier. The process by which nerve cells and their processes (axons) degenerate takes months to years to run its course. Therefore, it will be very interesting to see if Alemtuzumab normalises brain atrophy rates after 2 years? That will be the litmus test. If that is the case it will be protecting brain reserve and hopefully allow you to reach old age with sufficient brain to handle the cognitive stress of ageing and age-related brain disease, for example Alzheimer's disease and small vessel disease. It is clear that these diseases present earlier in people with reduced brain reserve." 

"Let's imagine for a moment that a treatment cures you of MS and prevents any further brain damage from MS. What will be the consequences of an early compared to a late MS cure? MSers, for arguments sake, who are cured very early in the course of their disease at a stage with little brain loss will present with Alzheimer's disease later than MSers who are cured of MS later in the course of the disease. The latter hypothesis is based on the brain or cognitive reserve theory that is now well established in the dementia field."

"The implications of this example is treat early with effective  therapies is to protect your brain so that you can maximise your chances of a good quality of life in old age."

PAPER 2: Coles et al. Alemtuzumab for patients with relapsing multiple sclerosis after disease-modifying therapy: a randomised controlled phase 3 trial. Lancet. 2012 Nov 24;380(9856):1829-39.

PAPER 3: Button et al. Magnetization transfer imaging in multiple sclerosis treated with alemtuzumab. Mult Scler. 2013 Feb;19(2):241-4.

Background: The magnetization transfer ratio reflects the integrity of tissue structure, including myelination and axonal density. 

Results: Mean magnetization transfer ratio fell in 18 untreated MSers with multiple sclerosis both in normal appearing grey (-0.25 pu/year, p < 0.001) and white matter (-0.12 pu/year, p = 0.004). Conversely, mean magnetization transfer ratio was stable in 20 alemtuzumab-treated MSers (grey matter: -0.01 pu/year, p = 0.87; white matter: -0.02 pu/year, p = 0.51). The gradient difference in grey matter was 0.25 pu/year (p < 0.001) after age-adjustment. 

Conclusion: These data suggest that in multiple sclerosis alemtuzumab protects against tissue damage in normal-appearing grey matter, perhaps by preventing new lesion formation.

PAPER 4: Paolillo et al. Quantitative MRI in patients with secondary progressive MS treated with monoclonal antibody Campath 1H. Neurology. 1999 Sep 11;53(4):751-7.

BACKGROUND: To assess the long-term effect of the lymphocyte-depleting humanized monoclonal antibody Campath 1H on MR markers of disease activity and progression in secondary progressive MSers.

METHODS: Twenty-five MSers participated in a crossover treatment trial with monthly run-in MR scans for 3 months, followed (after a single pulse of Campath 1H) by monthly MR scans from months 1 to 6 and again from months 12 to 18. MR analysis was performed to provide measurements of the number and volume of gadolinium (Gd)-enhancing lesions as well as the hypointense lesion volume on a T1-weighted sequence. In addition, serial measurements of T2 brain lesion volume, brain volume, and spinal cord cross-sectional area were made over the duration of the study. The relationship between clinical and MR measures of disease evolution was also assessed.

RESULTS: Treatment was associated with a reduction in the number and volume of Gd-enhancing lesions (p < 0.01). Despite this, a decrease in brain volume was seen in 13 MSers during the 18 months post-treatment. The mean pretreatment Gd-enhancing lesion volume was predictive of subsequent reduction in brain volume (r = 0.77, p = 0.002). Reduction in brain volume also correlated with the change in T1 hypointense lesion volume after treatment (r = 0.53, p < 0.01). A reduction in spinal cord area was also seen throughout the study duration, and this correlated with an increase in disability (r = 0.65, p = 0.01).

CONCLUSION: Campath 1H treatment was associated with a sustained and marked reduction in the volume of Gd enhancement, indicating suppression of active inflammation. Nevertheless, many patients developed increasing brain and spinal cord atrophy, T1 hypointensity, and disability. This study highlights the potential role for novel MR techniques in monitoring the effect of treatment on the pathologic process in MS.

CoI: multiple

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