Gordon S. Francis

Proton magnetic resonance spectroscopy for metabolic characterization of plaques in multiple sclerosis

We are investigating the potential of in vivo proton magnetic resonance spectroscopy for noninvasive characterization of the chemical pathology of plaques in magnetic resonance brain images from patients with multiple sclerosis. Spectra localized to chronic, irreversible plaques showed a decrease in the ratio of N-acetyl/creatine resonance intensities relative to normal-appearing white matter. Spectra localized to active plaques showed different metabolite changes as compared with spectra from identical, plaque-free volumes in the contralateral hemispheres. Some active plaques showed either no abnormalities or only an increase in tissue lactate. Spectra from others showed an increased ratio of choline/creatine resonance intensities, with or without a decreased N-acetyl/creatine resonance intensity ratio. In one case, serial observations showed an evolution of changes in spectra from a single plaque from an increased choline/creatine ratio to a decreased N-acetyl/creatine ratio. These observations suggest that proton magnetic resonance spectroscopy may be able to distinguish acute or active from chronic plaques and to characterize the pathologic evolution of active plaques by measurement of local tissue metabolite levels.

Axonal metabolic recovery in multiple sclerosis patients treated with interferon β-1b

Abstract Patients with multiple sclerosis (MS) can benefit from treatment with interferon β–1b. However, the mechanisms of action of this drug are incompletely understood and effects of interferon β–1b on axonal injury are not known. A measure of axonal injury can be obtained in vivo using magnetic resonance spectroscopy to quantify the resonance intensity of the neuronal marker, N-acetylaspartate (NAA). In a small pilot study, we performed combined magnetic resonance imaging and magnetic resonance spectroscopic imaging on 10 patients with relapsing-remitting MS before and 1 year after starting treatment with subcutaneous interferon β–1b. Resonance intensities of NAA relative to creatine (Cr) were measured in a large, central brain volume. These measurements were compared with those made in a group of 6 untreated patients selected to have a similar range of scores on the Expanded Disability Status Scale and mean NAA/Cr at baseline. NAA/Cr in the treated group [2.74 (0.16), mean (SD)] showed an increase of 5.5 % 12 months after the start of therapy [2.89 (0.24), p = 0.05], while NAA/Cr in the untreated group decreased, but not significantly [2.76 (0.1) at baseline, 2.65 (0.14) at 12 months, p > 0.1]. NAA/Cr had become significantly higher in the treated group at 12 months than in the untreated group (p = 0.03). Our data suggest that, in addition to losing axons, patients with chronic multiple sclerosis suffer from chronic, sublethal axonal injury that is at least partially reversible with interferon β–1b therapy.

Multiple sclerosis patients—benefit-risk preferences: Serious adverse event risks versus treatment efficacy

Objective:The aim of this study is to estimate the willingness of multiple sclerosis (MS) patients to accept life-threatening adverse event risks in exchange for improvements in their MS related health outcomes.Methods:MS patients completed a survey questionnaire that included a series of choice-format conjoint tradeoff tasks. Patients chose hypothetical treatments from pairs of treatment alternatives with varying levels of clinical efficacy and associated risks.Results:Among the 651 patients who completed the survey, delay in years to disability progression was the most important factor in treatment preferences. In return for decreases in relapse rates from 4 to 1 and increases in delay in progression from 3 to 5 years, patients were willing to accept a 0.38% annual risk of death or disability from PML, a 0.39% annual risk of death from liver failure or a 0.48% annual risk of death from leukemia.Conclusions:Medical interventions carry risks of adverse outcomes that must be evaluated against their clinical benefits. Most MS patients indicated they are willing to accept risks in exchange for clinical efficacy. Patient preferences for potential benefits and risks can assist in decision-making.

Axonal dysfunction and disability in a relapse of multiple sclerosis: Longitudinal study of a patient

In a 6-year longitudinal study of a patient with relapsing progressive multiple sclerosis (MS), we used proton magnetic resonance spectroscopy to asses N-acetylaspartate (NAA) from a large central brain volume to evaluate the relationship between this marker of neuronal integrity and clinical disability. During the follow-up period, there was one major relapse and its subsequent partial remission. Changes in the brain NAA to creatine ratio correlated strongly with clinical disability (Spearman rank coefficient= -0.73, p < 0.001). We interpret this as evidence that axonal dysfunction or loss contributes to functional impairment of patients with MS. Because the NAA signal in the large volume of interest originated predominantly from white matter than appeared normal on conventional MRI, these results also suggest that some degree of axonal dysfunction may be widespread in acute, severe relapses.

Contribution of a single DQβ chain residue to multiple sclerosis in French Canadians

Putative disease susceptibility and resistance HLA class II alleles were studied in 78 French Canadian multiple sclerosis (MS) patients and 79 controls by using sequence-specific oligonucleotide probes to analyze in vitro amplified DNA (PCR-SSOP) typing). In this relatively homogeneous ethnic group, MS was positively associated with DRB5*0101, DQB1*0602, and DQA1*0102 and negatively associated with DQB1*0301. The strongest disease association was with DQB1*0602. Complete DQB1 typing of these individuals, plus RFLP DQ beta typing of an additional five patients showed that 98% of patients compared with 73% of controls carry DQB1 alleles encoding leucine at residue 26. In contrast, 16% of patients compared with 38% of controls carry DQB1 alleles encoding tyrosine at the same residue, and 22% of patients versus 44% of controls carry DQB1 alleles encoding glycine at residue 26. The positive disease correlation was confirmed with SSO probes designed to hybridize to codons for amino acids 22-27 of DQB1*0602, 0603, 0604, 0302, 0303 or to codons for amino acids 25-31 of DQB1*0201; all of these alleles encode Leu 26. These findings suggest that DQ beta chain polymorphisms at a single residue contribute to the development of MS in the French Canadian population.

Importance of benefit-to-risk assessment for disease-modifying drugs used to treat MS

Abstract.Interferon (IFN) β has been shown to be an effective therapy in pivotal studies of multiple sclerosis (MS), with differences in outcomes based on dose and/or frequency of administration. Glatiramer acetate (GA) has also shown to have an effect on relapses and magnetic resonance imaging measures, but not on disability. All products are associated with adverse events, and utilisation of a specific therapy needs to consider benefit in relation to risk. Evidence-based medicine provides a means of assessing benefit and risk in the context of the number of patients one needs to treat to obtain benefit (NNT) compared with the number needed to treat for an adverse outcome (NNH). Efficacy and safety data are presented from IFN β-1a (Rebif®) clinical trials, including relevant NNT and NNH values, to allow assessment of the overall benefit-to-risk ratio compared with placebo. Additional comparisons are made with published data for other IFN products and GA. The indirect comparative information reviewed demonstrates that IFN appears to have a better benefit- to-risk ratio than GA. Indirect comparisons suggest better efficacy of thrice weekly (tiw) IFN β-1a compared with alternate-day IFN β-1b, but no direct comparative data are available. Direct comparative data show that IFN β-1a at a dose of 44 mcg tiw has a favourable benefit-to-risk ratio compared with both 22 mcg tiw and 30 mcg once weekly, suggesting that 44 mcg tiw currently has the best benefit- to-risk ratio for the treatment of relapsing MS.

Failure of intravenous immunoglobulin to arrest progression of multiple sclerosis: a clinical and MRI based study

Due to the modest benefit, inconvenience and high cost of currently available therapies for MS, it is appropriate to seek alternative treatments. Based on anecdotal evidence suggestive of benefit for IVIG in MS, we conducted an open-label, unblinded protocol of IVIG in nine MS patients. The patients were given induction doses of IVIG followed by monthly boosters for I year and had clinical, MRI and CSF analyses performed. Patients included were both progressive and relapsing. There was no clinical benefit nor apparent MRI benefit utilizing this protocol. During treatment, the majority of patients continued to progress or have attacks and MRI demonstrated continued accumulation of T2-weighted lesions. CSF was unaffected by treatment