Multiple Sclerosis: Petkau J

Polman CH, Reingold SC, Barkhof F, Calabresi PA, Clanet M, Cohen JA, Cutter GR, Freedman MS, Kappos L, Lublin FD, McFarland HF, Metz LM, Miller AE, Montalban X, O'Connor PW, Panitch H, Richert JR, Petkau J, Schwid SR, Sormani MP, Thompson AJ, Weinshenker BG, Wolinsky JS. · Department of Neurology, Free University Medical Center in Amsterdam, PO Box 4075, 1007 MB Amsterdam, The Netherlands. · Neurology. · Pubmed #18362273 No free full text.

Abstract: The increasing number of established effective therapies for relapsing multiple sclerosis (MS) and emerging consensus for early treatment raise practical concerns and ethical dilemmas for placebo-controlled clinical trials in this disease. An international group of clinicians, ethicists, statisticians, regulators, and representatives from the pharmaceutical industry convened to reconsider prior recommendations regarding the ethics of placebo-controlled trials in MS. The group concluded that placebo-controlled trials can still be done ethically, with restrictions. For patients with relapsing MS for which established effective therapies exist, placebo-controlled trials should only be offered with rigorous informed consent if the subjects refuse to use these treatments, have not responded to them, or if these treatments are not available to them for other reasons (e.g., economics). Suggestions are provided to protect subject autonomy and improve informed consent procedures. Recommendations are tighter than previously suggested for placebo-controlled trials in "resource-restricted" environments where established therapies may not be available. Guidance is also provided on the ethics of alternative trial designs and the balance between study subject burden and risk, scientific rationale and interpretability of trial outcomes.

Polman C, Kappos L, White R, Dahlke F, Beckmann K, Pozzilli C, Thompson A, Petkau J, Miller D, Anonymous00007. · Department of Neurology, VU Medical Center, Amsterdam, The Netherlands. · Neurology. · Pubmed #12525715 No free full text.

Abstract: OBJECTIVE: To investigate the relationship between neutralizing antibodies (NAB) and disease progression, relapses, and MR measures of MS. METHODS: Sequential serum samples from all 718 patients of the European Study Group in Interferon beta-1b in Secondary Progressive MS were analyzed to investigate relations between NAB and disease progression, relapses, and MR measures. RESULTS: This study showed no attenuating effect of NAB development on progression in disability. The effects of NAB on relapse rate showed substantial variation, depending on the statistical approach and definition of positivity, though analyses comparing low- and high-NAB+ periods with NAB- periods suggested a titer-related effect. MR T2 lesion volume changes from baseline were significantly higher for NAB+ patients but remained lower than for placebo patients. A substantial proportion of NAB+ patients became NAB-. No untoward effect of NAB development on safety was observed. CONCLUSION: These results support the conclusion that even though high NAB titers appear to have impact on treatment efficacy with respect to relapses, treatment decisions should be based primarily on clinical grounds.

Petkau J, Reingold SC, Held U, Cutter GR, Fleming TR, Hughes MD, Miller DH, McFarland HF, Wolinsky JS. · Department of Statistics, University of British Columbia, Vancouver, BC, Canada. · Mult Scler. · Pubmed #18535021 links to  free full text

Abstract: BACKGROUND: Magnetic resonance imaging (MRI) of lesions in the brain may be the best current candidate for a surrogate biological marker of clinical outcomes in relapsing remitting multiple sclerosis (MS), based on its role as an objective indicator of disease pathology. No biological surrogate marker has yet been validated for MS clinical outcomes. OBJECTIVE: The objective of this study was to use a multi-phased study to determine if a valid surrogate relationship could be demonstrated between counts of contrast enhancing lesions (CELs) and occurrence of relapses in MS. METHODS: We examined correlations for the concurrent and predictive relationship between CELs over 6 months and MS relapses over the same 6 months and an additional 6 months (total: 12 months), using available data on untreated patients from a large clinical trial and natural history database. RESULTS: Concurrent and predictive correlations were inadequate to justify continuation of this study to the planned additional phases required to demonstrate a surrogate relationship between CELs and MS relapses. CONCLUSIONS: Confidence intervals for correlations between CELs and MS relapses exclude the possibility that CELs can be a good surrogate for relapses over the time scales we investigated. Further exploration of surrogacy between MRI measures and MS clinical outcomes may require improved datasets, the development of MRI techniques that couple better to clinical disease, and the ability to test a wide range of imaging- and clinically-based hypotheses for surrogacy.

Tremlett H, Seemüller S, Zhao Y, Yoshida EM, Oger JD, Petkau J. · Faculty of Medicine, Department of Medicine, Division of Neurology, University of British Columbia, Vancouver, BC, Canada. · Neurology. · Pubmed #17030771 No free full text.

Abstract: The risk of an abnormal liver test in 813 patients with multiple sclerosis or clinically isolated syndrome enrolled in placebo arms of clinical trials was greater than expected for alanine aminotransferase (ALT) (relative risk [RR] 3.7; 95% CI: 2.3 to 6.0) and aspartate aminotransferase (AST) (RR 2.2; 95% CI: 1.3 to 3.6), although not alkaline phosphatase (AP) or total bilirubin, at first presentation. Abnormal test results were associated with higher body mass index (ALT only), male gender (ALT only), and a relapsing-remitting (vs secondary-progressive) course (ALT and AST only).

Li DK, Held U, Petkau J, Daumer M, Barkhof F, Fazekas F, Frank JA, Kappos L, Miller DH, Simon JH, Wolinsky JS, Filippi M, Anonymous00368. · University of British Columbia, Vancouver, British Columbia, Canada. · Neurology. · Pubmed #16682671 No free full text.

Abstract: BACKGROUND: Previous studies have shown only modest correlation between multiple sclerosis (MS) lesions on MRI and clinical disability. OBJECTIVE: To investigate the relationship between proton density/T2-weighted (T2) burden of disease (BOD) quantitatively measured on MRI scans and clinical determinants including disability. METHODS: Using the Sylvia Lawry Centre for Multiple Sclerosis Research (SLCMSR) database, the authors studied baseline T2 BOD data from a pooled subsample of 1,312 placebo MS patients from 11 randomized controlled trials. Univariate comparisons guided development of multiple regression models incorporating the most important clinical predictors. RESULTS: Significant, although weak to moderate, correlations were found between T2 BOD and age at disease onset, disease duration, disease course, disability (as measured by the Expanded Disability Status Scale [EDSS]), relapse rate, certain presenting symptoms, and gadolinium enhancement. An unexpected but key finding that persisted in the multiple regression analyses was a plateauing relationship between T2 BOD and disability for EDSS values above 4.5. CONCLUSIONS: This study confirmed the limited correlation between clinical manifestations and T2 burden of disease (BOD) but revealed an important plateauing relationship between T2 BOD and disability.

Barkhof F, Held U, Simon JH, Daumer M, Fazekas F, Filippi M, Frank JA, Kappos L, Li D, Menzler S, Miller DH, Petkau J, Wolinsky J, Anonymous00220. · Department of Radiology, VU Medical Centre, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands. · Neurology. · Pubmed #16275834 No free full text.

Abstract: BACKGROUND: Gadolinium enhancement is often used in randomized clinical trials to evaluate the efficacy of new drugs in multiple sclerosis (MS). Knowledge about predictors of enhancement status is important for the selection of patients for MRI monitored trials. METHODS: Data from 17 trials were available in anonymized format through the Sylvia Lawry Centre for MS Research. In an open part containing 1,328 (non primary progressive) patients, two logistic regression analyses were explored, including demographic, clinical, and MRI predictors. The authors examined the area under the curve (AUC) and the increase in positive predictive value (PPV). The final selection of models was validated in a closed part of 848 comparable patients. RESULTS: Age at onset, disease duration, and disease course (CIS/RR/SP) were important predictors from the multivariate models. Further, a multivariate model including T2 burden of disease was more predictive than one with only clinical predictors (AUC 0.719 vs 0.625, p < 0.001). For the model with T2 burden of disease, the PPV was 66.8%, compared to 58.5% for the model without (a priori chance 46.4%). These findings were unequivocally confirmed in the closed part of the database. CONCLUSION: Gadolinium status can be predicted by a set of baseline variables, certainly when T2 burden of disease is included. These findings may benefit the design and statistical power of future randomized clinical trials.

Cutter GR, Baier ML, Rudick RA, Cookfair DL, Fischer JS, Petkau J, Syndulko K, Weinshenker BG, Antel JP, Confavreux C, Ellison GW, Lublin F, Miller AE, Rao SM, Reingold S, Thompson A, Willoughby E. · AMC Cancer Research Center, Center for Research Methodology and Biometrics, Lakewood, Colarado 80214, USA. · Brain. · Pubmed #10355672 links to  free full text

Abstract: The primary clinical outcome measure for evaluating multiple sclerosis in clinical trials has been Kurtzke's expanded disability status scale (EDSS). New therapies appear to favourably impact the course of multiple sclerosis and render continued use of placebo control groups more difficult. Consequently, future trials are likely to compare active treatment groups which will most probably require increased sample sizes in order to detect therapeutic efficacy. Because more responsive outcome measures will be needed for active arm comparison studies, the National Multiple Sclerosis Society's Advisory Committee on Clinical Trials of New Agents in Multiple Sclerosis appointed a Task Force that was charged with developing improved clinical outcome measures. This Task Force acquired contemporary clinical trial and historical multiple sclerosis data for meta-analyses of primary and secondary outcome assessments to provide a basis for recommending a new outcome measure. A composite measure encompassing the major clinical dimensions of arm, leg and cognitive function was identified and termed the multiple sclerosis functional composite (MSFC). The MSFC consists of three objective quantitative tests of neurological function which are easy to administer. Change in this MSFC over the first year of observation predicted subsequent change in the EDSS, suggesting that the MSFC is more sensitive to change than the EDSS. This paper provides details concerning the development and testing of the MSFC.

Polman CH, Kappos L, Petkau J, Thompson A. · No affiliation provided · J Neurol Neurosurg Psychiatry. · Pubmed #12876268 links to  free full text

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Cover KS, Petkau J, Li DK, Paty DW. · No affiliation provided · Neurology. · Pubmed #9932990 No free full text.

This publication has no abstract.