Relapse rates and enhancing lesions in a phase II trial of natalizumab in multiple sclerosis

Paul O'Connor, David Miller, Katherine Riester, Minhua Yang, Michael Panzara, Catherine Dalton, Katherine Miszkiel, Omar Khan, George Rice, William Sheremata, G. J. Barker, D. G. MacManus, C. Webb, C. Middleditch, S. Lewis, T. Pepple, E. Riddle, C. Coombs, M. Agius, D. RichmanJ. Adams, M. Buonocore, J. Al-Omaishi, K. Markopoulou, K. Healey, P. Sorensen, D. Bates, J. Forsyth, J. Curlis, P. English, L. Blumhardt, V. Orpe, T. Jaspen, J. Bowen, M. Chang, H. Lew, M. Burke, T. Richards, J. L. Carter, D. Dodick, J. Takata, M. Malikowski, K. Nelson, D. A.H. Cross, J. Trotter, D. Derrington, J. Lauber, C. Martinez, G. Foster, T. Conturo, V. Devonshire, J. Oger, L. Wang, W. Morrison, L. Costley, C. Hawkins, C. Mathews, C. Gibson, J. Hebert, I. Rozentsvit, L. Capolino, J. P. Kelly, M. Kaufman, S. Putman, A. Diedrich, R. Follmer, S. Dombrowski, C. Graves, B. Harwick, A. C. Tselis, M. Din, C. Caon, M. Cochran, Z. Latif, R. P. Lisak, M. Zvartau-Hinds, L. Metz, J. Scott, D. Patry, M. Yeung, J. Heuser, C. Wallace, S. Curtis, A. Miller, E. Drexler, M. J. Keilson, K. Bruining, A. Schneider, R. Wolintz, L. Sciarra, H. Oltazewska, R. S. Murray, A. Bowling, R. E. Kramer, K. Bracht, C. O'Brien, L. Seeberger, J. Leitch, E. Prenger

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


Background: Natalizumab, a humanized monoclonal IgG4 antibody, is an α4-integrin antagonist, which inhibits the migration of inflammatory cells into the central nervous system, a key pathogenic mechanism in multiple sclerosis (MS). In a six month, phase II clinical trial of patients with relapsing MS, natalizumab significantly reduced the formation of new gadolinium-enhanced (Gd+) lesions and the number of clinical relapses. Objective: To investigate the relationship of historical relapse rate and new Gd+ lesion number with subsequent MS disease activity and natalizumab treatment in the phase II study. Methods: Patients who participated in the phase II study were stratified into subgroups according to: (i) the number of relapses in the two years prior to entry into the study: 2 relapses (n = 108), 3 relapses (n = 57), and >3 relapses (n = 48); (ii) the number of new Gd+ lesions at baseline (Month 0): 0 (n = 129), 1-2 (n = 50), and >2 (n = 33). Relapses and new Gd+ lesions during the treatment phase of the trial were determined and compared for each subgroup. Results: Both the prestudy relapse rate and number of new Gd+ lesions at baseline were related to the subsequent risk of a relapse; baseline number of Gd+ lesions was related to the likelihood of subsequent new Gd+ lesion formation. There was a lower proportion of subjects with an on-study relapse and fewer new Gd+ lesions in all natalizumab-treated subgroups when compared with their placebo counterpart; the difference was most apparent in the subgroups of patients with >3 relapses in the two years prior to study entry and >2 new Gd+ lesions at Month 0. Conclusions: There was a lower proportion of subjects with an on-study relapse in natalizumab-treated patients, particularly in those with a more active disease at study entry. Larger ongoing phase III studies will allow more definitive investigation of these preliminary subgroup findings.

Original languageEnglish (US)
Pages (from-to)568-572
Number of pages5
JournalMultiple Sclerosis
Issue number5
StatePublished - Oct 2005


  • Gadolinium-enhancing lesions
  • Natalizumab
  • Relapsing MS

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology


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