From Multiple Sclerosis Journal, February 13, 2015:
Progression rates and sample size estimates for PPMS based on the CLIMB study population
Kesav Raghavan
Partners Multiple Sclerosis Center, Brigham and Women’s Hospital, USA
Brian C Healy
Partners Multiple Sclerosis Center, Brigham and Women’s Hospital, USA/Biostatistics Center, Massachusetts General Hospital, USA
Robert L Carruthers
Partners Multiple Sclerosis Center, Brigham and Women’s Hospital, USA
Tanuja Chitnis
Partners Multiple Sclerosis Center, Brigham and Women’s Hospital, USA
Partners MS Center, Brigham and Women’s Hospital, 1 Brookline Place, Suite 602, Brookline, MA 02445, USA. tchitnis@partners.org
Background:
The clinical trial design for primary progressive multiple sclerosis (PPMS) requires understanding of disability progression in modern patient cohorts.
Objective:
The objective of this paper is to characterize demographic and clinical characteristics of PPMS and assess rate of disability progression.
Methods:
We studied PPMS (n = 73) and relapsing-onset MS (ROMS) patients (n = 1541) enrolled in CLIMB, a longitudinal study of MS patients at the Brigham and Women’s Hospital (Boston, MA). Disability progression for each group was compared using interval-censored survival analysis and time to six-month sustained progression.
Results:
The PP group had a 1.09:1 male:female ratio compared to 1:2.89 for the RO group and greater mean age of onset (PP: 44.4±9.6; RO: 32.7±9.9; p < 0.0001). Motor symptoms at onset and first symptoms localized to spinal cord were each strongly associated with PPMS (p < 0.001). Median time from onset to EDSS 6.0 was faster in PPMS (p < 0.001). PPMS patients progressed faster to EDSS 3 (p < 0.001) and from EDSS 3 to 6 (p < 0.001). Median time to sustained progression in the PP group was 4.85 years (95% CI 2.83–8.35), significantly faster than the RO group (p < 0.001).
Conclusions:
Our modern PPMS cohort is demographically similar to previously studied cohorts. PPMS is associated with faster disability accrual than ROMS. Current real-world observations of time to sustained progression will inform design of new clinical trials for PPMS.