CHICAGO – At least three phase 3 randomized scleroderma treatment trials presented at the annual meeting of the American College of Rheumatology failed to meet modified Rodnan Skin Score–based primary endpoints, but a different story emerged when data from the trials were analyzed using the novel ACR Composite Response Index in Systemic Sclerosis (CRISS).
Dr. Robert F. Spiera
The differences highlight the limitations of individual outcome measures like the modified Rodnan Skin Score (mRSS) and underscore the need for new measures that capture the complexity of systemic sclerosis (SSc) and are more sensitive to changes in disease severity, according to Robert Spiera, MD, director of the vasculitis and scleroderma program at the Hospital for Special Surgery in New York.
Such measures are needed to better assess the effects of treatment interventions in scleroderma trials, Dr. Spiera said in an interview.
The ACR CRISS
Development of the ACR CRISS was led by Dinesh Khanna, MBBS, a professor of medicine and director of the scleroderma program at the University of Michigan, Ann Arbor. He and his colleagues described the measure in 2016 (Arthritis Rheumatol. 2016 Feb;68[2]:299-311. doi: 10.1002/art.39501).
Its use involves a two-step process of identifying any significant disease worsening or new end-organ damage, and then calculating the probability of patient improvement after 1 year of treatment on a 0- to 1-point scale based on changes from baseline in five variables: the mRSS, percent predicted forced vital capacity (FVC), patient and physician global assessments, and the Health Assessment Questionnaire Disability Index (HAQ-DI).
A CRISS score of 0.6 or higher indicates likelihood that a patient improved on treatment. Of note, subjects with significant worsening of renal or cardiopulmonary involvement are classified as not improved (score of 0), regardless of improvements in other core items.
To devise the CRISS, the investigators compiled 150 patient profiles with standardized clinical outcome elements using patients with diffuse cutaneous systemic sclerosis (dcSSc). The profiles were assessed by 40 scleroderma experts who rated patient improvement or lack thereof over 12 months.
Using the 79% of profiles for which a consensus was reached, the investigators “fit logistic regression models in which the binary outcome referred to whether the patient was improved or not, and the changes in the core set items from baseline to follow-up were entered as covariates,” they explained.
This led to the selection of the five measures included in the final version, which was found to have sensitivity of 0.982 and specificity of 0.931. When evaluated in a previously completed 1-year randomized controlled trial, the index differentiated the effect of methotrexate from the effect of placebo (P = .02), they reported.
Based on these findings, the ACR board of directors granted “provisional” endorsement of the CRISS for use in SSc clinical studies, signifying that it had been quantitatively validated using patient data, but had not undergone validation using an external data set.
New data presented at the 2018 ACR meeting will likely lead to full approval of the measure once the studies validating the measure are published, according to Dr. Spiera.