CHICAGO – Changes in quantitative lung CT scores for scleroderma-related interstitial lung disease independently validate the superiority of hematopoietic stem cell transplantation versus cyclophosphamide for severe systemic sclerosis, according to findings in a subset of patients from the SCOT (Scleroderma: Cyclophosphamide or Transplantation) trial.
Mitchel L. Zoler/MDedge News
Dr. Keith M. Sullivan
The recently published findings from the SCOT trial showed that myeloablation followed by autologous hematopoietic stem cell transplant (HSCT) significantly improved event-free and overall survival of systemic sclerosis patients at 54 months, compared with 12 monthly treatments with intravenous cyclophosphamide (N Engl J Med. 2018;378:35-47).
In a subset of 75 patients from the SCOT trial, the investigators analyzed changes in lung parenchymal abnormalities on high-resolution CT scans between baseline and serial follow-up exams performed yearly for up to 5 years. Follow-up scans at 14, 26, 48, and 54 months in available patients at each time point showed that whole-lung quantitative interstitial lung disease (QILD) scores – a validated measure that combines various CT texture-based characteristics to determine disease extent – decreased significantly by 7% at 54 months in patients who underwent HSCT, compared with no change in those who received cyclophosphamide (CYC; P = .024), Keith M. Sullivan, MD, reported at the annual meeting of the American College of Rheumatology.
Additionally, whole-lung quantitative lung fibrosis (QLF) scores were stable (–1%) in the HSCT patients, but increased 3% in the CYC patients (P = .047), said Dr. Sullivan, a professor of medicine at Duke University, Durham, N.C.
Dr. Sullivan was the first author on the SCOT trial, and he reported the current study results on behalf of lead investigator Jonathan Goldin, MD, PhD, of the department of radiologic sciences at the University of California, Los Angeles.
“These are really kind of meaningful associations, especially since the worst of the [CYC] treatment group didn’t make it to month 54,” Dr. Sullivan said.
Quantitative scores of scleroderma-related interstitial lung disease were measured using computer-based quantitative image analysis of standardized, noncontrast, volumetric, thin-section, thoracic, high-resolution CT. The same CT machine was used for all time points (except for one subject) with careful attention to breath hold reproducibility and image quality. Baseline characteristics were not different between the HSCT and CYC groups, he noted, stressing the rigorous study design.
CT assessments were also compared for the most severe lobe in each patient and showed similar findings, with both QILD and QLF scores for that lobe improving in the HSCT patients relative to the CYC patients (P = .004 and P = .002, respectively), Dr. Sullivan said, adding that the direction of change in structural measures of QILD and QLF for both whole lung and most severe lobe CTs tracked with physiological pulmonary function tests, including forced vital capacity (FVC), forced expiratory volume in 1 second, and diffusing capacity of the lungs for carbon monoxide.
“The FVC improved while QILD decreased, and that’s what you would expect to see,” he said. “So for each of these ways of displaying data, there was an expected and sensible inverse correlation.”
Scleroderma-related interstitial lung disease is a major cause of morbidity and mortality in severe systemic sclerosis. In the wake of the SCOT trial findings, questions remained with respect to correlation between those findings and pulmonary function; if the improvements with HSCT are real and meaningful, they should have meaningful correlation with pulmonary function, and these findings demonstrate those correlates, he said.
“Changes in quantitative lung CT scoring of scleroderma lung disease provide an objective radiologic validation of the long-term benefits of transplant compared to cyclophosphamide in individuals with severe scleroderma and lung involvement. Improvement in imaging after transplant continues for up to 54 months after randomization, giving radiologic confirmation of a durable treatment benefit,” Dr. Sullivan concluded.
The investigators reported having no relevant disclosures.
SOURCE: Goldin J et al. Arthritis Rheumatol. 2018;70(Suppl 10): Abstract 901.