Real-World Data Back Stem Cell Transplant for Systemic Sclerosis
Current selection criteria for autologous hematopoietic stem cell transplant (AHSCT) in patients with rapidly progressing systemic sclerosis were validated in a study presented at the annual meeting of the Canadian Rheumatology Association.
The study, which associated AHSCT with improvement in overall survival and an acceptable risk of adverse events, “provides valuable real-world, long-term data pertaining to key clinical outcomes to support the use of AHSCT in patients with rapidly progressing systemic sclerosis,” reported Nancy Maltez, MD, a rheumatologist and clinical investigator who is on the faculty of the University of Ottawa.
The prospective study enrolled 85 patients in Canada and 41 patients in France with rapidly progressing systemic sclerosis. The patients in both countries were enrolled with the same eligibility criteria for AHSCT, but patients in France underwent AHSCT while the patients in Canada were treated with conventional therapies, such as cyclophosphamide.
On the primary outcome of overall survival, the Kaplan-Meier curve split almost immediately in favor of AHSCT. At 4 years, more than 25% of patients in the conventional therapy group had died versus less than 5% of those who underwent AHSCT. Although the mortality curve did slope downwards in the AHSCT group over the subsequent 6 years of follow-up, it largely paralleled and remained superior to convention therapy.
About 50% Survival Advantage Seen for AHSCT
In this nonrandomized study, the statistical survival advantage of AHSCT was not provided, but the survival graph showed about 75% survival at 8 years of follow-up in the AHSCT group, compared with about 50% survival in the conventional-therapy group.
Many of the secondary outcomes, including those evaluating skin involvement, preservation of lung function, and absence of renal complications also favored AHSCT, according to Maltez.
On the modified Rodnan skin score, a significant difference (P < .001) observed at 12 months was sustained at 36 months, when the score was 4.48 points lower among patients treated with AHSCT. The difference in forced vital capacity (FVC) was about 10% higher (P < .0001) in the AHSCT group.
Over long-term follow-up, the incidence of scleroderma renal crisis per 100 person-years was 6.02 cases in the conventional therapy group versus 0.58 cases (P < .001) in the AHSCT group. There was no significant difference in the proportion of patients in the two groups receiving a pacemaker over the course of follow-up, but the rate of new malignancies per 100 person-years was 3.71 in the conventional care group versus 0.58 (P < .001) in the AHSCT group.
Significant complications attributed to AHSCT were uncommon. This is important, because AHSCT was not uniformly well tolerated in the initial trials. The first of three randomized trials with AHSCT in progressive systemic sclerosis was published more than 10 years ago after a series of promising early phase trials. Each associated AHSCT with benefit, but patient selection appeared to be important.
In the ASSIST trial of 2011, AHSCT was associated with significant reductions in skin involvement and improvements in pulmonary function relative to cyclophosphamide, but enrollment was stopped after only 19 patients, and follow-up extended to only 2 years.
Substantial AHSCT-related Mortality in ASTIS
In the second trial, called ASTIS, AHSCT was associated with a higher rate of mortality than cyclophosphamide after 1 year of follow-up, although there was a significantly greater long-term event-free survival for AHSCT when patients were followed out to 4 years. This study reinforced the need for cardiac screening because of because of concern that severe cardiac compromise contributed to the increased risk of AHSCT-related mortality.
The SCOT trial employed a high-intensity myeloablative conditioning regimen and total body irradiation prior to AHSCT. It is not clear that these contributed to improved survival, particularly because of the risk for irradiation to exacerbate complications in the lung and kidney, but AHSCT-related mortality was only 3% at 54 months. Patient enrollment criteria in this trial were also suspected of having played a role in the favorable results.
In the Canadian-French collaborative study, patients were considered eligible for AHSCT if they met the enrollment criteria used in the ASTIS trial, according to Maltez. She attributed the low rates of early mortality and relative absence of transplant-related death to the lessons learned in the published trials.
Overall, the data support the routine but selective use of AHSCT in rapidly progressing systemic sclerosis, Maltez concluded.
Maria Carolina Oliveira, MD, of the department of internal medicine at the University of São Paulo, generally agreed. A coauthor of a recent review of AHSCT for systemic sclerosis, Oliveira emphasized that patient selection is critical.
“AHSCT for systemic sclerosis has very specific inclusion criteria. Indeed, it is indicated for patients with severe and progressive disease but under two specific conditions: severe and progressive diffuse skin involvement and/or progressive interstitial lung disease,” she said in an interview.
Because of the thin line between benefit and risk according to disease subtypes and comorbidities, she said that it is important to be aware of relative contraindications and to recognize the risks of AHSCT.
At this time, and in the absence of better biomarkers to identify those most likely to benefit, “patients with other forms of severe scleroderma, such as those with pulmonary hypertension, scleroderma renal crisis, or severe cardiac involvement, for example, are not eligible,” she said.
Maltez and Oliveira reported having no potential conflicts of interest.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.
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