Extracorporeal photopheresis for systemic sclerosis: A meta-analysis of randomized clinical trials

Systemic sclerosis (scleroderma) (SSc) is a rare autoimmune disorder characterized by excessive production of collagen. Extracorporeal photopheresis (photochemotherapy, phototherapy) (ECP) involves repeated exposure of peripheral blood lymphocytes to ultraviolet A (UVA) radiation. The rationale for treating patients with SSc by ECP lies in its presumed immunomodulatory effects, though, rigorous data on the specific effects of ECP are limited, particularly in patients with SSc. The objective was to evaluate the effects of extracorporeal photopheresis as a treatment modality for patients with SSc. We searched the databases CENTRAL and MEDLINE on 13 March 2022 and included randomized clinical trials (RCTs) on patients diagnosed with SSc and treated with ECP. Primary outcome was the change of skin scores. We applied independent extraction and judgment by multiple observers. We conducted a meta-analysis applying the inverse variance method and the random effects model; the main outcome measure was standard mean difference of skin scores. We identified three relevant RCTs including 162 randomized (132 analyzed) people who received ECP in a simple parallel design. Pooled data of the three studies were indifferent. We estimated a standard mean difference from baseline of -0.11 (95% confidence interval -0.45 to 0.23), p = 0.54, I²  = 0%. We did not identify serious treatment-related adverse events. The evidence base for extracorporeal photopheresis on skin scores in patients with systemic sclerosis was not high enough to support a superior effect when compared to no treatment, sham photopheresis, or D-penicillamine.