Inline and offline extracorporeal photopheresis: Device performance, cell yields and clinical response

Real-World Experience in Extracorporeal Photopheresis for Adults with Graft-versus-Host Disease

Extracorporeal photopheresis (ECP) has shown efficacy in treating graft-versus-host disease (GVHD). We aim to summarize eight years of real-world experience with off-line ECP in our institution, in order to validate this treatment schedule and analyze predictive factors. All consecutive adult patients with steroid-dependent or steroid-refractory GVHD undergoing off-line ECP were included in this single-center retrospective study. ECP was performed with a Spectra Optia device, processing 1 total blood volume, at a twice-weekly frequency for acute GVHD (aGVHD) and once weekly for chronic GVHD (cGVHD), and tapered individually according to clinical response. The cumulative incidence of response, including complete response (CR) and partial response (PR), were compared among patients grouped by different baseline, apheresis, and disease characteristics. Between January 2015 and May 2022, a total of 1382 ECP procedures were proposed for 82 patients. No incidents were reported in 97% of the ECP sessions. GVHD responded in 78% of patients (aGVHD: 57% CR and 4% PR; cGVHD, 39% CR and 48% PR). Overall survival was statistically greater for aGVHD patients who responded to ECP compared to those who did not respond (67.5% versus 26% at 1 year; P = 0.037). Severity was an independent predictor of response in aGVHD, whereas the absence of mouth involvement and lower lymphocyte counts in the apheresis product correlated with a higher response in cGVHD. Our findings support the effectiveness of this treatment schedule for GVHD. Further investigation is required to identify ECP-specific predictive factors, given that findings are not homogeneous across studies.

Extracorporeal Photopheresis in Graft-versus-Host Disease

Graft-versus-host disease (GVHD) is a major cause of mortality and morbidity following allogeneic hematopoietic stem cell transplantation. Extracorporeal photopheresis (ECP), which exposes mononuclear cells to ultraviolet A irradiation in the presence of a photosensitizing agent, has shown efficacy in the treatment of GVHD. Recent observations in molecular and cell biology have revealed the mechanisms by which ECP can reverse GVHD, including lymphocyte apoptosis, differentiation of dendritic cells from circulating monocytes, and modification of the cytokine profile and T cell subpopulations. Technical innovations have made ECP accessible to a broader range of patients; however, logistical constraints may limit its use. In this review, we scrutinize the development of ECP from its origins to recent insights into the biology underlying ECP efficacy. We also review practical aspects that may complicate successful ECP treatment. Finally, we analyze how these theoretical concepts translate into clinical practice, summarizing the published experiences of leading research groups worldwide.

Increasing the collection flow rate to 2 mL/min is effective and reduces the procedure time in off-line photopheresis

BACKGROUND

Extracorporeal photopheresis (ECP) treatment, mostly based on apheresis technology, is used for immunomodulation in various diseases such as cutaneous T-cell lymphoma, graft versus host disease and other (auto)immune disorders. The aim of this study was to collect high cell counts and purity in shorter procedure times using an ECP off-line system with an increased collection flow rate of 2 mL/min to a target volume of 200 mL buffy coat.

STUDY DESIGN AND METHODS

In this prospective study, data of routinely performed off-line photopheresis treatments were collected and analyzed at the Central Institute for Blood Transfusion & Department of Immunology (ZIB) of the Tirol Kliniken, to assess absolute cell counts and procedure times and to calculate collection efficiencies (CE2).

RESULTS

A total of 22 patients participated in this study. The processed blood volume was 4312 mL, the collection time 120 min, overall procedure time 157 min and the absolute cell counts of treated white blood cells (WBC) and mononuclear cells (MNC) were 5.0 and 4.3 × 109 respectively (median values). The calculated CE2 for WBC and MNC was 21.1% and 58.5%, the proportion of treated MNCs of the total number of MNCs present was 55.0%.

CONCLUSION

The data presented in this study show high therapeutically effective cell counts collected with a high MNC purity within a shorter overall collection/procedure time due to an increased collection flow rate.

Optimierung der extrakorporalen Photopherese

Die Extrakorporale Photopherese ist ein etabliertes Therapieverfahren für Patienten mit T-Zell vermittelten Erkrankungen. Dabei besteht das Verfahren aus der Gewinnung autologer mononukleärer Zellen, deren Behandlung mit 8-Methoxypsoralen und UVA-Licht und die Retransfusion der behandelten Zellen.

Die Wirkmechanismen der Photopherese sind zwar noch nicht vollständig geklärt, ein zentraler Mechanismus stellt jedoch die Apoptose mononukleärer Zellen dar. Das Ziel der Studie war eine Optimierung der Photopherese im Hinblick auf die Behandlung der Zellen mit 8-Methoxypsoralen/UVA und der daraus induzierten verstärkten Apoptose der Lymphozyten. Dabei sind einige Faktoren bekannt, welche die Effektivität der 8-Methoxypsoralen/UVA-Behandlung der Zellen beeinflussen können, wie z.B. der Hämatokrit oder die UVA-Dosis. Unser Fokus lag auf der Verfügbarkeit der photoaktiven Substanz und dem Einfluss der Zellsuspensionsmatrix auf die Apoptose der Lymphozyten.

Die Verfügbarkeit von 8-Methoxypsoralen für die Aufnahme in die Zellen reduzierte sich durch Absorption an Kunststoffe der Bestrahlungssysteme sowie durch Bindung an Proteine bei der Verwendung von autologem Plasma bei der Suspendierung der Zellen. Eine Steigerung der Zugabe von 8-Methoxypsoralen auf 340 ng/mL anstelle von 200 ng/mL führte zu einem Anstieg der T-Zell Apoptose, die sich unter Verwendung von physiologischer Kochsalzlösung als Zellsuspensionsmatrix weiter erhöhte. Eine Anpassung des Verfahrens mit NaCl anstelle von Plasma und die Verwendung einer höheren 8-Methoxypsoralen Konzentration führte zu einer gesteigerten Apoptoseinduktion der T-Zellen. Inwiefern sich eine Erhöhung der Apoptose auf die klinische Wirksamkeit auswirkt, bedarf hingegen noch weiterer klinischen Untersuchungen.

Mechanisms of Action of Extracorporeal Photopheresis in the Control of Bronchiolitis Obliterans Syndrome (BOS): Involvement of Circulating miRNAs

Clinical evidence suggests an improvement or stabilization of lung function in a fraction of patients with bronchiolitis obliterans syndrome (BOS) treated by extracorporeal photopheresis (ECP); however, few studies have explored the epigenetic and molecular regulation of this therapy. The aim of present study was to evaluate whether a specific set of miRNAs were significantly regulated by ECP. Total RNA was isolated from serum of patients with established BOS grade 1–2 prior to the start and after 6 months of ECP treatment. We observed a significant downregulation of circulating hsa-miR-155-5p, hsa-miR-146a-5p and hsa-miR-31-5p in BOS patients at the start of ECP when compared to healthy subjects. In responders, increased miR-155-5p and decreased miR-23b-3p expression levels at 6 months were found. SMAD4 mRNA was found to be a common target of these two miRNAs in prediction pathways analysis, and a significant downregulation was found at 6 months in PBMCs of a subgroup of ECP-treated patients. According to previous evidence, the upregulation of miR-155 might be correlated with a pro-tolerogenic modulation of the immune system. Our analysis also suggests that SMAD4 might be a possible target for miR-155-5p. Further longitudinal studies are needed to address the possible role of miR-155 and its downstream targets.

Comparison of procedure times and collection efficiencies using integrated and multistep nonintegrated procedures for extracorporeal photopheresis

Background

Extracorporeal photopheresis (ECP) is a blood‐based therapeutic procedure increasingly used for modulation of immune dysregulation in various underlying disease settings. The aim of this study was to compare the procedure times and blood collection efficiencies between the two approaches currently utilized in European centers: the integrated versus the multistep nonintegrated procedures.

Methods

A retrospective data analysis was conducted, comparing treatment data from patients who received ECP therapy at the Central Institute for Blood Transfusion & Department of Immunology (ZIB) of the Tirol Kliniken GmbH, where the integrated and multistep nonintegrated procedures are routinely used in an approximated setup.

Results

During the observation period, a total of 15 patients who were treated with alternating systems on 2 consecutive days were identified. This allowed treatment pair comparisons with minimal interpatient variabilities, similar to a cross‐over design even though analyzed retrospectively. Total average procedure times with the integrated system were 99.3 vs 122.0 minutes with the multistep nonintegrated procedures, respectively. Significant differences were observed for all steps of the ECP procedure: (a) time for buffy coat collection, 66.5 vs 74.7; (b) handling/transfer, 2.8 vs 18.7; (c) irradiation, 20.3 vs 11.7; and (d) reinfusion/handling time, 9.6 vs 16.3 minutes. The calculated collection throughput was 7.79 mL/min for the integrated and 7.84 mL/min for the multistep nonintegrated procedures, and with a white blood cell (WBC) collection efficiency of 34.2% and 21.0%, respectively.

Conclusion

The data presented in this study show a significant shorter overall procedure time and higher WBC collection efficiency for the integrated ECP system.

In situ off-line extracorporeal photopheresis conducted in a real-life situation at a Hemobiotherapy Department in France: A comparison of costs vs on-line procedure

BACKGROUND

The off-line extracorporeal photopheresis (ECP) procedure requires photosensitization in an external cell therapy laboratory as per the French regulatory requirement. This regulation results in higher time and costs compared with the on-line alternative performed entirely at the patient's bedside. Recently, full in situ execution of the off-line procedure has been implemented in the Pitié-Salpêtrière Hospital Hemobiotherapy Department (Paris, France). This report summarizes the center's experience regarding the organizational and costs impacts of this change compared with the on-line procedure.

MATERIAL AND METHODS

ECP was broken down into stages, and several procedures were monitored prospectively in real-life settings. The total costs associated with both procedures were the sum of the fixed costs and variable costs related to all stages of the procedures, nursing-time costs, property costs, and patient-related production loss costs.

RESULTS

Eight off-line ECP and fourteen on-line ECP procedures were monitored during five consecutive days. Procedure duration was not different (median 137.5 vs 154.0 minutes, P = .29). Times and costs associated with nursing were higher but offset by lower fixed costs of the off-line ECP. Total direct costs per procedure associated with using the off-line ECP were significantly lower than those of the on-line procedure (459.6 ± 7.1 EUR vs 953.8 ± 6.5 EUR; P = .0002). Similar results were observed when including the costs of patient production loss.

CONCLUSIONS

As a competitive time procedure, the in situ off-line method proved to be cost-efficient by effectively offering similar patient treatment per year compared with the on-line procedure.