Does Offline Beat Inline Treatment: Investigation into Extracorporeal Photopheresis

Recent insights into extracorporeal photopheresis for graft-versus-host disease

INTRODUCTION

Extracorporeal Photopheresis (ECP) may be considered the unique large-scale cell therapy currently available. It is currently employed mainly as second-line treatment, especially in steroid-resistant or steroid-dependent Graft versus Host Disease (GvHD) with good results and very few limitations.

AREAS COVERED

Many points need to be clarified regarding the ECP mechanism of action, that conditions the lack of uniqueness among the different centers, essentially cycle frequency, treatment duration, and the number of cells to be treated to obtain a response, according to the organs involved. Moreover, reliable biomarkers for prediction of response are lacking, as well as the best pharmacological combination. We will focus on the recent advances concerning ECP for GvHD treatment. We performed a systematic literature research in Pubmed and Embase as of September 2023.

EXPERT OPINION

The recent studies on ECP mechanism of action along with the promising biomarkers of response, and the synergistic benefit of ECP in association with the new drugs render this therapy an important weapon for GvHD resistant to conventional treatment and can be proposed as a valid first-line therapy option with promising results. We believe that it should be used early in all categories of patients, considering its high safety profile.

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.

Validation of a new automated irradiation system for off-line ECP

Extracorporeal photopheresis (ECP) is a cell therapy originally employed for cutaneous T cell lymphoma and later for GvHD, solid organ rejection and other immunological diseases demonstrating an excellent safety profile. Mononuclear cell (MNCs) apoptosis triggered by UV-A light irradiation in the presence of 8-methoxypsoralene has a key role in priming the cells, ultimately leading to immunomodulation. We report preliminary data about an evaluation of the new automated irradiator device LUMILIGHT (Pelham Crescent srl) for off-line ECP. Fifteen MNCs samples collected by apheresis from 15 adult patients undergoing ECP at our Center were cultured immediately after irradiation along with untreated samples and evaluated at 24, 48 and 72 h timepoints for T cell apoptosis and viability by flow cytometry with Annexin V and Propide Iodidum staining. Post irradiation Hematocrit (HCT), calculated by the device, was compared with that of the automated cell counter. Bacterial contamination was also tested. In irradiated samples after 24-48 and 72 h, the average total apoptosis was 47 %, 70 % and 82 %, respectively, showing a significant difference from untreated samples; residual viable lymphocytes at 72 h were, on average, 18 %. The greatest initiation of apoptosis occurred from 48 h of irradiation onwards. Average early apoptosis of irradiated samples decreased over time (26 %, 17 % and 10 % at 24, 48 and 72 h, respectively). HCT measured by LUMILIGHT was over-estimated, possibly due to the low pre irradiation red blood cell contamination. Bacterial tests resulted negative. Our study showed the LUMILIGHT device to be a valid instrument for MNCs irradiation with good handling and no major technical problems as well as no adverse events in the patients. Our data need to be confirmed in larger studies.

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.

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.