Inline extracorporeal photopheresis: evaluation of cell collection efficiency

Mononuclear cell recruitment during extracorporeal photopheresis: Partial results of a phase 1/2 randomized clinical trial in multiple sclerosis

BACKGROUND

Despite the routine clinical use of extracorporeal photopheresis (ECP) for the last decades, there has been no sufficient investigation on the intra-apheresis dynamics of mononuclear cells (MNCs).

OBJECTIVE

This research aims to verify the "intra-apheresis recruitment" (IAR) of MNCs, which may be particularly useful in cases with low preapheresis MNC counts.

METHODS

Prospective data of ECP procedures for patients with multiple sclerosis (MS) in the context of the PHOMS study (NCT05168384) were analyzed. ECPs were performed with the use of the Therakos® CellEx® Photopheresis System, and the recruitment factor (RF), collection efficiency 1 (CE1), and fold enrichment (FE) for MNCs, lymphocytes, monocytes, and neutrophils were calculated at various intervals per the approved protocol.

RESULTS

A total of 252 ECP procedures were performed on nine patients with MS, and data from 45 ECPs were analyzed for this study. IAR (RF ≥ 1) of MNCs, lymphocytes, and monocytes was observed in the 93.3 %, 95.5 %, and 88.8 % of the ECP procedures, respectively. CE1 exceeded 100 % for these populations in 13.3 %, 11.1 %, and 24.4 % of ECPs, while FE ≥ 1 for MNCs and lymphocytes was found in all ECPs, and in 97.8 % of ECPs for monocytes. Additionally, RF correlated positively with CE1 for MNCs (r = 0.40, p = 0.006) and lymphocytes (r = 0.43, p = 0.003), as well as with FE for monocytes (r = 0.39, p = 0.01) and lymphocytes (r = 0.48, p = 0.001), further improving collection quality.

CONCLUSIONS

Administering photopheresis with suboptimal MNC counts was plausible and did not worsen the anticipated cytopenias. Moreover, our findings revealed sustained IAR of MNCs in patients with MS who underwent ECP.

Comparison of two inline photopheresis systems: A paired crossover trial

BACKGROUND

Extracorporeal photopheresis (ECP) has been demonstrated as an effective treatment for graft-versus-host disease (GvHD). The inline system was developed by Therakos in 1987. Recently, Fresenius Kabi implemented an integration of cell separator Amicus and a UVA photoactivation device (Phelix), realizing an inline photopheresis system.

STUDY DESIGN AND METHODS

In 2022 we designed a prospective paired crossover trial (NCT05718674) comparing two integrated ECP protocols: Therakos CELLEX and Amicus ECP system. Twenty patients affected by corticosteroid resistant GvHD were submitted to 80 ECP, 40 paired procedures.

RESULTS

All procedures were well tolerated, with no significant differences in procedure duration. CELLEX cell product showed higher granulocytes and platelet content, while Amicus cell product exhibited higher enrichment of lymphocytes, resulting in significantly higher MNC purity (92.9% vs. 84%). A significantly higher granulocytes and platelets absolute content was observed in CELLEX cell products, while Amicus cell products showed a significantly higher number of TNCs and MNCs. Differences in granulocyte and platelet content remained significant even after normalization of the data according to blood volume processed. These findings are confirmed by a statistically significant higher CE2% for CELLEX for granulocytes and platelets along with the lack of significant difference observed for TNCs and MNCs.

DISCUSSION

Our analysis shows differences in the characteristics of the procedure and the cell product. Anyway, both devices are effective for performing ECP procedure, as they collect a cell product suitable for photopheresis. At present, our results represent the first data set comparing two available inline ECP devices.

Evaluating a New Photopheresis System: A Comparison with Two Established Systems on Cell Yield and Collection Efficiency

Background/Objectives: Extracorporeal photopheresis (ECP) is a well-established and efficacious cell therapy for a range of diseases. The objective of this retrospective study was to compare the new Amicus Blue inline system with the Therakos Cellex inline system and the Spectra Optia offline system in terms of collection efficiency, mononuclear cell (MNC) yield of mononuclear cell products (MCPs), processing time and correlation between MCP cell count and peripheral blood count of patients.

METHODS

This retrospective study compared 127 procedures utilizing the Spectra Optia offline system, 93 procedures employing the Amicus Blue inline system, and 81 procedures applying the Therakos Cellex inline system. The MNCs were subjected to flow cytometry analysis for CD45 and CD14 expression in order to ascertain the precise composition of the collected lymphocyte and monocyte fractions.

RESULTS

The Therakos inline system demonstrated the highest MNC collection efficiency (Therakos: 74.42 ± 1.82; Optia: 65.79 ± 1.48; Amicus: 56.32 ± 2.80; p < 0.01). Regarding the content of collected MNCs (×10⁶/kg body weight), the Spectra Optia offline system was superior to the other systems (Optia: 42.69 ± 1.42; Therakos: 31.21 ± 1.66; Amicus: 27.56 ± 1.54; p < 0.01).

CONCLUSIONS

This study represents the first direct comparison of the new Amicus Blue inline system with the two most commonly used ECP systems in the same patient cohort of a single center. The data show that the Amicus Blue inline system collects sufficient MNCs to perform an ECP, but it has a significantly lower CE than the other systems and a significantly lower amount of collected MNCs than the Spectra Optia offline system.

Extracorporeal photopheresis induces NETosis in neutrophils derived from patients with chronic graft-vs-host disease

INTRODUCTION

Extracorporeal photopheresis (ECP) is considered an effective treatment for patients with chronic graft vs host disease (cGVHD) and demonstrates efficacy in ameliorating GVHD. The mechanism by which ECP acts against cGVHD is not fully understood. Preliminary observations have hinted at the potential involvement of neutrophil extracellular traps (NETs) formation in the pathogenesis of cGVHD. We aimed to assess the influence of ECP on the formation of NETs in patients with cGVHD as a potential mechanism in this setting.

METHODS

Patients treated with ECP for cGVHD at the Rabin Medical Center were included in this study. Blood samples were obtained at three different time points: before starting an ECP cycle, at the end of the first day of treatment, and 24 h following the initiation of the ECP treatment cycle. Neutrophils were harvested from all blood samples. NET formation was assessed by measurement of NET-bound specific neutrophil elastase activity and by immunofluorescence staining.

RESULTS

Six patients (two females and four males) with cGVHD were included in the study. We observed a significant increase in NET formation among all six patients following ECP. Net-bound specific neutrophil elastase activity was elevated from a median value of 2.23 mU/mL (interquartile range [IQR] 2.06-2.47 mU/mL) at baseline to a median value of 13.06 mU/mL (IQR 10.27-15.97 mU/mL) immediately after the treatment and to a peak median value of 14.73 mU/mL (IQR 9.6-22.38 mU/mL) 24 h following the initiation of the ECP cycle. A qualitative assessment of NET formation using immunofluorescence staining has demonstrated markedly increased expression of citrullinated histone H3, a marker of NET formation, following ECP treatment.

CONCLUSIONS

Our preliminary data indicate that ECP induces NET formation among patients with cGVHD. The contribution of increased NET formation to the therapeutic effect of cGVHD should be further investigated.

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.

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.

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

BACKGROUND

Extracorporeal photopheresis (ECP) is an effective treatment for graft-vs-host-disease (GvHD). Photopheresis can be performed in offline or inline method. The first uses a conventional cell separator for collection of mononuclear-cells that are photoactivated by a separate device and manually reinfused; the second one involves a dedicated device performing the entire procedure (collection, photoactivation and reinfusion).

STUDY DESIGN AND METHODS

The objective was to compare the two methods and cell product features to highlight key process, devices performance, and to evaluate ECP clinical response. Patients developing steroid-resistant GvHD underwent ECP as second-line treatment using either inline (Therakos CellEx) or offline system (Terumo BCT Spectra or Optia and UVA PIT system). Data about patients' features, pre-apheresis blood-count, cell product characteristics and clinical response were collected for analysis.

RESULTS

We evaluated 494 procedures performed on 28 patients from April 2018 to March 2019. The offline procedure allows to achieve greater cell yield, it is characterized by larger processed blood volume, longer runtime, and higher ACD consumption. The inline procedure shows shorter runtime, high mononuclear-cells percentage and low percentage of granulocytes in cell product. We observed a significant difference in cell yields between inline and offline system; furthermore we did not find a significant relationship between cell dose and clinical response.

CONCLUSION

Inline ECP is fast, highly automated and productive, making it particularly suitable for ECP treatments. Offline ECP collects high cell yields implying longer procedure and greater operator intervention. Our study did not find a significant relationship between cell dose and GVHD response.

Pilot study of a new online extracorporeal photopheresis system in patients with steroid refractory or dependent chronic graft vs host disease

BACKGROUND

A new protocol has been developed on the Amicus Separator that enables the device to perform online extracorporeal photopheresis (ECP) procedures when used in conjunction with the Phelix photoactivation device and associated disposable kit. The objective of this study was to evaluate the safety and performance of the Amicus ECP System in adult subjects with steroid-refractory or dependent chronic graft vs host disease (cGVHD).

STUDY DESIGN AND METHODS

Eight subjects with mild to severe cGVHD underwent 31 procedures. Subject safety evaluations were performed pre and post procedure and adverse events (AEs) were recorded during treatment and 24 hours after the last procedure. In vitro evaluations of the treated cells included hematology counts and lymphocyte apoptosis, viability and proliferation as measures for ECP procedure validation.

RESULTS

For n = 23 evaluable procedures, median (range) procedure time was 88 (78-110) minutes, during which 2.9 (0.6-4.7) × 10⁹ TNCs (approximately 90% MNCs) were treated and reinfused to the subjects. All subject safety evaluations (vitals, cell counts, plasma hemoglobin and bacterial and endotoxin testing) were within expected ranges. All device or procedure related AEs were mild in nature. After 24 hours in culture, 86 (52-98)% of treated lymphocytes were apoptotic compared to 27 (15-51)% in controls. Inhibition of lymphocyte proliferation was >91% in all procedures.

CONCLUSION

ECP procedures were safely completed in adult subjects with SR-cGVHD treated using the new online Amicus ECP system.

Bacterial contamination rates in extracorporeal photopheresis

BACKGROUND

Extracorporeal photopheresis (ECP) is an immunosuppressive treatment that involves leukocyte apheresis, psoralen and UV light treatment, and subsequent reinfusion. Patients treated with ECP are usually immunosuppressed. Bacterial contamination therefore poses a much unwanted risk, but incidence data are lacking.

PATIENTS AND METHODS

We screened all 1922 consecutive ECP procedures scheduled within a roughly 3-year period for eligibility. Those with missing data on ECP method (inline or offline) or type of venous access (peripheral or central) were excluded. ECPs with complete aerobic and anaerobic microbial testing of baseline patient blood samples (n = 1637) and of ECP cell concentrates (n = 1814) were included in the analysis.

RESULTS

A test for microbial contamination was positive for 1.82% of the cell concentrates, with central venous access was the most significant risk factor for the contamination (odds ratio = 19). Patient blood samples were positive in 3.85% of cases, but no patients became septic. Staphylococcus spp. were most abundant, and products with bacterial contamination did not cause side effects after reinfusion. There were no significant differences in contamination rates between inline and offline ECP.

CONCLUSION

These findings stress the importance of sterile procedures and the benefits of using peripheral over central venous access for reducing the risk of bacterial contamination in ECP.