Optimization of lymphapheresis for manufacturing autologous CAR-T cells

Collection efficiency and safety of large-volume leukapheresis for the manufacturing of tisagenlecleucel

BACKGROUND

In patients with relapsed or refractory B cell acute lymphoblastic leukemia or B cell non-Hodgkin lymphoma (r/r B-ALL/B-NHL) with low CD3+ cells in the peripheral blood (PB), sufficient CD3+ cell yield in a single day may not be obtained with normal-volume leukapheresis (NVL). Large-volume leukapheresis (LVL) refers to the processing of more than three times the total blood volume (TBV) in a single session for PB apheresis; however, the efficiency and safety of LVL for manufacturing of tisagenlecleucel (tisa-cel) remain unclear. This study aimed to investigate the tolerability of LVL.

STUDY DESIGN AND METHODS

We retrospectively collected data on LVL (≥3-fold TBV) and NVL (<3-fold TBV) performed for patients with r/r B-ALL/B-NHL in our institution during November 2019 and September 2023. All procedures were performed using a continuous mononuclear cell collection (cMNC) protocol with the Spectra Optia.

RESULTS

Although pre-apheresis CD3+ cells in the PB were significantly lower in LVL procedures (900 vs. 348/μL, p < .01), all patients could obtain sufficient CD3+ cell yield in a single day with a comparably successful rate of final products (including out-of-specification) between the two groups (97.2% vs. 100.0%, p = 1.00). The incidence and severity of citrate toxicity (no patients with grade ≥ 3) during procedures was not significantly different between the two groups (22.2% vs. 26.1%, p = .43) and no patient discontinued leukapheresis due to any complications.

CONCLUSION

LVL procedures using Spectra Optia cMNC protocol was well tolerated and did not affect the manufacturing of tisa-cel.

Leukapheresis and Tisagenlecleucel Manufacturing Outcomes in Patients Age <3 Years with Relapsed/Refractory Acute Lymphoblastic Leukemia

Tisagenlecleucel is approved for the treatment of relapsed/refractory (r/r) B cell acute lymphoblastic leukemia (B-ALL) in patients up to age 25 years based on the results of a pivotal trial (ELIANA) in pediatric and young adult patients. However, that trial did not include patients age <3 years because of the challenges posed by leukapheresis of very young and low-weight patients. Data on leukapheresis material and manufacturing outcomes among patients age <3 years have been collected since the time of global regulatory approval. Here we report leukapheresis characteristics and manufacturing outcomes for tisagenlecleucel produced for patients age <3 years in US and non-US commercial settings. Qualified patients with r/r B-ALL were age <3 years at the time of request for commercial tisagenlecleucel, with manufacturing data starting after August 30, 2017 (date of first US Food and Drug Administration approval). Leukapheresis and manufacturing outcomes data were stratified by age and weight. CD3+ cell count and CD3+/total nucleated cell (TNC) percentages were obtained from the leukapheresis material; leukocyte subpopulations were obtained via quality control vials. Of the 146 tisagenlecleucel quality control batches analyzed for CD3+ cell count and CD3+/TNC%, 86 batches (84 patients) were from US sites and 60 batches were from non-US sites. The median patient age and weight were 1.2 years and 10.4 kg at US sites and 1.5 years and 10.5 kg at non-US sites. Globally, 137 of 146 batches (94%) were manufactured within specifications across 16 countries. Among tisagenlecleucel batches manufactured in the United States between 2017 and 2021, there was a trend toward increasing CD3+ counts, CD3+/TNC%, and manufactured dose of chimeric antigen receptor (CAR) T cells; there was no difference in median days of collection by patient age or weight. Globally, a trend toward 1 or more potential additional collection days was observed for patients weighing ≤10 kg. Leukapheresis and tisagenlecleucel manufacturing in pediatric patients with r/r B-ALL age <3 years, including infants (<1 year), and low weight are feasible. As global experience with leukapheresis and patient identification for CAR-T cell therapy increased over time, a corresponding improvement in tisagenlecleucel manufacturing success has been observed. Clinical outcome data for these patients are currently being explored.

Collection of peripheral blood mononucleated cells for chronic graft-versus-host disease immunology research: safety and effectiveness of leukapheresis in 132 patients

Background

Chronic graft-versus-host disease (GVHD) is a major cause of late morbidity and non-relapse mortality in recipients of allogeneic hematopoietic cell transplantation (HCT). Its biology, however, remains poorly understood, making the studies of its biology and immunomodulatory therapies a difficult task. Such research is often hampered by lymphopenia which is common in these patients and precludes studies of critical cellular subsets across the spectrum of severity of disease. This study explores the potential of leukapheresis to safely acquire and efficiently store immune cells for immunology research in chronic GVHD.

Methods

This is a cross-sectional study in which 132 consecutively accrued patients undergo optional research leukapheresis and a one-week comprehensive outpatient evaluation. Baseline clinical and laboratory data and efficiency of the procedure were reported.

Results

Ninety-four of 132 patients (71%) achieved the goal collection of 2 × 10^9 PBMNCs with a mean volume processed of 4.6 L. Only mild decreases in hemoglobin, platelet, lymphocyte and monocytes were observed. All adverse events were mild (grade 1) and had resolved by the time of discharge from the apheresis unit.

Conclusion

This study demonstrates feasibility, safety, and efficiency of research leukapheresis in a frail patient population. Results presented promote leukapheresis as a standard research practice option in studies of chronic GVHD in humans which may expedite advances in our understanding of this complex multisystem disease.