Suprachoroidal spheroidal mesenchymal stem cell implantation in retinitis pigmentosa: clinical results of 6 months follow-up

PURPOSE

This prospective clinical case series aimed to evaluate the effect of suprachoroidal implantation of mesenchymal stem cells (MSCs) in the form of spheroids as a stem cell therapy for retinitis pigmentosa (RP) patients with relatively good visual acuity.

METHODS

Fifteen eyes of 15 patients with RP who received suprachoroidal implantation of MSCs in the form of spheroids were included. Best-corrected visual acuity (BCVA), 10-2 and 30-2 visual field examination and multifocal electroretinography (mfERG) recordings were recorded at baseline, postoperative 1st, 3rd and 6th months during follow-up.

RESULTS

Baseline median BCVA of RP patients was 1.30 (1.00-2.00) logMAR. BCVA has improved to 1.00 (0.50-1.30), 0.80 (0.40-1.30) and 0.80 (0.40-1.30) at the postoperative 1st, 3rd and 6th months, respectively. The improvements from baseline to the 3rd and 6th months were statistically significant (p = 0.03 and p < 0.001, respectively). In the 30-2 VF test, median MD was significantly improved at the 6th month compared to baseline (p = 0.030). In the 10-2 VF test, the median MD value was significantly different at the 6th month compared to the baseline (p = 0.043). The PSD value of the 10-2 VF test was significantly different at the 6th month compared to the 3rd month (p = 0.043). The amplitudes of P1 waves in < 2°, 5°-10° and 10°-15° rings improved significantly at the postoperative 6th month (p = 0.014, p = 0.018 and p = 0.017, respectively). There was also a statistically significant improvement in implicit times of P1 waves in 10°-15° ring at the postoperative 6th month (p = 0.004).

CONCLUSION

Suprachoroidal implantation of MSCs in the form of spheroids as a stem cell therapy for RP patients with relatively good visual acuity has an improving effect on BCVA, VF and mfERG recordings during the 6-month follow-up period. Spheroidal MSCs with enhanced effects may be more successful in preventing apoptosis and improving retinal tissue healing in RP patients.

In Vitro FVIII-Encoding Transgenic Mesenchymal Stem Cells Maintain Successful Coagulation in FVIII-Deficient Plasma Mimicking Hemophilia A

Objective

Hemophilia A is an X-linked recessive bleeding disorder caused by a deficiency of plasma coagulation factor VIII (FVIII), and it accounts for about 80%-85% of all cases of hemophilia. Plasma-derived therapies or recombinant FVIII concentrates are used to prevent and treat the bleeding symptoms along with FVIII-mimicking antibodies. Recently, the European Medicines Agency granted conditional marketing approval for the first gene therapy for hemophilia A. The aim of this study was to determine the effectiveness of coagulation in correcting FVIII deficiency with FVIII-secreting transgenic mesenchymal stem cells (MSCs).

Materials and Methods

A lentiviral vector encoding a B domain-deleted FVIII cDNA sequence with CD45R0 truncated (CD45R0t) surface marker was designed to develop a transgenic FVIII-expressing primary cell line by transducing MSCs. The efficacy and functionality of the FVIII secreted from the MSCs was assessed with anti-FVIII ELISA, CD45R0t flow cytometry, FVIII western blot, and mixing test analysis in vitro.

Results

The findings of this study showed that the transgenic MSCs maintained persistent FVIII secretion. There was no significant difference in FVIII secretion over time, suggesting stable FVIII expression from the MSCs. The functionality of the FVIII protein secreted in the MSC supernatant was demonstrated by applying a mixing test in coagulation analysis. In the mixing test analysis, FVIII-deficient human plasma products were mixed with either a saline control or FVIII-secreted MSC supernatant. The mean FVIII level of the saline control group was 0.41±0.03 IU/dL, whereas the mean level was 25.41±33.38 IU/dL in the FVIII-secreting MSC supernatant mixed group (p<0.01). The mean activated partial thromboplastin time (aPTT) of the saline control group was 92.69±11.38 s, while in the FVIII-secreting MSC supernatant mixed group, the mean aPTT level decreased to 38.60±13.38 s (p<0.001).

Conclusion

The findings of this in vitro study suggest that the new method presented here is promising as a possible treatment for hemophilia A. Accordingly, a study of FVIII-secreting transgenic MSCs will next be initiated in a FVIII-knockout animal model.

In Vitro FVIII Encoding Transgenic Mesenchymal Stem Cells Maintain A Successful Coagulation in FVIII- Deficient Plasma Mimicking Hemophilia A

Objective

Hemophilia A is an X-linked recessive bleeding disorder caused by deficiency of plasma coagulation factor VIII (FVIII), and accounts for about 80-85% of patients with hemophilia. Plasma-derived therapies or recombinant factor VIII concentrates and also FVIII mimicking antibodies are used to prevent and treat the bleeding symptoms. Recently, EMA granted a conditional marketing approval for the first gene therapy of Hemophilia A. Aim of this study was to determine the effectiveness of coagulation in correcting FVIII deficiency with FVIII secreting transgenic mesenchymal stem cells (MSC).

Materials and Methods

A lentiviral vector encoding B-domain-deleted Factor VIII cDNA sequence with CD45 R0 truncated (CD45R0t) surface marker was designed to develop a transgenic FVIII expressing primary cell line by transducing MSC. Efficacy and functionality of secreted FVIII from MSCs was assessed with anti- FVIII ELISA, CD45R0t flow cytometry, FVIII Western Blot and Mixing Test analysis in vitro.

Results

Results of this study showed that the transgenic MSCs maintain a persistent FVIII secretion. There was no significant difference in FVIII secretion over time, suggesting stable FVIII expression from the MSCs. Functionality of FVIII protein secreted in MSC supernatant was demonstrated by using Mixing Test in coagulation analysis. In the Mixing Test analysis, FVIIIdeficient human plasma products were mixed either with saline control or FVIII-secreted MSC supernatant. Mean FVIII levels of saline control group were 0.41±0.03 IU/dL whereas mean FVIII levels were 25.41±33.38 IU/dL (p<0.01) in FVIII-secreting MSC supernatant mixed group. Mean activated partial thromboplastin time (aPTT) of saline control group was 92.69±11.38 seconds whereas in FVIII-secreting MSC supernatant mixed group, mean aPTT levels were decreased to 38.60±13.38 seconds (p<0.001).

Conclusion

Findings of this in vitro study shows a promising new method applicable to treat Hemophilia A. Accordingly, a FVIII secreting transgenic mesenchymal stem cell study will be initiated in FVIII knock-out animal model.

Preliminary Report of the Academic CAR-T (ISIKOK-19) Cell Clinical Trial in Turkey: Characterization of Product and Outcomes of Clinical Application

Objective:

Chimeric antigen receptor T (CAR-T) cell therapies have already made an impact on the treatment of B-cell malignancies. Although CAR-T cell therapies are promising, there are concerns about commercial products regarding their affordability and sustainability. In this preliminary study, the results of the first production and clinical data of an academic CAR-T cell (ISIKOK-19) trial in Turkey are presented.

Materials and Methods:

A pilot clinical trial (NCT04206943) designed to assess the safety and feasibility of ISIKOK-19 T-cell therapy for patients with relapsed and refractory CD19+ tumors was conducted and participating patients received ISIKOK-19 infusions between October 2019 and July 2021. The production data of the first 8 patients and the clinical outcome of 7 patients who received ISIKOK-19 cell infusions are presented in this study.

Results:

Nine patients were enrolled in the trial [5 with acute lymphoblastic leukemia (ALL) and 4 with non-Hodgkin lymphoma (NHL)], but only 7 patients could receive treatment. Two of the 3 participating ALL patients and 3 of the 4 NHL patients had complete/ partial response (overall response rate: 72%). Four patients (57%) had CAR-T-related toxicities (cytokine release syndrome, CAR-T-related encephalopathy syndrome, and pancytopenia). Two patients were unresponsive and had progressive disease following CAR-T therapy. Two patients with partial response had progressive disease during follow-up.

Conclusion:

Production efficacy and fulfillment of the criteria of quality control were satisfactory for academic production. Response rates and toxicity profiles were also acceptable for this heavily pretreated/refractory patient group. ISIKOK-19 cells appear to be a safe, economical, and efficient treatment option for CD19+ tumors. However, the findings of this study need to be supported by the currently ongoing ISIKOK-19 clinical trial.

Preclinical Assessment of Efficacy and Safety Analysis of CAR-T Cells (ISIKOK-19) Targeting CD19-Expressing B-Cells for the First Turkish Academic Clinical Trial with Relapsed/Refractory ALL and NHL Patients

Objective:

Relapsed and refractory CD19-positive B-cell acute lymphoblastic leukemia (ALL) and non-Hodgkin lymphoma (NHL) are the focus of studies on hematological cancers. Treatment of these malignancies has undergone recent transformation with the development of new gene therapy and molecular biology techniques, which are safer and well-tolerated therapeutic approaches. The CD19 antigen is the most studied therapeutic target in these hematological cancers. This study reports the results of clinical-grade production, quality control, and in vivo efficacy processes of ISIKOK-19 cells as the first academic clinical trial of CAR-T cells targeting CD19-expressing B cells in relapsed/refractory ALL and NHL patients in Turkey.

Materials and Methods:

We used a lentiviral vector encoding the CD19 antigen-specific antibody head (FMC63) conjugated with the CD8-CD28-CD3ζ sequence as a chimeric antigen receptor (CAR) along with a truncated form of EGFR (EGFRt) on human T-lymphocytes (CAR-T). We preclinically assessed the efficacy and safety of the manufactured CAR-T cells, namely ISIKOK-19, from both healthy donors’ and ALL/NHL patients’ peripheral blood mononuclear cells.

Results:

We showed significant enhancement of CAR lentivirus transduction efficacy in T-cells using BX-795, an inhibitor of the signaling molecule TBK1/IKKƐ, in order to cut the cost of CAR-T cell production. In addition, ISIKOK-19 cells demonstrated a significantly high level of cytotoxicity specifically against a CD19+ B-lymphocyte cancer model, RAJI cells, in NOD/SCID mice.

Conclusion:

This is the first report of preclinical assessment of efficacy and safety analysis of CAR-T cells (ISIKOK-19) targeting CD19-expressing B cells in relapsed/refractory ALL and NHL patients in Turkey.