#30-Cell and Gene Therapy Today
Stay up to date with the latest developments in your field with our weekly digest of industry news and research articles.
I’m Pedro Silva Couto, and this is Cell and Gene Therapy Today. Here I will be sharing of the most recent news in CGT field as well as summarizing research articles focused on translational research, manufacturing and clinical studies featuring cell and gene therapy product candidates.
CGT News this week:
🤝 British giant AstraZeneca to invest $245M in Cellectis (leader in allogeneic CAR-T cell space) (news here). After stopping UCARTCS1 designed for patients suffering from multiple myeloma (NCT04142619), Cellectics will leverage this new investment to push UCART22, UCART123 and UCART20x22 through phase 1/2 clinical trials. These product candidates will remain under Cellectis’ ownership and control.
📈 Curocell TX on track to deliver South Korea's first CAR-T cell therapy approval planned for 2025 after completing a phase 2 clinical trial (news here). The company recently reported interim results of a clinical trial evaluating its next-generation CD19 CAR-T therapy that targets relapsed or refractory DLBCL (Diffuse Large B-cell Lymphoma) showing a 71% complete response rate (CRR).
🤝 MeiraGTX secures $30 M investment from Sanofi with the London-based gene therapy company looking for additional partnerships to validate its gene editing platform (news here). The agreement seemed to surround Meira’s riboswitch-based gene-expression platform designed to rely on a small molecule inducer to drive in vitro or in vivo protein expression.
📈 King Faisal Hospital celebrates 100 patients treated with CAR-T cell therapy products (news here). This advancement aligns with Saudi Vision 2030's healthcare objectives, reducing the need to send such cases abroad and emphasizing King Faisal Hospital's global leadership in specialised healthcare and medical innovation.
📂 NurExone Biologic granted US FDA orphan-drug designation for ExoPTEN therapy in acute spinal cord injury treatment (news here). ExoPTEN therapy utilises human mesenchymal stem cell (MSC) derived extracellular vesicles (EVs) loaded with siRNA to target the PTEN protein, representing a promising advancement in spinal cord injury treatment.
CGT Research this week:
Next-generation CAR-NK therapeutics
Study demonstrated increased in vivo potency of IL-15 “armoured” CAR-NK as strategy to overcome tumor resistance resulting from loss of metabolic activity in NK cell custers once administered (study here).
This study from Katy Rezvani’s lab puts forward IL-15 "armoured CAR-NK as a pathway to overcome tumour resistance to CAR-NK cell therapy. The authors started by demonstrating that CAR-NK engineered with IL-15 secreting capabilities showed higher metabolic activity when compared to CAR-NK cells or NK cells secreting IL-15 when exposed to target cells (Raji cells). At this stage, it was also mentioned that IL-15 armoured CAR-NK were more efficient at killing target cells when compared to the other studied groups. The authors went on to evaluate the in vivo performance of this armoured CAR-NK product. When injected into a lymphoma mouse model it was demonstrated that IL-15 was responsible for increasing CAR-NK activity via sustaining NK cell function and persistence in the model for longer periods. The in vivo work conducted in this paper established a positive correlation between the metabolic activity of the IL-15-CAR-NK product and its antitumor capabilities. The authors attributed this loss in functionality to the inability of the CAR-NK cells to compete for nutrients in the tumour microenvironment over time. At the end of the manuscript, the authors presented evidence in favour of a double injection of IL-15 secreting CAR-NK (at different time points) as a strategy to increase product metabolic activity and therefore functionality during a period of low tumour burden. The manufacturing process used to produce these IL-15-CAR-NK relied on a retrovirus resulting from the transfection of 293T cells with Peg-Pam-e plasmid containing the sequence for MoMLV gag-pol, and the DRF plasmid containing the sequence for the RD114 envelope using Fugene (Promega) as transfection reagent. NK cell isolation was performed using a negative isolation kit whereas NK pre-expansion was performed in the presence of irradiated universal antigen-presenting (uAPCs) at a 1:2 ratio in complete serum-free stem cell medium (Cellgenix) supplemented with 200 IU/mL of IL-2. Transduction was performed 4 days after isolation, on fibronectin-cultured plates. The expansion stage comprised 9 additional days totalling a 14-day manufacturing process for this cord blood-derived IL-15 armoured CAR-NK product.
Markers to predict adverse effects of CAR-T therapy
Study focused on evaluating expansion in vivo demonstrated a strong correlation between CAR-T cell mRNA expression levels and the development of immune-effector cell-associated nerotoxicity syndrome (ICANS), longer hospitalization and potentially, cytokine release syndrome (CRS) (study here).
This study reflects on some of the safety limitations of CAR-T cell therapeutics (cytokine release syndrome and neurotoxicity) and highlights the need for identifying surrogate markers capable of predicting therapeutic efficacy and adverse effects. The current perception in the field is that in vivo expansion is a requirement for CAR-T cell therapy efficacy. However, the importance of cell expansion on tumour regression and overall therapy efficacy remains poorly understood. To try to establish a correlation between in vivo expansion and safety/efficacy metrics, the authors conducted an mRNA and DNA analysis on CAR-T-treated patients and compared clinical outcomes. The authors started by demonstrating that peak CAR-T mRNA and DNA expression was reported 9 days after infusion. No difference was reported during the 3-month time period between high and low producers of CAR-T DNA/mRNA suggesting that peak expression alone does not guarantee higher cell persistence, and by extension, product efficacy. In this study, overall response and survival rates did not differ between high and low CAR-T cell peak expression groups. On a safety note, the authors also found that neurotoxicity was more prevalent in patients with higher values of CAR-T cell peak expression, which resulted in longer hospitalisations and higher rates of admissions to intensive care units. Finally, the paper puts forward the idea that lymph nodes and multi-organ response are more relevant for the response to CAR-T cell therapy and that efficacy can not be solely predicted by in vivo product expansion.
Extracellular vesicles in pre-clinical applications
Hypoxia demonstrated to improve MSC and MSC-EV related potency using an animal model for pulmonary arterial hypertension (PAH). Improved functionality over MSC/MSC-EVs expanded in normoxia was demonstrated via downregulation of vimentin and its impact on improved endothelial to mesenchymal transition (study here).
In this study, the authors put forward MSCs and EVs as potential alternatives to the limited treatment options for patients suffering from pulmonary arterial hypertension (PAH). The standard therapeutic approach relies on vasodilatory small molecules which have limited capabilities to avoid disease progression. Here, the authors put forward hMSCs and EVs as therapeutic candidates due to their capabilities of reducing inflammation and secreting blood vessel formation/repair molecules (like VEGF). The authors further hypothesised that manufacturing these hMSC/EV products under hypoxia would potentially have the added benefit of upregulating the hypoxia-inducible factor 1 (HIF-1), capable of modulating expression of several genes involved in migration, proliferation and cell apoptosis amongst others. Throughout the paper, the researchers demonstrated via in vivo studies that: (1) both MSC and EVs (in both hypoxia and normoxia conditions) led to a reduction in systolic pressure and ventricle hypertrophy, (2) MSC and EVs were associated with a decrease in perivascular collagen fiber content, vascular wall thickness and (3) EVs expanded under hypoxia was the only experimental treatment that led to a reduction in vimentin in the pulmonary arterioles. The manufacturing steps undertaken by the authors comprised a sequence of steps: (1) expansion of MSCs using IMDM supplemented with 10% FBS and 10% horse serum, (2) establishment of a working cell bank with these cells with MSCs at P3, (3) upon thawing cells there cultured in the same medium formulation with different oxygen conditions (normoxia versus hypoxia). The EVs were harvested after a 48h serum deprivation period featuring a total medium exchange with IMDM without any serum. EV isolation was then carried out using several centrifugation steps starting with a 20-minute cycle at 3000g designed to remove cells and debris followed by an EV precipitation step delivered by a ultracentrifugation process at 100 000G for 2 hours.
This is it for this week’s Cell and Gene Therapy Today, which I aim to send you every Wednesday. If you found it valuable, please feel free to sign up or consider sending it to someone who finds this content useful!
I am currently a post-doctoral researcher at the University College London, and my project is focused on scalable CAR-T cell manufacturing using non-viral methods. You can find more about my research on my Google Scholar or my LinkedIn page.
Last but not least, this content was only possible to produce with the sponsorship of celltrials.org, the leading online portal tracking the clinical trial landscape of cell and gene therapy products. They have data packages on CAR-T, hMSCs, Extracellular Vesicles, and Cell-Free products, as well as in vivo gene therapy products (visit celltrials.org).