Abstract 1785: Multi-step engineering of gene-edited CAR T cells using RNA lipid nanoparticles

Autologous chimeric antigen receptor (CAR) T therapies utilize patient cells and can be limited by cell quality, and the high manufacturing burden of viral vectors. As such, there is a need for allogeneic, “off-the-shelf” CAR T cells to make these transformative treatments widely available. However, allogeneic therapies require multiple genetic engineering steps to express CAR and to delete proteins responsible for graft-versus-host disease. Messenger RNA (mRNA) is a promising approach for expression of therapeutic proteins and gene editing nucleases. In this work, we demonstrate a new method for multi-step engineering of gene-edited CAR T cells using RNA lipid nanoparticles (LNPs).

LNPs encapsulating Spy-Cas9 mRNA, TCR and CD52 guide RNA (sgRNA), and CAR mRNA were produced using microfluidics. The CAR construct contained an anti-CD19 scFv binding domain and CD3ζ/4-1BB co-stimulatory domains. Microgram quantities of RNA LNPs were produced to optimize LNP packaging, cargo ratios, and sgRNA combinations. Lead candidates were scaled to milligrams. Purified human primary T cells were cultured, activated, and expanded in serum-free media in plates, flasks and bioreactors. CAR+, TCR− or CD52− cells were generated by addition of the corresponding LNP to activated cells. Cytotoxic killing was determined by co-culture assays with leukemia cells. Gene knockout, CAR expression, viability and cell killing were measured using flow-cytometry.

CD19 CAR was selected as a relevant protein for expression, with TCR and CD52 proteins as gene knockout targets. Single-step addition of CAR LNPs to T cells resulted in transfection efficiencies of 95.0 ± 2.1% and high protein expression. Upon TCR or CD52 LNP addition to T cells, the onset of gene editing was within 48 hours, reaching single target knockout efficiencies of 92.3 ± 3.0% (TCR−), and double knockouts (TCR−/CD52−) of 74.5 ± 6.1%. Similar results were obtained when comparing different LNP batch sizes (microgram to milligram RNA) and cell culture vessels (125,000 to 45 million cells), demonstrating scalability of both the LNP production and cell treatment. Cell viabilities above 90% were maintained at all steps and for all RNA LNPs. Finally, as proof-of-concept for multi-step engineering, sequential addition of TCR LNPs and CAR LNPs resulted in simultaneous CAR expression and TCR gene knockout. These “off-the-shelf” gene-edited CAR T cells were functionally equivalent to non-edited cells in a B cell killing assay, efficiently clearing over 80% of leukemia target cells at a 1:1 ratio.

Our findings demonstrate the advantages of LNPs for RNA delivery to T cells. The simple and gentle nature of LNP cell treatment allows for multiple genetic engineering steps for simultaneous expression and deletion of proteins. Furthermore, LNPs can be easily manufactured using microfluidics, enabling small-scale screening of RNA libraries and rapid scale-up of lead candidates for clinical translation.

Citation Format: Samuel Clarke, R Geczy, A Balgi, S Park, R Zhao, M Swaminathan, R Tieu, N Hoang, C Webb, E Watt, M Wong, M Fujisawa, N Jain, Angela Zhang, Anitha Thomas. Multi-step engineering of gene-edited CAR T cells using RNA lipid nanoparticles [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1785.

The experience of dysphagia and its effect on the quality of life of patients with oesophageal cancer

This qualitative study was designed to explore the experience of dysphagia in oesophageal cancer and how this impacts on quality of life. The aim of the study was to add to the knowledge and comprehension of this poorly understood symptom. Data was collected through in-depth interview and administration of the EORTC QLQ-C30 and EORTC QLQ-OES24 quality of life tools with six people with incurable oesophageal cancer who had dysphagia. The interviews were tape-recorded and then transcribed verbatim for each participant. Through a thematic analysis of the interview data and a descriptive analysis of the questionnaires a detailed description of the experience of dysphagia and its impact on quality of life was obtained. Five basic themes emerged from the participant's accounts and these were recognizing dysphagia, the physical experience, the emotions evoked, the impact on social life and dysphagia and treatment. In conclusion dysphagia is a troublesome symptom which affects all aspects of quality of life.

Randomized clinical trial comparing self-expanding metallic stents with plastic endoprostheses in the palliation of oesophageal cancer

BACKGROUND

There is little evidence of the clinical and cost effectiveness of self-expanding metallic stents in the palliation of oesophageal cancer. The aims of this randomized trial were to evaluate the immediate and medium-term clinical outcomes following palliative intubation, examine patient quality of life, and evaluate costs and benefits from the perspective of the health service.

METHODS

Fifty patients with inoperable oesophageal cancer were randomly allocated a metallic stent (n = 25) or plastic endoprosthesis (n = 25). Patients were followed up monthly until death.

RESULTS

There was no significant difference in procedure-related complications or mortality rate between the two groups. There was a trend towards significance in favour of metallic stents with respect to quality of life and survival (median survival 62 versus 107 days for plastic prosthesis and metallic stent respectively). The cost of the initial placement of metallic stents was significantly higher than that of plastic endoprostheses ( pound 983 versus pound 296). After 4 weeks, cost differences were no longer significant.

CONCLUSION

Metallic stents may contribute to improved survival and quality of life in patients with oesophageal cancer. Although initially more expensive, this cost difference does not last beyond 4 weeks. A larger trial involving approximately 300 patients would be required to detect a quality of life benefit of the magnitude observed in this trial.

Time of day urinary catheters are removed: a study of current practices

Nursing abounds with rituals and routines that guide every day clinical practice, including nursing practices concerned with the timing of urinary catheter removal in adult acute care patients. Many of the underlying assumptions regarding the time of day that urinary catheters are removed are questionable and indicate a need for further study. An understanding of current practices has the potential to contribute to establishing scientific principles on which rational nursing care can be based.

An exploration of the way in which the concept of patient advocacy is perceived by registered nurses working in an acute care hospital

The purpose of this study was to provide a beginning exploration of the way in which registered general nurses perceived the concept of patient advocacy. A qualitative approach was taken using the techniques of the grounded theory method. A volunteer sample of eight registered nurses working in an adult acute care ward of a major metropolitan hospital were interviewed using an semi-structured format. Areas explored during the interviews included personal definitions of patient advocacy, elements of the advocate role, and the rationale for the nurse acting as patient advocate. Data analysis commenced during the data collection phase, where initial interviews were transcribed, coded and beginning categories were identified. The findings indicate that for the participants, advocacy is based on respect for the person, and acknowledgement of human rights. The quality of the relationship between the nurse and the patient appears to be the basis for the advocate role. Three initial categories emerged that describe the major elements of the participant's conceptualization of patient advocacy. These are, informing, supporting and representing.

Psychologic predictors of compliance in children with recent onset of diabetes mellitus

A group of 57 children with recent onset of insulin-dependent diabetes mellitus was studied over 18 months. Compliance with the prescribed diabetic treatment deteriorated over this period. Adolescents (aged 13 to 15 years) were less compliant than preadolescents (aged 9 to 12 years). Initial patient reports of self-esteem, perceived competence, social functioning, behavioral symptoms, and their adjustment to diabetes predicted subsequent compliance behaviors. The findings highlight the linkage of child personality and adjustment with self-care of diabetes, and suggest that psychosocial assessment soon after diabetes is diagnosed may help identify patients at risk for later compliance problems.

Acute drug testing with nitrates: angina relief during treadmill exercise

To evaluate the effect of sublingual nitroglycerin (N) and chewable isosorbide dinitrate (I) in patients with angina pectoris, 12 subjects underwent treadmill exercise to the point of onset of angina. At that juncture, N or I or placebo (P) was administered and walking was continued until moderately severe angina recurred. For those patients who completed the initial 10-minute exercise period, testing was repeated until moderately severe angina recurred or until a total test time of three hours elapsed. Retesting ensured that each patient was tested separately with N, I and P within a two-week period. Within the I group, four patients experienced the onset of angina relief (AR) at 10 minutes (') 6 seconds (*) +/- 3' 4" with a mean recurrence time (RT) of 154' 3" +/- 4' 27" (P less than or equal to 0.05), for a significant difference. Within the N group, six patients had AR of 8' 3" +/- 1' 1" with an RT of 49' 39" +/- 1' 15" (P less than or equal to 0.01), for a significant effect. Within the P group, only one patient experienced AR. For all other patients in each group, testing was terminated because of moderately severe angina in the 5-8' period of the first test. In comparing subgroups for RT during I therapy (4 patients) versus N therapy (6 patients), a significant difference was noted (154' 3" +/- 27" versus 49' 39" +/- 1' 15") (P less than 0.05). The data suggest a possible benefit of I in selected patients. The effect may last as long as three to four hours. There is also an enhanced benefit of N with the patient in the upright position. This effect may last as long as 40-50'. Treadmill testing is recommended with nitrate administration to determine which drug (I or N) is the more suitable for the specific patient.

Initial work tolerance of extremely obese patients

Initial work tolerance (walking) of 16 extremely obese (133 to 238 kg) patients entering a multidisciplinary rehabilitation program was low, as previously reported, but also highly variable. Some were capable of walking one mile nonstop while others required as much as eight weeks of progressive exercise training to reach this goal. Treadmill test - indirect calorimetry results indicate that patients required approximately 20 minutes to walk one mile at their fastest pace (3 mph), displayed near steady state aerobic metabolism and expended approximately 150 to 200 net kcal/mile. Patients were screened for abnormal cardiac responses to work using graded exercise test procedures with electrocardiography and there were no apparent hazardous episodes during rehabilitative training.