Impact of the Pandemic was Minor Compared to Systemic Decrease in Fidelity of Assertive Community Treatment Services- A Provincial Study in Ontario, Canada

Assertive Community Treatment (ACT) model is the gold standard in community psychiatry serving people with severe mental illness. With its outreach-based design, the pandemic has profoundly affected the operations and functioning of ACT. The Dartmouth ACT Scale (DACTS) provides a standardized comprehensive and quantitative way to evaluate ACT quality. Results could inform nature of impact and identify areas for improvement. Current online survey used DACTS during the pandemic in April-May 2021. Clinical and administrative leadership of the 80 ACT teams in Ontario, Canada cross-sectionally rated ACT quality one-year pre-Covid (2018-2019) and one-year post the start of Covid (2020-2021). The overall pre-Covid Ontario ACT DACTS fidelity was 3.65. The pandemic led to decreases in all domains of DACTS (Human Resources: -4.92%, p < 0.001, 95% CI [0.08-0.27]; Organizational Boundary: -1.03%, p < 0.013,95%CI [0.01-0.07]; and Nature of Services: -6.18%, p < 0.001, 95%CI [0.16-0.26]). These changes were accounted by expected lower face-to-face encounters, time spent with clients, reduction in psychosocial services, less interactions with hospitals and diminished workforces. The magnitude of change was modest (-3.84%, p < 0.001, 95%CI [0.09-0.19]). However, the Ontario ACT pre-Covid DACTS was substantially lower (-13.5%) when compared to that from a similar survey 15 years ago (4.22), suggestive of insidious systemic level loss of fidelity. Quantitative fidelity evaluation helped to ascertain specific pandemic impact. Changes were significant and specific, but overall relatively modest when compared to the larger system level drop over the last decade. There is both evidence for model adaptability and resilience during Covid disruption, and concerns over larger downward drift in ACT fidelity and quality.

Mucin-1-Targeted Chimeric Antigen Receptor T Cells Are Effective and Safe in Controlling Solid Tumors in Immunocompetent Host

The chimeric antigen receptor (CAR) T-cell therapy in solid epithelial tumors has been explored, however, with limited success. As much of the preclinical work has relied on xenograft models in immunocompromised animals, the immune-related efficacies and toxicities may have been missed. In this study, we engineered syngeneic murine CAR T cells targeting the tumor form of human mucin-1 (tMUC1) and tested the MUC1 CAR T cells' efficacy and toxicity in the immunocompetent human MUC1-expressing mouse models. The MUC1 CAR T cells significantly eliminated murine pancreatic and breast cancer cell lines in vitro. In vivo, MUC1 CAR T cells significantly slowed the mammary gland tumor progression in the spontaneous PyVMT×MUC1.Tg (MMT) mice, prevented lung metastasis, and prolonged survival. Most importantly, there was minimal short or long-term toxicity with acceptable levels of transient liver toxicity but no kidney toxicity. In addition, the mice did not show any signs of weight loss or other behavioral changes with the treatment. We also report that a single dose of MUC1 CAR T-cell treatment modestly reduced the pancreatic tumor burden in a syngeneic orthotopic model of pancreatic ductal adenocarcinoma given at late stage of an established tumor. Taken together, these findings suggested the further development of tMUC1-targeted CAR T cells as an effective and relatively safe treatment modality for various tMUC1-expressing solid tumors.

Engineering a Dual Specificity γδ T-Cell Receptor for Cancer Immunotherapy

γδ T-cells provide immune surveillance against cancer, straddling both innate and adaptive immunity. G115 is a clonal γδ T-cell receptor (TCR) of the Vγ9Vδ2 subtype which can confer responsiveness to phosphoantigens (PAgs) when genetically introduced into conventional αβ T-cells. Cancer immunotherapy using γδ TCR-engineered T-cells is currently under clinical evaluation. In this study, we sought to broaden the cancer specificity of the G115 γδ TCR by insertion of a tumour-binding peptide into the complementarity-determining region (CDR) three regions of the TCR δ2 chain. Peptides were selected from the foot and mouth disease virus A20 peptide which binds with high affinity and selectivity to αvβ6, an epithelial-selective integrin that is expressed by a range of solid tumours. Insertion of an A20-derived 12mer peptide achieved the best results, enabling the resulting G115 + A12 T-cells to kill both PAg and αvβ6-expressing tumour cells. Cytolytic activity of G115 + A12 T-cells against PAg-presenting K562 target cells was enhanced compared to G115 control cells, in keeping with the critical role of CDR3 δ2 length for optimal PAg recognition. Activation was accompanied by interferon (IFN)-γ release in the presence of either target antigen, providing a novel dual-specificity approach for cancer immunotherapy.

Harnessing Nanomedicine to Potentiate the Chemo-Immunotherapeutic Effects of Doxorubicin and Alendronate Co-Encapsulated in Pegylated Liposomes

Encapsulation of Doxorubicin (Dox), a potent cytotoxic agent and immunogenic cell death inducer, in pegylated (Stealth) liposomes, is well known to have major pharmacologic advantages over treatment with free Dox. Reformulation of alendronate (Ald), a potent amino-bisphosphonate, by encapsulation in pegylated liposomes, results in significant immune modulatory effects through interaction with tumor-associated macrophages and activation of a subset of gamma-delta T lymphocytes. We present here recent findings of our research work with a formulation of Dox and Ald co-encapsulated in pegylated liposomes (PLAD) and discuss its pharmacological properties vis-à-vis free Dox and the current clinical formulation of pegylated liposomal Dox. PLAD is a robust formulation with high and reproducible remote loading of Dox and high stability in plasma. Results of biodistribution studies, imaging with radionuclide-labeled liposomes, and therapeutic studies as a single agent and in combination with immune checkpoint inhibitors or gamma-delta T lymphocytes suggest that PLAD is a unique product with distinct tumor microenvironmental interactions and distinct pharmacologic properties when compared with free Dox and the clinical formulation of pegylated liposomal Dox. These results underscore the potential added value of PLAD for chemo-immunotherapy of cancer and the relevance of the co-encapsulation approach in nanomedicine.

The realities of Medical Assistance in Dying in Canada

OBJECTIVES

To examine the impact of the Canadian MAiD program and analyze its safeguards.

METHODS

A working group of physicians from diverse practice backgrounds and a legal expert, several with bioethics expertise, reviewed Canadian MAiD data and case reports. Grey literature was also considered, including fact-checked and reliable Canadian mainstream newspapers and parliamentary committee hearings considering the expansion of MAiD.

RESULTS

Several scientific studies and reviews, provincial and correctional system authorities have identified issues with MAiD practice. As well, there is a growing accumulation of narrative accounts detailing people getting MAiD due to suffering associated with a lack of access to medical, disability, and social support.

SIGNIFICANCE OF RESULTS

The Canadian MAiD regime is lacking the safeguards, data collection, and oversight necessary to protect Canadians against premature death. The authors have identified these policy gaps and used MAiD cases to illustrate these findings.

The Role and Regulation of the NKG2D/NKG2D Ligand System in Cancer

The family of human NKG2D ligands (NKG2DL) consists of eight stress-induced molecules. Over 80% of human cancers express these ligands on the surface of tumour cells and/or associated stromal elements. In mice, NKG2D deficiency increases susceptibility to some types of cancer, implicating this system in immune surveillance for malignancy. However, NKG2DL can also be shed, released via exosomes and trapped intracellularly, leading to immunosuppressive effects. Moreover, NKG2D can enhance chronic inflammatory processes which themselves can increase cancer risk and progression. Indeed, tumours commonly deploy a range of countermeasures that can neutralise or even corrupt this surveillance system, tipping the balance away from immune control towards tumour progression. Consequently, the prognostic impact of NKG2DL expression in human cancer is variable. In this review, we consider the underlying biology and regulation of the NKG2D/NKG2DL system and its expression and role in a range of cancer types. We also consider the opportunities for pharmacological modulation of NKG2DL expression while cautioning that such interventions need to be carefully calibrated according to the biology of the specific cancer type.

Chimeric Antigen Receptor (CAR) T-Cell Therapy for Patients with Lung Cancer: Current Perspectives

Immunotherapy using chimeric antigen receptor (CAR)-engineered T-cells has achieved unprecedented efficacy in selected hematological cancers. However, solid tumors such as lung cancer impose several additional challenges to the attainment of clinical success using this emerging therapeutic modality. Lung cancer is the biggest cause of cancer-related mortality worldwide, accounting for approximately 1.8 million deaths worldwide each year. Obstacles to the development of CAR T-cell immunotherapy for lung cancer include the selection of safe tumor-selective targets, accounting for the large number of candidates that have been evaluated thus far. Tumor heterogeneity is also a key hurdle, meaning that single target-based approaches are susceptible to therapeutic failure through the emergence of antigen null cancers. There is also a need to enable CAR T-cells to traffic efficiently to sites of disease, to infiltrate tumor deposits and to operate within the hostile tumor microenvironment formed by solid tumors, resisting the onset of exhaustion. Multiple immune, metabolic, physical and chemical barriers operate at the core of malignant lesions, with potential for further heterogeneity and evolution in the face of selective therapeutic pressures. Although the extraordinarily adaptable nature of lung cancers has recently been unmasked, immunotherapy using immune checkpoint blockade can achieve long-term disease control in a small number of patients, establishing clinical proof of concept that immunotherapies can control advanced lung carcinomas. This review summarizes pre-clinical CAR T-cell research that is specifically focused on lung cancer in addition to published and ongoing clinical trial activity. A number of advanced engineering strategies are also described which are designed to bridge the gap to the attainment of meaningful efficacy using genetically engineered T-cells.

Impact of COVID-19 on the lives of people with severe mental illness-front-line community psychiatry workers observation from a provincial survey of assertive community treatment teams in Ontario, Canada

Using an online survey distributed to members of the provincial organization that represents the 88 Assertive Community Treatment (ACT) and Flexible ACT teams in Ontario, Canada, this descriptive study relied on the unique vantage points and observations of the front-line community psychiatry workers who maintained contact with patients through outreach and telecommunication during the height of COVID-19. The patients who suffer from serious mental illness (SMI) were uniquely affected by COVID-19 due to the changes, reduction or shut down of many essential clinical and community support services. Thematic and quantitative analyses of the workers' observations highlighted 6 main areas of note, including significant social isolation and loneliness, clinical course deterioration and life disruption, increased hospital and ER use, police and legal contacts, and substance abuse and related deaths. There were also encouraging signs of positive adaptations in terms of independence and resilience. Reflections of these impacts and potential ameliorating approaches are further discussed.

Intratumoral pan-ErbB targeted CAR-T for head and neck squamous cell carcinoma: interim analysis of the T4 immunotherapy study

BACKGROUND

Locally advanced/recurrent head and neck squamous cell carcinoma (HNSCC) is associated with significant morbidity and mortality. To target upregulated ErbB dimer expression in this cancer, we developed an autologous CD28-based chimeric antigen receptor T-cell (CAR-T) approach named T4 immunotherapy. Patient-derived T-cells are engineered by retroviral transduction to coexpress a panErbB-specific CAR called T1E28ζ and an IL-4-responsive chimeric cytokine receptor, 4αβ, which allows IL-4-mediated enrichment of transduced cells during manufacture. These cells elicit preclinical antitumor activity against HNSCC and other carcinomas. In this trial, we used intratumoral delivery to mitigate significant clinical risk of on-target off-tumor toxicity owing to low-level ErbB expression in healthy tissues.

METHODS

We undertook a phase 1 dose-escalation 3+3 trial of intratumoral T4 immunotherapy in HNSCC (NCT01818323). CAR T-cell batches were manufactured from 40 to 130 mL of whole blood using a 2-week semiclosed process. A single CAR T-cell treatment, formulated as a fresh product in 1-4 mL of medium, was injected into one or more target lesions. Dose of CAR T-cells was escalated in 5 cohorts from 1×107-1×109 T4+ T-cells, administered without prior lymphodepletion.

RESULTS

Despite baseline lymphopenia in most enrolled subjects, the target cell dose was successfully manufactured in all cases, yielding up to 7.5 billion T-cells (67.5±11.8% transduced), without any batch failures. Treatment-related adverse events were all grade 2 or less, with no dose-limiting toxicities (Common Terminology Criteria for Adverse Events V.4.0). Frequent treatment-related adverse events were tumor swelling, pain, pyrexias, chills, and fatigue. There was no evidence of leakage of T4+ T-cells into the circulation following intratumoral delivery, and injection of radiolabeled cells demonstrated intratumoral persistence. Despite rapid progression at trial entry, stabilization of disease (Response Evaluation Criteria in Solid Tumors V.1.1) was observed in 9 of 15 subjects (60%) at 6 weeks post-CAR T-cell administration. Subsequent treatment with pembrolizumab and T-VEC oncolytic virus achieved a rapid complete clinical response in one subject, which was durable for over 3 years. Median overall survival was greater than for historical controls. Disease stabilization was associated with the administration of an immunophenotypically fitter, less exhausted, T4 CAR T-cell product.

CONCLUSIONS

These data demonstrate the safe intratumoral administration of T4 immunotherapy in advanced HNSCC.

CAR-Based Immunotherapy of Solid Tumours-A Survey of the Emerging Targets

Immunotherapy with CAR T-cells has revolutionised the treatment of B-cell and plasma cell-derived cancers. However, solid tumours present a much greater challenge for treatment using CAR-engineered immune cells. In a partner review, we have surveyed data generated in clinical trials in which patients with solid tumours that expressed any of 30 discrete targets were treated with CAR-based immunotherapy. That exercise confirms that efficacy of this approach falls well behind that seen in haematological malignancies, while significant toxic events have also been reported. Here, we consider approximately 60 additional candidates for which such clinical data are not available yet, but where pre-clinical data have provided support for their advancement to clinical evaluation as CAR target antigens.

CAR Based Immunotherapy of Solid Tumours-A Clinically Based Review of Target Antigens

Immunotherapy with CAR-engineered immune cells has transformed the management of selected haematological cancers. However, solid tumours have proven much more difficult to control using this emerging therapeutic modality. In this review, we survey the clinical impact of solid tumour CAR-based immunotherapy, focusing on specific targets across a range of disease indications Among the many candidates which have been the subject of non-clinical CAR T-cell research, clinical data are available for studies involving 30 of these targets. Here, we map out this clinical experience, highlighting challenges such as immunogenicity and on-target off-tumour toxicity, an issue that has been both unexpected and devastating in some cases. We also summarise how regional delivery and repeated dosing have been used in an effort to enhance impact and safety. Finally, we consider how emerging armouring systems and multi-targeted CAR approaches might be used to enhance tumour access and better enable discrimination between healthy and transformed cell types.

290 THE VARIABLE INDICATIVE OF PLACEMENT IN ACUTE HOSPITAL OUTPATIENT CLINICS IDENTIFIES OLDER ADULTS WHO BENEFIT FROM SPECIALIST GERIATRIC ASSESSMENT

Background

Opportunistic screening of older adults results in early detection of frailty. The Variable Indicative of Placement (VIP) is validated to identify those being admitted to hospital who may benefit from specialist geriatric assessment. VIP screening was gradually introduced throughout hospital-based outpatient clinics in April 2021. The aim of this study was to quantify patient benefit following VIP screening.

Methods

A positive VIP triggered referral for Comprehensive Geriatric Assessment (CGA). Exclusion criteria included prior CGA within a year, nursing home resident or patient declined assessment. Data was prospectively entered onto Excel by a trained administrator. Demographics, Clinical Frailty Score (CFS), modified Barthel Index (mBI) and patient interventions post CGA, between July 2021 and April 2022, were analysed using descriptive statistics.

Results

Of 168 referrals received, 52 were excluded, 53 completed and 63 await review. Thirty-five of those excluded had a prior CGA. Mean (SD) age of patients receiving CGA was 79 (7.6) years. Male:female ratio was 1:1.4. Median (SD) CFS was 6 (0.8) and median (SD) mBI was 16(3.9). There was a mean (SD) of 2.8 (1.6) targeted interventions per patient. Eighty three percent (n=43) required medication changes, 47% (n=25) bone health management, 28% (n=15) dietician, 26% (n=14) occupational therapy, 17% (n=9) public health nursing, 17% (n=9) speech and language therapy, 17% (n=9) memory assessment and 15% (n=8) physiotherapy.

Conclusion

Outpatient clinic VIP screening resulted in identification of frail older adults who benefited from CGA. The VIP should be validated in various outpatient settings.

233 COGNITIVE OUTCOMES AFTER A FIRST EPISODE OF DELIRIUM IN HOSPITAL – RESULTS FROM AN ADVANCED NURSE PRACTITIONER DELIRIUM CLINIC

Background

Cognitive outcomes for frail older adult inpatients with a first episode of Delirium are unknown. Aim: To determine cognitive outcomes of frail older inpatients after a first episode of Delirium.

Methods

Consecutive frail older inpatients with a 4AT score &gt;/= 4, without a previous history of cognitive impairment, over a 12-month period (January to December 2021) were invited for formal cognitive assessment 8-12 weeks after their delirium occurred. Collateral history, medication review, Addenbrookes (ACE III), bloods and CT brain were undertaken. Data was prospectively entered onto Excel and analysed using descriptive statistics.

Results

Fifty-one patients with a mean age of 82 years (SD=6) were referred to the Advanced Nurse Practitioner (ANP) Delirium Clinic. Median Clinical Frailty Score (CFS) was 6 with a male: female ratio of 1:2. Forty- seven percent (n=24) attended; 35 % (n-18) did not attend; 18 % (n=9) died prior to assessment. The ratio of male to female attendees was 1: 2.4. There was no difference in CFS or age between attenders and non-attenders. Thirty-three percent (n=8) of patients who attended had potentially reversible causes (high anti-cholinergic burden, folate deficiency, sleep disorder) of cognitive impairment requiring intervention. Sixty-seven percent (n=16) were diagnosed with dementia at the Delirium Clinic; 16.6% (n=4) were diagnosed with Mild Cognitive Impairment; 4% (n=1) had a resolved delirium; 8% (n=2) were referred to consultant Memory Clinic and one patient remained too unwell to assess. The median ACE III score of patients diagnosed with dementia was 54/100 (SD = 18).

Conclusion

Pro-active follow up of patients with a first episode of Delirium led to early diagnosis of dementia and mild cognitive impairment with supportive interventions. Earlier ANP intervention, during the acute phase of delirium, has been introduced in order to improve clinic attendance.

330 RISK OF MALNUTRITION AND ITS ASSOCIATION WITH FRAILTY-ASSOCIATED FACTORS IN THE OLDER PERSON

Background

The aetiology of malnutrition is multifactorial, with age a facilitating factor. It is associated with poorer physical and mental health and functional ability in frail older persons. Nutritional screening is a key domain in Comprehensive Geriatric Assessment (CGA). This study assessed the relationship between malnutrition risk and other drivers of frailty in the older person by CGA.

Methods

All patients who had a CGA completed by an Integrated Care Team for Older Persons from March 2020 to July 2021 inclusive were studied. Data was entered onto an Excel database by a trained administrator. The variables included were: age, gender, swallow screen, living alone, cognition, loneliness, Clinical Frailty Scale (CFS) score, falls history and risk of malnutrition using the Malnutrition-Screening Tool (MST). Odds ratio (OR), 95% Confidence Intervals (CI) was used to determine if there was an association between malnutrition risk and each variable in the total group.

Results

In total, 567 patients (325 female, 242 male), mean age 82yrs (SD =19), with median CFS of 6 were studied. Sixty-eight percent (n=384) reported a fall, 37.2% (n=211) had a positive swallow screen, 44% (n=251) lived alone, 35% (n=198) had positive cognitive screening, 14% (n=80) reported loneliness and 31.6% (n=179) were identified as at risk of malnutrition. A positive association was identified between risk of malnutrition and cognitive impairment (OR 1.9, 95%CI 1.2-3.1) and a reported fall (OR 2.2, 95%CI 1.4-3.5). In the population who had a fall and risk of malnutrition, the association remained in those aged ≥80yrs (OR 2.6, 95% CI 1.46 – 4.5) and female (OR 3.6, 95%CI 1.7 – 7.4).

Conclusion

The risk of malnutrition is associated with falls risk and cognitive impairment in frail older persons. Frail older persons identified by integrated care team for older persons with falls risk & cognitive impairment will be targeted for specialist dietetic intervention.

P06.08.B Radiation therapy enhances anti-tumor activity of a MET CAR T-based immunotherapy for glioblastoma

Background

Glioblastoma is the most frequent primary brain tumor with dismal prognosis after standard treatment with surgery, and chemoradiation (the Stupp protocol). After a decade of failed clinical trials, tumor-treating fields have been first to show the added benefit of improved overall survival compared to the Stupp protocol (20.9 months vs 16.0 months). However, GBM remains a devastating disease, with almost inevitable recurrence, and limited options for second-line therapy. Radiation therapy (RT), is a standard therapy option for GBM, and it is used in most GBM cases affecting tumor through induction of DNA-damage. Recently, RT has been investigated as a mediator of T cell-based therapies in the context of immunosuppressive GBM microenvironment. The findings have shown promise in combination of T cell-based therapies, such as chimeric antigen receptor (CAR) T cell therapies, in improving the tumor infiltration, and penetration with immune cells. MET is a relevant oncogene in the context of GBM, being involved in stem-like properties, radiation response and resistance․ Hence, MET appeared to be a plausible target for combination with RT. In our research, we use MET-targeting CAR T cells (MET-CAR T cells) combined with radiation, and hypothesize synergistic interaction for GBM treatment.

Material and Methods

We used adherent (2D) and stem-like (3D) human GBM cell lines with different levels of MET expression. For MET-CAR T cell generation we did retrovirus-mediated transduction of activated human T cells and sorted the CAR-positive cells. We co-cultured MET-CAR T cells with GBM cells with or without RT, and assessed the killing and cytokine production in CAR T cells.

Results

Our results indicated that 5Gy radiation combined with MET-CAR T cells increases their potential in tumor cell killing. We observed increased CAR T cells effect at lower CAR T to target cells ratios when combined with radiation, even when radiation treatment did not lead to a significant decrease in viability. This phenomenon was similar across different types of cell lines (adherent, stem-like), different levels of MET expression, and different sensitivity to CAR T cells. We investigated the underlying mechanisms via intracellular cytokine measurement. We observed the most prominent response in TNF-α-expression. We also observed an increase in Granzyme B expression in co-culture with some of the GBM cell lines, especially in CD8+ subpopulation of CAR T cells. IFN-gamma expression increased in some adherent glioma cell lines but not in stem-like cell lines.

Conclusion

In conclusion, our data demonstrates the potency of MET-CAR T cells against GBM, and increased efficiency when combined with radiation. The suggested mechanism is the increased activation of T cells in TNF-α-dependent-manner. To validate these results we are testing our setup in an orthotopic mouse GBM model.

CAR T-Cell Targeting of Macrophage Colony-Stimulating Factor Receptor

Macrophage colony-stimulating factor receptor (M-CSFR) is found in cells of the mononuclear phagocyte lineage and is aberrantly expressed in a range of tumours, in addition to tumour-associated macrophages. Consequently, a variety of cancer therapies directed against M-CSFR are under development. We set out to engineer chimeric antigen receptors (CARs) that employ the natural ligands of this receptor, namely M-CSF or interleukin (IL)-34, to achieve specificity for M-CSFR-expressing target cells. Both M-CSF and IL-34 bind to overlapping regions of M-CSFR, although affinity of IL-34 is significantly greater than that of M-CSF. Matched second- and third-generation CARs targeted using M-CSF or IL-34 were expressed in human T-cells using the SFG retroviral vector. We found that both M-CSF- and IL-34-containing CARs enable T-cells to mediate selective destruction of tumour cells that express enforced or endogenous M-CSFR, accompanied by production of both IL-2 and interferon (IFN)-γ. Although they contain an additional co-stimulatory module, third-generation CARs did not outperform second-generation CARs. M-CSF-containing CARs mediated enhanced cytokine production and cytolytic activity compared to IL-34-containing CARs. These data demonstrate the feasibility of targeting M-CSFR using ligand-based CARs and raise the possibility that the low picomolar affinity of IL-34 for M-CSFR is detrimental to CAR function.

Generation and application of TGFβ-educated human Vγ9Vδ2 T cells

Clinical trials that tested the antitumor activity of γδ T cells have been mostly unsuccessful. To address this, we expanded human Vγ9Vδ2 T cells in TGFβ1, a cytokine which enhances their viability, trafficking properties, and intrinsic antitumor activity. This protocol summarizes the production and in vitro functional characterization of TGFβ1 educated human Vγ9Vδ2 cells and highlights their compatibility with chimeric antigen receptor (CAR) engineering. We also describe in vivo testing of the antitumor activity of these CAR T cells in mice.

For complete details on the use and execution of this protocol, please refer to Beatson et al. (2021).

•

TGFβ promotes viability and retards differentiation of Vγ9Vδ2 cells

•

TGFβ-educated Vγ9Vδ2 cells achieve greater invasion and anticancer activity

•

Specificity of these cells can be reprogrammed using chimeric antigen receptors

Generation of human parallel chimeric antigen receptor (pCAR) T cells to achieve synergistic T cell co-stimulation

Dual co-stimulation may be harnessed using parallel chimeric antigen receptors (pCARs) in which two distinct co-stimulatory units are adjacently localized on the plasma membrane. This protocol summarizes construct design, human T cell isolation, retroviral transduction, tissue culture expansion, and preclinical testing of pCAR T cells, exemplified by receptors that co-target avb6 integrin and ErbB dimers.

For complete details on the use and execution of this protocol, please refer to Muliaditan et al. (2021).

•

A protocol to enable robust generation of pCAR T cells

•

Effective dual co-stimulation is provided by this platform

•

Sustained and enhanced antitumor activity by pCAR T cells

•

Detailed in vitro and in vivo evaluation of pCAR technology

Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.

Engineering of an Avidity-Optimized CD19-Specific Parallel Chimeric Antigen Receptor That Delivers Dual CD28 and 4-1BB Co-Stimulation

Co-stimulation is critical to the function of chimeric antigen receptor (CAR) T-cells. Previously, we demonstrated that dual co-stimulation can be effectively harnessed by a parallel (p)CAR architecture in which a CD28-containing second generation CAR is co-expressed with a 4-1BB containing chimeric co-stimulatory receptor (CCR). When compared to linear CARs, pCAR-engineered T-cells elicit superior anti-tumor activity in a range of pre-clinical models. Since CD19 is the best validated clinical target for cellular immunotherapy, we evaluated a panel of CD19-specific CAR and pCAR T-cells in this study. First, we generated a panel of single chain antibody fragments (scFvs) by alanine scanning mutagenesis of the CD19-specific FMC63 scFv (V_H domain) and these were incorporated into second generation CD28+CD3ζ CARs. The resulting panel of CAR T-cells demonstrated a broad range of CD19 binding ability and avidity for CD19-expressing tumor cells. Each scFv-modified CAR was then converted into a pCAR by co-expression of an FMC63 scFv-targeted CCR with a 4-1BB endodomain. When compared to second generation CARs that contained an unmodified or mutated FMC63 scFv, each pCAR demonstrated a significant enhancement of tumor re-stimulation potential and IL-2 release, reduced exhaustion marker expression and enhanced therapeutic efficacy in mice with established Nalm-6 leukemic xenografts. These data reinforce the evidence that the pCAR platform delivers enhanced anti-tumor activity through effective provision of dual co-stimulation. Greatest anti-tumor activity was noted for intermediate avidity CAR T-cells and derived pCARs, raising the possibility that effector to target cell avidity is an important determinant of efficacy.

Highly effective liquid and solid phase extraction methods to concentrate radioiodine isotopes for radioiodination chemistry

Radioactive iodine isotopes play a pivotal role in radiopharmaceuticals. Large-scale production of multi-patient dose of radioiodinated nuclear medicines requires high concentration of radioiodine. We demonstrate that tetrabutylammonium chloride and methyltrioctylamonium chloride are effective phase transfer reagents to concentrate iodide-124, iodide-125 and iodide-131 from the corresponding commercial water solutions. The resulting concentrated radioiodide, in the presence of either phase transfer reagent, does not hamper the chemical reactivity of aqueous radioiodide in the copper (II)-mediated one-pot three-component click chemistry to produce radioiodinated iodotriazoles.

Synergistic T cell signaling by 41BB and CD28 is optimally achieved by membrane proximal positioning within parallel chimeric antigen receptors

Second generation (2G) chimeric antigen receptors (CARs) contain a CD28 or 41BB co-stimulatory endodomain and elicit remarkable efficacy in hematological malignancies. Third generation (3G) CARs extend this linear blueprint by fusing both co-stimulatory units in series. However, clinical impact has been muted despite compelling evidence that co-signaling by CD28 and 41BB can powerfully amplify natural immune responses. We postulate that effective dual co-stimulation requires juxta-membrane positioning of endodomain components within separate synthetic receptors. Consequently, we designed parallel (p)CARs in which a 2G (CD28+CD3ζ) CAR is co-expressed with a 41BB-containing chimeric co-stimulatory receptor. We demonstrate that the pCAR platform optimally harnesses synergistic and tumor-dependent co-stimulation to resist T cell exhaustion and senescence, sustaining proliferation, cytokine release, cytokine signaling, and metabolic fitness upon repeated stimulation. When engineered using targeting moieties of diverse composition, affinity, and specificity, pCAR T cells consistently elicit superior anti-tumor activity compared with T cells that express traditional linear CARs.

TGF-β1 potentiates Vγ9Vδ2 T cell adoptive immunotherapy of cancer

Despite its role in cancer surveillance, adoptive immunotherapy using γδ T cells has achieved limited efficacy. To enhance trafficking to bone marrow, circulating Vγ9Vδ2 T cells are expanded in serum-free medium containing TGF-β1 and IL-2 (γδ[T2] cells) or medium containing IL-2 alone (γδ[2] cells, as the control). Unexpectedly, the yield and viability of γδ[T2] cells are also increased by TGF-β1, when compared to γδ[2] controls. γδ[T2] cells are less differentiated and yet display increased cytolytic activity, cytokine release, and antitumor activity in several leukemic and solid tumor models. Efficacy is further enhanced by cancer cell sensitization using aminobisphosphonates or Ara-C. A number of contributory effects of TGF-β are described, including prostaglandin E2 receptor downmodulation, TGF-β insensitivity, and upregulated integrin activity. Biological relevance is supported by the identification of a favorable γδ[T2] signature in acute myeloid leukemia (AML). Given their enhanced therapeutic activity and compatibility with allogeneic use, γδ[T2] cells warrant evaluation in cancer immunotherapy.

Prospects for Development of Induced Pluripotent Stem Cell-Derived CAR-Targeted Immunotherapies

Technologies required to generate induced pluripotent stem cells (iPSC) were first described 15 years ago, providing a strong impetus to the field of regenerative medicine. In parallel, immunotherapy has finally emerged as a clinically meaningful modality of cancer therapy. In particular, impressive efficacy has been achieved in patients with selected haematological malignancies using ex vivo expanded autologous T cells engineered to express chimeric antigen receptors (CARs). While solid tumours account for over 90% of human cancer, they currently are largely refractory to this therapeutic approach. Nonetheless, given the considerable innovation taking place worldwide in the CAR field, it is likely that effective solutions for common solid tumours will emerge in the near future. Such a development will create significant new challenges in the scalable delivery of these complex, costly and individualised therapies. CAR-engineered immune cell products that originate from iPSCs offer the potential to generate unlimited numbers of homogeneous, standardised cell products in which multiple defined gene modification events have been introduced to ensure safety, potency and reproducibility. Here, we review some of the emerging strategies in use to engineer CAR-expressing iPSC-derived drug products.

124 OUTCOME OF SPEECH AND LANGUAGE THERAPY CLINICAL DYSPHAGIA ASSESSMENT FOLLOWING AN INTERDISCIPLINARY SWALLOW SCREEN

Background

A 7 question non-validated swallow screen (Any reported swallowing difficulties? Any coughing with food or fluids? Any choking? Does food get stuck when eating? Any recurrent chest infections? Any pain when swallowing? Any difficulty swallowing tablets?) is used by an integrated care team for older persons to prioritise referrals to the Speech and Language Therapy (SLT) service.

This study identified the proportion of patients screened who appropriately required a clinical dysphagia assessment and intervention.

Methods

This was a retrospective study from September 2020 to June 2021. Patients were assessed by the Clinical Specialist SLT who determined if swallow impairment was present and whether intervention was required. Age, gender and clinical frailty score were documented. Patients who resided out of the catchment area or who had already received an SLT service were excluded.

Results

The average age was 80 years, range 67–103. The male to female ratio was 2:1 and the average clinical frailty score (CFS) was 5. N = 42(32%) screened positive. N = 29(69%) attended for SLT assessment. N = 27(93.1%) had a swallow impairment identified. N = 20 were discharged following a single intervention and 9 required further SLT intervention.

Conclusion

Presbyphagia is generally asymptomatic and results from age related anatomical and physiological changes, reduced functional reserve and sarcopenia. Older adults compensate for these difficulties and do not seek assistance. Presbyphagia may progress to dysphagia, resulting in adverse outcomes. The high rate of SLT confirmed swallow impairment and need for SLT intervention highlights a need to prospectively refine and validate this 7 question swallow screen.

179 WHAT MATTERS TO THE FRAIL OLDER PERSON CHANGES DURING COVID-19 AND SHOULD INFORM PATIENT CENTRED CHANGE

Background

Methods

Results

Conclusion

44 BONE HEALTH AND FRACTURE RISK: KNOWLEDGE, OPINION AND PRACTICE OF PHYSIOTHERAPISTS

Background

Osteoporotic-related fractures are responsible for excess mortality, morbidity, chronic pain, reduction in quality of life, admission to long-term care and health and social care costs (Papaioannou et al, 2010).

Evidence for using Fracture Risk Assessment Tool (FRAX®) based community-screening in older people is increasing (Kanis et al, 2020). There is no published evidence on the use of FRAX® by Physiotherapists.

Methods

A questionnaire was sent to South Eastern Branch members of the Irish Society of Chartered Physiotherapists (ISCP).

Survey themes were: participant characteristics, knowledge and opinion in the areas of Bone Health and Fracture Risk. Responses were downloaded from Survey Monkey and analysed using descriptive statistics.

Results

The response rate was 27% (n = 56). 72% (n = 40) of those surveyed had at least 10 years clinical experience. For 65% (n = 37) of participants, older people made up more than half of their clinical caseload. 96% (n = 54) of participants treated people with frailty and other bone health risk factors; falls (93%), osteoporosis (89%), fracture or reduced mobility (87%).

On a scale of 1–10 (1 = least confident, 10 = most confident) 49% of respondents rated confidence in prescribing Bone Health Physiotherapy interventions at ≤5.

When interpreting results of a DEXA scan; 80% reported confidence to be ≤5.

Half (49%) of participants had never heard of FRAX®.

95% of respondents felt fracture risk was under addressed in clinical practice. All felt it was within their professional responsibility to discuss fracture risk with patients.

Conclusion

This is the first evaluation of bone health and fracture risk knowledge, opinion and practice of physiotherapists. The need for more knowledge of DEXA, FRAX® and bone health was highlighted. The use of FRAX® may improve fracture risk assessment in patients attending Physiotherapy. Based on these results, FRAX® has been introduced into a Rehabilitation Unit by Physiotherapists as part of Quality Improvement Project.

126 A QUALITY INITIATIVE TO IMPROVE THE ASSESSMENT AND RECOMMENDATION FOR TOTAL CALCIUM INTAKE

Background

This study assessed factors affecting adherence to calcium supplementation, estimated total calcium intake and potential to increase dietary calcium in the frail older adult.

Methods

Frail Older Adults who completed a comprehensive geriatric assessment (CGA) between January—June 2021 were included. Those taking calcium supplements were telephoned by a Dietitian. Nursing home residents, hospital inpatients and those unable to complete a telephone questionnaire were excluded. A modified version of the Short Calcium Intake List (SCAIL) was used and potential to improve dietary calcium was assessed (1). Data was analysed using descriptive statistics.

Results

N = 50 patients were taking a calcium supplement. N = 15 were excluded. 26 women and 9 men, aged 70 -96 yrs were included. Dietary intake ranged from 250– 1904 mg. 17% (N = 6) achieved &gt;1,000 mg/day dietary calcium requirements from diet. 66% (N = 23) had potential to increase their dietary calcium. 97% (N = 34) were prescribed a Calcium supplement, ranging from 500– 2000 mg/day. Total Calcium Intake including supplementation ranged from 850 mg—2,737 mg. 82% (N = 29) exceeded their daily requirements.40% (N = 14) reported reduced compliance due to swallowing difficulties; 25%(N = 9) gastrointestinal upset; 11% (N = 4,) taste/consistency and 8% forgetting (N = 3).Dietitian recommendations included 31% (N = 11) to stop supplementation, 34% (N = 12) to reduce, 11% (N = 4) advice on managing concerns relating to supplement and 22% (N = 8) dietary education.

Conclusion

Most older adults did not meet their nutritional requirements for dietary calcium. Over two thirds could reduce or stop supplementation following dietary calcium assessment and advice. A dietary calcium estimator for the older adult, with education can be used to correct calcium intake. This modified SCAIL will be integrated into the CGA as part of a quality improvement initiative for the frail older adult.

Reference

1. Rasch L et al. (2017), Content Validity of a Short Calcium Intake List to Estimate Daily Dietary Calcium intake of Patients with Osteoporosis, Calcified Tissue International, 100(3): 271–277.

Closing the Osteoporotic-Fracture Care Gap for Frail Older Persons

Aim To implement standardised fracture risk assessment in the frail older person. Methods Frail older patients underwent opportunistic screening for fracture risk. Roadblocks to standardised assessment were identified. An Integrated Care Team for older persons (ICT) trained in fracture risk assessment using FRAX. Clinical assessment was via a locally agreed algorithm. Data was entered onto Excel. The SQUIRE guidelines for quality improvement programmes were used to report the results. Results Of 96 patients opportunistically screened, the average age was 84 years. FRAX was completed for 19% (n=18). 89% (n=16) met the pharmacotherapy threshold. Nine were recommended pharmacotherapy. Of sixteen patients recommended for DXA, just 31% (n=5) were booked. Following implementation of a quality improvement project, 100 patients were assessed, and average age was 80 years. FRAX was completed for 62% (n=63) and 95% (n=60) required pharmacotherapy. 24% (n=14) had untreated prior fracture. All had pharmacotherapy prescribed. 59% (n=59) required DXA scanning. 70% (n=41) had DXA ordered. Conclusion ICT ownership increased FRAX assessment 3-fold and point of contact prescribing to 100%.

Development and Validation of a Good Manufacturing Process for IL-4-Driven Expansion of Chimeric Cytokine Receptor-Expressing CAR T-Cells

Adoptive cancer immunotherapy using chimeric antigen receptor (CAR) engineered T-cells holds great promise, although several obstacles hinder the efficient generation of cell products under good manufacturing practice (GMP). Patients are often immune compromised, rendering it challenging to produce sufficient numbers of gene-modified cells. Manufacturing protocols are labour intensive and frequently involve one or more open processing steps, leading to increased risk of contamination. We set out to develop a simplified process to generate autologous gamma retrovirus-transduced T-cells for clinical evaluation in patients with head and neck cancer. T-cells were engineered to co-express a panErbB-specific CAR (T1E28z) and a chimeric cytokine receptor (4αβ) that permits their selective expansion in response to interleukin (IL)-4. Using peripheral blood as starting material, sterile culture procedures were conducted in gas-permeable bags under static conditions. Pre-aliquoted medium and cytokines, bespoke connector devices and sterile welding/sealing were used to maximise the use of closed manufacturing steps. Reproducible IL-4-dependent expansion and enrichment of CAR-engineered T-cells under GMP was achieved, both from patients and healthy donors. We also describe the development and approach taken to validate a panel of monitoring and critical release assays, which provide objective data on cell product quality.

Approaches for refining and furthering the development of CAR-based T cell therapies for solid malignancies

Introduction: Chimeric antigen receptor-engineered T-cells typically use the binding domains of antibodies to target cytotoxicity toward tumors. This approach has produced great efficacy against selected hematological cancers, but benefit in solid tumors has been limited. Characteristically, the microenvironment in solid tumors restricts CAR T cell function, thereby limiting success. Enhancing efficacy will depend on novel target discovery to refine specificity and reduce toxicity. Additionally, overcoming immunosuppressive mechanisms may be achieved by altering the structure of the CAR itself, together with ancillary gene expression or additional therapeutic interventions.Areas covered: Herein, the authors discuss approaches for refining and further developing CAR T cell therapies specifically for use with solid malignancies. The authors survey the existing literature and provide perspectives for the future.Expert opinion: Pronounced efficacy in solid tumors will likely require combination therapies, targeting both the tumor itself and associated immunosuppressive mechanisms. Future exploration of CAR T cell therapies for solid tumors is likely to incorporate next-generation designs that couple more precise targeting of cancer-associated targets with enhanced potency and resistance to exhaustion.

How Can We Engineer CAR T Cells to Overcome Resistance?

Chimeric antigen receptor (CAR) T cell therapy has achieved unrivalled success in the treatment of B cell and plasma cell malignancies, with five CAR T cell products now approved by the US Food and Drug Administration (FDA). However, CAR T cell therapies for solid tumours have not been nearly as successful, owing to several additional challenges. Here, we discuss mechanisms of tumour resistance in CAR T cell therapy and the emerging strategies that are under development to engineer CAR T cells to overcome resistance.

Abstract PO-039: Radiation therapy enhances anti-tumor activity of a MET CAR T-based immunotherapy approach for glioblastoma multiforme

Glioblastoma multiforme (GBM) is the most prevalent primary malignant brain tumor, which has an aggressive phenotype and mostly fatal recurrence after standard therapy. MET, the hepatocyte growth factor (HGF) receptor is a relevant target for GBM treatment as it is expressed in up to 50% of cases and its expression, which may be induced by radiation therapy (RT), can potentially contribute to RT-resistance of GBM stem cells, and tumor recurrence. MET-based chimeric antigen (CAR) T cell therapy is currently being evaluated in several solid tumor working settings. A combination of T cell-based therapies with RT may improve the efficacy of the CAR T cell therapy through by the RT-induced immune activation via release of cytokines and induction of antigen expression, similarly as has been observed when combining RT with immune checkpoint inhibitors. Here we investigated the combination of MET-targeting CAR T cells with RT for GBM treatment, hypothesizing enhanced anti-tumor effects. The current study used a panel of MET-proficient and MET-deficient human GBM and GBM stem-like cell lines. Cells have been irradiated with a single dose of 0, 2, 5, or 10 Gy and RT impact on MET expression has been assessed at various time points after RT administration. Results show MET increase after RT in some cell lines. To test MET-targeting CAR T effect on the GBM cell lines, CAR constructs that are based on HGF-MET binding elements have been introduced into virus-producing cells and used for human T cells transduction to generate MET-targeting CAR T cells. CAR T cells co-cultured with GBM cell lines in vitro have specifically and significantly decreased viability of MET-positive cancer cells. Data resulting from combination of RT and CAR T cells treatment suggest that radiation exhibits an enhancement of CAR T cells anti-tumor killing activity, indicating a synergism between the two modalities. In conclusion, our data are the first to indicate the efficacy of a MET-based CAR T immunotherapy approach in GBM cell lines. The results also demonstrate a basis for the combination of a MET CAR T modality together with RT. The mechanisms for understanding the interaction between RT and the MET CAR T cells are under investigation.

Citation Format: Lusine Hovhannisyan, Daniel M. Aebersold, John Maher, Adrian F. Ochsenbein, Carsten Riether, Michaela Medova, Yitzhak Zimmer. Radiation therapy enhances anti-tumor activity of a MET CAR T-based immunotherapy approach for glioblastoma multiforme [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-039.

An overview of CAR T-cell clinical trial activity to 2021

Immunotherapy of cancer using chimeric antigen receptor-engineered T-cells has transformed the management of selected haematological malignancies, triggering intense clinical trial activity in this arena. This article summarises trial activity that has been published to date across the spectrum of haematological and solid tumour types.

Chimeric Antigen Receptor T Cells Targeting Integrin αvβ6 Expressed on Cholangiocarcinoma Cells

Cholangiocarcinoma (CCA) is a lethal bile duct cancer that responds poorly to current standard treatments. A new therapeutic approach is, therefore, urgently needed. Adoptive T cell transfer using chimeric antigen receptor (CAR) T cells is a new therapeutic modality with demonstrated efficacy in hematologic malignancies. However, its efficacy against solid tumors is modest, and further intensive investigation continues. An important factor that influences the success of CAR T cell therapy is the selection of a target antigen that is highly expressed on cancer cells, but markedly less so in normal cells. Integrin αvβ6 is upregulated in several solid tumors, but is minimally expressed in normal epithelial cells, which suggests integrin αvβ6 as an attractive target antigen for CAR T cell immunotherapy in CCA. We investigated integrin αvβ6 expression in pathological tissue samples from patients with liver fluke-associated CCA. We then created CAR T cells targeting integrin αvβ6 and evaluated their anti-tumor activities against CCA cells. We found overexpression of the integrin αvβ6 protein in 23 of 30 (73.3%) CCA patient tissue samples. Significant association between high integrin αvβ6 expression and short survival time (p = 0.043) was also observed. Lentiviral constructs were engineered to encode CARs containing an integrin αvβ6-binding peptide (A20) derived from foot-and-mouth disease virus fused with a second-generation CD28/CD3ζ signaling domain (A20-2G CAR) or with a fourth-generation CD28/4-1BB/CD27/CD3ζ signaling domain (A20-4G CAR). The A20-2G and A20-4G CARs were highly expressed in primary human T cells transduced with the engineered lentiviruses, and they exhibited high levels of cytotoxicity against integrin αvβ6-positive CCA cells (p < 0.05). Interestingly, the A20-2G and A20-4G CAR T cells displayed anti-tumor function against integrin αvβ6-positive CCA tumor spheroids (p < 0.05). Upon specific antigen recognition, A20-4G CAR T cells produced a slightly lower level of IFN-γ, but exhibited higher proliferation than A20-2G CAR T cells. Thus, the A20-4G CAR T cells with lower level of cytokine production, but with higher proliferation represents a promising potential adoptive T cell therapy for integrin αvβ6-positive CCA.

Crosstown Traffic: Lymphodepleting Chemotherapy Drives CAR T Cells

CAR-engineered T cell immunotherapy has proven transformative in selected hematological malignancies. However, solid tumors largely remain impervious to these approaches. In addressing this challenge, Srivastava et al. in this issue demonstrate that oxaliplatin-based lymphodepleting chemotherapy promotes enhanced CAR T cell recruitment to lung tumors, boosting therapeutic impact in combination with anti-PD-L1.

T cell response to SARS-CoV-2 infection in humans: A systematic review

BACKGROUND

Understanding the T cell response to SARS-CoV-2 is critical to vaccine development, epidemiological surveillance and disease control strategies. This systematic review critically evaluates and synthesises the relevant peer-reviewed and pre-print literature published from 01/01/2020-26/06/2020.

METHODS

For this systematic review, keyword-structured literature searches were carried out in MEDLINE, Embase and COVID-19 Primer. Papers were independently screened by two researchers, with arbitration of disagreements by a third researcher. Data were independently extracted into a pre-designed Excel template and studies critically appraised using a modified version of the MetaQAT tool, with resolution of disagreements by consensus. Findings were narratively synthesised.

RESULTS

61 articles were included. 55 (90%) studies used observational designs, 50 (82%) involved hospitalised patients with higher acuity illness, and the majority had important limitations. Symptomatic adult COVID-19 cases consistently show peripheral T cell lymphopenia, which positively correlates with increased disease severity, duration of RNA positivity, and non-survival; while asymptomatic and paediatric cases display preserved counts. People with severe or critical disease generally develop more robust, virus-specific T cell responses. T cell memory and effector function has been demonstrated against multiple viral epitopes, and, cross-reactive T cell responses have been demonstrated in unexposed and uninfected adults, but the significance for protection and susceptibility, respectively, remains unclear.

CONCLUSION

A complex pattern of T cell response to SARS-CoV-2 infection has been demonstrated, but inferences regarding population level immunity are hampered by significant methodological limitations and heterogeneity between studies, as well as a striking lack of research in asymptomatic or pauci-symptomatic individuals. In contrast to antibody responses, population-level surveillance of the T cell response is unlikely to be feasible in the near term. Focused evaluation in specific sub-groups, including vaccine recipients, should be prioritised.

Antibody response to SARS-CoV-2 infection in humans: A systematic review

BACKGROUND

Progress in characterising the humoral immune response to Severe Acute Respiratory Syndrome 2 (SARS-CoV-2) has been rapid but areas of uncertainty persist. Assessment of the full range of evidence generated to date to understand the characteristics of the antibody response, its dynamics over time, its determinants and the immunity it confers will have a range of clinical and policy implications for this novel pathogen. This review comprehensively evaluated evidence describing the antibody response to SARS-CoV-2 published from 01/01/2020-26/06/2020.

METHODS

Systematic review. Keyword-structured searches were carried out in MEDLINE, Embase and COVID-19 Primer. Articles were independently screened on title, abstract and full text by two researchers, with arbitration of disagreements. Data were double-extracted into a pre-designed template, and studies critically appraised using a modified version of the Public Health Ontario Meta-tool for Quality Appraisal of Public Health Evidence (MetaQAT) tool, with resolution of disagreements by consensus. Findings were narratively synthesised.

RESULTS

150 papers were included. Most studies (113 or 75%) were observational in design, were based wholly or primarily on data from hospitalised patients (108, 72%) and had important methodological limitations. Few considered mild or asymptomatic infection. Antibody dynamics were well described in the acute phase, up to around three months from disease onset, but the picture regarding correlates of the antibody response was inconsistent. IgM was consistently detected before IgG in included studies, peaking at weeks two to five and declining over a further three to five weeks post-symptom onset depending on the patient group; IgG peaked around weeks three to seven post-symptom onset then plateaued, generally persisting for at least eight weeks. Neutralising antibodies were detectable within seven to 15 days following disease onset, with levels increasing until days 14-22 before levelling and then decreasing, but titres were lower in those with asymptomatic or clinically mild disease. Specific and potent neutralising antibodies have been isolated from convalescent plasma. Cross-reactivity but limited cross-neutralisation with other human coronaviridae was reported. Evidence for protective immunity in vivo was limited to small, short-term animal studies, showing promising initial results in the immediate recovery phase.

CONCLUSIONS

Literature on antibody responses to SARS-CoV-2 is of variable quality with considerable heterogeneity of methods, study participants, outcomes measured and assays used. Although acute phase antibody dynamics are well described, longer-term patterns are much less well evidenced. Comprehensive assessment of the role of demographic characteristics and disease severity on antibody responses is needed. Initial findings of low neutralising antibody titres and possible waning of titres over time may have implications for sero-surveillance and disease control policy, although further evidence is needed. The detection of potent neutralising antibodies in convalescent plasma is important in the context of development of therapeutics and vaccines. Due to limitations with the existing evidence base, large, cross-national cohort studies using appropriate statistical analysis and standardised serological assays and clinical classifications should be prioritised.

Lymphodepletion strategies to potentiate adoptive T-cell immunotherapy - what are we doing; where are we going?

INTRODUCTION

Adoptive immunotherapy of cancer has evolved from the use of ex vivo expanded lymphokine-activated killer cells and tumor-infiltrating lymphocytes to an increasing array of approaches involving genetically engineered T-cells. A pivotal advance in the enablement of these therapies has been the conditioning of patients with lymphodepleting chemotherapy.A broad range of lymphodepleting regimens has been employed in an effort to improve response rates, without any single consistent approach having emerged. Only a limited number of studies involving small numbers of patients has directly compared two or more regimens, making it challenging to infer which are the preferred agents and dosing schedules. This difficulty is compounded by the fact that both response rate and toxicity appear to be disease-, patient- and T-cell product specific.

EXPERT OPINION

This article surveys clinical experience with lymphodepleting regimens that have been used in conjunction with adoptive T-cell immunotherapy, focussing in particular on studies where different approaches have been employed. Harnessing this limited and evolving clinical experience, we set out to provide potential insights into how an optimal balance may be achieved between efficacy and safety. Intermediate dose fludarabine-based regimens are emerging as an increasingly popular option in an attempt to achieve this goal, although further studies are required to provide definitive evidence.

Developing a safe and effective CAR T-cell immunotherapy for breast cancer: progress and pitfalls

Current targeted therapies for breast cancer include hormone inhibitors, monoclonal antibodies and tyrosine kinase inhibitors. However, a significant unmet therapeutic need remains for refractory disease and in particular for the triple negative subtype, which lacks hormone receptors and HER2. Chimeric antigen receptors T cells are genetically engineered to deploy selective cytolytic activity against cells that express cognate native target. Durable remissions have been achieved in refractory hematological malignancies but similar success against solid tumors remains elusive. Several hurdles hinder progress, including the need to identify safe antigens, promote T-cell homing to tumor sites and to ensure the persistence of functional chimeric antigen receptors T cells within the immunosuppressive tumor microenvironment. Perspectives to enable the attainment of this goal are presented in this review.

Engineering of chimeric natural killer cell receptors to develop precision adoptive immunotherapies for cancer

Natural killer (NK) cells are innate immune effectors which play a crucial role in recognizing and eliminating virally infected and cancerous cells. They effectively distinguish between healthy and distressed self through the integration of signals delivered by germline‐encoded activating and inhibitory cell surface receptors. The frequent up‐regulation of stress markers on genetically unstable cancer cells has prompted the development of novel immunotherapies that exploit such innate receptors. One prominent example entails the development of chimeric antigen receptors (CAR) that detect cell surface ligands bound by NK receptors, coupling this engagement to the delivery of tailored immune activating signals. Here, we review strategies to engineer CARs in which specificity is conferred by natural killer group 2D (NKG2D) or other NK receptor types. Multiple preclinical studies have demonstrated the remarkable ability of chimeric NK receptor‐targeted T cells and NK cells to effectively and specifically eliminate cancer cells and to reject established tumour burdens. Importantly, such systems act not only acutely but, in some cases, they also incite immunological memory. Moreover, CARs targeted with the NKG2D ligand binding domain have also been shown to disrupt the tumour microenvironment, through the targeting of suppressive T regulatory cells, myeloid‐derived suppressor cells and tumour vasculature. Collectively, these findings have led to the initiation of early‐phase clinical trials evaluating both autologous and allogeneic NKG2D‐targeted CAR T cells in the haematological and solid tumour settings.

The eIF4A inhibitor silvestrol sensitizes T-47D ductal breast carcinoma cells to external-beam radiotherapy

•

Treatment of T-47D breast cancer cells with silvestrol sensitised them to radiation.

•

1 nM silvestrol caused a 34% reduction in cells exposed to 2 Gy.

•

Clonogenic assays revealed silvestrol had a dose modifying factor of 1.4.

•

Radiation was delivered to the tissue culture plate using a clinical LINAC machine.

Purpose

eIF4A is an RNA helicase that forms part of the machinery of translation initiation.

Proteomic analysis demonstrated eIF4A expression to be at least two-fold greater in a radioresistant derivative of T-47D breast cancer cells compared to parental cells.

Inhibition of eIF4A has previously been shown to re-sensitize lymphomas to chemotherapeutic agents that cause DNA damage.

The objective of this work is to investigate whether inhibition of eIF4A using silvestrol sensitizes breast cancer cells to radiotherapy in tissue culture, using T-47D as a model system.

Methods and materials

T-47D cells were incubated in medium containing 0 nM to 1 nM silvestrol either for 24 h prior to irradiation at 0 Gy to 10 Gy, delivered by linear accelerator (LINAC) or continually for six days post irradiation. MTT viability and clonogenic assays were used to quantify response.

Results

Pre-treatment of T-47D cells with 1 nM silvestrol caused a 34% reduction (p = 0.014) in viability on irradiation at 2 Gy compared to treatment with a DMSO control, as assessed by MTT assay.

Maintenance of cells in 1 nM silvestrol for six days following irradiation at 2 Gy caused a 58% reduction (p = <0.001) in tumor cell viability.

Clonogenic assays performed on cells maintained in 1 nM silvestrol following irradiation showed a dose modifying factor (DMF) of 1.4 (p = <0.001, one-way ANOVA).

Conclusions

Low concentrations of silvestrol sensitize T-47D breast cancer cells to radiation with minimal effects on unirradiated cells. This highlights the possible usefulness of eIF4A inhibition in potentiating radiation-induced damage at the tumor site without causing systemic toxicity.

CAR T-cell immunotherapy of B-cell malignancy: the story so far

Chimeric antigen receptor (CAR) T-cell immunotherapy has achieved unprecedented efficacy in the treatment of chemotherapy-resistant or refractory B-cell malignancies. Promising results from pivotal anti-CD19 CAR T-cell phase II trials have led to landmark approvals of two CD19-specific CAR T-cell products by the United States Food and Drug Administration and European Medicines Agency. However, several issues associated with CAR T-cell treatment remain unresolved, such as the management of severe toxicities and the frequent occurrence of both antigen-positive and antigen-negative relapse. Nonetheless, pre-clinical research is advancing at an unprecedented pace to develop innovative solutions to address these issues. Herein, we summarise recent clinical developments and outcomes of CD19-targeted CAR T-cell immunotherapy and discuss emerging strategies that may further improve the success, safety and broadened applicability of this approach.