Abstract 555: Allogeneic Natural Killer cells engineered to express HER2 CAR, Interleukin 15 and TGF beta dominant negative receptor effectively control HER2+ tumors

Despite the success of HER2 targeted therapies in HER2+ breast and gastric cancer, additional therapies are needed to address treatment-resistant metastatic disease. Adoptive immune cell therapy is a promising therapeutic modality given the remarkable clinical responses seen with autologous chimeric antigen receptor (CAR) T cells in hematological malignancies. However, success of cell therapy in solid tumors has been more limited. Three major impediments to the success of adoptive cell therapies in solid tumors are the heterogeneity of antigen expression, the immunosuppressive tumor microenvironment (TME), and the inherent challenges of manufacturing autologous cells and consequent variability of these cell products. Engineered, off-the-shelf, allogeneic Natural Killer (NK) cells provide a solution to these challenges. We describe here CAT-179, a novel engineered CAR-NK cell therapeutic for HER2+ solid tumors. CAT-179 cells express three transgenes: a HER2-directed CAR to effectively eliminate tumor cells, a Transforming Growth Factor (TGF) β dominant negative receptor (DNR) for resistance to TGFβ -mediated immunosuppression in the TME, and Interleukin 15 (IL15) cytokine to enhance NK cell persistence and activity for durable response. High efficiency engineering of the large (~3.7Kb) cargo containing CAR, IL15, and DNR in CAT-179 is enabled by the non-viral TC Buster™ Transposon System. Transposon engineering of CAT-179 results in high and stable expression of CAR (45% CAR at day 7 post gene delivery) without the need for post-engineering selection. CAT-179 demonstrates both CAR-dependent and innate NK receptor-dependent tumor cell killing in vitro, reducing the likelihood of tumor escape through antigen loss. CAT-179 effectively kills in vitro both high HER2-expressing SKOV3 cells as well as lower HER2-expressing HT-29 cells. CAT-179 also demonstrates resistance to TGFβ mediated immunosuppression, as evidenced by 75% reduction in TGFβ -induced phosphorylation of SMAD2 as well as prevention of TGFβ induced downregulation of NK cell activating receptors and restoration of NK cell cytotoxic activity. These data suggest CAT-179 cells will be protected from TGFβ -mediated immune suppression in the TME. Finally, the addition of IL15 in CAT-179 significantly enhances persistence for at least fourteen days in vitro without the need for exogenous cytokines. Moreover, CAT-179 administration to NSG mice showed expansion and persistence of the transferred cell product. CAT-179 addresses key hurdles to allogeneic cell therapy for solid tumors and is a promising new therapeutic approach for HER2 expressing breast, gastric and other tumors.

Citation Format: Celeste Richardson, Finola Moore, Andres Alvarez, Alexia Barandiaran, Luke Barron, Eugene Choi, Tucker Ezell, Charlotte Franco, Bashar Hamza, Jennifer Johnson, Annie Khamhoung, Taeyoon Kyung, Marilyn Marques, Dominic Picarella, Jared Sewell, Alex Storer, Meghan Walsh, Vipin Suri. Allogeneic Natural Killer cells engineered to express HER2 CAR, Interleukin 15 and TGF beta dominant negative receptor effectively control HER2+ tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 555.

Abstract LB-013: CAR-Ts armored with small molecule-regulated IL12 or CD40L cassettes for enhanced activity against solid tumors

Adoptive cell therapy with chimeric antigen receptor (CAR) modified T cells has demonstrated remarkable clinical efficacy in the treatment of certain B cell malignancies, and more recently in multiple myeloma. However, CAR-T therapy has been less successful in treating solid tumors due to multiple obstacles, including the lack of robust CAR-T cell expansion, the immunosuppressive tumor microenvironment, and tumor escape due to the loss of targeted antigen. Engineering CAR-T cells to produce immunomodulatory factors such as Interleukin 12 (IL12) and Cluster of Differentiation 40 Ligand (CD40L) has been shown to enhance functional activity by driving T cell expansion, conferring resistance to immunosuppression, improving antigen presentation, and inducing antigen spread. However, the clinical utility of both IL12 and activators of the CD40 signaling pathway have been limited by systemic toxicity associated with their potent pharmacological activities. Providing precise tuning of the timing and level of expression of these immunomodulatory factors in CAR-T cells could significantly enhance safety and therapeutic efficacy, in particular against solid tumor malignancies. We describe here the implementation of ligand-controlled regulation of IL12 and CD40L in vitro and in vivo in engineered primary human T cells via the use of destabilizing domain (DD) technology. DDs are small protein domains that are misfolded and inherently unstable in the cell, but which can be reversibly stabilized by the binding of approved pharmacologic agents. This conditional stability of DDs can be readily conferred to any protein of interest by fusing it to the DD, thus providing fine-tuned, exogenous regulation of protein expression and function. We have identified mutations in several human protein substrates, including phosphodiesterase 5 (PDE5), dihydrofolate reductase (DHFR), and estrogen receptor (ER), which convey DD activity and can be regulated by FDA-approved drugs. We show that transduction of human T cells with either DD-IL12 or DD-CD40L fusion constructs yields low expression levels in the basal state and a rapid, dose-dependent induction of IL12 or CD40L protein in the presence of the corresponding stabilizing ligand. Moreover, kinetically precise, on-demand production of either factor from CAR-T cells can be achieved in mice by oral dosing of stabilizing drugs. A CD19 CAR-T Nalm6 mouse model has been established that measures potent CAR-T expansion and enhanced anti-tumor efficacy with armored immunomodulatory constructs. Studies are underway in this model, as well as in solid tumor models, to test for enhanced CAR-T activity via drug-induced activation of IL12 and CD40L towards the development of next generation cell therapies with more favorable efficacy and safety profiles.

Citation Format: Michelle Ols, Michael Schebesta, Emily Brideau, Kutlu Elpek, Michelle Fleury, Jennifer Gori, Scott Heller, Dan Jun Li, Benjamin Primack, Christopher Reardon, Dhruv Sethi, Alex Storer, Dexue Sun, Karen Tran, Elizabeth Weisman, Michael Briskin, Celeste Richardson, Vipin Suri, Steven Shamah. CAR-Ts armored with small molecule-regulated IL12 or CD40L cassettes for enhanced activity against solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-013.

Diurnal variations in the phagocytic activity of zebrafish kidney leukocytes can be influenced by melatonin in a time-of-day dependent manner. (117.13)

Diurnal variations in immune system function result from rhythmic expression of clock genes. Their relationship with neuroendocrine regulators such as melatonin is not well understood. We explored the influence of melatonin on variations of phagocytic activity of zebrafish leukocytes. The percentage of kidney myeloid cells that phagocytosed pHrodo-labeled E. coli varied substantially throughout the day. The greatest increase in activity was between 6 AM and 10 AM, spanning the daily dark-to-light transition, a time when endogenous melatonin levels are falling to their daytime low. To determine whether extending the perceived night by prolonging the presence of melatonin would reduce the peak participation in phagocytosis observed at 10 AM, fish were exposed to exogenous melatonin for two hours beyond the beginning of the daily light period. Treatment with melatonin resulted in significantly lower participation in phagocytosis, similar to the normal 6 AM (dark phase) levels. The opposite effect was observed when fish received melatonin later in the day, prior to the evening light-to-dark transition. Fish exposed to melatonin prior to assay at 6 PM (late day) displayed a significant increase in phagocytosis over control fish, with participation levels surpassing normal 10 PM (early dark phase) levels. At both times of day, pre-treatment with the melatonin receptor antagonist luzindole prevented the changes in phagocytosis associated with extended melatonin presence.

Biological evaluation of carbon-fibre-reinforced polybutyleneterephthalate (CFRPBT) employed in a novel acetabular cup

Polymer composites are potentially useful materials for orthopaedic applications as they can be tailored to closely match the various moduli of bone. The Cambridge epiphyseal cup has been designed using one such material, carbon-fibre-reinforced polybutyleneterephthalate (CFRPBT), so that more of the load can be transferred to bone in order to reduce bone loss around the implant. We have evaluated the suitability of CFRPBT for this application using several standard and custom biological tests, both in vitro and in vivo, and have also started the initial clinical evaluation of the prosthesis. CFRPBT showed no toxicity in bulk form and only minimal toxicity as a particulate. It was non-haemolytic, non-immunogenic and showed no genotoxicity. No adverse responses were seen after in vivo implantation, and the results obtained following 9 months of clinical evaluation have been very encouraging with a good clinical outcome and good bone bonding to the hydroxyapatite-coated CFRPBT.

Cancer screening coverage of south Asian women in Wakefield

OBJECTIVE

To measure the cervical and breast screening coverage of south Asian women in Wakefield, compared with other city residents.

DESIGN

Pairwise measurement of screening histories of women whose names appeared to be south Asian, and of non-Asian women matched by date of birth and general practice.

DATA SOURCE

Computerised records of screening histories held by West Yorkshire Central Services Agency, for the eight general practices in central Wakefield.

RESULTS

67% of south Asians and 75% of non-Asians had acceptable (not overdue) cervical screening histories (chi(2)=13.75, p<0.001). 53% of south Asians and 78% of non-Asians had acceptable breast screening histories (chi(2)=8.5, p<0.01)

CONCLUSION

Interventions should be designed to improve coverage for breast screening among south Asian women. The need for such interventions for cervical screening is equivocal.