In addition to complications of acute diseases, chronic viral infections are linked to both malignancies and autoimmune disorders. Lack of adequate treatment options for Epstein-Barr virus (EBV), Human T-lymphotropic virus type 1 (HTLV-1), and human papillomavirus (HPV) remains. The NexImmune Artificial Immune Modulation (AIM) nanoparticle platform can be used to direct T cell responses by mimicking the dendritic cell function. In one application, AIM nanoparticles are used ex vivo to enrich and expand (E+E) rare populations of multi-antigen-specific CD8+ T cells for use of these cells as an AIM adoptive cell therapy. This study has demonstrated using E+E CD8+ T cells, the functional relevance of targeting EBV, HTLV-1, and HPV. Expanded T cells consist primarily of effector memory, central memory, and self-renewing stem-like memory T cells directed at selected viral antigen peptides presented by the AIM nanoparticle. T cells expanded against either EBV- or HPV-antigens were highly polyfunctional and displayed substantial in vitro cytotoxic activity against cell lines expressing the respective antigens. Our initial work was in the context of exploring T cells expanded from healthy donors and restricted to human leukocyte antigen (HLA)-A*02:01 serotype. AIM Adoptive Cell Therapies (ACT) are also being developed for other HLA class I serotypes. AIM adoptive cell therapies of autologous or allogeneic T cells specific to antigens associated with acute myeloid leukemia and multiple myeloma are currently in the clinic. The utility and flexibility of the AIM nanoparticle platform will be expanded as we advance the second application, an AIM injectable off-the-shelf nanoparticle, which targets multiple antigen-specific T cell populations to either activate, tolerize, or destroy these targeted CD8+ T cells directly in vivo, leaving non-target cells alone. The AIM injectable platform offers the potential to develop new multi-antigen specific therapies for treating infectious diseases, cancer, and autoimmune diseases.

BackgroundNexImmune is developing highly differentiated immunotherapies to target, activate and expand tumor antigen-specific T cells using the proprietary Artificial Immune Modulation (AIM™) nanotechnology platform. The AIM nanoparticle (AIM-np) technology functions as synthetic dendritic cells capable of directing a specific T cell-mediated immune response. By mimicking natural T cell biology, NexImmune’s cellular therapy product candidates (AIM ACT) are designed to combine the attributes of cellular precision, potency, and persistence with reduced potential for undesired toxicities. Human papilloma virus (HPV) is responsible for >45,000 cancers yearly in the United States, according to the CDC. From 2013–2017 an estimate 79% of cervical, vulva, penis, vaginal, anus, and oropharyngeal cancers were attributed to HPV and of these about 80% were associated with high-risk HPV types 16 and 18. Although multivalent vaccines against high-risk HPV infections exist, significant clinical challenges remain. A limited vaccination rate means many remain vulnerable and vaccination does not treat pre-existing HPV infections or malignancies.MethodsTherefore, NexImmune is employing its AIM-np technology to generate an adoptive cell therapy (ACT) using its proprietary enrichment and expansion (E+E) ex vivo process to expand clinically relevant numbers of CD8+ T cells that recognize the HPV16 and HPV18 oncogenic antigens (i.e., E6 and E7) expressed by malignant cells of head and neck, cervical, and anal cancers. Using the Immune Epitope Database and Analysis Resource (IEDB), 44 HLA-A2 restricted peptides were identified as potential immunogenic targets for preclinical screening. Using PBMCs from healthy donor-derived apheresis material, different combinations of these peptides were used in the E+E process to expand HPV-cancer specific CD8+ T cells.ResultsAfter multiple E+E experiments were concluded, 5 peptides were identified that consistently elicited the strongest T cell responses. Furthermore, these CD8+ T cells were predominantly from the central memory (CD62L+CD45RA-) and effector memory (CD62L-CD45RA-) phenotype (sum total 82.18 ± 8.29 [Mean ± SEM]) suggesting their in vivo functionality and persistence will combine anti-tumor activity with long-term immunologic memory.ConclusionsA similar E+E screening is being conducted with PBMCs isolated from HPV+ cancer patients. A comparison of the CD8+ T cell responses from healthy donor and cancer patient cells will provide critical preclinical data to support a planned FIH trial for HPV-associated malignancies. The current study demonstrates the ability for high-throughput peptide screening to identify clinically relevant peptide cocktails capable of expanding multi-antigen tumor-specific CD8+ T cell populations within 2 weeks.

Background NexImmune is developing novel, antigen-specific immunotherapies to meet serious unmet clinical needs. Here we report on the development of adoptive cell therapies (ACT) for virally driven malignancies. The proprietary Artificial Immune Modulation (AIM™) platform mimics natural T cell biology to target, activate and expand antigen-specific CD8 + T cells. EBV, HPV, and HTLV are estimated to contribute to 6-7% of global cancer cases. The targeted antigens are implicated in multiple malignancies including B cell lymphomas (EBV), adult T cell leukemia/lymphoma (HLTV1) as well as multiple HPV related malignancies such as oropharyngeal, cervical, and anal cancers. Methods Using the paramagnetic AIM nanoparticle as an artificial antigen presenting cell (aAPC), in two-weeks T cells were enriched and expanded from HLA-A*02:01 donor apheresis material against immunodominant antigens of EBV, HTLV, and HPV. The memory phenotype of these cells was determined by CD45RA, CD62L, and CD95 expression. Antigen specific killing was observed on HLA-A2+ cell lines and polyfunctional activity characterized by an intracellular cytokine staining assay.Results Greater than 90% of the total resulting CD8 + T cells display a phenotype of effector, central, or long-lived stemlike memory. From 8 independent healthy donor clinical scale manufacturing runs of NEXI-003, a pentavalent specific AIM ACT against the E6 and E7 antigens of both HPV-16 and HPV-18, as well as the tumor-associated antigen Survivin, 0.28E9 to 3.79E9 cells were generated. These cells showed dual HPV-16 + and HPV-18 + cancer antigen specificity and cytotoxic activity against HLA-A2 + cell lines, without significant cytotoxic activity against autologous PBMCs. With respect to EBV, using HLA-A2 + cell lines we further show antigen specific killing directed at LMP2, BRLF1, BMLF1, EBNA3, and LMP1 from a single healthy donor AIM ACT selected on 6 EBV antigens. In addition, these expanded memory T cells demonstrate a high degree of polyfunctional activity upon stimulation. Conclusions NEXI-003 is an immunotherapy for HPV cancers in HLA*A02:01 patients that recently received IND clearance and it is anticipated to begin clinical trials in 2022. In addition to B cell lymphomas, B cells that are present in the plaques of multiple sclerosis patients have been found to express EBV antigens. Therefore, by directing a multivalent EBV T cell response there is the potential to treat other EBV-associated diseases using one AIM ACT product. Results reported here, will support the expansion of the AIM platform modalities for use in the treatment of virally driven malignancies, as well as potential virally associated autoimmune and infection diseases.