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154 Marrow-infiltrating lymphocytes (MILs): A novel adoptive immunotherapy for hematological and solid tumors
  1. Eric Lutz1,
  2. Lakshmi Rudraraju1,
  3. Elizabeth DeOliveira1,
  4. Amanda Seiz1,
  5. Monil Shah1,
  6. Celine Colmenares2,
  7. Beverly Dan Fu2,
  8. Daniela Bota2,
  9. Collin Brummel3,
  10. Chad Brenner3,
  11. Paul Swiecicki3,
  12. Nicole Fredrich4,
  13. David Page4,
  14. Eleni Efstatihiou5,
  15. Ivan Borrello6 and
  16. Kimberly Noonan1
  1. 1WindMIL Therapeutics, Baltimore, MD, USA
  2. 2University of California – Irvine, Irvine, CA, USA
  3. 3University of Michigan, Ann Arbor, MI, USA
  4. 4Providence Portland Medical Center, Portland, OR, USA
  5. 5The University of Texas MD Anderson Canc, Houston, TX, USA
  6. 6Johns Hopkins University School of Medi, Baltimore, MD, USA


Background Marrow infiltrating lymphocytes (MILsTM) are the product of activating and expanding bone marrow T cells.1 The bone marrow is a specialized niche in the immune system enriched for antigen-experienced, memory T cells. In patients with multiple myeloma and other hematological malignancies that relapse post-transplant, MILs have been shown to contain tumor antigen-specific T cells and adoptive cell therapy (ACT) using MILs has demonstrated antitumor activity.2 3 The bone marrow has been shown to harbor tumor-antigen specific T cells in patients with melanoma,4 5 glioblastoma,6 breast,7 non-small-cell lung8 and pancreatic cancers.9 Here, we sought to determine if tumor-specific MILs could be expanded from the bone marrow of patients with a range of different solid tumors.

Methods Bone marrow and blood samples were collected from patients with advanced and metastatic cancers. To date, samples have been collected from a minimum of four patients with non-small cell lung cancer (NSCLC), prostate cancer, head and neck cancer, glioblastoma, and breast cancer. Samples from patients with multiple myeloma were used as a reference control. Utilizing a 10-day proprietary process, MILs and peripheral blood lymphocytes (PBLs) were activated and expanded from patient bone marrow and blood samples, respectively. T cell lineage-specific markers (CD3, CD4 and CD8) were characterized by flow cytometry pre- and post-expansion.Tumor-specific T cells were quantitated in expanded MILs and PBLs using a previously described cytokine-secretion assay [2]. Briefly, autologous antigen-presenting cells (APCs) were pulsed with lysates from allogeneic cancer cell lines and co-cultured with activated MILs or PBLs. APCs pulsed with irrelevant mis-matched cancer cell line lysates or media alone were used as negative controls. Tumor-specific T cells were defined as the IFNgamma-producing population by flow cytometry.

Results MILs were successfully expanded from all patient bone marrow samples tested, regardless of tumor type. Cytokine-producing tumor-specific CD4+ and CD8+ T cells were detected in each of the expanded MILs. In contrast, tumor-specific T cells were not detected in any of the matched activated and expanded PBLs.

Conclusions MILs have been successfully grown for all solid tumor types evaluated, including NSCLC, prostate, head and neck, glioblastoma and breast cancer. Clinical studies have been completed in patients with multiple myeloma and other hematological cancers. 2 3 A phase IIa trial to evaluate MILs in combination with a checkpoint inhibitor is underway in patients with anti-PD1/PDL1-refractory NSCLC ( Identifier: NCT04069936). The preclinical data presented herein demonstrate that expanding MILs is feasible. MILs-based therapies hold therapeutic promise across a wide range of tumor indications.

Ethics Approval This study was approved by each participating instituion’s IRB.


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