BackgroundRecombinant human interleukin-2 (rhIL-2, aldesleukin) is Food and Drug Administration approved for the treatment of metastatic melanoma and renal cell carcinoma and has achieved durable response in a subset of patients. However, its utility as an immunotherapeutic drug is limited by undesirable activation of immune suppressive regulatory T cells (Tregs) and a short half-life requiring frequent high dose administration, leading to unacceptable toxicities. We have engineered MDNA11, a long-acting IL-2 superkine, to overcome these limitations by (1) modifying receptor selectivity in favor of anti-cancer immune cells to increase therapeutic efficacy and (2) fusion to human albumin to extend the pharmacokinetic (PK) profile, circumventing the need for frequent dosing.MethodsMDNA11 was evaluated using in vitro and in vivo studies including: binding analyses to measure receptor affinity, IL-2 pathway signaling, PK studies in mice, and efficacy studies in syngeneic tumor models as single agent and in combination with immune checkpoint inhibitors. Finally, the safety and pharmacodynamic profile of MDNA11 was assessed in non-human primate (NHP).ResultsBinding studies with MDNA11 demonstrated increased affinity for IL-2Rβ (CD122) and no binding to IL-2Rα (CD25). As a result, MDNA11 exhibits reduced/limited Treg stimulation while triggering an enhanced activation of natural killer and naïve CD8 T cells compared with rhIL-2. When administered to animals with pre-established tumors, MDNA11 controlled tumor growth in a monotherapy setting and in combination with anti-PD1 or anti-CTLA4 to induce durable tumor clearance with a once weekly dosing regimen. In a NHP model, MDNA11 was well tolerated while triggering durable and potent immune responses including expansion of lymphocytes without significant effect on Tregs and eosinophils, the latter been linked to an increased risk of vascular leak syndrome.ConclusionMDNA11 is a next generation long-acting IL-2 immunotherapeutic with a highly favorable pharmacodynamic profile that translates to a strong therapeutic efficacy in preclinical tumor models and a strong and durable immune response in NHP.

The systemic administration of recombinant interleukin-2 (rIL-2) with or without lymphokine-activated killer (LAK) cells, a new treatment for patients with advanced cancer, is associated with a presumed "third-space" syndrome. To further define the extent and time course of this toxicity, we established a chronic sheep model and monitored changes in systemic and central vascular pressures, cardiac function, and gas exchange during a 72-h continuous intravenous infusion of rIL-2 at a total dose of 5 (group 3) or 9 x 10(5) U/kg (group 4). At 72 h, caudal mediastinal lymph flow, histology, and extravascular lung water-to-dry lung weight ratio (EVLW/DLW) were obtained. During the rIL-2 infusion there was a dose-dependent significant decrease in systemic blood pressure and arterial Po2 and an increase in core temperature. In group 4, pulmonary arterial pressure increased from a base line of 13 +/- 5 to 21 +/- 6 mmHg (P less than 0.05). Lung lymph flow was significantly increased in groups 3 and 4 compared with animals receiving 0.9% NaCl or excipient infusions (groups 1 and 2). EVLW/DLW values were elevated in groups 3 and 4 (P less than 0.01). In animals receiving rIL-2, histological evaluation revealed a dose-dependent infiltration of lung tissue by lymphoblastoid cells that stained esterase negative. We conclude that rIL-2 infusion in doses comparable to those given to humans results in alterations in systemic and central hemodynamics, gas exchange, high-protein lung lymph flow, and infiltration of lymphoblastoid cells into the lung parenchyma.

Recombinant interleukin 2 (rIL-2) administration, a new form of therapy for patients with far-advanced cancer, is associated with a "third space" syndrome, i.e., pulmonary edema, respiratory distress, and hypoxemia, which limits the dose and duration of treatment. To extend our knowledge regarding this toxicity, we established a sheep chronic lung lymph fistula model and measured hemodynamics, arterial blood gases, caudal mediastinal (lung) lymph flow (QL), and blood and lung lymph cellular changes before, during, and after (recovery) a 3-day continuous rIL-2 infusion (9 x 10(5) U/kg). Moderate systemic hypotension, mild pulmonary hypertension, and an increase in alveolar-arterial PO2 gradient was present on day 3 of rIL-2 infusion. QL increased from a base line of 1.9 +/- 0.2 to a maximum of 4.3 +/- 1.1 ml/15 min on day 3 of rIL-2 infusion. At no time was there a change in lymph-to-plasma protein ratio. The leukocyte count increased significantly to 16.1 +/- 4.5 x 10(3) cells/mm3 at recovery day 1. The percentage of blood lymphocytes decreased significantly by day 1 of rIL-2 infusion, returned to base-line levels on day 3, and significantly increased on day 2 of recovery. Lung lymph lymphocytes decreased significantly on days 1 and 2 of rIL-2 infusion. There was a shift in their size; i.e., their area increased from 32 +/- 7 to 57 +/- 19 micron 2 (P less than 0.05) by day 2 of rIL-2 infusion. By day 1 of recovery, lung lymph lymphocyte counts increased significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

e14220 Background: Proleukin (a cysteine-modified variant of interleukin (IL)-2) is the only common-γc cytokine approved for the treatment of metastatic melanoma and renal cell carcinoma. Its therapeutic use is however hampered by its short half-life and severe toxicity. At low doses, Proleukin administration leads to preferential activation of regulatory T cells (Tregs) due to their expression of the high affinity trimeric IL-2 receptor (IL-2R) consisting of CD25, CD122 and CD132 instead of cytotoxic CD8 T cells expressing the intermediate affinity IL-2R (CD122 and CD132). Methods: To bypass these limitations, we evaluated engineered variants of IL-2 (MDNA109 superkine) exhibiting enhanced affinity towards CD122 including their long-acting and bispecific superkine fusions. This approach allows preferential activation of CD8 T cells while displaying reduced adverse effects in vivo. Results: Both Biacore analysis and signaling studies on human peripheral blood mononuclear cells confirmed enhanced binding of MDNA109 to CD122 and STAT5 activation, respectively. When tested in vivo, MDNA109 co-administration with the immune-checkpoint blockers anti-programmed cell death (PD)-1 or anti-cytotoxic T-Lymphocyte-Associated Protein (CTLA)4 cured mice with pre-established MC38 or CT26 colon cancers respectively. In addition, bi-weekly administration of the long-acting MDNA109-Fc fusion led to similar therapeutic outcomes in the B16F10 model when compared to MDNA109 administered daily. Finally, in vitro and in-vivo results using (a) MDNA109 muteins with completely impaired CD25 binding activity and (b) novel bispecific superkine fusions consisting of MDNA109 and a dual IL-4/IL-13 super-antagonist capable of selective CD8 T-cell activation while mitigating the suppressive functions of myeloid-derived suppressor cells and tumor-associated macrophages will be presented. Conclusions: Altogether, these data demonstrate that both MDNA109 and MDNA109-Fc are therapeutically superior to Proleukin. Furthermore, use of MDNA109-based strategies will not only ensure complete abrogation of adverse effects, but will in addition eliminate immunosuppression caused by both Tregs and myeloid cells.

employed several non-coding RNAs (ncRNAs) in modulating the tumor microenvironment and oncogenic profile of TNBC. Therefore, the aim of this study is to unravel the impact of ncRNAs and their interplay on immunogenic profile of TNBC at the immune-synapse with CTLs and NKs.Methods: Breast biopsies were collected from 25 BC patients. Several computational prediction analysis was performed. MDA-MB-231 and MCF7 cells were cultured. TNBC cells were transfected with miR-486-5p, miR-17-5p and H19 lncRNA oligonucleotides. Total RNA was extracted and quantified by qRT-PCR.Results: MICA/B were found to be down-regulated in MDA-MB-231 compared to MCF-7 cells. Yet it was not expressed on normal BC tissues. Insilico analysis was performed where miR-486-5p, miR-17-5p and H19 lncRNA were predicted to target MICA/B and CD155. miR-486-5p and miR-17-5p were found to be markedly down-regulated in BC patients, while lncRNA H19 was found to be up-regulated. Ectopic expression of either miR-486-5p or miR-17-5p induced MICA/B expression levels. Moving to CD155 expression, it was found to be paradoxically altered by miR-486-5p and miR-17-5p. This finding grabbed our attention to consider another factor missing in this loop having the upper hand. Knocking down of H19 solved the puzzle where it induced CD155 expression on TNBC cells.Conclusion: This study crystallizes lncRNA H19, miR-486-5p and miR-17-5p as novel immunomodulatory ncRNAs in TNBC patients with promising effects on CTLs and NKs cytotoxic ability to eradicate TNBC.