Oncolytic reovirus can be delivered both systemically and intratumorally, in both preclinical models and in early phase clinical trials. Reovirus has direct oncolytic activity against a variety of tumor types and antitumor activity is directly associated with immune activation by virus replication in tumors. Immune mechanisms of therapy include both innate immune activation against virally infected tumor cells, and the generation of adaptive antitumor immune responses as a result of in vivo priming against tumor-associated antigens. We tested the combination of local oncolytic reovirus therapy with systemic immune checkpoint inhibition. We show that treatment of subcutaneous B16 melanomas with a combination of intravenous (i.v.) anti-PD-1 antibody and intratumoral (i.t.) reovirus significantly enhanced survival of mice compared to i.t. reovirus (P < 0.01) or anti-PD-1 therapy alone. In vitro immune analysis demonstrated that checkpoint inhibition improved the ability of NK cells to kill reovirus-infected tumor cells, reduced T(reg) activity, and increased the adaptive CD8(+) T-cell-dependent antitumor T-cell response. PD-1 blockade also enhanced the antiviral immune response but through effector mechanisms which overlapped with but also differed from those affecting the antitumor response. Therefore, combination with checkpoint inhibition represents a readily translatable next step in the clinical development of reovirus viroimmunotherapy.

Cancer Research UK, Janssen-Cilag, and Chugai Pharma UK.

No abstract

Regulatory T-cells (TReg cells) are increased in patients with multiple myeloma (MM). We investigated whether MM cells could generate and/or expand TReg cells as a method of immuno-surveillance avoidance. In an in vitro model, CD4+CD25- FoxP3 - T-cells co-cultured with malignant plasma cells (primary MM cells and cell lines) induced a significant generation of CD4+CD25+ FoxP3 + inducible TReg cells (tTReg cells; p<0.0001), in a contact-dependent manner. tTReg cells were polyclonal, demonstrated a suppressive phenotype and phenotypically, demonstrated increased FoxP3 (p = 0.0001), increased GITR (p<0.0001), increased PD1 (p = 0.003) and decreased CD62L (p = 0.007) expression compared with naturally occurring TReg cells. FACS-sorted tTReg cells differentiated into FoxP +IL-17+ and FoxP3 -IL-17+ CD4+ cells upon TCR-mediated stimulation. Blocking experiments with anti-ICOS-L MoAb resulted in a significant inhibition of tTReg cell generation whereas both IL-10 & TGFβ blockade did not. MM tumour cells can directly generate functional TReg cells in a contact-dependent manner, mediated by ICOS/ICOS-L. These features suggest that tumour generation of TReg cells may contribute to evasion of immune surveillance by the host.

The naturally occurring oncolytic virus (OV), reovirus, replicates in cancer cells causing direct cytotoxicity, and can activate innate and adaptive immune responses to facilitate tumour clearance. Reovirus is safe, well tolerated and currently in clinical testing for the treatment of multiple myeloma, in combination with dexamethasone/carfilzomib. Activation of natural killer (NK) cells has been observed after systemic delivery of reovirus to cancer patients; however, the ability of OV to potentiate NK cell-mediated antibody-dependent cellular cytotoxicity (ADCC) is unexplored. This study elucidates the potential of oncolytic reovirus for the treatment of chronic lymphocytic leukaemia (CLL), both as a direct cytotoxic agent and as an immunomodulator. We demonstrate that reovirus: (i) is directly cytotoxic against CLL, which requires replication-competent virus; (ii) phenotypically and functionally activates patient NK cells via a monocyte-derived interferon-α (IFNα)-dependent mechanism; and (iii) enhances ADCC-mediated killing of CLL in combination with anti-CD20 antibodies. Our data provide strong preclinical evidence to support the use of reovirus in combination with anti-CD20 immunotherapy for the treatment of CLL.

PURPOSESalvage autologous stem-cell transplantation (sASCT) in patients with multiple myeloma (MM) relapsing after a prior autologous stem-cell transplantation leads to increased remission duration and overall survival. We report a comprehensive study on patient-reported outcomes, including quality of life (QoL) and pain in sASCT.METHODSPatients were randomly assigned to either sASCT or nontransplantation consolidation (NTC). Pain and QoL were assessed as secondary outcomes using validated QoL instruments (European Organisation for Research and Treatment of Cancer QLQ-C30 and myeloma-specific module, QLQ-MY20; the Brief Pain Inventory [Short Form]; and the Leeds Assessment of Neuropathic Symptoms and Signs [Self-Assessment] scale).RESULTSA total of 288 patients (> 96%) consented to the QoL substudy. The median follow-up was 52 months. The European Organisation for Research and Treatment of Cancer QLQ-C30 Global health status scores were higher (better) in the NTC group at 100 days after random assignment (P = .0496), but not at later time points. Pain interference was higher (worse) in the sASCT group than in the NTC group at 6 months after random assignment (P = .0267), with patients with sASCT reporting higher scores for Pain interference with daily living for up to 2 years after random assignment. Patients reporting lower concerns about adverse effects of treatment after sASCT had a time to progression advantage.CONCLUSIONPatients with sASCT with relapsed MM demonstrated a comparative reduction in QoL and greater impact of treatment adverse effects lasting for 6 months and up to 2 years for pain, after which patients who had received sASCT reported better outcomes. Patients who experienced lower adverse effects after sASCT had longer time to progression and overall survival, showing the need to improve symptom management peritransplantation. To our knowledge, this study provides the most comprehensive picture of QoL before and after sASCT in patients with relapsed MM.

Background The oncolytic virus, coxsackievirus A21 (CVA21), has shown promise as a single agent in several clinical trials and is now being tested in combination with immune checkpoint blockade. Combination therapies offer the best chance of disease control; however, the design of successful combination strategies requires a deeper understanding of the mechanisms underpinning CVA21 efficacy, in particular, the role of CVA21 anti-tumor immunity. Therefore, this study aimed to examine the ability of CVA21 to induce human anti-tumor immunity, and identify the cellular mechanism responsible. Methods This study utilized peripheral blood mononuclear cells from i) healthy donors, ii) Acute Myeloid Leukemia (AML) patients, and iii) patients taking part in the STORM clinical trial, who received intravenous CVA21; patients receiving intravenous CVA21 were consented separately in accordance with local institutional ethics review and approval. Collectively, these blood samples were used to characterize the development of innate and adaptive anti-tumor immune responses following CVA21 treatment. Results An Initial characterization of peripheral blood mononuclear cells, collected from cancer patients following intravenous infusion of CVA21, confirmed that CVA21 activated immune effector cells in patients. Next, using hematological disease models which were sensitive (Multiple Myeloma; MM) or resistant (AML) to CVA21-direct oncolysis, we demonstrated that CVA21 stimulated potent anti-tumor immune responses, including: 1) cytokine-mediated bystander killing; 2) enhanced natural killer cell-mediated cellular cytotoxicity; and 3) priming of tumor-specific cytotoxic T lymphocytes, with specificity towards known tumor-associated antigens. Importantly, immune-mediated killing of both MM and AML, despite AML cells being resistant to CVA21-direct oncolysis, was observed. Upon further examination of the cellular mechanisms responsible for CVA21-induced anti-tumor immunity we have identified the importance of type I IFN for NK cell activation, and demonstrated that both ICAM-1 and plasmacytoid dendritic cells were key mediators of this response. Conclusion This work supports the development of CVA21 as an immunotherapeutic agent for the treatment of both AML and MM. Additionally, the data presented provides an important insight into the mechanisms of CVA21-mediated immunotherapy to aid the development of clinical biomarkers to predict response and rationalize future drug combinations. Electronic supplementary material The online version of this article (10.1186/s40425-019-0632-y) contains supplementary material, which is available to authorized users.

Opiate reinforcement was evaluated under a progressive ratio (PR) schedule often used for psychostimulant self-administration (termed 'PR 3-4' because the third response requirement was four lever presses) and three additional schedules that were modified to provide successively lower levels of difficulty by decreasing the steepness of response requirement progression (termed 'PR 9-4', 'PR 14-4', and 'PR 26-4' because a response requirement of four was reached with step numbers of 9, 14 and 26, respectively). With the exception of the PR 3-4 schedule, all of the schedules supported morphine self-administration, and morphine self-administration during initial exposure and reacquisition did not differ by more than 10%. In contrast to morphine, cocaine was self-administered under the PR 3-4 schedule, with responding clearly exceeding levels during extinction. The PR 9-4 schedule was most suitable for morphine self-administration because it provided an intermediate level of difficulty, which supported levels of self-administration that exceeded values obtained under extinction but were less than those observed under FR-1. Under the PR 9-4 schedule, the number of self-administered injections of morphine was 61.5% of the number of injections obtained under a simple FR-1 schedule. This compares with a value of 21.0% for cocaine self-administration under the PR 3-4 schedule compared to an FR-1 schedule. These results show important differences in self-administration behavior supported by morphine and cocaine, which are consistent with a lower reinforcing efficacy for opiates relative to psychostimulants.