Amplimmune (United States)

Data sharing not applicable to this article as no datasets were generated or analysed during the current study.

We evaluated the relationship between benralizumab (30 mg every 4 and 8 weeks (Q4W, Q8W)) pharmacokinetic (PK) exposure and end points of asthma exacerbation rates (AERs) and change from baseline in prebronchodilator forced expiratory volume in 1 second (FEV1) for patients with severe, uncontrolled eosinophilic asthma in the SIROCCO/CALIMA phase III trials. In empirical assessment, AER ratios in SIROCCO were similar across PK quartiles. However, the lowest PK quartile in CALIMA had reduced efficacy; low CALIMA placebo AER possibly confounded this result. In population modeling, estimated benralizumab 90% effective concentration for AER reduction was 927 ng/mL, below the Q8W dosage steady‐state average PK concentration (1,066 ng/mL). Benralizumab treatment resulted in more rapid FEV1 improvement vs. placebo (estimated half‐maximum time: 7.6 vs. 18 days); this response was greater for patients with greater baseline eosinophil counts. These results confirmed 30 mg Q8W is the optimal benralizumab dosage for patients with severe eosinophilic asthma.

This work presents the optimization and critical evaluation of continuous capture chromatography in the downstream process of a recombinant enzyme. For the upstream manufacturing of this molecule, a perfusion process was implemented due to benefits for product quality and productivity. This process is, however, characterized by low titer and significant changes over the course of the harvest duration in terms of active enzyme concentration and impurity content. We evaluated the feasibility and benefits of a continuous capture operation. This case study illustrates the design approach that can be utilized to address challenges presented by a changing feedstream, and the statistical measures that can be employed to characterize and optimize the operating space under material and time constraints. Process economic modeling in conjunction with Monte Carlo simulations indicate that even for a nonaffinity capture step utilizing a relatively cheap ion-exchange resin, the smaller column volume used in a continuous set-up results in cost savings compared to the batch process. We compare this option to the scenario of repeated processing using a small capture column in batch mode. Our analysis establishes that continuous processing becomes economically attractive for processes where only a small portion of the potential column lifetime can be utilized or for column steps with slow mass transport and shallow breakthrough curves. In cases where column breakthrough is sharp and resin lifetime is relatively short, continuous processing may offer an improvement over traditional batch processing, but much of the productivity and cost savings can be realized through repeated column cycling. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 2018 © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1195-1204, 2018.

Combination therapies that depend on checkpoint inhibitor antibodies (Abs) such as for PD-1 or its ligand (PD-L1) together with immune stimulatory agonist Abs like anti-OX40 are being tested in the clinic to achieve improved antitumor effects. Here, we studied the potential therapeutic and immune effects of one such combination: Ab to PD-1 with agonist Ab to OX40/vaccine. We tested the antitumor effects of different treatment sequencing of this combination. We report that simultaneous addition of anti-PD-1 to anti-OX40 negated the antitumor effects of OX40 Ab. Antigen-specific CD8+ T-cell infiltration into the tumor was diminished, the resultant antitumor response weakened, and survival reduced. Although we observed an increase in IFNγ-producing E7-specifc CD8+ T cells in the spleens of mice treated with the combination of PD-1 blockade with anti-OX40/vaccine, these cells underwent apoptosis both in the periphery and the tumor. These results indicate that anti-PD-1 added at the initiation of therapy exhibits a detrimental effect on the positive outcome of anti-OX40 agonist Ab. These findings have important implications on the design of combination immunotherapy for cancer, demonstrating the need to test treatment combination and sequencing before moving to the clinic. Cancer Immunol Res; 5(9); 755-66. ©2017 AACR.

Continuous disk-stack centrifugation is typically used for the removal of cells and cellular debris from mammalian cell culture broths at manufacturing-scale. The use of scale-down methods to characterise disk-stack centrifugation performance enables substantial reductions in material requirements and allows a much wider design space to be tested than is currently possible at pilot-scale. The process of scaling down centrifugation has historically been challenging due to the difficulties in mimicking the Energy Dissipation Rates (EDRs) in typical machines. This paper describes an alternative and easy-to-assemble automated capillary-based methodology to generate levels of EDRs consistent with those found in a continuous disk-stack centrifuge. Variations in EDR were achieved through changes in capillary internal diameter and the flow rate of operation through the capillary. The EDRs found to match the levels of shear in the feed zone of a pilot-scale centrifuge using the experimental method developed in this paper (2.4×105 W/Kg) are consistent with those obtained through previously published computational fluid dynamic (CFD) studies (2.0×105 W/Kg). Furthermore, this methodology can be incorporated into existing scale-down methods to model the process performance of continuous disk-stack centrifuges. This was demonstrated through the characterisation of culture hold time, culture temperature and EDRs on centrate quality.

Murine syngeneic tumor models are critical to novel immuno-based therapy development, but the molecular and immunologic features of these models are still not clearly defined. The translational relevance of differences between the models is not fully understood, impeding appropriate preclinical model selection for target validation, and ultimately hindering drug development. Across a panel of commonly used murine syngeneic tumor models, we showed variable responsiveness to immunotherapies. We used array comparative genomic hybridization, whole-exome sequencing, exon microarray analysis, and flow cytometry to extensively characterize these models, which revealed striking differences that may underlie these contrasting response profiles. We identified strong differential gene expression in immune-related pathways and changes in immune cell-specific genes that suggested differences in tumor immune infiltrates between models. Further investigation using flow cytometry showed differences in both the composition and magnitude of the tumor immune infiltrates, identifying models that harbor "inflamed" and "non-inflamed" tumor immune infiltrate phenotypes. We also found that immunosuppressive cell types predominated in syngeneic mouse tumor models that did not respond to immune-checkpoint blockade, whereas cytotoxic effector immune cells were enriched in responsive models. A cytotoxic cell-rich tumor immune infiltrate has been correlated with increased efficacy of immunotherapies in the clinic, and these differences could underlie the varying response profiles to immunotherapy between the syngeneic models. This characterization highlighted the importance of extensive profiling and will enable investigators to select appropriate models to interrogate the activity of immunotherapies as well as combinations with targeted therapies in vivo Cancer Immunol Res; 5(1); 29-41. ©2016 AACR.

B cell-activating factor (BAFF) plays a major role in activation of B cells and in adaptive humoral immune responses. In chronic obstructive pulmonary disease (COPD), lymphoid follicles have been associated with disease severity, and overexpression of BAFF has been demonstrated within lymphoid follicles of patients with severe COPD. To investigate expression and localization of BAFF in the lungs of patients with COPD and to study the role of BAFF in COPD by antagonizing BAFF in a mouse model of chronic cigarette smoke (CS) exposure. We quantified and localized BAFF expression in lungs of never-smokers, smokers without COPD, and patients with COPD and in lungs of air- or CS-exposed mice by reverse-transcriptase polymerase chain reaction, ELISA, immunohistochemistry, and confocal imaging. Next, to investigate the role of BAFF in COPD, we antagonized BAFF by prophylactic or therapeutic administration of a soluble fusion protein of the BAFF-receptor, BAFFR-Fc, in mice exposed to air or CS for 24 weeks and evaluated several hallmarks of COPD and polarization of lung macrophages. BAFF expression was significantly increased in lungs of patients with COPD and CS-exposed mice. BAFF staining in lymphoid follicles was observed around B cells, CD4(+) cells, dendritic cells, follicular dendritic cells, and fibroblastic reticular cells. Prophylactic and therapeutic administration of BAFFR-Fc in mice reduced pulmonary B-cell numbers and prevented CS-induced formation of lymphoid follicles and increases in immunoglobulin levels. Interestingly, prophylactic BAFFR-Fc administration significantly attenuated pulmonary inflammation and destruction of alveolar walls. Moreover, antagonizing BAFF altered the phenotype of alveolar and interstitial macrophages. BAFF is significantly increased in lungs of patients with COPD and is present around both immune and stromal cells within lymphoid follicles. Antagonizing BAFF in CS-exposed mice attenuates pulmonary inflammation and alveolar destruction.

While most vaccine studies have focused on factors that could promote adaptive immunity, little is known about negative factors induced under certain conditions by vaccines that may suppress immune responses. Using a vaccine strategy of peptide priming followed by a modified vaccinia Ankara (MVA) boost in rhesus macaques, we found that an SIV vaccine incorporating molecular adjuvants achieved partial protection against rectal SIVmac251 challenge evidenced by a reduced viral load (VL) compared to naive controls. Unexpectedly, animals treated with adjuvant alone had the greatest VL reduction compared to both the vaccine-treated groups and the naïve controls. The significantly reduced VLs occurred in the Mamu-A*01 subset of the adjuvant-only group and were largely dependent on CD8+ T cells. While investigating this paradoxical observation, we found that the set-point VL was associated with the expansion of myeloid-derived suppressor cells (MDSC), which were able to suppress T cell responses in vitro. The fact that MDSC expansion was not observed in the adjuvant-only group, but only in animals receiving vaccine, suggested that the vaccine itself induced the MDSC expansion. Thus, the induced expansion of MDSCs during vaccination and early SIV infection might affect the induction and function of protective CD8+ T cellular responses, which otherwise might mediate protection against SIV. These data suggest that some of the current SIV/HIV vaccine regimens, aimed to induce a strong cellular response, might inadvertently trigger the induction of MDSCs, which attenuate or abolish the T cell–mediated protection. Therefore, prevention of this MDSC expansion may be critical to achieving vaccine efficacy.

Individual or combinations of somatic mutations found in genes from colorectal cancers can redirect the effects of chemotherapy and targeted agents on cancer cell survival and, consequently, on clinical outcome. Novel therapeutics with mechanisms of action that are independent of mutational status would therefore fulfill a current unmet clinical need. Here the CEA and CD3 bispecific single-chain antibody MEDI-565 (also known as MT111 and AMG 211) was evaluated for its ability to activate T cells both in vitro and in vivo and to kill human tumor cell lines harboring various somatic mutations commonly found in colorectal cancers. MEDI-565 specifically bound to normal and malignant tissues in a CEA-specific manner, and only killed CEA positive cells. The BiTE® antibody construct mediated T cell-directed killing of CEA positive tumor cells within 6 hours, at low effector-to-target ratios which were independent of high concentrations of soluble CEA. The potency of in vitro lysis was dependent on CEA antigen density but independent of the mutational status in cancer cell lines. Importantly, individual or combinations of mutated KRAS and BRAF oncogenes, activating PI3KCA mutations, loss of PTEN expression, and loss-of-function mutations in TP53 did not reduce the activity in vitro. MEDI-565 also prevented growth of human xenograft tumors which harbored various mutations. These findings suggest that MEDI-565 represents a potential treatment option for patients with CEA positive tumors of diverse origin, including those with individual or combinations of somatic mutations that may be less responsive to chemotherapy and other targeted agents.