Development of a high-throughput platform for screening lipid nanoparticles for mRNA delivery

mRNA lipid nanoparticles (LNPs) are at the forefront of nucleic acid intracellular delivery, as exemplified by the recent emergency approval of two mRNA LNP-based COVID-19 vaccines. The success of an LNP product largely depends on the systematic optimisation of the four lipidic components, namely the ionisable lipid, PEG lipid, structural and helper lipids. However, the in vitro screening of novel lipidic components and LNP compositions is limited by the low-throughput of LNP preparation. To address these issues, we herein present an automated high-throughput screening platform to select novel ionisable lipids and corresponding LNPs encapsulating mRNA in vitro. This high-throughput platform employs a lab-based automated liquid handling system, amenable to high-throughput (up to 384 formulations per plate and several plates per run) and allows precise mixing and reproducible mRNA LNP preparation which ensures a direct head-to-head comparison of hundreds and even thousands of novel LNPs. Most importantly, the robotic process has been successfully applied to the screening of novel LNPs encapsulating mRNA and has identified the same novel mRNA LNP leads as those from microfluidics-mixing technology, with a correlation coefficient of 0.8751. This high-throughput platform can facilitate to narrow down the number of novel ionisable lipids to be evaluated in vivo. Moreover, this platform has been integrated into a fully-automated workflow for LNP property control, physicochemical characterisation and biological evaluation. The high-throughput platform may accelerate proprietary lipid development, mRNA LNP lead optimisation and candidate selection to advance preclinical mRNA LNP development to meet urgent global needs.

Abstract 1828: AZD8853: A novel antibody targeting GDF15 for immunotherapy refractory tumors

Immunotherapy has revolutionized patient care, however, the majority of patients with cancer still do not benefit from this treatment modality. This is due to many factors, including a complex tumor microenvironment (TME) that has too few functional effector cells and/or the presence of many inhibitory cells. Understanding how to remodel the TME to potentiate productive immunity against cancer cells is an active area of research. Growth and Differentiation Factor 15 (GDF-15) is a member of the TGF-beta superfamily that is overexpressed by many solid tumors and is implicated in dampening immune responses. The present study was aimed at understanding the role of GDF-15 in tumor immune biology. We show that GDF-15 can inhibit the differentiation and activation of human monocyte-derived dendritic cells (DCs) and prevent T cell activation. Furthermore blockade of GDF-15 by AZD8853, an anti-GDF15 monoclonal antibody, can restore these activities in vitro. Tumors derived from GDF15 knock-out syngeneic cell lines, Renca and MC-38, show 2-3 fold increases in T cells and activated DCs in the TME as compared to tumors derived from isogeneic parental cells. Treatment of mice with anti-GDF15 mAb leads to substantial anti-tumor activity in anti-PD-L1 refractory LL/2 and MBT2 syngeneic tumors with 50% of the animals showing complete tumor regressions. Coupled with this anti-tumor activity, we show that after 2 doses of anti-GDF15 mAb there is an increase in both activated T cells and DCs in the TME. Depletion of T cells, using anti-CD4 and anti-CD8, in mice ablates the anti-tumor activity observed with anti-GDF15 mAb treatment. These results suggest that inhibition of GDF15 by AZD8853 may be an attractive therapeutic strategy for patients with solid tumors that have high expression of GDF15.

Citation Format: Elaine Hurt, Suneetha Thomas, Kathy Mulgrew, Stephen Blackmore, James Moynihan, Fiona Cusdin, Roger Dodd, Peter Cariuk, Anna Sigurdardottir, Emily Brannigan, Claire Dobson, Rakesh Kumar, Mark Cobbold. AZD8853: A novel antibody targeting GDF15 for immunotherapy refractory tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1828.

Campylobacter jejuni cellulitis in a patient with pan-hypogammaglobulinaemia

The case of a 17-year-old male with recurrent episodes of cellulitis affecting his left shin is presented. The cellulitis had been present on an intermittent basis over an 18-month period despite several courses of both intravenous and oral antibiotics. Each course of antibiotics resulted in a temporary remission, but on four occasions the cellulitis then relapsed. The patient was known to have pan-hypogammaglobulinaemia and was receiving intravenous IgG replacement therapy every 3 weeks. Other than cellulitis, he remained generally well. The organism responsible for the cellulitis was unknown until Campylobacter jejuni was grown in blood cultures during one of the relapse episodes. Based on microbial sensitivity, the patient was treated with ciprofloxacin. This resulted in full resolution of the cellulitis and he remains well. This case illustrates the value of blood cultures in helping microbial identification, particularly in immunocompromised patients with atypical infections.

Impact of the use of aminoglycosides in combination antibiotic therapy on septic shock and mortality due to Staphylococcus aureus bacteremia

BACKGROUND

The purpose of this study was to evaluate the possible impact of antimicrobial combination regimens containing an aminoglycoside (AG) on morbidity and mortality associated with S. aureus bacteremia.

METHODS

All inpatients over 18 years of age with S. aureus bacteremia were prospectively enrolled in three tertiary care hospitals in France and Ireland. Patients were included in the group "treated with AG" if they received at least 24 h of aminoglycoside therapy within 7 days after a positive blood culture in combination with an effective antimicrobial against the S. aureus. A Cox's proportional hazard model was used in univariate and multivariate survival analysis, the covariate "treatment with AG" being introduced as a time-dependent covariate.

RESULTS

Nine percent of the 90 patients who received AG died because of infection versus 13% in the group that did not receive a combination including an AG (p>0.05). In the multivariate Cox model, stratified by septic shock and controlling for age and Charlson-weighted index of comorbidity, the adjusted odds ratio for death due to S. aureus infection associated with the use of AG was 0.6 [95% CI: (0.2-1.9); p=0.4]. However, AG was found to have a protective effect on septic shock occurrence [OR=0.3; 95% CI: (0.1-0.7), p=0.004], controlling for age, portal of entry not related to catheter infection, and diabetes.

CONCLUSION

Although there was no decrease in mortality due to S. aureus infection in patients treated with AG therapy, we found a significant benefit of AG in preventing septic shock. This data argues for the early use of AG in patients with S. aureus bacteremia.

Quality of Life in Patients Treated with First-Line Antiretroviral Therapy Containing Nevirapine And/Or Efavirenz

Objective

To assess whether differences in safety profiles between nevirapine (NVP) and efavirenz (EFV), as observed in the 2NN study, translated into differences in ‘health related quality of life’ (HRQoL).

Design

A sub-study of the 2NN study, with antiretro-viral-naive patients randomly allocated to NVP (once or twice daily), EFV or NVP+EFV, in addition to stavudine and lamivudine.

Methods

Comparing differences in changes of HRQoL over 48 weeks as measured with the Medical Outcomes Study HIV Health Survey (MOS-HIV) questionnaire, using analysis of variance.

Results

The 2NN study enrolled 1216 patients. No validated questionnaires were available for 244 patients, and 55 patients had no HRQoL data at all, leaving 917 patients eligible for this sub-study. A total of 471 (51%) had HRQoL measurements both at baseline and week 48. The majority (69%) of patients without HRQoL measurements did, however, complete the study. The change in the physical health score (PHS) was 3.9 for NVP, 3.4 for EFV and 2.4 for NVP+EFV ( P=0.712). For the mental health score (MHS) these values were 6.1, 7.0 and 3.9, respectively ( P=0.098). A baseline plasma HIV-1 RNA concentration (pVL) ≥100 000 copies/ml and a decline in pVL (per log10) were independently associated with an increase of PHS. An increase of MHS was only associated with pVL decline. Patients experiencing an adverse event during follow-up had a comparable change in PHS but a significantly smaller change in MHS, compared with those without an adverse event.

Conclusions

First-line ART containing NVP and/or EFV leads to an improvement in HRQoL. The gain in HRQoL was similar for NVP and EFV, but slightly lower for the combination of these drugs.

Positive surveillance blood culture is a predictive factor for secondary metastatic infection in patients with Staphylococcus aureus bacteraemia

PURPOSE

Staphylococcus aureus bacteraemia (SAB) may be complicated by secondary metastatic infection such as endocarditis, osteomyelitis or septic arthritis. This cohort study aimed to assess the prognostic value of sustained bacteraemia for outcomes related to Staphylococcus aureus bacteraemia.

SUBJECTS AND METHODS

The study took place in three tertiary-care, university-affiliated hospitals. Patients were prospectively included if they agreed to participate and if the following data were available: (a). surveillance blood culture taken between 24 and 48 h after commencement of effective antibiotic therapy; (b). appropriate investigations (at least a TTE) performed as suggested by the infectious diseases consult service. Patients with sustained bacteraemia defined as persistent positive blood cultures more than 24 h after commencement of effective antibiotic therapy were compared to patients for whom the surveillance blood culture was negative.

RESULTS

One hundred and four patients were enrolled, including 51 patients diagnosed with sustained bacteraemia. Sustained bacteraemia was significantly associated with a higher frequency of secondary metastatic infection (p<0.001) and with a higher frequency of CRP>100 mg/l. Frequency of acute complications due to infection, septic shock and death due to bacteraemia was higher for patients with sustained bacteraemia but this difference was not statistically significant. Using a Cox model, the risk for death associated with sustained SAB, controlling for Index of comorbidity and age (categorised as<or>or=70 years), was 1.2 (95% CI: (0.5, 3); p>0.05).

CONCLUSION

In conclusion, surveillance blood cultures, especially performed on effective antibiotic therapy, may be a simple and cost-effective way to select a population at risk for secondary metastatic infection from SAB.