Preclinical Characterization of AZD9574, a Blood-Brain Barrier Penetrant Inhibitor of PARP1

PURPOSE

We evaluated the properties and activity of AZD9574, a blood-brain barrier (BBB) penetrant selective inhibitor of PARP1, and assessed its efficacy and safety alone and in combination with temozolomide (TMZ) in preclinical models.

EXPERIMENTAL DESIGN

AZD9574 was interrogated in vitro for selectivity, PARylation inhibition, PARP-DNA trapping, the ability to cross the BBB, and the potential to inhibit cancer cell proliferation. In vivo efficacy was determined using subcutaneous as well as intracranial mouse xenograft models. Mouse, rat, and monkey were used to assess AZD9574 BBB penetration and rat models were used to evaluate potential hematotoxicity for AZD9574 monotherapy and the TMZ combination.

RESULTS

AZD9574 demonstrated PARP1-selectivity in fluorescence anisotropy, PARylation, and PARP-DNA trapping assays and in vivo experiments demonstrated BBB penetration. AZD9574 showed potent single agent efficacy in preclinical models with homologous recombination repair deficiency in vitro and in vivo. In an O6-methylguanine-DNA methyltransferase (MGMT)-methylated orthotopic glioma model, AZD9574 in combination with TMZ was superior in extending the survival of tumor-bearing mice compared with TMZ alone.

CONCLUSIONS

The combination of three key features-PARP1 selectivity, PARP1 trapping profile, and high central nervous system penetration in a single molecule-supports the development of AZD9574 as the best-in-class PARP inhibitor for the treatment of primary and secondary brain tumors. As documented by in vitro and in vivo studies, AZD9574 shows robust anticancer efficacy as a single agent as well as in combination with TMZ. AZD9574 is currently in a phase I trial (NCT05417594). See related commentary by Lynce and Lin, p. 1217.

Experiences of Successful PrEP Uptake Among Adolescent Sexual Minority Men in the United States: A Qualitative Exploration

Male adolescent sexual minorities are at elevated risk of HIV acquisition yet demonstrate low rates of PrEP uptake. Understanding the experiences of adolescents who have successfully accessed PrEP may inform ways to best support adolescents seeking PrEP. Adolescent sexual minorities (N = 100) who reported utilizing PrEP responded to open-ended items asking about their initial PrEP experiences and advice for others. Qualitative analysis suggested that adolescents' ability to access PrEP is influenced by managing parental involvement and seeking culturally competent health care providers. Additionally, they reported how the benefits and drawbacks of taking PrEP played a role in their PrEP use. Findings suggest that educational PrEP interventions targeted at this population could improve uptake by incorporating discussions on side effects and mental health benefits associated with PrEP use. Structural interventions are warranted that improve adolescents' ability to seek sexual health care independently and make room for parental involvement when adolescents could benefit from their support.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

New Zealanders with low back pain seeking health care: a retrospective descriptive analysis of Accident Compensation Corporation-funded low back pain healthcare service usage

Introduction Most New Zealanders experience low back pain (LBP) at least once throughout their lifetime and many seek help from the large range of health providers in primary care. Accident Compensation Corporation (ACC) funds a significant proportion of those claims, but which services are they funding and what are the costs? Method This was a retrospective audit and descriptive analysis of ACC-funded, non-public hospital healthcare service use by people with LBP in New Zealand (NZ). Outcome measures were the healthcare services accessed by people with ACC-funded LBP,the claims (all occurrences for a service that has generated a payment/year), single contact (with a service), and costs (NZ$) for services between 2009 and 2020. Results The number of claims for services were 129 000 for physiotherapy, 105 000 for general practitioner and 59 000 for radiology services. Per single contact, elective surgery and radiology services were the most expensive. During 2009-2020, there were 3.3 million ACC claims for LBP with a total cost of NZ$4 billion. Over this time, there was an increase in claims, costs and single contacts. Costs decreased slightly during 2010 due to changes in healthcare funding and in 2020 due to the COVID-19 pandemic. Discussion Consumers have considerable choice in where they access health care for ACC-funded LBP services. This study shows the services they use most frequently and the cost to NZ for those services. These data can inform service planning for ACC-funded LBP health care in NZ.

Drug Permeability - Best Practices for Biopharmaceutics Classification System (BCS)-Based Biowaivers: A workshop Summary Report

The workshop "Drug Permeability - Best Practices for Biopharmaceutics Classification System (BCS) Based Biowaivers" was held virtually on December 6, 2021, organized by the University of Maryland Center of Excellence in Regulatory Science and Innovation (M-CERSI), and the Food and Drug Administration (FDA). The workshop focused on the industrial, academic, and regulatory experiences in generating and evaluating permeability data, with the aim to further facilitate implementation of the BCS and efficient development of high-quality drug products globally. As the first international permeability workshop since the BCS based biowaivers was finalized as the ICH M9 guideline, the workshop included lectures, panel discussions, and breakout sessions. Lecture and panel discussion topics covered case studies at IND, NDA, and ANDA stages, typical deficiencies relating to permeability assessment supporting BCS biowaiver, types of evidence that are available to demonstrate high permeability, method suitability of a permeability assay, impact of excipients, importance of global acceptance of permeability methods, opportunities to expand the use of biowaivers (e.g. non-Caco-2 cell lines, totality-of-evidence approach to demonstrate high permeability) and future of permeability testing. Breakout sessions focused on 1) in vitro and in silico intestinal permeability methods; 2) potential excipient effects on permeability and; 3) use of label and literature data to designate permeability class.

Nucleolar Architecture Is Modulated by a Small Molecule, the Inositol Pyrophosphate 5-InsP7

Inositol pyrophosphates (PP-InsPs); are a functionally diverse family of eukaryotic molecules that deploy a highly-specialized array of phosphate groups as a combinatorial cell-signaling code. One reductive strategy to derive a molecular-level understanding of the many actions of PP-InsPs is to individually characterize the proteins that bind them. Here, we describe an alternate approach that seeks a single, collective rationalization for PP-InsP binding to an entire group of proteins, i.e., the multiple nucleolar proteins previously reported to bind 5-InsP₇ (5-diphospho-inositol-1,2,3,4,6-pentakisphosphate). Quantitative confocal imaging of the outer nucleolar granular region revealed its expansion when cellular 5-InsP₇ levels were elevated by either (a) reducing the 5-InsP₇ metabolism by a CRISPR-based knockout (KO) of either NUDT3 or PPIP5Ks; or (b), the heterologous expression of wild-type inositol hexakisphosphate kinase, i.e., IP6K2; separate expression of a kinase-dead IP6K2 mutant did not affect granular volume. Conversely, the nucleolar granular region in PPIP5K KO cells shrank back to the wild-type volume upon attenuating 5-InsP₇ synthesis using either a pan-IP6K inhibitor or the siRNA-induced knockdown of IP6K1+IP6K2. Significantly, the inner fibrillar volume of the nucleolus was unaffected by 5-InsP₇. We posit that 5-InsP₇ acts as an 'electrostatic glue' that binds together positively charged surfaces on separate proteins, overcoming mutual protein-protein electrostatic repulsion the latter phenomenon is a known requirement for the assembly of a non-membranous biomolecular condensate.

DDDR-01. AZD9574 IS A NOVEL, BRAIN PENETRANT PARP-1 SELECTIVE INHIBITOR WITH ACTIVITY IN AN INTRACRANIAL XENOGRAFT MODEL OF TRIPLE NEGATIVE BREAST CARCINOMA WITH HOMOLOGOUS RECOMBINATION REPAIR DEFICIENCY

The Poly (ADP-ribose) polymerase (PARP) family has numerous essential functions in cellular processes such as transcription, chromatin remodelling, DNA damage response and repair as well as apoptosis. PARP inhibition blocks base excision repair and results in conversion of SSBs to DNA double-strand break (DSBs), the most deleterious form of DNA damage. DSBs can be repaired by homologous recombination repair (HRR) or non-homologous end joining (NHEJ). The physiological importance of HRR is underscored by the observation of genomic instability in HRR-deficient (HRD+) cells and, importantly, the association of cancer predisposition and developmental defects with mutations in HRR genes. PARP1 and PARP2 are required for SSB repair, while PARP1 is also involved in the repair of DNA double-strand breaks (DSBs) and replication fork damage. AZD9574 is a novel brain penetrant PARP1 inhibitor that acts by selectively inhibiting and trapping PARP1 at the sites of SSBs. While AZD9574 inhibited PARP1 enzymatic activity in all tested cell lines irrespective of the HRR status (IC50 range between 0.3 – 2 nM), colony formation assay in isogenic cell lines pairs confirmed higher potency and selectivity towards HRD+ models. In vivo, AZD9574 demonstrated dose-dependent efficacy in a BRCA1 mutant MDA-MB-436 subcutaneous xenograft model. Anti-tumour effects of AZD9574 were manifested by significant growth regressions that were durable after treatment withdrawal. An intracranial xenograft model of breast cancer brain metastases was developed to assess the efficacy of AZD9574 in the context of blood-brain barrier penetrance. Treatment of animals with established intracranial lesions showed sustained tumour growth suppression resulting in a significantly extended survival of tumour-bearing mice. Collectively, we believe that our data support the development of AZD9574 as a potential therapy for patients with HRD+ breast cancer whose disease has spread to the brain.This abstract was previously presented at AACR 2022 (Hamerlik et al, AACR 2022, Abs #3880)

First Leptophobic Dark Matter Search from the Coherent-CAPTAIN-Mills Liquid Argon Detector

We report the first results of a search for leptophobic dark matter (DM) from the Coherent-CAPTAIN-Mills (CCM) liquid argon (LAr) detector. An engineering run with 120 photomultiplier tubes (PMTs) and 17.9×10^{20} protons on target (POT) was performed in fall 2019 to study the characteristics of the CCM detector. The operation of this 10-ton detector was strictly light based with a threshold of 50 keV and used coherent elastic scattering off argon nuclei to detect DM. Despite only 1.5 months of accumulated luminosity, contaminated LAr, and nonoptimized shielding, CCM's first engineering run has already achieved sensitivity to previously unexplored parameter space of light dark matter models with a baryonic vector portal. With an expected background of 115 005 events, we observe 115 005+16.5 events which is compatible with background expectations. For a benchmark mediator-to-DM mass ratio of m_{V_{B}}/m_{χ}=2.1, DM masses within the range 9  MeV≲m_{χ}≲50  MeV are excluded at 90% C. L. in the leptophobic model after applying the Feldman-Cousins test statistic. CCM's upgraded run with 200 PMTs, filtered LAr, improved shielding, and 10 times more POT will be able to exclude the remaining thermal relic density parameter space of this model, as well as probe new parameter space of other leptophobic DM models.

Abstract 2609: AZD9574 is a novel, brain penetrant PARP-1 selective inhibitor with activity in an orthotopic, intracranial xenograft model with aberrant DNA repair

The Poly (ADP-ribose) polymerase (PARP) family has numerous essential functions in cellular processes such as transcription, chromatin remodelling, DNA damage response and repair as well as apoptosis. PARP inhibition blocks base excision repair and results in conversion of SSBs to DNA double-strand break (DSBs). DSBs are the most deleterious form of DNA damage that can be generated by exogenous DNA damaging agents or endogenous replication stress. DSBs can be repaired by homologous recombination repair (HRR) or non-homologous end joining (NHEJ). The physiological importance of HRR is underscored by the observation of genomic instability in HRR-deficient (HRD+) cells and, importantly, the association of cancer predisposition and developmental defects with mutations in HRR genes. PARP1 and PARP2 are required for SSB repair, while PARP1 is also involved in the repair of DNA double-strand breaks (DSBs) and replication fork damage. Recent reports suggest the PARP1 inhibition is sufficient to elicit an anti-proliferative effect and that PARP2 is essential for the survival of hematopoietic stem and progenitor cells in animal models.AZD9574 is a novel brain penetrant PARP1 inhibitor that acts by selectively inhibiting and trapping PARP1 at the sites of SSBs. AZD9574 exhibited &gt;8000-fold selectivity for PARP1 compared to PARP2 and other members of the PARP family (PARP2, PARP3, PARP5a and PARP6) in biochemical assays. While AZD9574 inhibited PARP1 enzymatic activity in all tested cell lines irrespective of the HRR status (IC50 range between 0.3 - 2 nM), colony formation assay in isogenic cell lines pairs confirmed higher potency and selectivity towards HRD+ models (DLD1 BRCA2-/-; SKOV-3 BRCA2-/- and SKOV-3 PALB2-/-). For example, AZD9574 IC50 in the BRCA2-/- DLD1 cells was 1.38 nM compared to IC50 &gt; 40 µM BRCA2wt cells, which corresponds to a ~20,000-fold greater efficacy in the BRCA2-/-cells (ratio of AZD9574 IC50 in BRCA2wt divided by BRCA2-/-) compared to the wild type parental line. In vivo, AZD9574 demonstrated dose-dependent efficacy in a BRCA1 mutant MDA-MB-436 subcutaneous xenograft model. Anti-tumour effects of AZD9574 were manifested by pronounced growth regressions that were durable after treatment withdrawal. An intracranial xenograft model of breast cancer brain metastases was developed to assess the efficacy of AZD9574 in the context of blood-brain barrier penetrance. Treatment of animals with established intracranial lesions using a dose of 3 mg/kg AZD9574 showed sustained tumour growth suppression resulting in a significantly extended survival of tumour-bearing mice. Collectively, we believe that our data support the development of AZD9574 as a potential therapy for patients with HRD+ breast cancer whose disease has spread to the brain.

Citation Format: Kunzah Jamal, Anna Staniszewska, Jacob Gordon, Shenghua Wen, Frank McGrath, Gregory Dowdell, Dominic Kabbabe, Giuditta illuzzi, Matthew Griffin, Barry R. Davies, Petra Hamerlik. AZD9574 is a novel, brain penetrant PARP-1 selective inhibitor with activity in an orthotopic, intracranial xenograft model with aberrant DNA repair [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2609.

Abstract 6303: Activity and tolerability of combination of venetoclax with the Aurora kinase B Inhibitor AZD2811 in preclinical diffuse large B-cell lymphoma models

Diffuse large B-cell lymphoma (DLBCL) is an aggressive type of non-Hodgkin lymphoma (NHL) and the most common form of adult lymphoma. Despite efforts to develop new therapies, the standard of care for DLBCL remains chemotherapy based. The current standard of care is comprised of a regimen of 4 drugs (cyclophosphamide, doxorubicin, vincristine, and prednisone) combined with immunotherapy using a chimeric mAb against the protein CD20 (rituximab), R-CHOP. Unfortunately only 50 to 60% of patients with DLBCL achieve and maintain complete remission after first-line therapy and 40 to 50 % relapse or have refractory disease. In addition, the average age at the time of diagnosis for DLBCL is 64 which makes intensive chemotherapy challenging. Therefore, the development of new treatment options is critical. We explored preclinical activity of AZD2811 nanoparticle, a potent and selective inhibitor of Aurora B kinase combined with venetoclax, an inhibitor of BCL2 currently used as standard of care in treatment of Haematological cancers, in B-Cell non-Hodgkin lymphoma models. Twenty five B-cell NHL cell lines including 11 Diffuse Large B-cell Lymphoma (DLBCL) cell lines were exposed to a 7 x 7 matrix of AZD2811 and venetoclax for 72 hrs. Cell viability was assessed using Celltiter-glo. Strong combination activity (HSA &gt; 0.1 and combination Emax &gt; 0.5) was observed in 6 cell lines including 2 DLBCL cell lines (WSU-DLCL2 and KARPAS_422). Moreover, pre-treatment with pan caspase inhibitor Q-VD-OPH, increased cell viability in cells treated with the combination. Next we explored the significant gene expression and mutation biomarkers (effect size &gt; 1, p &lt; 0.05) for this combination associated with Bliss and combination Emax in B-cell NHL cell lines. We found downregulation of 4 genes (FLT4, TIE1, PRKN) and mutations in 2 genes (EP300 and PTEN) to be associated with Bliss score and upregulation of one gene (FGR) associated with combination Emax. In vivo, antitumor activity of AZD2811 combined with venetoclax was assessed in mice bearing WSU-DLCL2luc xenografts. Once weekly intravenous administration of 25 mg/kg AZD2811 resulted in a statistically significant tumor growth inhibition (TGI) of 74%, while daily oral gavage of 100 mg/kg venetoclax resulted in 49% TGI but failed to reach statistical significance. While both monotherapies were unable to prevent progressive tumor growth, a combination dosing regimen of AZD2811 and venetoclax drove progressive tumor regression resulting in statistically significant complete regression (98% regression) by the third week of dosing. These results suggest combining AZD2811 with venetoclax has potential to be active in DLBCL patients.

Citation Format: Azadeh Cheraghchi-Bashi, Brandon Willis, Kevin. Mongeon, Jacob Gordon, Krishna Bulusu, Elizabeth Coker, Patricia Jaaks, Mathew Garnett, Jerome Mettetal. Activity and tolerability of combination of venetoclax with the Aurora kinase B Inhibitor AZD2811 in preclinical diffuse large B-cell lymphoma models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6303.

The effects of dietary nitrate supplementation on endurance exercise performance and cardiorespiratory measures in healthy adults: a systematic review and meta-analysis

BACKGROUND

Nitrate supplementation is thought to improve performance in endurance sports.

OBJECTIVE

To meta-analyze studies evaluating the effect of nitrate supplementation on endurance sports performance among adults.

DATA SOURCES

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Web of Science and CINAHL without language restrictions.

METHODS

We included studies that: 1) compared nitrate supplementation with placebo; 2) enrolled adults engaging in an endurance-based activity; and 3) reported a performance measure or surrogate physiologic outcome. We evaluated risk of bias using the Cochrane Collaboration tool and pooled data with a random-effects model. We used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to evaluate confidence in estimates.

RESULTS

We included 73 studies (n = 1061). Nitrate supplementation improved power output (MD 4.6 watts, P < 0.0001), time to exhaustion (MD 25.3 s, P < 0.00001), and distance travelled (MD 163.7 m, P = 0.03). We found no significant difference on perceived exertion, time trial performance and work done. Nitrate supplementation decreased VO₂ (MD - 0.04 L/min, P < 0.00001) but had no significant effect on VO_2max or blood lactate levels.

CONCLUSION

The available evidence suggests that dietary nitrate supplementation benefits performance-related outcomes for endurance sports.

Abstract 2957: A novel circulating tumor DNA (ctDNA) assay enables monitoring of disease progression and treatment response in disseminated preclinical hematologic cancer models

We have established a novel assay to assess circulating tumor DNA (ctDNA) in mice engrafted with disseminated cell line and patient-derived xenografts (PDX) of hematologic malignancies. Disseminated models recapitulate many features of human disease, but engraftment in multiple tissues makes monitoring of disease and treatment response difficult. Existing assays also lack the sensitivity required to assess minimal residual disease (MRD). This novel ddPCR assay targets highly conserved human-specific regions of LINE-1 and HERV-K repeat elements resulting in exceptionally sensitive detection of shed human ctDNA. Initial data shows sensitivity of 0.8 haploid genome equivalents (one haploid genome is ~3.3pg of human DNA), whereas ctDNA monitoring assays currently on the market require 1,000 times more input DNA to reach a sensitivity of just 2-9 genome equivalents. Serial dilution experiments confirm this assay is suitable to detect increases in ctDNA over several orders of magnitude, while also establishing a minimum plasma input of 40uL. To validate the assay we assessed the ability of ctDNA to detect disease alongside traditional histology, bioluminescence imaging, and flow cytometry assays in 10 leukemia and lymphoma models. Levels of ctDNA correlated well with disease progression across models engrafting in bone marrow, spleen, liver, blood and other tissues. In all cases where early stage disease was analyzed, the ctDNA assay was able to detect disease earlier relative to other methods due to its increased sensitivity, and these data can be effectively used for randomization into treatment groups. We also assessed the utility of ctDNA for determining drug treatment response in mice engrafted with a disseminated mantle cell lymphoma PDX. Baseline ctDNA assessment was completed on day 11 post-engraftment confirming ctDNA levels above baseline, at which point mice were divided into 7 treatment groups: Vehicle, Acalabrutinib, and 5 combination arms of Acalabrutinib plus clinically used agents. After 4 weeks of treatment disease burden was assessed by flow cytometry of the bone marrow (femur) compared to ctDNA detected in plasma. Efficacy readouts from both assays agreed for all groups, while the ctDNA assay was able to identify a significant difference between the two best responding arms which appeared to have near complete responses when assessed by flow cytometry alone. The fold difference between the two best responding arms was 1.1 fold by flow cytometry and 3.6 fold by ctDNA, illuminating a greater disparity in MRD and relapse potential between these 2 groups. This novel ctDNA assay allows for robust experimental designs to answer questions about the depth and durability of treatment responses, as well as to identify early stage disease. Work is ongoing to explore extended monitoring for relapse and application to solid tumor models.

Citation Format: Amanda L. Christie, Paul Labrousse, Courtney L. Andersen, Justine E. Roderick, Jacob Gordon, Deborah Lawson, Denise Hughes, Kimberly Maratea, Daniel Stetson, Brandon Willis, Andrew Bloecher, Corinne Reimer, Brian Dougherty. A novel circulating tumor DNA (ctDNA) assay enables monitoring of disease progression and treatment response in disseminated preclinical hematologic cancer models [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 2957.

OP0171 PHASE 3 TRIAL OF LENABASUM, A CB2 AGONIST, FOR THE TREATMENT OF DIFFUSE CUTANEOUS SYSTEMIC SCLEROSIS (DCSSC)

Background:

Lenabasum is an oral CB2 agonist that attenuates inflammation and fibrosis in SSc animal models and showed clinical benefit with acceptable safety in a Phase 2 trial in dcSSc.

Objectives:

Test efficacy and safety of lenabasum in a Phase 3 trial in dcSSc.

Methods:

Subjects ≥18 years old with disease duration ≤ 6 years were randomized 1:1:1 to lenabasum 5 mg, 20 mg, or placebo (PBO), all BID, with stable background immunosuppressant therapy (IST) allowed. The primary efficacy endpoint was ACR CRISS score, and secondary endpoints were ΔmRSS, ΔHAQ-DI, and ΔFVC, all at Week 52 for lenabasum 20 mg vs PBO.

Results:

363 adults were dosed; 37 (10%) stopped study drug early, with only 1 subject (PBO cohort) stopping due to adverse event (AE). Baseline demographics were similar among groups. Disease duration was ≤ 3 years in 60% and 66%, mean mRSS score was 22.0 and 23.3, and background IST was used by 89% and 84% of lenabasum 20 mg and PBO groups, respectively.

Safety results showed serious AEs and severe AEs occurred in 9.2% and 5.8% vs 14.6% and 13.0%, respectively, of lenabasum 20 mg and PBO groups.

Efficacy results (Table) demonstrated:

Table 1.

Primary and secondary efficacy endpoints and post-hoc analyses, Week 52

Group, by IST treatmentCohortNΔmRSS, mean (SD)ΔFVC% mean (SD)ΔFVC, mL mean (SD)ΔHAQ-DI mean (SD)ACR CRISS medianmITT population, MMRM primary analysis methodAllPlacebo123-8.1 (7.72)-1.0 (8.68)-51 (317)-0.13 (0.468)0.887Lenabasum 20 mg120-6.7 (6.59)-1.6 (6.91)-78 (265)-0.13 (0.436)0.888Placebo subjects, per protocol completers, LOCFNo ISTPlacebo16-2.3 (9.4)-2.8 (7.4)-97 (244)0.12 (0.34)0.417All ISTPlacebo97-8.9 (7.07)-1.0 (9.2)-43 (330)-0.17 (0.474)0.936MMF, no other ISTPlacebo29-10.7 (8.1)-0.58 (7.1)-37 (235)-0.12 (0.456)0.935MMF ≤ 2 years, no other ISTPlacebo23-11.7 (8.1)-0.3 (6.0)-41 (197)-0.13 (0.495)0.935Non-MMF ≤ 2 yearsPlacebo24-6.7 (6.2)-1.4 (7.87)-52 (281)-0.15 (0.357)0.931Post-hoc comparisons, per protocol completers, LOCFNo ISTPlacebo16-2.3 (9.4)-2.8 (7.4)-97 (244)0.12 (0.34)0.417Lenabasum 20 mg10-6.3 (6.02)-2.3 (5.58)-99 (209)-0.06 (0.498)0.811Established IST1Placebo26-6.1 (5.35)-4.6 (10.11)-170 (350)-0.17 (0.445)0.619Lenabasum 20 mg38-7.4 (5.08)-0.4 (5.70)2-21 (233)3-0.07 (0.357)0.941Established IST, subjects with ILDPlacebo22-5.9 (5.28)-3.7 (5.43)-133 (206)-0.10 (0.372)0.553Lenabasum 20 mg33-7.2 (5.70)-1.0 (10.5)-47 (365)-0.06 (0.391)0.819

2 P = 0.0386 two-sample t-test; 3 P = 0.0481 two-sample t-test; other comparisons were not significant

• No significant differences were seen in primary and secondary efficacy endpoints. Primary MMRM analyses with treatment-by-time-by-subgroup interactions showed that background mycophenolate (MMF) significantly influenced the outcome

•oSubjects on no IST with disease duration ≤3 years were only 7% of PBO subjects and showed little improvement on PBO, in line with other dcSSc trials in which IST was restricted. Post-hoc subgroup analyses of these subjects on no IST suggested improvement in ΔmRSS and ΔHAQ-DI, for lenabasum 20 mg vs PBO

•uUnexpectedly high improvement occurred in PBO subjects receiving IST, notably those on MMF started within 2 years of baseline

•nPost-hoc analyses of subjects on established IST (MMF or, if no MMF, ≥ 1 non-MMF IST started > 2 years before baseline) suggested improvement in ΔFVC% (nominal P = 0.0386) and ΔFVC mL (nominal P = 0.0481) for lenabasum 20 mg vs PBO. Improvement in FVC was also seen in subjects on established IST who had ILD at baseline, lenabasum 20 mg vs PBO

•mACR CRISS score demonstrated a ceiling effect and correlated most highly with ΔmRSS (r = -0.739) and moderately with MDGA (-0.432), HAQ-DI (-0.362), FVC% (0.366), and PtGA (-0.288)

Conclusion:

Lenabasum was safely used in this study. Unexpectedly high improvement on background IST, especially MMF, has not been previously reported at this level. The primary endpoint was not met. Post-hoc analyses showed greater improvement in lenabasum- vs PBO-treated subjects who were not on background IST and those on established IST, including subjects with ILD.

Disclosure of Interests:

Robert Spiera Consultant of: Abbvie, Roche-Genetech, GSK, CSL Behring, Sanofi, Janssen, Chemocentryx, Formation Biologics, Mitsubishi Tanabe, Grant/research support from: Roche-Genetech, GSK, Boehringer Ingelheim, Chemocentryx, Corbus, Formation Biologics, Sanofi, Inflarx, Astra Zeneca, Kadmon, Masataka Kuwana Speakers bureau: Boehringer-Ingelheim, Chugai, Janssen, Consultant of: Boehringer-Ingelheim, Chugai, Corbus, Grant/research support from: Boehringer-Ingelheim, Chugai, MBL, Ono Pharmaceuticals, Tanabe-Mitsubishi, Dinesh Khanna Shareholder of: Eicos Sciences, Inc (less than 5%). Leadership/Equity position – Chief Medical Officer, CiviBioPharma/Eicos Sciences, Inc, Consultant of: Acceleron, Actelion, Abbvie, Amgen, Bayer, Boehringer Ingelheim, CSL Behring, Corbus, Gilead, Galapagos, Genentech/Roche, GSK, Horizon, Merck, Mitsubishi Tanabe Pharma, Sanofi-Aventis, and United Therapeutics, Grant/research support from: NIH, Immune Tolerance Network, Bayer, BMS, Horizon, Pfizer, Laura Hummers Consultant of: CSL Behring, Boehringer Ingelheim, Grant/research support from: Investigator for study sponsored by Corbus Pharmaceuticals. Corbus, Boehringer Ingelheim, Medpace, Kadmon, Cumberland, CSL Behring, Tracy Frech Grant/research support from: Investigator for study sponsored by Corbus Pharmaceuticals, Wendy Stevens Grant/research support from: Investigator for study sponsored by Corbus Pharmaceuticals, Jessica Gordon Grant/research support from: Investigator for study sponsored by Corbus Pharmaceuticals. Research funding for EICOS Pharmaceuticals and Cumberland Pharmaceuticals., Suzanne Kafaja Grant/research support from: Investigator for study sponsored by Corbus Pharmaceuticals, Marco Matucci-Cerinic Consultant of: Actelion, Janssen, Inventiva, Bayer, Biogen, Boehringer, CSL Behring, Corbus, Galapagos, Mitsubishi, Samsung, Regeneron, Acceleron, MSD, Chemomab, Lilly, Pfizer, Roche, Grant/research support from: Investigator for study sponsored by Corbus Pharmaceuticals, Oliver Distler Consultant of: Consultancy relationship and/or has received research funding in the area of potential treatments for systemic sclerosis and its complications from (last three years): Abbvie, Acceleron Pharma, Amgen, AnaMar, Arxx Therapeutics, Baecon Discovery, Blade Therapeutics, Bayer, Boehringer Ingelheim, ChemomAb, Corbus Pharmaceuticals, CSL Behring, Galapagos NV, Glenmark Pharmaceuticals, GSK, Horizon (Curzion) Pharmaceuticals, Inventiva, iQvia, Italfarmaco, iQone, Kymera Therapeutics, Lilly, Medac, Medscape, Mitsubishi Tanabe Pharma, MSD, Novartis, Pfizer, Roche, Sanofi, Serodapharm, Topadur, Target Bioscience and UCB., Eun Bong Lee Grant/research support from: Investigator for study sponsored by Corbus Pharmaceuticals, Yair Levy Grant/research support from: Investigator for study sponsored by Corbus Pharmaceuticals, Jae-Bum Jun Consultant of: Consultant to Boehringer Ingelheim Korea, Jeil Pharma, Dae Woong Pharma, Kwangdong Pharma, and Sama Pharma., Grant/research support from: Investigator for study sponsored by Corbus Pharmaceuticals, Scott Constantine Employee of: Employee of Corbus Pharmaceuticals, Nancy Dgetluck Employee of: Employee of Corbus Pharmaceuticals, Barbara White Employee of: Employee and stockholder of Corbus Pharmaceuticals, Daniel Furst Consultant of: Corbus, Galapagos, Pfizer, CSL Behring, Mitsubishi Tanabi, Actelion, Amgen, Novartis, Roche/Genentech, Gilead, Talaris, and Boehringer Ingelheim., Grant/research support from: grants from Corbus, Galapagos, GSK, Pfizer, Talaris, CSL Behring, Mitsubishi Tanabi, Christopher Denton Consultant of: Consultancy fees and/or honoraria from Corbus, Actelion, GlaxoSmithKline, Bayer, Sanofi, Galapagos, Inventiva, Boehringer Ingelheim, Roche, CSL Behring, Acceleron, Horizon, Arxx Therapeutics

Structural overview of macromolecular machines involved in ribosome biogenesis

The production of ribosomes is essential for ensuring the translational capacity of cells. Because of its high energy demand ribosome production is subject to stringent cellular controls. Hundreds of ribosome assembly factors are required to facilitate assembly of nascent ribosome particles with high fidelity. Many ribosome assembly factors organize into macromolecular machines that drive complex steps of the production pathway. Recent advances in structural biology, in particular cryo-EM, have provided detailed information about the structure and function of these higher order enzymatic assemblies. Here, we summarize recent structures revealing molecular insight into these macromolecular machines with an emphasis on the interplay between discrete active sites.

HEPN RNases - an emerging class of functionally distinct RNA processing and degradation enzymes

HEPN (Higher Eukaryotes and Prokaryotes Nucleotide-binding) RNases are an emerging class of functionally diverse RNA processing and degradation enzymes. Members are defined by a small α-helical bundle encompassing a short consensus RNase motif. HEPN dimerization is a universal requirement for RNase activation as the conserved RNase motifs are precisely positioned at the dimer interface to form a composite catalytic center. While the core HEPN fold is conserved, the organization surrounding the HEPN dimer can support large structural deviations that contribute to their specialized functions. HEPN RNases are conserved throughout evolution and include bacterial HEPN RNases such as CRISPR-Cas and toxin-antitoxin associated nucleases, as well as eukaryotic HEPN RNases that adopt large multi-component machines. Here we summarize the canonical elements of the growing HEPN RNase family and identify molecular features that influence RNase function and regulation. We explore similarities and differences between members of the HEPN RNase family and describe the current mechanisms for HEPN RNase activation and inhibition.

Cryo-EM structures of the SARS-CoV-2 endoribonuclease Nsp15 reveal insight into nuclease specificity and dynamics

Nsp15, a uridine specific endoribonuclease conserved across coronaviruses, processes viral RNA to evade detection by host defense systems. Crystal structures of Nsp15 from different coronaviruses have shown a common hexameric assembly, yet how the enzyme recognizes and processes RNA remains poorly understood. Here we report a series of cryo-EM reconstructions of SARS-CoV-2 Nsp15, in both apo and UTP-bound states. The cryo-EM reconstructions, combined with biochemistry, mass spectrometry, and molecular dynamics, expose molecular details of how critical active site residues recognize uridine and facilitate catalysis of the phosphodiester bond. Mass spectrometry revealed the accumulation of cyclic phosphate cleavage products, while analysis of the apo and UTP-bound datasets revealed conformational dynamics not observed by crystal structures that are likely important to facilitate substrate recognition and regulate nuclease activity. Collectively, these findings advance understanding of how Nsp15 processes viral RNA and provide a structural framework for the development of new therapeutics.

Laser-driven x-ray and proton micro-source and application to simultaneous single-shot bi-modal radiographic imaging

Radiographic imaging with x-rays and protons is an omnipresent tool in basic research and applications in industry, material science and medical diagnostics. The information contained in both modalities can often be valuable in principle, but difficult to access simultaneously. Laser-driven solid-density plasma-sources deliver both kinds of radiation, but mostly single modalities have been explored for applications. Their potential for bi-modal radiographic imaging has never been fully realized, due to problems in generating appropriate sources and separating image modalities. Here, we report on the generation of proton and x-ray micro-sources in laser-plasma interactions of the focused Texas Petawatt laser with solid-density, micrometer-sized tungsten needles. We apply them for bi-modal radiographic imaging of biological and technological objects in a single laser shot. Thereby, advantages of laser-driven sources could be enriched beyond their small footprint by embracing their additional unique properties, including the spectral bandwidth, small source size and multi-mode emission.

Here the authors show a synchronized single-shot bi-modal x-ray and proton source based on laser-generated plasma. This source can be useful for radiographic and tomographic imaging.

Cryo-EM Structures of the SARS-CoV-2 Endoribonuclease Nsp15

New therapeutics are urgently needed to inhibit SARS-CoV-2, the virus responsible for the on-going Covid-19 pandemic. Nsp15, a uridine-specific endoribonuclease found in all coronaviruses, processes viral RNA to evade detection by RNA-activated host defense systems, making it a promising drug target. Previous work with SARS-CoV-1 established that Nsp15 is active as a hexamer, yet how Nsp15 recognizes and processes viral RNA remains unknown. Here we report a series of cryo-EM reconstructions of SARS-CoV-2 Nsp15. The UTP-bound cryo-EM reconstruction at 3.36 Å resolution provides molecular details into how critical residues within the Nsp15 active site recognize uridine and facilitate catalysis of the phosphodiester bond, whereas the apo-states reveal active site conformational heterogeneity. We further demonstrate the specificity and mechanism of nuclease activity by analyzing Nsp15 products using mass spectrometry. Collectively, these findings advance understanding of how Nsp15 processes viral RNA and provide a structural framework for the development of new therapeutics.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

AB0295 CHANGE IN DISEASE ACTIVITY AND TREATMENT RESPONSE AFTER ABATACEPT TREATMENT FOR RHEUMATOID ARTHRITIS: REAL-WORLD EVIDENCE FROM THE UK

Background:

Patients with moderate to severe active rheumatoid arthritis (RA) may be treated with biological disease-modifying antirheumatic drugs (bDMARDs), such as abatacept, after treatment failure with conventional synthetic DMARDs (csDMARDs). Abatacept has shown equivalent efficiency with other targeted therapies for RA in clinical trials and network meta-analyses. However, there is limited real-world evidence on patient outcomes associated with abatacept treatment in UK routine clinical practice.

Objectives:

To describe the clinical outcomes of RA patients treated with abatacept in UK real-world clinical practice.

Methods:

A multi-centre, retrospective observational study was undertaken in RA patients treated with abatacept at any line of therapy (LOT). Data were extracted from medical records at four UK hospitals. Patients aged 18 years or older who received abatacept between 1 January 2013 and 31 December 2017 were included. The index date was the date of first bDMARD initiation, with follow-up from index date to latest RA clinic visit, death or 31 December 2017, whichever occurred first.

Clinical outcomes (disease activity and response to treatment) were measured using the 28-joint Disease Activity Score based on erythrocyte sedimentation rate (DAS28-ESR) and European League Against Rheumatism (EULAR) response criteria1-3.

Results:

The study included 213 patients (mean age 55.2 years, 71.4% female, 7.0 years mean duration of RA at index date). Where ACPA and RF status were recorded, 66.1% of patients were anti-citrullinated protein antibodies (ACPA) and rheumatoid factor (RF) positive at index. Mean DAS28-ESR at index was 6.2 (SD 1.0) and 80.9% of patients were categorised with high disease activity.

Irrespective of LOT, changes in DAS28-ESR (where recorded) from LOT initiation among patients treated with abatacept versus other bDMARDs were -1.59 vs -1.56 (LS mean (SE): -0.04; 95% CI: -0.45,0.38; p=0.86) at 6 months and -1.98 vs -1.42 (LS mean (SE): -0.56; 95% CI: -1.04,-0.07; p=0.03) at 12 months, respectively. Table 1 shows that compared with other bDMARDs, patients treated with abatacept at any LOT experienced good response to treatment at 6 months (22.8%, n= 21/92 vs 15.9%, n= 24/151) and 12 months (27.9%, n= 17/61 vs 20.5%, n= 24/117) according to EULAR criteria.

Table1.

Treatment response at 6 and 12 months after initiation of any LOT*

EULAR response6 months12 monthsAbatacept,n = 92Other bDMARDs,n = 151Abatacept,n = 61Other bDMARDs,n = 117Good21 (22.8%)24 (15.9%)17 (27.9%)24 (20.5%)Moderate38 (41.3%)60 (39.7%)22 (36.1%)40 (34.2%)None33 (35.9%)67 (44.4%)22 (36.1%)53 (45.3%)

n = number of unique LOTs in which a patient has both a DAS28-ESR collected at initiation and 6 and/or 12 months (a patient may be included in this analysis multiple times)

Patients who received abatacept remained on treatment for significantly longer than patients who received other bDMARDs at LOT1 (median 53.4 vs 17.4 months; p<0.01) (Figure 1) and at LOT2 (median 40.1 vs 17.1 months; p<0.01).

Figure 1.

Time on treatment from first LOT initiation, abatacept versus other bDMARDs

Conclusion:

RA patients who received bDMARDs, including abatacept, experienced reduced disease activity. These findings are comparable with those from a European, multicentre, observational study on patients receiving abatacept4. The mechanisms associated with such clinical benefit should be elucidated in future research.

References:

[1]Prevoo et al. Arthritis Rheum 1995;38:44–8.

[2]Fransen & van Riel. Clin Exp Rheumatol 2005;23:S93–9.

[3]van Gestel et al. Arthritis Rheum 1998;41:1845–50.

[4]Alten et al. Clin Rheumatol (2019) 38: 1413.

Acknowledgments:

Yusuf Patel

Srinivasan Venkatachalam

James Maxwell

Usman Farooqui

Kevin Pollock

Disclosure of Interests:

Sadie Henning Shareholder of: Sadie Henning is a shareholder for Bristol-Myers Squibb Pharmaceuticals Ltd., Employee of: Sadie Henning is employed by Bristol-Myers Squibb Pharmaceuticals Ltd., Lara Groves Grant/research support from: Lara Groves is an employee of Health Economics and Outcomes Research Ltd., Cardiff, UK, who received fees from Bristol-Myers Squibb Pharmaceuticals Ltd in relation to this study., Michael Hurst Grant/research support from: Michael Hurst is an employee of Health Economics and Outcomes Research Ltd., Cardiff, UK, who received fees from Bristol-Myers Squibb Pharmaceuticals Ltd in relation to this study., Daniel Sugrue Grant/research support from: Daniel Sugrue is an employee of Health Economics and Outcomes Research Ltd., Cardiff, UK, who received fees from Bristol-Myers Squibb Pharmaceuticals Ltd in relation to this study., Jason Gordon Grant/research support from: Jason Gordon is an employee of Health Economics and Outcomes Research Ltd., Cardiff, UK, who received fees from Bristol-Myers Squibb Pharmaceuticals Ltd in relation to this study., Ernest Choy Grant/research support from: Amgen, Bio-Cancer, Chugai Pharma, Ferring Pharmaceuticals, Novimmune, Pfizer, Roche, UCB, Consultant of: AbbVie, Amgen, AstraZeneca, Biogen, Boehringer Ingelheim, Bristol-Myers Squibb, Celgene, Chelsea Therapeutics, Chugai Pharma, Daiichi Sankyo, Eli Lilly, Ferring Pharmaceuticals, GlaxoSmithKline, Hospita, Ionis, Janssen, Jazz Pharmaceuticals, MedImmune, Merck Sharp & Dohme, Merrimack Pharmaceutical, Napp, Novartis, Novimmune, ObsEva, Pfizer, R-Pharm, Regeneron Pharmaceuticals, Inc., Roche, SynAct Pharma, Sanofi Genzyme, Tonix, UCB, Speakers bureau: Amgen, Boehringer Ingelheim, Bristol-Myers Squibb, Chugai Pharma, Eli Lilly, Hospira, Merck Sharp & Dohme, Novartis, Pfizer, Regeneron Pharmaceuticals, Inc., Roche, Sanofi-Aventis, UCB

It takes two (Las1 HEPN endoribonuclease domains) to cut RNA correctly

The ribosome biogenesis factor Las1 is an essential endoribonuclease that is well-conserved across eukaryotes and a newly established member of the higher eukaryotes and prokaryotes nucleotide-binding (HEPN) domain-containing nuclease family. HEPN nucleases participate in diverse RNA cleavage pathways and share a short HEPN nuclease motif (RφXXXH) important for RNA cleavage. Most HEPN nucleases participate in stress-activated RNA cleavage pathways; Las1 plays a fundamental role in processing pre-rRNA. Underscoring the significance of Las1 function in the cell, mutations in the human LAS1L (LAS1-like) gene have been associated with neurological dysfunction. Two juxtaposed HEPN nuclease motifs create Las1's composite nuclease active site, but the roles of the individual HEPN motif residues are poorly defined. Here using a combination of in vivo experiments in Saccharomyces cerevisiae and in vitro assays, we show that both HEPN nuclease motifs are required for Las1 nuclease activity and fidelity. Through in-depth sequence analysis and systematic mutagenesis, we determined the consensus HEPN motif in the Las1 subfamily and uncovered its canonical and specialized elements. Using reconstituted Las1 HEPN-HEPN' chimeras, we defined the molecular requirements for RNA cleavage. Intriguingly, both copies of the Las1 HEPN motif were important for nuclease function, revealing that both HEPN motifs participate in coordinating the RNA within the Las1 active site. We also established that conformational flexibility of the two HEPN domains is important for proper nuclease function. The results of our work reveal critical information about how dual HEPN domains come together to drive Las1-mediated RNA cleavage.

Nol9 Is a Spatial Regulator for the Human ITS2 Pre-rRNA Endonuclease-Kinase Complex

The ribosome plays a universal role in translating the cellular proteome. Defects in the ribosome assembly factor Las1L are associated with congenital lethal motor neuron disease and X-linked intellectual disability disorders, yet its role in processing precursor ribosomal RNA (pre-rRNA) is largely unclear. The Las1L endoribonuclease associates with the Nol9 polynucleotide kinase to form the internal transcribed spacer 2 (ITS2) pre-rRNA endonuclease-kinase machinery. Together, Las1L-Nol9 catalyzes RNA cleavage and phosphorylation to mark the ITS2 for degradation. While ITS2 processing is critical for the production of functional ribosomes, the regulation of mammalian Las1L-Nol9 remains obscure. Here we characterize the human Las1L-Nol9 complex and identify critical molecular features that regulate its assembly and spatial organization. We establish that Las1L and Nol9 form a higher-order complex and identify the regions responsible for orchestrating this intricate architecture. Structural analysis by high-resolution imaging defines the intricate spatial pattern of Las1L-Nol9 within the nucleolar sub-structure linked with late pre-rRNA processing events. Furthermore, we uncover a Nol9-encoded nucleolar localization sequence that is responsible for nucleolar transport of the assembled Las1L-Nol9 complex. Together, these data provide a mechanism for the assembly and nucleolar localization of the human ITS2 pre-rRNA endonuclease-kinase complex.

Specialized tobacco quitline and basic needs navigation interventions to increase cessation among low income smokers: Study protocol for a randomized controlled trial

Smoking in the United States follows a clear socioeconomic gradient: low-income Americans smoke more and quit less than those with more education and income. Evidence-based interventions like tobacco quitlines are designed to make effective cessation services available on a population basis to all smokers. However, these interventions do not address many of the unique challenges faced by low-income smokers, including unmet basic needs like food, housing, personal safety and money for necessities that often supersede health needs. Research is needed to maximize the use and effectiveness of tobacco quitlines in low-income populations. This paper details the rationale, design and methods for a 2 × 2 randomized controlled trial currently underway comparing the effects of Standard and Specialized Tobacco Quitlines with and without Basic Needs Navigation on intervention engagement and smoking cessation among low-income smokers. Smokers are recruited from United Way 2-1-1 in Missouri and all participants receive tobacco quitline services from Optum. Quitline and navigation services are provided for 3 months. Participants complete telephone surveys at baseline, 3- and 6-month follow up. The primary study outcome is self-reported 7-day point prevalence abstinence at 6-month follow up. Embedding the study in practice agencies will accelerate dissemination and scalability should our findings demonstrate intervention effectiveness.

Abstract P5-13-10: Recommendations to improve the lived experience of early stage and metastatic breast cancer patients in Canada

Introduction: In 2017, the Canadian Breast Cancer Network (CBCN) undertook two surveys of Canadians who have experienced a breast cancer diagnosis to better understand the lived experience of patients and what opportunities exist to improve support for patients, survivors and their families and minimize the impact of this disease. There were 278 people diagnosed with early stage breast cancer, defined as stage I, II or III for the purpose of this report, and 180 people living with metastatic breast cancer, or stage IV breast cancer, who responded to these surveys.

Results: The survey data shows that while patients feel supported and well cared for in certain aspects there are still significant opportunities for improvement. CBCN has identified five overarching factors that could greatly improve health outcomes and the quality of life of Canadians who experience a breast cancer diagnosis.

1. Improved Educational Resources: The quality and availability of patient education has increased over the past couple of decades; however, there are still some patient friendly educational resources including, specific resources for newly diagnosed metastatic breast cancer patients; decision aids that support breast cancer surgery and post-surgery decisions; navigation of financial resources; treatment timelines and recovery expectations; private insurance navigation and information on dying-well.

2. Increased Access to Treatments: This challenge was specifically identified and vocalized by people living with metastatic breast cancer. Efforts need to continue to shorten the drug approval process time, increase equitable access to new medications for all Canadians, and ensure equitable access for take home oral cancer medications.

3. Increased Access to Information: Information available to patients about their health and treatment has increased; however, there is still information that isn't always communicated to patients that would help them make informed decisions about their health. This includes information about breast density, palliative care options and information around clinical trials.

4. Integrated Systemic Supports: The health care system as a whole is responsible for many of the services and supports that patients need to achieve optimal health and manage their breast cancer; however, these supports can be challenging to navigate and are sometimes lacking. Supports that need to be addressed at a systemic level include developing survivorship care plans for early stage patients, patient navigation, communication tools to support general practitioners during the diagnosis process, access to psychosocial professionals and increased Employment Insurance Sickness Benefits.

5. Increased Awareness and Understanding of Metastatic Breast Cancer: A lack of accurate statistics and overall awareness of metastatic breast cancer makes it challenging to truly understand the impact of this disease and also leaves people living with an incurable form of breast cancer feeling isolated and disconnected. Accurate statistics and increased awareness would help further the understanding of the impact of this stage of breast cancer and better support those with it.

Citation Format: Gordon J, Ammendolea C, Chari N, Armstrong R, Hall W. Recommendations to improve the lived experience of early stage and metastatic breast cancer patients in Canada [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-13-10.

Implementing a Fee-for-Service Cervical Cancer Screening and Treatment Program in Cameroon: Challenges and Opportunities

Background: Cervical cancer screening is one of the most effective cancer prevention strategies, but most women in Africa have never been screened. In 2007, the Cameroon Baptist Convention Health Services, a large faith-based health care system in Cameroon, initiated the Women's Health Program (WHP) to address this disparity. Trained nurses provide fee-for-service cervical cancer screening using visual inspection with acetic acid enhanced by digital cervicography (VIA-DC), prioritizing care for women living with HIV/AIDS. They also provide clinical breast examination, family planning (FP) services, and treatment of reproductive tract infections (RTI) and refer for further tests and treatment indicated. Methods: We retrospectively reviewed and analyzed WHP medical records from women who presented for cervical cancer screening from 2007-2014. Results: In 8 years, WHP nurses screened 44,979 women for cervical cancer. The number of women screened increased nearly every year. The WHP is sustained primarily on fees-for-service, with external funding totaling about $20,000 annually. In 2014, of 12,191 women screened for cervical cancer, 99% received clinical breast exams, 19% received FP services, and 4.7% received treatment of RTIs. We document successes, challenges, solutions implemented, and recommendations for optimizing this screening model. Conclusion: The WHP's experience using a cost-recovery model and offering multiple services in a single clinic rather than stand-alone cervical cancer screening may be a practical model to make cervical cancer screening services accessible, comprehensive and sustainable. Integrating other women's health services enabled women to address additional health care needs.

Financial Resources Digital Navigation Tool for Metastatic Breast Cancer Patients

Background and context: Although Canadians enjoy a universal health care system, there continues to be costs to patients that are not covered by the system. The economic impact of breast cancer is huge and, in many cases, devastating for patients and their families. As a result there is a need for educational and navigational resources that assist patients with the financial burden of facing a metastatic breast cancer diagnosis. Aim: The aim of this project is to develop an online navigation tool that will assist Canadians living with metastatic breast cancer source financial supports and resources to help lessen the financial impact of their diagnosis. Strategy/Tactics: An advisory board of people living with metastatic breast cancer was convened to help guide this project and provide input on the lived experience and financially challenges of Canadians living with this stage of the disease. The input from the advisory board along with the responses from a survey of over 150 Canadian metastatic breast cancer patients informed the type of information that should be included in the resource. Through an environmental scan and research of various financial supports, a comprehensive list of financial resources available locally, regionally and nationally was compiled. This data were integrated into a database that will be accessed through an intuitive online interface that will be integrated with CBCN´s Web site. The advisory board reviewed the draft content and framework to ensure that identified needs and priorities have been addressed. All content was translated into French as this tool will be offered in both French and English. The anticipated launch of this resource is November 2018. Outcomes: CBCN anticipates that over 1200 people living with metastatic breast cancer will access this resource in the first year and that over 50 institutions will be informed that this tool is available for their patients. Given that this will be a unique resource, CBCN expects that patients, health care professionals and support workers will access this resource to better support people living with metastatic breast cancer. What was learned: This resource has not launched, but based on CBCN´s research and the feedback of the patient advisory board, it is understood that there is a great need for this financial resources navigation tool.

Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

An environmental scan of emergency response systems and services in remote First Nations communities in Northern Ontario

Background: Approximately 24,000 Ontarians live in remote Indigenous communities with no road access. These communities are a subset of Nishnawbe Aski Nation (NAN), a political grouping of 49 First Nations communities in Northern Ontario, Canada. Limited information is available regarding the status of emergency care in these communities.

Objective: We aimed to understand emergency response systems, services, and training in remote NAN communities.

Design: We used an environmental scan approach to compile information from multiple sources including community-based participatory research. This included the analysis of data collected from key informant interviews (n=10) with First Nations community health leaders and a multi-stakeholder roundtable meeting (n=33) in October 2013.

Results: Qualitative analysis of the interview data revealed four issues related to emergency response systems and training: (1) inequity in response capacity and services, (2) lack of formalised dispatch systems, (3) turnover and burnout in volunteer emergency services, and (4) challenges related to first aid training. Roundtable stakeholders supported the development of a community-based emergency care system to address gaps.

Conclusions: Existing first response, paramedical, and ambulance service models do not meet the unique geographical, epidemiological and cultural needs in most NAN communities. Sustainable, context-appropriate, and culturally relevant emergency care systems are needed.