Human mutations in high-confidence Tourette disorder genes affect sensorimotor behavior, reward learning, and striatal dopamine in mice

Tourette disorder (TD) is poorly understood, despite affecting 1/160 children. A lack of animal models possessing construct, face, and predictive validity hinders progress in the field. We used CRISPR/Cas9 genome editing to generate mice with mutations orthologous to human de novo variants in two high-confidence Tourette genes, CELSR3 and WWC1. Mice with human mutations in Celsr3 and Wwc1 exhibit cognitive and/or sensorimotor behavioral phenotypes consistent with TD. Sensorimotor gating deficits, as measured by acoustic prepulse inhibition, occur in both male and female Celsr3 TD models. Wwc1 mice show reduced prepulse inhibition only in females. Repetitive motor behaviors, common to Celsr3 mice and more pronounced in females, include vertical rearing and grooming. Sensorimotor gating deficits and rearing are attenuated by aripiprazole, a partial agonist at dopamine type II receptors. Unsupervised machine learning reveals numerous changes to spontaneous motor behavior and less predictable patterns of movement. Continuous fixed-ratio reinforcement shows that Celsr3 TD mice have enhanced motor responding and reward learning. Electrically evoked striatal dopamine release, tested in one model, is greater. Brain development is otherwise grossly normal without signs of striatal interneuron loss. Altogether, mice expressing human mutations in high-confidence TD genes exhibit face and predictive validity. Reduced prepulse inhibition and repetitive motor behaviors are core behavioral phenotypes and are responsive to aripiprazole. Enhanced reward learning and motor responding occur alongside greater evoked dopamine release. Phenotypes can also vary by sex and show stronger affection in females, an unexpected finding considering males are more frequently affected in TD.

Design, analysis, and interpretation of treatment response heterogeneity in personalized nutrition and obesity treatment research

It is increasingly assumed that there is no one-size-fits-all approach to dietary recommendations for the management and treatment of chronic diseases such as obesity. This phenomenon that not all individuals respond uniformly to a given treatment has become an area of research interest given the rise of personalized and precision medicine. To conduct, interpret, and disseminate this research rigorously and with scientific accuracy, however, requires an understanding of treatment response heterogeneity. Here, we define treatment response heterogeneity as it relates to clinical trials, provide statistical guidance for measuring treatment response heterogeneity, and highlight study designs that can quantify treatment response heterogeneity in nutrition and obesity research. Our goal is to educate nutrition and obesity researchers in how to correctly identify and consider treatment response heterogeneity when analyzing data and interpreting results, leading to rigorous and accurate advancements in the field of personalized medicine.

Outreach, Screening, and Randomization of APOE ε4 Carriers into an Alzheimer's Prevention Trial: A global Perspective from the API Generation Program

BACKGROUND

Alzheimer's disease (AD) prevention trials require a large outreach and screening funnel to identify cognitively unimpaired adults who meet the study's inclusion criteria, such as certain clinical or demographic criteria, genetic risk factors, and/or biomarker evidence of the disease.

OBJECTIVES

Describe tactics and strategies to identify and enroll cognitively unimpaired adults with one (heterozygotes [HT]) or two (homozygotes [HM]) copies of the APOE ε4 allele, a genetic risk factor for dementia due to AD, into the Alzheimer's Prevention Initiative (API) Generation Program, the largest and only prevention trials for late onset AD using this enrichment technique.

DESIGN AND SETTING

The Generation Program was comprised of two global, randomized, double-blind, placebo-controlled, parallel group adaptive design with variable treatment duration clinical trials. Generation Study 1 randomized participants into one of two cohorts: Cohort 1 which evaluated CAD106 vs. placebo or Cohort 2 which evaluated umibecestat vs placebo. Generation Study 2 randomized participants into two doses of umibecestat vs. placebo. The Generation Program was terminated early in 2019, while enrollment was still occurring.

PARTICIPANTS

Both Generation Study 1 and Generation Study 2 enrolled cognitively unimpaired APOE ε4 HMs aged 60-75; Generation Study 2 also enrolled APOE ε4 HTs ages 60-75 with elevated brain amyloid.

METHODS AND MEASUREMENTS

Describe results of the centralized and localized outreach, recruitment, screening strategies and tactics as well as characteristics of sites successful at enrolling genetically eligible participants, with a particular focus on APOE ε4 HMs given the 2-3% prevalence of this genotype.

RESULTS

At the time the trial program was terminated, 35,333 individuals had consented to the optional prescreening ICF1a/ICFA and provided a sample of DNA for APOE genotyping, 1,138 APOE ε4 HMs consented to screening for Generation Study 1 (ICF1b), and 1,626 APOE ε4 carriers were randomized into either Generation Study 1 or Generation Study 2. Genetic testing registries, partnerships with genetic testing/counseling companies, and the optional prescreening ICF1a/ICFA were the most successful strategies for identifying genetically eligible participants for screening.

CONCLUSIONS

It is feasible to recruit, screen and randomize cognitively unimpaired APOE ε4 carriers, particularly APOE ε4 HMs for a global AD prevention trial. The Generation Program was on track to complete enrollment by end of 2019. Factors that were key to this success included: working with sites to develop customizable outreach, recruitment, and screening programs specific to their site needs, providing forums for sites to exchange best practices, and developing partnerships between the sponsor team and trial sites.

ODP258 CRHR1 gene shows extensive linkage to major depression and type 2 diabetes in Italian families

Background

Major Depressive Disorder (MDD) and Type 2 Diabetes (T2D) are heterogeneous polygenic and complex disorders and are often comorbid. This shared comorbidity can be partially explained by several genetic, environmental, and hormonal factors such as hypercortisolism in MDD and a subset of patients with T2D. CRH receptor-1 (CRHR1) dysfunction may explain the MDD- and T2D-hypercortisolism, at least in a subgroup of patients. CRHR1-variants predisposing to impaired CRHR1 dosage and/or function may lead to hypercortisolism (substrate for serotonin dysfunction and MDD), as well as hyperglycemia, insulin resistance, and increased visceral fat, all T2D-traits. We hypothesize that CRHR1-variants may impair the stress and cortisol response, conferringincreased risk for MDD, T2D, and MDD-T2D comorbidity.

Methods

Using 212 Italian families with T2D, enriched T2D-familial history, and MDD, we amplified and tested 158 CRHR1 SNPs by two-point parametric analysis for linkage and linkage-disequilibrium (LD), using the models dominant (D) and recessive (R), with complete (1) and incomplete (2) penetrance (Pseudomarker).

Results

We detected linkage to and/or LD with MDD: for 93 SNPs (D1), 57 SNPs (D2), 91 SNPs (R1), and 14 (R2); and T2D for 15 SNPs (D1), 18 SNPs (D2), twelve SNPs (R1) and ten SNPs (R2), for a total of 122 SNPs. Specific LD-blocks’ underlined each disorder without overlap. Of note, three independent SNPs were comorbid forMDD and T2D. All risk SNPs are intronic, except for one synonymous, one splice site, one missense, and one 3'UTR. In-silicoanalysis detected functional gene and tridimensional protein changes in a risk-SNP.

Conclusion

We are the first to report CRHR1 in linkage and LD with MDD and T2D in T2D-families. CRHR1contribution to MDD appears stronger thanthe contribution to T2D and may thus antecede its onset . Genetically impaired stress and cortisol response may lead to comorbid MDD-T2D, likely a molecular-clinical entity in a subset of families. Our findings should be replicated in families from other ethnic groups.

Presentation: No date and time listed

Modeling of short-pulse laser-metal interactions in the warm dense matter regime using the two-temperature model

A numerical model for laser-matter interactions in the warm dense matter regime is presented with broad applications, e.g., ablation, thermionic emission, and radiation. A unique approach is adopted, in which a complete set of collisional and transport data is calculated using a quantum model and incorporated into the classical two-temperature model for the electron and lattice-ion temperatures. The data set was produced by the average atom model that combines speed, conceptual simplicity, and straightforward numerical development. Such data are suitable for use in the warm dense matter regime, where most of the laser-matter interactions at moderate intensities occur, thus eliminating deficiencies of previous models, e.g., interpolation between solid and ideal plasma regimes. In contrast to other works, we use a more rigorous definition of solid and plasma states of the metal, based on the physical condition of the lattice, crystalline (ordered) versus melted (disordered), rather than a definition based on electron temperature. The synergy between the two-temperature and average atom models has been demonstrated on a problem involving heating and melting of the interior of Al by a short-pulse laser with duration 0.1-1 ps and laser fluences 1×10^{3}-3×10^{4}J/m^{2}(0.1-3J/cm^{2}). The melting line, which separates the solid and plasma regimes, has been tracked in time and space. The maximum melting depth has been determined as a function of laser fluence: l_{melt}(μm)≅4×10^{3}F(J/m^{2}).

The impact of a nationwide hands-on workshop on the diagnostic rates and management of obstetrical anal sphincter Injuries in Israel

AIM

The aim was to evaluate the influence of a half day, hands-on, workshop on the detection and repair of obstetric anal sphincter injuries (OASIs).

METHOD

Starting in February 2011, hands-on workshops for the diagnosis and repair of OASIs were delivered by trained urogynaecologists in departments of tertiary medical centres in Israel. The structure of the hands-on workshop resembles the workshop organized at the International Urogynecological Association annual conferences. Participants included medical staff, midwives and surgical residents from each medical centre. We collected data regarding the rate of OASIs, 1 year before and 1 year following the workshop, in 11 medical centres. The study population was composed of parturients with the following inclusion criteria: singleton pregnancy, vertex presentation and vaginal delivery. Pre-viable preterm gestations (< 24 weeks), birth weight < 500 g, stillborn, and those with major congenital anomalies, multifoetal pregnancies, breech presentations and caesarean deliveries were excluded from the analysis.

RESULTS

In the reviewed centres, 70 663 (49.3%) women delivered prior to the workshop (pre-workshop group) and 72 616 (50.7%) women delivered following the workshop (post-workshop group). Third- or fourth-degree perineal tears occurred in 248 women (0.35%) before the workshop, and in 328 (0.45%) following the workshop, a significant increase of 28.7% (P = 0.002). The increase in diagnosis was significant also in women with third-degree tears alone, 226 women (0.32%) before the workshop and 298 (0.41%) following the workshop, an increase of 28.3% (P = 0.005).

CONCLUSION

The detection rate of OASIs has significantly increased following the hands-on workshop. The implementation of such programmes is crucial for increasing awareness and detection rates of OASI following vaginal deliveries.

Favorable therapeutic index of an orally-active small-molecule antagonist of the platelet protease-activated receptor-4, BMS-986141, compared with the P2Y12 antagonist ticagrelor in cynomolgus monkeys

Introduction

BMS-986141 is an orally-active small-molecule platelet thrombin receptor antagonist selective for the protease-activated receptor-4 (PAR4), a human platelet thrombin receptor.

Purpose

This study assessed effects of BMS-986141 vs. the P2Y12 antagonist ticagrelor, a standard of care antiplatelet agent, on arterial thrombosis (AT), mesenteric bleeding time (MBT) and platelet aggregation in monkeys.

Methods

Studies were conducted in models of electrically-mediated carotid artery thrombosis and MBT in anesthetized monkeys. Monkeys were given a single oral dose of BMS-986141 (0.05, 0.1, 0.5 mg/kg) or vehicle (n=8/group). At 2 hr post-dose, in vivo AT, MBT as well as ex vivo platelet aggregation were monitored in the same animal. Ticagrelor was studied as a comparator and given as IV bolus plus infusion at 0.0023+0.017 to 0.075+0.6 (mg/kg+mg/kg/h) (n=5–6/group). Thrombus weight reduction, MBT increase over vehicle, and platelet aggregation inhibition were determined. Peak platelet aggregation responses to activation peptides selective for PAR4 (PAR4-AP, 12.5 μM) and PAR1 (PAR1-AP, 18 μM), to collagen (5 μg/ml) and to ADP (20 μM) were determined by whole blood aggregometry.

Results

BMS-986141 inhibited platelet aggregation induced by PAR4-AP in human and monkey blood in vitro with comparable IC50 of 1.8±0.3 and 1.2±0.3 nM, respectively. BMS-986141 at 0.5 mg/kg completely inhibited platelet aggregation induced by PAR4-AP but not PAR1-AP, ADP and collagen, suggesting PAR4 receptor selectivity. In the AT model, BMS-986141 at 0.05, 0.1 and 0.5 mg/kg reduced thrombus weight by 36±7*, 63±8*, and 88±3%*, respectively (*P&lt;0.05 vs. vehicle). BMS-986141 increased MBT by up to 1.2-fold. In a separate study, ticagrelor at 0.0023+0.017, 0.0068+0.055, 0.0255+0.18 and 0.075+0.6 (mg/kg+mg/kg/h IV) reduced thrombus weight by 19±8, 36±5*, 76±6* and 89±1%*, and increased MBT by respectively by 1.7-, 6.4-*, &gt;10-*, and &gt;10-fold*, respectively (*P&lt;0.05 vs. vehicle).

Conclusion

Comparable antithrombotic efficacy was observed between BMS-986141 and ticagrelor in monkeys. BMS-986141 exhibited lower MBT compared with ticagrelor at equivalent antithrombotic doses. This study suggests that PAR4 antagonism provides a potentially safer antiplatelet therapy.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Research was supported by Bristol-Myers Squibb

Childhood maltreatment, serotonin transporter gene, and risk for callous and unemotional traits: A prospective investigation

Previous studies have reported associations between the serotonin transporter 5-HTTLPR genotype and antisocial and aggressive traits and between child maltreatment and antisocial traits. However, few studies have examined whether 5-HTTLPR moderates the influence of childhood maltreatment on callous and unemotional traits, a hallmark of psychopathy. Using a prospective cohort design, children with documented cases of maltreatment and matched controls were followed up and interviewed in adulthood. DNA was extracted from blood and saliva (N = 414) and callous-unemotional (CU) traits were assessed. Childhood maltreatment predicted higher CU scores in adulthood, whereas the effect of 5-HTTLPR was not significant. The effect of child maltreatment on CU traits did not differ by genetic risk (high or low activity 5-HTTLPR), whereas controls with the LL genotype had higher CU scores than controls with the SS genotype. Similar results were found for females and White, non-Hispanics, but not for males and Blacks. Variations in 5-HTTLPR did not affect the impact of child maltreatment on CU traits in adulthood. Genetic risk had a stronger effect on adults with lower environmental risk (controls). Having a history of child maltreatment or the LL genotype placed participants at risk for higher levels of callous and unemotional trait scores.

SAT0143 A PHASE 1 STUDY IN HEALTHY VOLUNTEERS EXPLORING THE SAFETY, PHARMACOKINETICS AND PHARMACODYNAMICS OF ATI-450: A NOVEL ORAL MK2 INHIBITOR

Background:

ATI-450, is an investigational small molecule inhibitor of the MAPK-activated protein kinase 2 (MK2) signaling pathway. This pathway drives the expression of multiple cytokines including TNFα, IL-1α and β, and IL-6.

Objectives:

We evaluated the safety and tolerability of ATI-450 in healthy volunteers as well as pharmacokinetics (PK) and pharmacodynamics (PD). Here we present data from single and multiple ascending dose cohorts. The aim was to select a dose for evaluation in phase 2 in patients with rheumatoid arthritis.

Methods:

Safety, PK and PD were assessed in a randomized, observer-blind, placebo-controlled, phase 1 study in male and female healthy subjects aged 18-55 (n=77).

Safety and tolerability of ATI-450 was evaluated based on adverse events, clinical laboratory, vital signs, 12-lead ECG, Holter monitoring, and physical examination. Blood was drawn for PK analysis at 0.5, 1, 2, 4, 6, 8, 12 hours, 24, 36, and 48 hours post dose in the SAD cohort and on day 7 of the MAD cohort. PD of ATI-450 were explored by investigating the inhibition of a target biomarker, phospho-HSP27 (pHSP27) and proinflammatory cytokines, TNFα, IL1β, IL6 and IL8 inex-vivoLPS-stimulated blood samples collected 4 and 12 hours post dose on day 7 from subjects in the MAD cohorts.

Results:

ATI-450 was generally well tolerated. No serious adverse events or severe adverse events were reported, and no adverse events led to discontinuation of the study medication. The most common adverse events (reported by 2 or more subjects who received ATI-450) observed during the trial were dizziness, headache, upper respiratory tract infection, constipation, nausea, and abdominal pain. All adverse events were mild. A trend of a decrease in absolute neutrophil count (ANC) was observed without correlated clinical sequelae.

ATI-450 had dose proportional PK with a terminal half-life (t½) of 9-12 hours in the MAD cohort on day 7. A dose and concentration dependent inhibition ofex vivostimulated cytokines and target biomarker was observed. On day 7, patients in the 50mg BID dose (the dose with the highest degree of inhibition) recorded mean trough drug levels (12 hours post dose) that were 1.4, 2.5, 2.5 and 2.4 times greater than the IC80for TNFα, IL1β, IL8 and pHSP27 respectively. Mean Cmax drug levels (4 hours post dose) were 3.6, 6.4, 6.2 and 6.0 times greater than the IC80for TNFα, IL1β, IL8 and pHSP27 respectively. IL6 levels were inhibited by more than 50% for part of the dosing interval.

Conclusion:

Oral ATI-450 was generally well tolerated at all doses with dose proportional PK. The t½ suggests that once or twice daily oral dosing may be possible. At the 50mg BID dose, marked inhibition of TNFα, IL1β and IL8, IL6 and pHSP27 was observed. ATI-450 has the potential to be an oral, small molecule drug which can target multiple cytokines. Exploration of its benefit to risk profile in patients with rheumatoid arthritis is warranted.

Disclosure of Interests:

Judy Schnyder Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, Joe Monahan Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, Walter Smith Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, Heidi Hope Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, Deborah Kelly Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, David Burt Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, E Huff Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, A Kaul Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, A Hildebrand Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, B Burnette Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, N Klug Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics, M Bangs Shareholder of: Aclaris Therapeutics, Employee of: Aclaris Therapeutics, David Gordon Shareholder of: aclaris therapeutics, Employee of: aclaris therapeutics

Efficacy of influenza vaccine (Fluvax) in cancer patients on treatment: a prospective single arm, open-label study

PURPOSE

Influenza virus infection has significant morbidity and mortality in patients with medical co-morbidities who are also immunosuppressed. The efficacy of the seasonal influenza vaccine has not been well studied in patients receiving chemotherapy. We assessed the efficacy of seasonal influenza vaccine in patients with non-haematological malignancy on active treatment (chemotherapy and targeted therapy).

METHODS

A prospective single arm, open label study with 53 patients with non-haematological cancers recruited during the 2011 and 2012 influenza seasons. Participants had one dose of 2011/2012 trivalent vaccine containing strains A/California/7/2009(H1N1), A/Perth/16/2009 (H3N2) and B/Brisbane/60/2008 (Fluvax) prior to or in-between treatment cycles. Haemagglutination inhibition antibody (HIA) titres in serum were measured at baseline 3, 6 and 24 weeks. Primary endpoint: seroconversion rate (SCR) at 3 weeks. Secondary endpoints: late SCR at 6 weeks. rate of sustained sero-protection titres (SPR) at 24 weeks. Seroconversion was defined as postvaccination ≥ 4-fold increase in HIA titre and sero-protection defined as a HIA ≥ 1:40.

RESULTS

The SCR at 3 weeks were 35%, 30% and 22.5% to the H1N1, H3N2 and B/Bris strains, respectively. There were no new cases of late SC at 6 weeks or 24 weeks. The SPR at 3 weeks were 72.5%, 65% and 40%, respectively, to H1N1, H3N2 and B/Bris. The SPR at 24 weeks to H1N1, H3N2 and B/Bris were 40%, 52.5% and 17.5%, respectively.

CONCLUSIONS

Patients on various solid tumour treatments achieve sero-protection rate congruent with the general population. The sero-protection HIA titres were not sustained at 24 weeks postvaccination.

Anion-Exchange Method for Determination of Phytate in Foods: Collaborative Study

Phytate, a naturally occurring organic compound found in plant seeds, roots, and tubers, was determined in a collaborative study using a modified anion-exchange method. Seven samples (peanut flour, oats, rice, isolated soybean protein, a vegetarian diet composite, wheat bran, and whole wheat bread), supplied as blind duplicate samples, were analyzed in triplicate by 7 collaborators. Phytate concentrations in the samples ranged from 2.38 to 46.70 mg/g. Relative standard deviations (RSD = CV) for repeatability ranged from 2.5 to 10.1%, and for reproducibility, from 4.5 to 11.0%. The method has been adopted official first action.

Abstract LB-039: Chronic inflammation-mediated contribution of bone marrow-derived epithelial cells and hair follicle stem cells to development of cutaneous neoplasms

Bone marrow-derived epithelial cells (BMDECs) are recruited to sites of chronic inflammation; however, their clinical significance has not been determined. Here, we used gender-mismatched allogeneic bone marrow transplantation (BMT) in the context of the classical multistage model for murine cutaneous carcinogenesis to probe the recruitment of BMDECs in skin tumors initiated with the carcinogen, dimethylbenz[a]anthracene (DMBA), and promoted with the phorbol ester, 12-O-tetradecanolyphorbol-13-acetate (TPA). We detected clusters of bone marrow-derived cells (BMDCs) in over 40% of papillomas, where they occupied 25% or more of the epithelial lesional area. In the dysplastic ulcers which arose in some irradiated DMBA/TPA treated mice, the magnitude of the recruitment was greater. The BMDCs clustered in the cutaneous epithelium where they became immunoreactive to epidermal keratins, and proliferated and stratified, thereby contributing to the lesions comparably with the progeny of hair follicle stem cells in engrafted Krt1-15Cre;R26R mice. Moreover, cytokeratins were detected by immunostaining and Q-PCR in plastic adherent bone marrow cells (BMCs) cultured in the presence of filter-separated epidermal keratinocytes (KCs). Cytokeratin production was enhanced by bone morphogenetic protein 5 (BMP5). Moreover, BMCs migrated towards the alarmin protein, High Mobility Group Box 1 (HMGB1), as well as towards epidermal KCs in ex vivo invasion assays. Furthermore, when naïve female mice received BMTs from donors previously treated with DMBA, several papillomas and a squamous cell carcinoma were observed after TPA promotion alone.

We conclude that surprisingly large numbers of BMDECs are recruited to a subset of cutaneous papillomas and dysplastic ulcers and reflect a previously unrecognized systemic contribution to these lesions. We also conclude that carcinogen-exposed cells originating in the BMCs are sufficient to initiate a subset of benign and malignant lesions upon tumor promotion. Ultimately, these findings may provide novel targets for treatment of non-melanoma skin cancers as well as other cancers.

Citation Format: Heuijoon Park, Sonali Lad, Kelsey Boland, Kelly Johnson, Nyssa Readio, Guangchun Jin, Samuel A sfaha, Kelly S. Patterson, Ashok Singh, Xiangdong Yang, Douglas Londono, Anupama Singh, Carol Trempus, Derek Gordon, Timothy C. Wang, Rebecca J. Morris. Chronic inflammation-mediated contribution of bone marrow-derived epithelial cells and hair follicle stem cells to development of cutaneous neoplasms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-039.

Offering maternal composite ewes higher levels of nutrition from mid-pregnancy to lambing results in predictable increases in birthweight, survival and weaning weight of their lambs

Management of nutrition during pregnancy for maternal composite ewes has the potential to improve lamb production and survival in prime lamb production systems but existing condition score (CS) guidelines developed for Merinos may not be appropriate for the optimum production of maternal ewes. To address this, three replicated experiments were conducted at two research sites in Victoria and one in Western Australia. Ewes (781–800 per site) were allocated to four CS treatments following pregnancy scanning (~Day 50) and differentially fed to reach approximate targets of CS 2.4, 2.8, 3.2 and 3.6 by lambing. Single and multiple bearing ewes grazed together, and nutritional treatments were applied until the end of lambing after which ewes and lambs were aggregated into management groups containing all treatments. At lambing, maternal ewe liveweight had a range between treatments of 13.7–19.1 kg (average 16.4 kg) and CS varied by 1.1–1.5 of a CS (average 1.24). Across site analysis indicated that lamb birthweight and weaning weight increased with application of higher CS treatments (P &lt; 0.001). There was also an improvement in survival of multiple born lambs with increasing CS at lambing (P &lt; 0.001). Birthweight was significantly related to survival (P &lt; 0.001) at all sites with no significant effect of birth type on lamb survival. Changes in birthweight and weaning weight could be predicted from ewe joining liveweight, ewe liveweight change to Day 90 and ewe liveweight change Day 90 to lambing. The coefficients derived for each of these effects were similar to those found in previous experiments examining Merino and crossbred Border Leicester Merino ewes. The optimum CS targets for multiple bearing maternal composite ewes may be higher than the industry recommended target for Merino ewes based on advantages in lamb survival and weaning weight.

Bone marrow-derived epithelial cells and hair follicle stem cells contribute to development of chronic cutaneous neoplasms

We used allogeneic bone marrow transplantation (BMT) and a mouse multistage cutaneous carcinogenesis model to probe recruitment of bone marrow-derived epithelial cells (BMDECs) in skin tumors initiated with the carcinogen, dimethylbenz[a]anthracene (DMBA), and promoted with 12-O-tetradecanolyphorbol-13-acetate (TPA). BMDECs clustered in the lesional epithelium, expressed cytokeratins, proliferated, and stratified. We detected cytokeratin induction in plastic-adherent bone marrow cells (BMCs) cultured in the presence of filter-separated keratinocytes (KCs) and bone morphogenetic protein 5 (BMP5). Lineage-depleted BMCs migrated towards High Mobility Group Box 1 (HMGB1) protein and epidermal KCs in ex vivo invasion assays. Naive female mice receiving BMTs from DMBA-treated donors developed benign and malignant lesions after TPA promotion alone. We conclude that BMDECs contribute to the development of papillomas and dysplasia, demonstrating a systemic contribution to these lesions. Furthermore, carcinogen-exposed BMCs can initiate benign and malignant lesions upon tumor promotion. Ultimately, these findings may suggest targets for treatment of non-melanoma skin cancers.

Real-world outcomes of unrestricted direct-acting antiviral treatment for hepatitis C in Australia: The South Australian statewide experience

In March 2016, the Australian government offered unrestricted access to direct-acting antiviral (DAA) therapy for chronic hepatitis C virus (HCV) to the entire population. This included prescription by any medical practitioner in consultation with specialists until sufficient experience was attained. We sought to determine the outcomes and experience over the first twelve months for the entire state of South Australia. We performed a prospective, observational study following outcomes of all treatments associated with the state's four main tertiary centres. A total of 1909 subjects initiating DAA therapy were included, representing an estimated 90% of all treatments in the state. Overall, SVR12 was 80.4% in all subjects intended for treatment and 95.7% in those completing treatment and follow-up. 14.2% were lost to follow-up (LTFU) and did not complete SVR12 testing. LTFU was independently associated with community treatment via remote consultation (OR 1.50, 95% CI 1.04-2.18, P = .03), prison-based treatment (OR 2.02, 95% CI 1.08-3.79, P = .03) and younger age (OR 0.98, 95% CI 0.97-0.99, P = .05). Of the 1534 subjects completing treatment and follow-up, decreased likelihood of SVR12 was associated with genotype 2 (OR 0.23, 95% CI 0.07-0.74, P = .01) and genotype 3 (OR 0.23, 95% CI 0.12-0.43, P ≤ .01). A significant decrease in treatment initiation was observed over the twelve-month period in conjunction with a shift from hospital to community-based treatment. Our findings support the high responses observed in clinical trials; however, a significant gap exists in SVR12 in our real-world cohort due to LTFU. A declining treatment initiation rate and shift to community-based treatment highlight the need to explore additional strategies to identify, treat and follow-up remaining patients in order to achieve elimination targets.

Efficacy and Safety of Subcutaneous Belimumab in Anti-Double-Stranded DNA-Positive, Hypocomplementemic Patients With Systemic Lupus Erythematosus

OBJECTIVE

To investigate the efficacy and safety of belimumab, a human immunoglobulin monoclonal antibody against B lymphocyte stimulator, in a subset of patients with systemic lupus erythematosus (SLE) who were hypocomplementemic (C3 <90 mg/dl and/or C4 <10 mg/dl) and anti-double-stranded DNA (anti-dsDNA) positive (≥30 IU/ml) at baseline.

METHODS

In this phase III, double-blind, placebo-controlled study (BEL112341; ClinicalTrials.gov identifier: NCT01484496), patients with moderate to severe SLE (Safety of Estrogens in Lupus Erythematosus National Assessment version of the Systemic Lupus Erythematosus Disease Activity Index [SELENA-SLEDAI] score ≥8) were randomized (2:1) to receive weekly subcutaneous (SC) belimumab 200 mg or placebo, plus standard SLE therapy, for 52 weeks. The primary end point was SLE Responder Index 4 (SRI-4) response rate at week 52. Secondary end points were time to severe flare and reduction in corticosteroid dose (weeks 40-52). Safety was assessed throughout.

RESULTS

Of the 836 patients in the intent-to-treat (ITT) population, 356 were hypocomplementemic and anti-dsDNA positive at baseline (108 in the placebo group and 248 in the SC belimumab 200 mg group). Compared with placebo, the belimumab group contained more SRI-4 responders (47.2% versus 64.6%; P = 0.0014), had a lower incidence of severe flare according to the SELENA-SLEDAI flare index (31.5% versus 14.1%), and had a greater percentage of patients who reduced corticosteroid dosage by ≥25% to ≤7.5 mg/day during weeks 40-52 (11.4% versus 20.7%; P = 0.0844). Adverse events (AEs) were similar between treatment groups.

CONCLUSION

Our findings indicate that in hypocomplementemic, anti-dsDNA-positive SLE patients, weekly SC belimumab 200 mg significantly improves SRI-4 response, decreases severe flare incidence, and reduces corticosteroid use versus placebo; a trend toward greater benefit compared with the overall ITT population was observed. AEs were consistent with the known safety profile of belimumab.

Abstract LB-332: Evidence for cutaneous squamous tumors derived from carcinogen-exposed bone marrow

Cytokeratins are frequently found in the blood and bone marrow of patients with epithelial cancers and are attributed to metastasis. We wondered whether we could find keratin expression in blood and bone marrow in untreated adult mice. To address this problem, we have used classical immunoreactivity, Krt1-14;mTmG transgenic mice together with fluorescence activated cell sorting, and quantitative reverse transcriptase polymerase chain reaction. We have made several novel findings. First, we discovered, rare but distinctive, keratin-14 and keratin-15 immunoreactive cells the size of small lymphocytes in blood and bone marrow of untreated mice. Second, using Krt1-14;mTmG transgenic mice, we found low (8.6 GFP positive cells per 10^6 cells analyzed), but significant numbers (p&lt0.0005) of GFP positive cells in bone marrow of normal adult mice when compared with negative controls. Third, qRT-PCR demonstrated very low but reproducibly detectable expression of keratin-14 mRNA in blood and bone marrow when compared with epidermal keratinocytes: with blood expressing one thousand times, and bone marrow, one hundred thousand times, less than epidermal keratinocytes. Moreover, FACS analysis of fresh bone marrow disclosed a subpopulation of keratin-14 immunoreactive cells that was negative for hematopoietic lineage markers. Furthermore, and even more curious, recipients of bone marrow transplants from DMBA-treated UBC/GFP mice (“toxic bone marrow”) developed GFP-immunoreactive skin tumors upon TPA tumor promotion: four of fifteen mice developed GFP-immunoreactive skin tumors. Of these tumors, four were squamous papillomas, and one was a squamous cell carcinoma. None of the ten control mice receiving normal whole bone marrow developed any skin tumors upon tumor promotion. We conclude from these observations that keratin-14 protein and mRNA are expressed at low, but detectable levels in the blood and bone marrow of mice, and that a subset of “toxic bone marrow” derived cells can be recruited to form epithelial benign and malignant squamous tumors. Building upon these observations should open new avenues of understanding for cutaneous biology, non-melanoma skin cancer, and other epithelia and their cancers.

Citation Format: Sonali Lad, Kelly Johnson, Kelsey Boland, Nyssa Readio, Todd Schuster, Yong Li, Derek Gordon, Rebecca J. Morris. Evidence for cutaneous squamous tumors derived from carcinogen-exposed bone marrow [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-332.

A 6-month open-label extension study of the safety and efficacy of subcutaneous belimumab in patients with systemic lupus erythematosus

Objective

To evaluate the safety, tolerability and efficacy of subcutaneous (SC) belimumab in patients with systemic lupus erythematosus (SLE) beyond 1 year.

Methods

This was a 24-week, open-label extension following a 52-week, double-blind, placebo-controlled trial of belimumab SC. Patients who completed the double-blind phase were eligible to enter the open-label phase. All patients received weekly belimumab 200 mg SC plus standard SLE therapy. Outcome measures included safety and efficacy (SLE Response Index (SRI) and SLE Flare Index (SFI) rates), and changes in biomarker and B cell levels.

Results

Of 677 patients who completed the 52-week, double-blind phase, 662 entered the open-label phase; 206 had previously received placebo and 456 had previously received belimumab. Despite differences in total belimumab exposure (24 weeks in the placebo-to-belimumab group versus 76 weeks in the belimumab group), the proportions of patients experiencing more than one adverse event (AE) or a serious AE in the open-label phase were similar between groups (placebo-to-belimumab: 51.5 and 6.8%; belimumab: 48.2 and 5.5%, respectively). Most AEs were mild/moderate in severity. Efficacy was maintained through the extension phase. An SRI response was achieved by 16.1% of patients in the placebo-to-belimumab group and 76.3% patients in the belimumab group. Furthermore, 1.0% of patients in the placebo-to-belimumab group and 2.6% of patients in the belimumab group experienced a severe SFI flare.

Conclusion

Belimumab SC was well tolerated and efficacy was maintained during the extension phase of this study. The safety profile of belimumab SC is consistent with that of previous experience with belimumab.

Trial registration

ClinicalTrials.gov identifier: NCT01484496

A randomized, open-label study to investigate the effect of belimumab on pneumococcal vaccination in patients with active, autoantibody-positive systemic lupus erythematosus

Objective Intravenous belimumab 10 mg/kg is approved as an add-on therapy in patients with active, autoantibody-positive systemic lupus erythematosus. This study aimed to assess the impact of belimumab on immune response to pneumococcal vaccination in patients with systemic lupus erythematosus. Methods This was a Phase 4, open-label study (GSK BEL115470; NCT01597492) conducted in the United States. Patients were randomized (7:9) to receive a 23-valent pneumococcal vaccination four weeks prior to (pre-belimumab cohort) or 24 weeks after (belimumab-concurrent cohort) commencing four-weekly belimumab 10 mg/kg intravenous treatment plus standard systemic lupus erythematosus therapy. Analyses of vaccine titers were performed on the as-treated population (received ≥1 dose of belimumab). The primary endpoint was the proportion of patients with positive antibody responses (≥2-fold increase from pre-vaccination levels, or post-vaccination level ≥ 0.6 µg/mL if pre-vaccination levels were unquantifiable) to ≥1 of 23 pneumococcal vaccine serotypes, four weeks post vaccination. Other endpoints included the proportion of patients with positive antibody responses to ≥2 to ≥10, and ≥11-23 (post hoc analysis) of serotypes. Safety was assessed by monitoring adverse events. Results Seventy-nine patients received pneumococcal vaccination (pre-belimumab cohort, n = 34; belimumab-concurrent cohort, n = 45). The majority (87.3% [69/79]) completed the study; 10 (12.7%) withdrew (patient request, n = 3; adverse event, n = 3; lost to follow-up, n = 2; other, n = 2). At Week 4 post-vaccination, 97.0% (32/33) and 97.6% (40/41) of patients (pre-belimumab and concurrent belimumab cohorts, respectively) had a positive response to ≥1 of 23 pneumococcal serotypes. Over 85% of patients in both cohorts responded to ≥10 of serotypes, approximately 80% responded to ≥12 serotypes, and approximately two-thirds responded to ≥16 serotypes. Little difference was observed between cohorts across a broad response, up to 23 serotypes. Eight (23.5%) patients experienced an adverse event considered by the investigator to be treatment-related in the pre-belimumab cohort and four (8.9%) in the belimumab-concurrent cohort; seven patients experienced non-fatal serious adverse events (pre-belimumab cohort, 11.8% [ n = 4]; concurrent-belimumab cohort, 6.7% [ n = 3]), and no deaths were reported. Conclusion The proportion of patients generating a response to ≥1 pneumococcal serotype did not differ between the pre-belimumab and belimumab-concurrent cohorts; the proportions were also comparable across a broader response (from ≥2 serotypes to 23 serotypes).

An Analytic Solution to the Computation of Power and Sample Size for Genetic Association Studies under a Pleiotropic Mode of Inheritance

Our motivation here is to calculate the power of 3 statistical tests used when there are genetic traits that operate under a pleiotropic mode of inheritance and when qualitative phenotypes are defined by use of thresholds for the multiple quantitative phenotypes. Specifically, we formulate a multivariate function that provides the probability that an individual has a vector of specific quantitative trait values conditional on having a risk locus genotype, and we apply thresholds to define qualitative phenotypes (affected, unaffected) and compute penetrances and conditional genotype frequencies based on the multivariate function. We extend the analytic power and minimum-sample-size-necessary (MSSN) formulas for 2 categorical data-based tests (genotype, linear trend test [LTT]) of genetic association to the pleiotropic model. We further compare the MSSN of the genotype test and the LTT with that of a multivariate ANOVA (Pillai). We approximate the MSSN for statistics by linear models using a factorial design and ANOVA. With ANOVA decomposition, we determine which factors most significantly change the power/MSSN for all statistics. Finally, we determine which test statistics have the smallest MSSN. In this work, MSSN calculations are for 2 traits (bivariate distributions) only (for illustrative purposes). We note that the calculations may be extended to address any number of traits. Our key findings are that the genotype test usually has lower MSSN requirements than the LTT. More inclusive thresholds (top/bottom 25% vs. top/bottom 10%) have higher sample size requirements. The Pillai test has a much larger MSSN than both the genotype test and the LTT, as a result of sample selection. With these formulas, researchers can specify how many subjects they must collect to localize genes for pleiotropic phenotypes.

Abstract S4-03: Targeted and selective degradation of estrogen receptor (ER) alpha by PROTACs

ERα-positive breast cancers comprise approximately 80% of all newly diagnosed cases. Current treatment approaches targeting ER signaling include antagonizing and/or downregulating ER or reducing estrogen levels. Faslodex (fulvestrant) is the only clinically-approved agent that is both a potent ER antagonist and downregulator but has limitations given its pharmacokinetics and route of administration. Over the past several years, targeted ER therapies have focused on developing selective estrogen receptor downregulators (SERDs, i.e, GDC-0810, GDC-0927, AZD9496, RAD1901). The mechanisms involved in ER downregulation by SERD binding are not completely understood, but evidence suggests that conformational changes in the receptor upon ligand binding combined with specific co-regulator interactions destabilize the receptor making it a target for passive proteasomal degradation. We hypothesized that the complex ER pharmacology required for SERD-based passive degradation might be different across various ER-positive cell lines and that targeted degradation of the receptor by actively recruiting the ubiquitin-proteasome machinery would provide a better approach for reducing ER levels. To test this hypothesis, we developed potent molecules directed against ER using our pioneering technology—proteolysis targeting chimeras (PROTACs). PROTACs are heterobifunctional molecules that actively recruit specific E3 ligases resulting in ubiquitylation and degradation of target proteins. When testing for ER degradation using several SERDs and ER PROTACs, we discovered that both fulvestrant and ER PROTACs provided robust degradation in all ER-positive lines (&lt;1 nM 50% degradation; &gt;90% reduction) whereas other SERDs did not degrade or only modestly degraded the receptor. Importantly, MCF-7 cells were uniquely sensitive to SERD-based degradation of ER compared to other cell lines. Subcutaneous administration of fulvestrant (1mpk) or ER PROTACs (10 mpk) reduced uterine ER alpha levels in immature rats (&gt;65% reduction). PROTAC-mediated degradation of ER was also achieved in breast cancer xenografts. To further validate the PROTAC mechanism, incubation of ER-positive cells with ER PROTACs resulted in increased levels of poly-ubiquitylated ERα when compared to SERDs. Lastly, to demonstrate the specificity of PROTAC-mediated ERα degradation, we utilized a cellular expression proteomics-based approach to examine over 7,000 proteins. In this experiment, only ERα and several known proteins whose genes are regulated by ERα, were significantly reduced by PROTACs. It remains to be seen how the current class of investigational downregulators will perform in the clinic. More importantly, a better understanding of the therapeutic potential and benefit of degrading the receptor instead of inhibiting the receptor needs to be explored. To that end, we continue to develop and characterize novel ER PROTACs with the anticipation that targeted ERα degradation will provide a greater clinical benefit than receptor antagonism.

Citation Format: Flanagan JJ, Rossi AK, Anderoli M, Willard RR, Gordon D, Harling J, Churcher I, Smith I, Zinn N, Bantscheff M, Crews CM, Crew A, Coleman KG, Winkler JD, Qian Y. Targeted and selective degradation of estrogen receptor (ER) alpha by PROTACs [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr S4-03.

Abstract P5-02-03: Evaluating the feasibility of a web-based preference-tolerant randomized trial of risk-based vs. annual breast cancer screening: WISDOM study pilot

Background: The WISDOM Study (Women Informed to Screen Depending on Measures of risk) aims to examine the effectiveness of personalized breast cancer screening and to bring objective recommendations to the current mammography screening debate. The WISDOM Study is a 100,000 woman randomized trial with a preference-tolerant design that will determine if risk-based screening (RBS) vs. annual screening, is as safe, less morbid, enables prevention and is preferred by women. A pilot was conducted to test the logistics of online participation and examine the acceptance of the study design and approach.

Methods: Women were recruited from the UCSF site of the Athena Breast Health Network, a clinical care-research cohort of 110,000 women from the 5 University of California Medical Centers and Sanford Health. The pilot recruited women via email who were 40 -74 years of age with no history of breast cancer and a normal mammogram in the past year. Those interested visited the WISDOM Study website (wisdomstudy.org), signed up, elected randomization or self-selection, provided electronic consent using DocuSign (eConsent), and completed genetic testing (RBS arm). The Breast Cancer Surveillance Consortium (BCSC) model (standard risk factors, ethnicity, and breast density) in addition to genetic testing (9 genes and 75 SNPs) was used to calculate breast cancer risks that informed the start and frequency of screening for women in the RBS arm. BCSC was also used in the annual screening arm but did not inform mammography screening recommendations. The pilot used a mixed method approach (using enrollment data, Exit Survey data, individual interviews and focus groups) to assess enrollment preferences, randomization acceptance and overall study workflow.

Results: The online electronic enrollment process and patient engagement portal was successfully implemented. In total, 639 women were invited, 235 registered (34%), and 171 (27%) consented to the pilot. Of these, 74% (127) elected to be randomized, and 26% chose to self-assign (66% chose annual screening (29)). Mean age was 56 years and the ethnic breakdown of the cohort was: 79% White, 10% Asian, 7% Latino, 3% Black, 1% other. 92% of those in the risk-based arm of the study completed genetic testing and were given results; only one genetic mutation was identified and occurred in CHEK2. Within the RBS arm (78), mammography recommendations were: 61% no further mammography until the age of 50, 22% biennial, 11% annual, and 6% every 6 month alternating MRI and mammogram. Exit Survey data illuminated confusion in study arm names (risk-based vs. annual), randomization acceptance (74%), annual arm preference in the self-selection group (66%), eConsent satisfaction (90%), enrollment process ease of use (88%), and website content, navigation and appearance satisfaction (66%). The pilot concluded in May 2016 to allow for refinements prior to the full trial.

Conclusion: Our pilot demonstrates that the majority of women are willing to be randomized and participate in an online screening study to answer the important question on optimal breast cancer screening. The pilot study results will inform implementation of the 100,000 women WISDOM Study which launches in fall of 2016.

Citation Format: Stover Fiscalini A, Theiner S, Kaplan C, Sarrafan S, Sawyer S, Liang A, Rosenberg-Wohl S, Gordon D, Frick M, Borowsky A, Anton-Culver H, Naeim A, LaCroix A, Cink T, Collaboration Athena Breast Health Network and Advocate Partners, Esserman L, van 't Veer L. Evaluating the feasibility of a web-based preference-tolerant randomized trial of risk-based vs. annual breast cancer screening: WISDOM study pilot [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-02-03.

p53, Cyclin D1, p21 (WAF1) and Ki-67 (MIB1) Expression at Invasive Tumour Fronts of Oral Squamous Cell Carcinomas and Development of Local Recurrence

BACKGROUND

Expression of p53, cyclin D1, p21 (WAF1) and Ki-67 (MIB1) was evaluated in oral squamous cell carcinoma (OSCC) to test whether levels of these markers at invasive tumour fronts (ITFs) could predict the development of local recurrence.

MATERIALS AND METHODS

Archived paraffin-embedded specimens from 51 patients with T1/T2 tumours were stained immunohistochemically and analysed quantitatively. Local recurrence-free survival was tested with Kaplan-Meier survival plots (log-rank test) using median values to define low and high expression groups and with a Cox's proportional hazards model in which the expression scores were entered as continuous variables.

RESULTS

The assessment of expression of all markers was highly reliable, univariate analysis showing that patients with clear surgical margins, with low cyclin D1 and high p21 expression at the ITF had the best local recurrence-free survival. Multivariate analysis showed that these three parameters were independent prognostic factors but that neither p53 nor MIB1 expression were of prognostic value.

CONCLUSIONS

Assessment of p53, cyclin D1, p21 (WAF1), and Ki-67 (MIB1) at the ITF could help to predict local recurrence in early stage oral squamous cell carcinoma cases.

The FIELDS Instrument Suite for Solar Probe Plus: Measuring the Coronal Plasma and Magnetic Field, Plasma Waves and Turbulence, and Radio Signatures of Solar Transients

NASA's Solar Probe Plus (SPP) mission will make the first in situ measurements of the solar corona and the birthplace of the solar wind. The FIELDS instrument suite on SPP will make direct measurements of electric and magnetic fields, the properties of in situ plasma waves, electron density and temperature profiles, and interplanetary radio emissions, amongst other things. Here, we describe the scientific objectives targeted by the SPP/FIELDS instrument, the instrument design itself, and the instrument concept of operations and planned data products.

The Epidemiology of Staphylococcus aureus and Panton-Valentine Leucocidin (pvl) in Central Australia, 2006-2010

Background

The Central Australian Indigenous population has a high incidence of Staphylococcus aureus bacteremia (SAB) but little is known about the local molecular epidemiology.

Methods

Prospective observational study of bacteremic and nasal colonizing S.aureus isolates between June 2006 to June 2010. All isolates underwent single nucleotide polymorphism (SNP) genotyping and testing for the presence of the Panton-Valentine Leucocidin (pvl) gene.

Results

Invasive isolates (n = 97) were predominantly ST93 (26.6 %) and pvl positive (54.3 %), which was associated with skin and soft tissue infections (OR 4.35, 95 % CI 1.16, 16.31). Non-multiresistant MRSA accounted for 31.9 % of bacteremic samples and showed a trend to being healthcare associated (OR 2.16, 95 % CI 0.86, 5.40). Non-invasive isolates (n = 54) were rarely ST93 (1.9 %) or pvl positive (7.4 %).

Conclusions

In Central Australia, ST93 was the dominant S.aureus clone, and was frequently pvl positive and associated with an aggressive clinical phenotype. Whether non-nasal carriage is more important with invasive clones or whether colonization occurs only transiently remains to be elucidated.

Comparison of intravenous and subcutaneous exposure supporting dose selection of subcutaneous belimumab systemic lupus erythematosus Phase 3 program

Background Belimumab is a recombinant, human, IgG1λ monoclonal antibody that targets B-lymphocyte stimulator. The intravenous formulation is indicated for the treatment of active, autoantibody-positive systemic lupus erythematosus (SLE). Belimumab has been formulated for subcutaneous (SC) administration to improve patient convenience. This post-hoc modeling and simulation analysis characterizes the population pharmacokinetics (PK) of SC belimumab, and compares the exposure profiles of the approved belimumab IV dose-10 mg/kg every four weeks-to the 200 mg SC weekly dose in SLE patients, highlighting key pharmacological differences relevant for clinicians. Methods Data from two Phase 1 studies in US American and Japanese healthy subjects were analyzed with a non-linear mixed effects modeling approach. The resulting SC population PK model and a previously developed IV population PK model were used to conduct simulation trials in a Phase 3 IV belimumab SLE patient population, comparing chronic exposure profiles and exposure ranges stratified by body weight tertiles for IV vs SC dosing. Results The PK of belimumab following SC administration was best described by a linear two-comment model. The estimates for clearance, steady-state volume of distribution, and bioavailability were 208 mL/day, 5250 mL, and 76%, respectively. After four weeks of SC dosing, simulated belimumab concentrations exceeded the steady-state trough concentrations of the IV dosing regimen. At steady state simulated serum profiles demonstrated comparable average belimumab concentrations (C_avg,ss) after IV and SC dosing. Simulated belimumab exposures demonstrated largely overlapping concentration ranges following 200 mg SC weekly and 10 mg/kg IV every four weeks dosing. Discussion The predicted C_avg,ss of belimumab in SLE patients was comparable following 200 mg SC weekly and 10 mg/kg IV every four weeks dosing. The simulated belimumab accumulation following SC weekly dosing indicated that administration of a loading dose was not required. Similar C_avg,ss ranges were predicted for fixed dose SC and weight-proportional IV regimens in the simulated SLE population, albeit with a reversed body-size-to-exposure relationship for the SC regimen. These findings provide rheumatologists with a better understanding of expected differences in belimumab exposure when comparing IV and SC dosing regimens.

Long-term organ damage accrual and safety in patients with SLE treated with belimumab plus standard of care

Objective

To examine long-term organ damage and safety following treatment with belimumab plus standard of care (SoC) in patients with systemic lupus erythematosus (SLE).

Methods

Pooled data were examined from two ongoing open-label studies that enrolled patients who completed BLISS-52 or BLISS-76. Patients received belimumab every four weeks plus SoC. SLICC Damage Index (SDI) values were assessed every 48 weeks (study years) following belimumab initiation (baseline). The primary endpoint was change in SDI from baseline at study years 5–6. Incidences of adverse events (AEs) were reported for the entire study period.

Results

The modified intent-to-treat (MITT) population comprised 998 patients. At baseline, 940 (94.2%) were female, mean (SD) age was 38.7 (11.49) years, and disease duration was 6.7 (6.24) years. The mean (SD) SELENA-SLEDAI and SDI scores were 8.2 (4.18) and 0.7 (1.19), respectively; 411 (41.2%) patients had organ damage (SDI = 1: 235 (23.5%); SDI ≥ 2: 176 (17.6%)) prior to belimumab. A total of 427 (42.8%) patients withdrew overall; the most common reasons were patient request (16.8%) and AEs (8.5%).

The mean (SD) change in SDI was +0.2 (0.48) at study years 5–6 (n = 403); 343 (85.1%) patients had no change from baseline in SDI score (SDI +1: 46 (11.4%), SDI +2: 13 (3.2%), SDI +3: 1 (0.2%)). Of patients without organ damage at baseline, 211/241 (87.6%) had no change in SDI and the mean change (SD) in SDI was +0.2 (0.44). Of patients with organ damage at baseline, 132/162 (81.5%) had no change in SDI and the mean (SD) change in SDI was +0.2 (0.53). The probability of not having a worsening in SDI score was 0.88 (95% CI: 0.85, 0.91) and 0.75 (0.67, 0.81) in those without and with baseline damage, respectively (post hoc analysis).

Drug-related AEs were reported for 433 (43.4%) patients; infections/infestations (282, 28.3%) and gastrointestinal disorders (139, 13.9%) were the most common.

Conclusion

Patients with SLE treated with long-term belimumab plus SoC had a low incidence of organ damage accrual and no unexpected AEs. High-risk patients with pre-existing organ damage also had low accrual, suggesting a favorable effect on future damage development.

Elevated BLyS levels in patients with systemic lupus erythematosus: Associated factors and responses to belimumab

Introduction

Patients with systemic lupus erythematosus (SLE) with B-lymphocyte stimulator (BLyS) levels ≥ 2 ng/mL are at increased risk of flare. A regression analysis was undertaken to identify routine clinical measures that correlate with BLyS ≥ 2 ng/mL. Efficacy and safety of belimumab 10 mg/kg were examined in patients with BLyS ≥ 2 ng/mL and < 2 ng/mL.

Methods

Data from BLISS-52 and -76 (N = 1684) were pooled post hoc. A univariate logistic regression was employed to identify factors predictive of baseline BLyS ≥ 2 ng/mL. Factors significant at the 0.05 level then entered a stepwise logistic regression as covariates. Efficacy endpoints included SLE responder index (SRI), ≥ 4-point reduction in Safety of Estrogens in Lupus National Assessment–Systemic Lupus Erythematosus Disease Activity Index (SELENA-SLEDAI) and risk of severe flare over 52 weeks. Adverse events (AEs) were analyzed for each treatment arm and BLyS subgroup.

Results

Baseline predictors of BLyS ≥ 2 ng/mL included positive anti-Smith (≥ 15 U/mL), low complement (C) 3 (< 900 mg/L), anti-double-stranded DNA (anti-dsDNA) 80–200 and ≥ 200 IU/mL, immunosuppressant usage, proteinuria, elevated C-reactive protein (CRP), and low total lymphocyte count for all patients. Belimumab 10 mg/kg led to significantly greater SRI responses over 52 weeks versus placebo in both BLyS subgroups, though treatment differences were numerically greater at Week 52 in the BLyS ≥ 2 ng/mL group (24.1%, p < 0.0001) compared with BLyS < 2 ng/mL (8.2%, p = 0.0158). Results were similar for ≥ 4-point reduction in SELENA-SLEDAI. Risk of severe flare over 52 weeks was significantly reduced with belimumab 10 mg/kg versus placebo in the BLyS ≥ 2 ng/mL group (p = 0.0002). AEs were similar across treatment arms and BLyS subgroups.

Conclusions

Positive anti-Smith, low C3, anti-dsDNA ≥ 80 IU/mL, immunosuppressant usage, proteinuria, elevated CRP, and low total lymphocyte count were predictors of BLyS ≥ 2 ng/mL. Monitoring these factors could identify patients with BLyS ≥ 2 ng/mL who are at risk of flare.

Deficits in Trabecular Bone Microarchitecture in Young Women With Type 1 Diabetes Mellitus

The pathophysiological mechanism of increased fractures in young adults with type 1 diabetes mellitus (T1DM) is unclear. We conducted a case-control study of trabecular bone microarchitecture and vertebral marrow adiposity in young women with T1DM. Thirty women with T1DM with a median age (range) age of 22.0 years (16.9, 36.1) attending one outpatient clinic with a median age at diagnosis of 9.7 years (0.46, 14.8) were compared with 28 age-matched healthy women who acted as controls. Measurements included MRI-based assessment of proximal tibial bone volume/total volume (appBV/TV), trabecular separation (appTb.Sp), vertebral bone marrow adiposity (BMA), and abdominal adipose tissue and biochemical markers of GH/IGF-1 axis (IGF-1, IGFBP3, ALS) and bone turnover. Median appBV/TV in cases and controls was 0.3 (0.22, 0.37) and 0.33 (0.26, 0.4), respectively (p = 0.018) and median appTb.Sp in T1DM was 2.59 (2.24, 3.38) and 2.32 (2.03, 2.97), respectively (p = 0.012). The median appBV/TV was 0.28 (0.22, 0.33) in those cases with retinopathy (n = 15) compared with 0.33 (0.25, 0.37) in those without retinopathy (p = 0.02). Although median visceral adipose tissue in cases was higher than in controls at 5733 mm(3) (2030, 11,144) and 3460 mm(3) (1808, 6832), respectively (p = 0.012), there was no difference in median BMA, which was 31.1% (9.9, 59.9) and 26.3% (8.5, 49.8) in cases and controls, respectively (p = 0.2). Serum IGF-1 and ALS were also lower in cases, and the latter showed an inverse association to appTbSp (r = -0.30, p = 0.04). Detailed MRI studies in young women with childhood-onset T1DM have shown clear deficits in trabecular microarchitecture of the tibia. Underlying pathophysiological mechanisms may include a microvasculopathy.