Case fatality risk of novel coronavirus diseases 2019 in China

OBJECTIVE

The outbreak of novel coronavirus disease 2019 (COVID-19) imposed a substanal health burden in mainland China and remains a global epidemic threat. Our objectives are to assess the case fatality risk (CFR) among CO VID-19 patients detected in mainland China, stratified by clinical category and age group.

METHODS

We collected individual information on laboratory-confirmed COVID-19 cases from publicly available official sources from December 29, 2019 to February 23, 2020. We explored the risk factors associated with mortality. We used methods accounting for right-censoring and survival analyses to estimatethe CFR among detected cases.

RESULTS

Of 12,863 cases reported outside Hubei, we obtained individual records for 9,651 cases, including 62 deaths and 1,449 discharged cases. The deceased were significantly older than discharged cases (median age: 77 vs 39 years, p<0.001). 58% (36/62) were male. Older age (OR 1.18 per year; 95% CI: 1.14 to 1.22), being male (OR 2.02; 95% CI: 1.02 to 4.03), and being treated in less developed economic regions (e.g., West and Northeast vs. East, OR 3.93; 95 %Cl:1.74 to 8.85) were mortality risk factors. The estimated CFR was 0.89-1.24% among all cases. The fatality risk among critical patients was 2-fold higher than that among severe and critical patients, and 24-fold higher than that among moderate, severe and critical patients.

CONCLUSIONS

Our estimates of CFR based on laboratory-confirmed cases ascertained outside of Hubei suggest that COVID-19 is not as severe as severe acute respiratory syndrome and Middle East respiratory syndrome, but more similar to the mortality risk of 2009 H1N1 influenza pandemic in hospitalized patients. The fatality risk of COVID-19 is higher in males and increases with age. Our study improves the severity assessment of the ongoing epidemic and can inform the COVID-19 outbreak response in China and beyond.

Long-term clinical prognosis of human infections with avian influenza A(H7N9) viruses in China after hospitalization

BACKGROUND

Mainland China has experienced five epidemics of human cases of avian influenza A(H7N9) virus infection since 2013. We conducted a prospective study to assess long-term clinical, pulmonary function testing, and chest computed tomography (CT) imaging findings after patients were discharged from hospital.

METHODS

A(H7N9) survivors in five provinces and one municipality underwent follow-up visits from August 2013 to September 2018, at three, six, and 12 months after illness onset, and a subset was also assessed at 18 and 64 months after onset. Thirteen patients were enrolled from the first A(H7N9) epidemic in 2013, 36 from the 2013-2014 second epidemic, and 12 from the 2016-2017 fifth epidemic. At each visit, A(H7N9) survivors received a medical examination, including the mMRC (modified Medical Research Council) dyspnea scale assessment, chest auscultation, pulmonary function testing and chest CT scans.

FINDINGS

The median age of 61 A(H7N9) survivors was 50 years. The cumulative rate of pulmonary dysfunction was 38·5% and 78·2% for chest CT scan abnormalities at the end of follow-up. Restrictive ventilation dysfunction was common during follow-up. Mild dyspnea was documented at three to 12-month follow-up visits.

INTERPRETATION

Patients who survived severe illness from A(H7N9) virus infection had evidence of persistent lung damage and long-term pulmonary dysfunction.

FUNDING

National Science Fund for Distinguished Young Scholars (grant number 81525023); Program of Shanghai Academic/Technology Research Leader (grant number 18XD1400300); National Science and Technology Major Project of China (grant numbers 2017ZX10103009-005, 2018ZX10201001-010).

Specificity, kinetics and longevity of antibody responses to avian influenza A(H7N9) virus infection in humans

OBJECTIVES

The long-term dynamics of antibody responses in patients with influenza A(H7N9) virus infection are not well understood.

METHODS

We conducted a longitudinal serological follow-up study in patients who were hospitalized with A(H7N9) virus infection, during 2013-2018. A(H7N9) virus-specific antibody responses were assessed by hemagglutination inhibition (HAI) and neutralization (NT) assays. A random intercept model was used to fit a curve to HAI antibody responses over time. HAI antibody responses were compared by clinical severity.

RESULTS

Of 67 patients with A(H7N9) virus infection, HAI antibody titers reached 40 on average 11 days after illness onset and peaked at a titer of 290 after three months, and average titers of ≥80 and ≥40 were present until 11 months and 22 months respectively. HAI antibody responses were significantly higher in patients who experienced severe disease, including respiratory failure and acute respiratory distress syndrome, compared with patients who experienced less severe illness.

CONCLUSIONS

Patients with A(H7N9) virus infection who survived severe disease mounted higher antibody responses that persisted for longer periods compared with those that experienced moderate disease. Studies of convalescent plasma treatment for A(H7N9) patients should consider collection of donor plasma from survivors of severe disease between 1 and 11 months after illness onset.

Evolving epidemiology of novel coronavirus diseases 2019 and possible interruption of local transmission outside Hubei Province in China: a descriptive and modeling study

Background

The COVID-19 epidemic originated in Wuhan City of Hubei Province in December 2019 and has spread throughout China. Understanding the fast evolving epidemiology and transmission dynamics of the outbreak beyond Hubei would provide timely information to guide intervention policy.

Methods

We collected individual information on 8,579 laboratory-confirmed cases from official publically sources reported outside Hubei in mainland China, as of February 17, 2020. We estimated the temporal variation of the demographic characteristics of cases and key time-to-event intervals. We used a Bayesian approach to estimate the dynamics of the net reproduction number (Rt) at the provincial level.

Results

The median age of the cases was 44 years, with an increasing of cases in younger age groups and the elderly as the epidemic progressed. The delay from symptom onset to hospital admission decreased from 4.4 days (95%CI: 0.0-14.0) until January 27 to 2.6 days (0.0-9.0) from January 28 to February 17. The mean incubation period was estimated at 5.2 days (1.8-12.4) and the mean serial interval at 5.1 days (1.3-11.6). The epidemic dynamics in provinces outside Hubei was highly variable, but consistently included a mix of case importations and local transmission. We estimate that the epidemic was self-sustained for less than three weeks with Rt reaching peaks between 1.40 (1.04-1.85) in Shenzhen City of Guangdong Province and 2.17 (1.69-2.76) in Shandong Province. In all the analyzed locations (n=10) Rt was estimated to be below the epidemic threshold since the end of January.

Conclusion

Our findings suggest that the strict containment measures and movement restrictions in place may contribute to the interruption of local COVID-19 transmission outside Hubei Province. The shorter serial interval estimated here implies that transmissibility is not as high as initial estimates suggested.

Disorderless Quasi-localization of Polar Gases in One-Dimensional Lattices

One-dimensional polar gases in deep optical lattices present a severely constrained dynamics due to the interplay between dipolar interactions, energy conservation, and finite bandwidth. The appearance of dynamically bound nearest-neighbor dimers enhances the role of the 1/r^{3} dipolar tail, resulting in the absence of external disorder, in quasi-localization via dimer clustering for very low densities and moderate dipole strengths. Furthermore, even weak dipoles allow for the formation of self-bound superfluid lattice droplets with a finite doping of mobile, but confined, holons. Our results, which can be extrapolated to other power-law interactions, are directly relevant for current and future lattice experiments with magnetic atoms and polar molecules.

[Analysis on influence of the self-confidence, motivation and authoritative advice factors on the use of child restraint]

Objective: To establish the model of the self-confidence, motivation and authoritative advice factors influencing the use of child restraint and use structural equation model to test it to provide scientific basis for promoting the advocacy of use of child restraint. Methods: Using multi-stage cluster random sampling method, 9 112 parents from the family with one or more private cars and 0-6 years old children in Shanghai and Shenzhen were investigated about the use of child restraint. A theoretical model of the self-confidence, motivation and authoritative advice factors influencing the use of child restraint was constructed. The theoretical model was validated and quantitatively analyzed by structural equation model. Results: The overall model accords with the expected theoretical model, and the goodness of model fit was fine. The indicators had met the standard. RMSEA=0.03, CFI=0.97. The standardization coefficients of each route showed statistical significance (P<0.05). The standardization coefficients of the influence of authoritative suggestions and motives on self-confidence were 0.45 and 0.30 respectively, and the standardization coefficients of the influence of self-confidence on the use of child restraint was 0.40. The standardization coefficient of the influence of authoritative suggestions on motivation was 0.61. Conclusions: In the advocacy of the use of child restraint, we should attach importance to the use of recommendations from experts and organizations with professional authority, good credibility and public welfare. We should take the status of children's road traffic safety and the mechanism of the role of child restraint as one of the key points of propaganda.

[Road traffic injury happened on the way to school, among primary and secondary school students in Mengzi city, Honghe prefecture, Yunnan province in 2018]

Objective: To understand the current situation of road traffic injuries among primary and secondary school students in Mengzi city. Methods: Using the cluster random sampling method, more than 9 000 primary and secondary school students from 20 primary and secondary schools in Mengzi city, were randomly sampled. A questionnaire survey was conducted on the occurrence of road traffic injuries in school students. Results: A total of 9 197 students were surveyed, including 150 from road traffic injuries. The incidence rates of road traffic injuries was 1.63% among students in Mengzi city and 2.85% among junior high school students, with the high incidence in May. The leading places of injuries were village roads (38.00%), city roads (33.33%) and district roads (12.67%), respectively. 26.67% of the traffic injuries occurred on the way to or from schools, with riding on electric bicycle (52.00%) as the major cause and contusion/abrasion (75.33%) appeared as the major signs. Both lower and upper limbs plus multiple parts were accounting for 45.51%, 22.16% and 16.17%, respectively of all the injuries. 70.67% of all the cases with road traffic injuries in children, recovered after treatment. Children with road traffic injuries would stay in the hospital for up to 90 days but spent less than 30 000 Yuan. Conclusion: The incidence of road traffic injuries among students in Mengzi city seemed relatively high, with junior high school students reached the highest. Riding electric bicycle appeared as the leading cause for traffic injuries in children in Mengzi city of Yunnan province.

[Occurrence of injuries among left-behind children from 27 poor rural areas in 12 provinces of China, 2016]

Objective: To understand the injuries among 16 459 left-behind children from 27 poor rural areas in 12 provinces of China, 2016. Methods: Data were collected from the survey of 'Health Service Needs Assessment' (HSNA) program on left-behind children, from poor rural areas in the middle and western parts of China. Factors including causes, types, locations, related activities, ways of treatment and outcomes among left-behind children with injuries in 2016, were described and analyzed by gender and age groups. Results: In 2016, per-person and person-time incidence rates of injuries were 8.88% and 11.21%, among the 16 459 left-behind children from 27 poor rural areas in 12 provinces of China, both higher in boys, than in girls. Most injuries were unintentional with its proportion higher in older children. The main types of injuries were seen as falls, blunt and sharp injuries, with burns and animal injuries more common in younger children. Injuries among left-behind children mainly took place at home, kindergarten/school, and on the highways/streets/roads, during playing. Most common ways of treatment would include at the emergency settings, self-treated, with older children more likely to treat by themselves. Most injuries were cured. Conclusions: In programs on prevention and control of injuries targeting the left-behind children in poor rural areas, special attention should be given to older boys, on falls and blunt/sharp injuries, at home or kindergarten/school. Education programs should pinpoint on self-rescue skills and guidance on kids by the parents, with behavioral norms and social support included. Related comprehensive prevention and control mechanism should be developed in families, schools and communities, with medical resources and insurance mechanism explored to serve these population and districts, including those left-behind children.

[Disease burden on falls among 0-19 years old population in China, in 1990 and 2017]

Objective: To analyze and compare the disease burden of falls in Chinese population aged 0-19, in 1990 and 2017. Methods: Indicators including number of deaths, mortality rates, years of life lost due to premature mortality (YLL), years lived with disability (YLD) and disability-adjusted of life years (DALY), on falls, were gathered from the Global Burden of Disease (GBD) 2017 and used to describe the disease burden and corresponding parameters on falls, between 1990 and 2017, in China. Results: In 2017, number of death, YLLs, YLDs, DALYs caused by falls were 5 321, 0.43 million person years, 0.14 million person years and 0.57 million person years respectively, among aged 0-19 group. Rates on standardized mortality, YLLs, YLDs and DALYs on falls were 1.76/100 000, 141.49/100 000, 46.99/100 000, and 188.48/100 000, respectively. The burden of falls decreased with the increase of age. Compared with 1990, disease burden of falls decreased in all age groups, both in male and female, with more seen in the lower age groups. Compared with 1990, the number of deaths, rates on YLLs, YLDs and DALYs caused by falls decreased by 65.08%, 46.63%, 47.38% and 36.33% respectively, in 2017. However, the YLDs rate increased by 73.31% between 1990 and 2017. The ratio of YLLs to DALYs decreased from 90.84% in 1990 to 75.07% in 2017, with a proportion as 17.36%. Conclusion: Compared with 1990, although the disease burden of falls among aged 0-19 group showed a decreasing trend, falls still caused serious disease burden for the aged 0-19 group. Research that targeting prevention on falls, should be continued.

[Economic evaluation on strategy for preventing mother-to-child transmission of hepatitis B in Zhejiang Province]

Objective: To evaluate the cost-benefit and cost-effectiveness of current strategy for preventing mother-to-child transmission (PMTCT) of hepatitis B virus. Methods: A decision tree model with the Markov process was developed and simulated over the lifetime of a birth cohort in Zhejiang Province in 2016. The current PMTCT strategy was compared with universal vaccination and non-vaccination. Costs were assessed from social perspective. Benefits were the savings from reduced costs associated with disease and effectiveness were measured by quality-adjusted of life-years (QALY) gained. The net present value (NPV), cost-benefit ratio (BCR) and incremental cost-effectiveness ratio (ICER) were calculated. Univariate and Probabilistic Sensitivity Analyses (PSA) were performed to assess parameter uncertainties. The parameters of costs and utilities value of hepatitis B-related disease came from the results of the field survey, which were obtained by face-to-face questionnaire survey combined with inpatient medical records, including eight county and municipal hospitals in Jinhua, Jiaxing and Taizhou. A total of 626 outpatients and 523 inpatient patients were investigated. The annual total costs of infection was calculated by combining the costs of outpatient and inpatient. Results: The PMTCT strategy showed a net-gain as 38 323.78 CNY per person, with BCR as 21.10, which was higher than 36 357.80 CNY per person and 13.58 respectively of universal vaccination. Compared with universal vaccination, the PMTCT strategy would save 2 787.07 CNY per additional QALY gained for every person, indicating that PMTCT would be cost-saving. The most important parameters that could affect BCR and ICER were the vaccine coverage rate and costs of hepatitis B related diseases respectively. The PSA showed the PMTCT strategy was preferable as it would gain more QALY and save costs. Conclusions: The PMTCT strategy appeared as highly cost-beneficial and highly cost-effective. High vaccination rate was a key factor of high economic value.

One-Dimensional Quasicrystals with Power-Law Hopping

One-dimensional quasiperiodic systems with power-law hopping, 1/r^{a}, differ from both the standard Aubry-André (AA) model and from power-law systems with uncorrelated disorder. Whereas in the AA model all single-particle states undergo a transition from ergodic to localized at a critical quasidisorder strength, short-range power-law hops with a>1 can result in mobility edges. We find that there is no localization for long-range hops with a≤1, in contrast to the case of uncorrelated disorder. Systems with long-range hops rather present ergodic-to-multifractal edges and a phase transition from ergodic to multifractal (extended but nonergodic) states. Both mobility and ergodic-to-multifractal edges may be clearly revealed in experiments on expansion dynamics.

Impact of capitation on outpatient expenses among patients with diabetes mellitus in Tianjin, China: a natural experiment

OBJECTIVES

Capitation policy, a new medical insurance settlement method implemented on 1 January 2014 in Tianjin, China, aimed to control unreasonable increases in medical costs. The goal of the current study was to evaluate the impact of capitation on outpatient expenses among patients with diabetes mellitus and provide scientific evidence for health policy-makers.

DESIGN

A natural experiment.

SETTING

The medical insurance database of Tianjin from 1 January 2010 to 31 December 2014.

PARTICIPANTS

In total, 35 529 records were included, comprising 9646 records in the pilot group (4907 records in 2014 and 4739 records in 2013) and 25 883 records in the control group (9814 records in 2014 and 16 069 records in 2013).

MAIN OUTCOME MEASURES

The outcome variables included annual total outpatient expenses, drug expenses, examination expenses, treatment expenses and other expenses.

RESULTS

Capitation produced an increase in total outpatient expenses of ¥1993.76 (95% CI, ¥1643.74 to ¥2343.77) in the pilot group relative to the control group. There was also an increase in drug expenses of ¥1904.30 (95% CI, ¥1578.63 to ¥2229.96) after the implementation of capitation. An increase in examination expenses of ¥44.90 (95% CI, ¥19.11 to ¥70.68) was found in the pilot group versus the control group. Capitation also produced an increase in treatment expenses of ¥3.55 (95% CI, ¥1.01 to ¥6.09) and an increase in other expenses of ¥43.46 (95% CI, ¥26.81 to ¥60.11) in the pilot group versus the control group.

CONCLUSION

Compared with those who participated in the 'control' policy, outpatient expenses of patients enrolled in capitation increased significantly. The increases were due to the actual needs of patients, changes in drug directories, and the autonomy and independence of hospitals. It is necessary for the government, policy-makers, hospitals, doctors, patients and supervisory agencies to improve the capitation policy.

The characteristics of internet-based venue sex-seeking and mobility among money boys in Tianjin, China

OBJECTIVES

Internet-based venue sex-seeking is prevalent among money boys (MBs), as is a high degree of mobility, which is crucial for HIV transmission in key populations with high risks of HIV infection. However, correlation studies in MBs are scarce because of the secretive nature of this hard-to-reach subpopulation. We conducted this project to explore the characteristics of MBs.

METHODS

This survey was conducted from December 2014 to June 2015 in Tianjin; a total of 330 MBs were recruited by convenience sampling. Demographic and behavioural data were collected for analysis.

RESULTS

Among the investigated MBs, 38 (11.52%) were HIV positive, 147 (44.55%) reported using internet-based venues to seek sexual partners and 257 (77.88%) had travelled to two or more destinations in the past 6 months. Compared with non-internet-based venue-using MBs, internet-based venue-using MBs were more likely to have part-time employment as MBs, to have a longer duration of working in the sex trade, to engage in finger intercourse and to present a history of substance abuse and sexually transmitted infections. However, internet-based venue-using MBs were less likely to exhibit consistent condom usage and undergo HIV testing. Origin of residence data showed that most MBs were from northern China, with Tianjin, Beijing and Shanghai as the main travel destinations. Mobile MBs were characterized as a group who were fully engaged in the sex trade and frequently took part in sexual activities but had a weak sense of self-protection.

CONCLUSIONS

Internet-based venue sex-seeking and mobility are prevalent in MBs. Renewed efforts in internet-based health promotion and school-based primary health examination programmes may benefit more mobile and/or internet-based venue sex-seeking MBs.

A comparison between high-intensity focused ultrasound and surgical treatment for the management of abdominal wall endometriosis

OBJECTIVE

The aim of this study was to compare the therapeutic outcomes of high-intensity focused ultrasound (HIFU) and surgical treatment for abdominal wall endometriosis.

DESIGN

A retrospective study.

SETTING

Gynaecological department of a teaching hospital in China.

POPULATION

Patients with abdominal wall endometriosis.

METHODS

Among the 51 patients, 23 patients were treated with ultrasound-guided HIFU and 28 patients with surgery. Pain relief and the size change of the nodule after each management were evaluated 1, 3, 6 and 12 months after treatment, respectively. The hospital stay and blood loss were also compared.

MAIN OUTCOME MEASURES

Difference between HIFU and surgical treatment for abdominal wall endometriosis.

RESULTS

No statistically significant differences were observed between the two groups in the pain relief in 1, 3, 6 and 12 months after treatment, respectively. The hospital stay was clearly shorter in the HIFU group than in the surgery group. Change in nodules was more remarkable in the group treated with surgery; no palpable nodules existed in most patients in the surgery group. HIFU had more advantages over surgery, such as no blood loss, no new scar, no anaesthesia and lower pain score immediately after treatment.

CONCLUSIONS

Based on our results, it appears that either HIFU or surgery is safe and effective in treating patients with AWE in short-term. Compared with surgery, HIFU treatment for AWE has the advantages of shorter hospital stay, no blood loss, no new scar, no anaesthesia and a lower immediate pain score.

TWEETABLE ABSTRACT

Either HIFU or surgical treatment is safe and effective in treating patients with AWE. HIFU has the advantages of a less invasive procedure and shorter hospital stay.

[Current status and change trend of violence against children in China from 2006 to 2015, an analysis on data from National Injury Surveillance System]

Objective: To understand the current status and change trend of violence against children in China and provide evidence for the risk factor and intervention priority identifications and intervention strategy development. Methods: The data of National Injury Surveillance System (NISS) from 2006 to 2015 were used to analyze the change in outpatient visit due to violence against children, injury cases'demographic characteristics, incidence of injury and clinical outcomes of injury cases. Results: A total of 44 319 injury cases caused by violence against children were reported through NISS during this period. The proportion of violence related child injury cases in total child injury cases decreased year by year. In child violence cases reported in 2015, boys accounted for 81.31%, the boy to girl ratio was 2.22∶1. Violence related injuries caused by blunt strike accounted for 65.69%. The incidences of child violence were low in February and during July-August and 48.87% of violence related injuries occurred in schools and public places, bruise accounted for 63.52%. The main injured body part caused by child violence was head (51.18%), and most violence caused injuries (82.66%) were mild, while 83.21% of the injury cases went home after treatment. Conclusions: Violence against children should not be ignored. Male students of middle/high schools are at high risk. Schools are the places where violence against children is prone to occur. Health and safety education should be strengthened to prevent the occurrence of campus violence and improve the child's awareness of self-protection and reduce the incidence of serious violence.

Prophage Diversity of 'Candidatus Liberibacter asiaticus' Strains in California

Huanglongbing (HLB) is a highly destructive citrus disease and is associated with a nonculturable bacterium, 'Candidatus Liberibacter asiaticus'. 'Ca. L. asiaticus' in the United States was first found in Florida in 2005 and is now endemic there. In California, 'Ca. L. asiaticus' was first detected in Hacienda Heights in Los Angeles County in 2012 and has now been detected in multiple urban locations in southern California. Knowledge of 'Ca. L. asiaticus' strain diversity in California is important for HLB management. In this study, genomic diversity among 10 'Ca. L. asiaticus' strains from six California locations were analyzed using a next-generation sequencing (NGS) (Illumina MiSeq and HiSeq) approach. Draft genome sequences of 'Ca. L. asiaticus' strains were assembled. Sequences of the 16S ribosomal RNA gene and nrdB confirmed 'Ca. L. asiaticus' identity. Prophages were detected in all 'Ca. L. asiaticus' strains. The California 'Ca. L. asiaticus' strains formed four prophage typing groups (PTGs): PTG1, with type 1 prophage only (strains from Anaheim, San Gabriel, and Riverside); PTG2, with type 2 prophage only (strains from Hacienda Heights); PTG1-3, with both type 1 and 3 prophages (a strain from Cerritos); and PTG1-2, with both type 1 and type 2 prophages (a strain from La Habra). Analyses of the terL sequence showed that all California 'Ca. L. asiaticus' strains were not introduced from Florida but likely from locations in Asia. Miniature inverted-repeat transposable elements were found in all 'Ca. L. asiaticus' strains, yet, a jumping-out event was detected in the 'Ca. L. asiaticus' strain from Cerritos. Altogether, this study demonstrated that the NGS approach focusing on prophage variation was sensitive and effective in revealing diversity of 'Ca. L. asiaticus' strains in California.

Abstract P6-17-39: BAT8001, a potent anti-HER2 antibody-drug conjugate with a novel stable linker for the treatment of HER2-positive breast cancer

Overexpression of HER2 occurs in approximately 20% of breast cancers and is associated with shortened survival. Trastuzumab emtansine (T-DM1), an anti-HER2 ADC, has shown efficacy in HER2-positive breast cancer patients and was approved by the FDA and EMA for advanced HER2-positive breast cancer. However T-DM1 causes grade 3 and 4 thrombocytopenia in up to 14.5% of patients as its major toxicity. The thrombocytopenia is likely caused by one of T-DM1's catabolites and payload, DM1, indicating T-DM1's linker can be cleaved. Here we adopted a novel noncleavable linker and created an anti-HER2 ADC, BAT8001, which is expected be efficacious in HER2-positive breast cancer and have a better side effect profile relative to T-DM1 due to the stability of BAT8001's noncleavable linker. BAT8001 is internalized in HER2-positive cancer cells. It inhibits proliferation of HER2-positive tumor cells with IC50s of ˜0.1 nM, similar to the potency of T-DM1. BAT8001 also induces apoptosis in HER2-positive cancer cells. In both cell-line and patient-derived mouse xenograft (PDX) models, BAT8001 demonstrates strong inhibition activity on tumor growth. For example, in a cell-line model of breast cancer (BT474), BAT8001 demonstrates potent activity with complete responses in all animals tested at the 15mg/kg dose level. Pharmacokinetics studies in monkey reveals BAT8001 has similar Cmax, AUC, and t1/2 as T-DM1. The major catabolite of BAT8001 is the Cys-linker-payload containing product. No free payload is observed. This compares favorably with T-DM1 where free DM1, T-DM1's payload, is one of the major catabolites. In a multiple dose toxicity study, BAT8001 had a NOAEL of 15 mg/kg versus 10 mg/kg for T-DM1. BAT8001 exhibits similar potency to T-DM1 on inhibiting HER2-positive cell proliferation and tumor growth, yet demonstrates better multiple dose toxicity than T-DM1. The improved toxicity profile of BAT8001 suggests that the novel noncleavable linker utilized in BAT8001 is more stable than the linker utilized in T-DM1. BAT8001 is very efficacious in cell-line xenograft models of breast cancer. The preclinical profile of BAT8001 warrants further development for the treatment of breast cancer and other HER2-positive cancers.

Citation Format: Tang W, Deng X, Ou Z, Gan J, Dong Q, Tan B, Lu L, Chen B, Bao C, Li S, Thomas B, Yu J-C. BAT8001, a potent anti-HER2 antibody-drug conjugate with a novel stable linker for the treatment of HER2-positive breast cancer [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 P6-17-39.

Mechanisms of endogenous repair failure during intervertebral disc degeneration

Intervertebral disc (IVD) degeneration is frequently associated with Low back pain (LBP), which can severely reduce the quality of human life and cause enormous economic loss. However, there is a lack of long-lasting and effective therapies for IVD degeneration at present. Recently, stem cell based tissue engineering techniques have provided novel and promising treatment for the repair of degenerative IVDs. Numerous studies showed that stem/progenitor cells exist naturally in IVDs and could migrate from their niche to the IVD to maintain the quantity of nucleus pulposus (NP) cells. Unfortunately, these endogenous repair processes cannot prevent IVD degeneration as effectively as expected. Therefore, theoretical basis for regeneration of the NP in situ can be obtained from studying the mechanisms of endogenous repair failure during IVD degeneration. Although there have been few researches to study the mechanism of cell death and migration of stem/progenitor cells in IVD so far, studies demonstrated that the major inducing factors (compression and hypoxia) of IVD degeneration could decrease the number of NP cells by regulating apoptosis, autophagy, and necroptosis, and the particular chemokines and their receptors played a vital role in the migration of mesenchymal stem cells (MSCs). These studies provide a clue for revealing the mechanisms of endogenous repair failure during IVD degeneration. This article reviewed the current research situation and progress of the mechanisms through which IVD stem/progenitor cells failed to repair IVD tissues during IVD degeneration. Such studies provide an innovative research direction for endogenous repair and a new potential treatment strategy for IVD degeneration.