Racial disparity of Crouzon syndrome in maxilla and mandible

The racial disparity of facial features in craniosynostosis patients is not fully understood. The aim of this study was to explore the difference in maxillary and mandibular morphology and spatial position in Asian and Caucasian Crouzon syndrome patients. Ninety-one computed tomography scans were included (12 Asian Crouzon syndrome patients, 22 Asian controls; 16 Caucasian Crouzon syndrome patients, 41 Caucasian controls) and measured using Materialise software. The maxillary and mandibular volumes of Asian patients were both reduced by 19% (P=0.102 and P=0.187), and those of Caucasian patients were reduced by 15% (P=0.142) and 14% (P=0.211) when compared to the respective race-specific controls. Maxilla length of Asian patients was reduced by 6.36mm (14%, P=0.003), while the reduction in Caucasian patients was 4.88mm (10%, P=0.038). ANS was retracted 11.99mm (P<0.001) in Asian patients and 11.54mm (P<0.001) in Caucasian patients. The ANB angle was narrowed by 13.17° (P<0.001) in Asian patients compared to Asian controls, and by 7.02° (P<0.001) in Caucasian patients compared to Caucasian controls. The retrusive midface profiles of Asian and Caucasian Crouzon syndrome look similar; both result from the combined effect of hypoplastic size and backward displacement. However, the insufficiency was found to be more a failure of the anteroposterior maxillary length in Asian patients, and more due to posterior maxillary positioning in Caucasian patients. Therefore, prognathism in Crouzon syndrome patients is more likely caused by displacement rather than elongation of mandibular length in both races. Crouzon syndrome results in the same extent of overall volume deficiency of the maxilla and mandible in these races.

An orally bioavailable broad-spectrum antiviral inhibits SARS-CoV-2 in human airway epithelial cell cultures and multiple coronaviruses in mice

Coronaviruses (CoVs) traffic frequently between species resulting in novel disease outbreaks, most recently exemplified by the newly emerged SARS-CoV-2, the causative agent of COVID-19. Here, we show that the ribonucleoside analog β-d-N4-hydroxycytidine (NHC; EIDD-1931) has broad-spectrum antiviral activity against SARS-CoV-2, MERS-CoV, SARS-CoV, and related zoonotic group 2b or 2c bat-CoVs, as well as increased potency against a CoV bearing resistance mutations to the nucleoside analog inhibitor remdesivir. In mice infected with SARS-CoV or MERS-CoV, both prophylactic and therapeutic administration of EIDD-2801, an orally bioavailable NHC prodrug (β-d-N4-hydroxycytidine-5'-isopropyl ester), improved pulmonary function and reduced virus titer and body weight loss. Decreased MERS-CoV yields in vitro and in vivo were associated with increased transition mutation frequency in viral, but not host cell RNA, supporting a mechanism of lethal mutagenesis in CoV. The potency of NHC/EIDD-2801 against multiple CoVs and oral bioavailability highlights its potential utility as an effective antiviral against SARS-CoV-2 and other future zoonotic CoVs.

Remdesivir potently inhibits SARS-CoV-2 in human lung cells and chimeric SARS-CoV expressing the SARS-CoV-2 RNA polymerase in mice

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in 2019 as the causative agent of the novel pandemic viral disease COVID-19. With no approved therapies, this pandemic illustrates the urgent need for safe, broad-spectrum antiviral countermeasures against SARS-CoV-2 and future emerging CoVs. We report that remdesivir (RDV), a monophosphoramidate prodrug of an adenosine analog, potently inhibits SARS-CoV-2 replication in human lung cells and primary human airway epithelial cultures (EC ₅₀ = 0.01 μM). Weaker activity was observed in Vero E6 cells (EC ₅₀ = 1.65 μM) due to their low capacity to metabolize RDV. To rapidly evaluate in vivo efficacy, we engineered a chimeric SARS-CoV encoding the viral target of RDV, the RNA-dependent RNA polymerase, of SARS-CoV-2. In mice infected with chimeric virus, therapeutic RDV administration diminished lung viral load and improved pulmonary function as compared to vehicle treated animals. These data provide evidence that RDV is potently active against SARS-CoV-2 in vitro and in vivo , supporting its further clinical testing for treatment of COVID-19.

Search for Electron Antineutrino Appearance in a Long-Baseline Muon Antineutrino Beam

Electron antineutrino appearance is measured by the T2K experiment in an accelerator-produced antineutrino beam, using additional neutrino beam operation to constrain parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. T2K observes 15 candidate electron antineutrino events with a background expectation of 9.3 events. Including information from the kinematic distribution of observed events, the hypothesis of no electron antineutrino appearance is disfavored with a significance of 2.40σ and no discrepancy between data and PMNS predictions is found. A complementary analysis that introduces an additional free parameter which allows non-PMNS values of electron neutrino and antineutrino appearance also finds no discrepancy between data and PMNS predictions.

A transition of ω-Fe3C → ω'-Fe3C → θ'-Fe3C in Fe-C martensite

Carbon steel is strong primarily because of carbides with the most well-known one being θ-Fe₃C type cementite. However, the formation mechanism of cementite remains unclear. In this study, a new metastable carbide formation mechanism was proposed as ω-Fe₃C → ω′-Fe₃C → θ′-Fe₃C based on the transmission electron microscopy (TEM) observation. Results shown that in quenched high-carbon binary alloys, hexagonal ω-Fe₃C fine particles are distributed in the martensite twinning boundary alone, while two metastable carbides (ω′ and θ′) coexist in the quenched pearlite. These two carbides both possess orthorhombic crystal structure with different lattice parameters (a_θ′ = a_ω′ = a_ω = \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sqrt{2}$$\end{document}2a_α-Fe = 4.033 Å, b_θ′ = 2 × b_ω′ = 2 × c_ω = \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sqrt{3}$$\end{document}3a_α-Fe = 4.94 Å, and c_θ′ = c_ω′ = \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sqrt{3}$$\end{document}3a_ω = 6.986 Å for a_α-Fe = 2.852 Å). The θ′ unit cell can be constructed simply by merging two ω′ unit cells together along its b_ω′ axis. Thus, the θ′ unit cell contains 12 Fe atoms and 4 C atoms, which in turn matches the composition and atomic number of the θ-Fe₃C cementite unit cell. The proposed theory in combination with experimental results gives a new insight into the carbide formation mechanism in Fe-C martensite.

[Association between brain glucose metabolism and cardiac dysfunction in patients with ischemic heart disease undergoing (18)F-FDG PET/CT imaging]

Objective: To evaluate the relationship between the brain glucose metabolism and left ventricular function parameters, and to explore the cerebral glucose metabolism reduction regions in patients with ischemic heart disease (IHD). Methods: A total of 110 consecutive IHD patients who underwent gated (99)Tc(m)-sestamibi (MIBI) SPECT/CT myocardial perfusion imaging, gated (18)F-fluorodeoxyglucose (FDG) PET/CT myocardial and brain glucose metabolic imaging within three days in Beijing Anzhen Hospital from April 2016 to October 2017, were enrolled in this study. Left ventricular functional parameters of SPECT/CT and PET/CT including end-diastolic volume (EDV), end-systolic volume (ESV) and left ventricular ejection fraction (LVEF) were analyzed by QGS software. Viable myocardium and myocardial infarction region were determined by 17-segment and 5 score system, and the ratio of viable myocardium and scar myocardium was calculated. According to the range of viable myocardium, the patients were divided into viable myocardium<10% group (n=44), viable myocardium 10%-<20% group (n=36) and viable myocardium≥20% group (n=30). Pearson correlation analysis was used to analyze the correlation between the range of viable myocardium and scar myocardium and the level of cerebral glucose metabolism. Brain glucose metabolism determined by the mean of standardized uptake value (SUV(mean)) was analyzed by SPM. The ratio of SUV(mean) in whole brain and SUV(mean) in cerebellum were calculated, namely taget/background ratio (TBR). Differences in cerebral glucose metabolism among various groups were analyzed by SPM. Results: There were 101 males, and age was (57±10) years in this cohort. The extent of viable myocardium and the extent of scar, LVEF evaluated by SPECT/CT and PET/CT were significantly correlated with TBR (r=0.280, r=-0.329, r=0.188, r=0.215 respectively,all P<0.05). TBR value was significantly lower in viable myocardium<10% group, compared with viable myocardium 10%-<20% group (1.25±0.97 vs. 1.32±0.17, P<0.05) and viable myocardium≥20% group (1.25±0.97 vs. 1.34±0.16, P<0.05). Furthermore, in comparison with viable myocardium≥20% group, the hypo-metabolic regions of viable myocardium<10% group were located in the precuneus, frontal lobe, postcentral gyrus, parietal lobe, temporal lobe, and so on. Conclusions: There is a correlation between impaired left ventricular function and brain glucose metabolism in IHD patients. In IHD patients with low myocardial viability, the level of glucose metabolism in the whole brain is decreased, especially in the brain functional areas related to cognitive function.

Biology and applications of Clonostachys rosea

Clonostachys rosea is a promising saprophytic filamentous fungus that belongs to phylum Ascomycota. Clonostachys rosea is widespread around the world and exists in many kinds of habitats, with the highest frequency in soil. As an excellent mycoparasite, C. rosea exhibits strong biological control ability against numerous fungal plant pathogens, nematodes and insects. These behaviours are based on the activation of multiple mechanisms such as secreted cell-wall-degrading enzymes, production of antifungal secondary metabolites and induction of plant defence systems. Besides having significant biocontrol activity, C. rosea also functions in the biodegradation of plastic waste, biotransformation of bioactive compounds, as a bioenergy sources and in fermentation. This mini review summarizes information about the biology and various applications of C. rosea and expands on its possible uses.

[Genomic recombination of the vibrio cholerae serogroup O1 El Tor pandemic strains]

Objective: To analyze the genomic recombination of the vibrio cholerae serogroup O1 El Tor pandemic strains. Methods: A total of 292 complete or draft genome sequences of Vibrio cholerae O1 serogroup El Tor strains isolated from 1937 to 2015 were selected from National Biotechnology Information Center database. The genome alignment of strains was computed by snippy software by using N16961 as reference sequence. Then ClonalFrameML software was used to do the recombinant analysis. The wilcox.test function in agricolae package was used to compare the number recombinant segments and the total length of recombinant regions between small and large chromosomes. The kruskal function was used to compare the number recombinant segments and the total length of recombinant regions among different isolation continents. The KOBAS tool was used to do the gene ontology enrichment analysis of recombinant hotspot genes. Results: Of all 292 strains of Vibrio cholerae, 163 strains (55.8%) were recombined. The median of normalized recombinant segment number of small chromosome was 4.7×10(-6) (9.3×10(-7), 2.0×10(-5)), which was significantly larger than that of large chromosome [2.4×10(-6) (3.4×10(-7), 5.7×10(-6))] (P<0.001). The median (P(25),P(75)) of recombinant segment number of strains isolated from Africa, Asia, Europe, North America and South America were 23(1.0,33.0), 1.0(0.0,34.0), 6.0(2.0,13.0), 0.0(0.0,1.0) and 29.5(6.8,56.8), respectively, and the difference was statistically significant (P<0.001). The median (P(25),P(75)) of total length of recombinant regions of strains isolated from Africa, Asia, Europe, North America and South America were 233.0(4.0, 461.0), 11.0(0.0, 695.5), 56.0(4.0,111.0), 0.0(0.0,9.0) and 347.5(132.8,1 323.5) bp, respectively, and the difference was statistically significant (P<0.001). Gene ontology Enrichment analysis showed that the functions of 62 recombinant hotspot genes were mainly enrichment in chemotaxis, taxis, response to external stimulus, receptor activity and molecular transducer activity. Conclustion: In this study, we found that there were significant differences in the number of recombinant fragments and the length of recombinant regions between large and small chromosomes of Vibrio cholerae El Tor. We also found significant differences in the number of recombinant fragments and the total length of recombinant regions among different continents.

[Safety and effectiveness of transoral robotic surgery for oropharyngeal cancer: a pilot study]

Objective: To evaluate the indication, safety and effectiveness of transoral robotic surgery (TORS) for oropharyngeal cancer based on our preliminary experience. Methods: Twelve patients, including six with tonsil cancer, five with tongue base cancer and one with posterior pharyngeal wall cancer, who underwent TORS with Da Vinci Si surgical system from March 2017 to October 2018 at Tongji Hospital of Huazhong University of Science Technology were respectively analyzed. And the surgical time, intraoperative blood loss, postoperative local bleeding, dyspnea, nerve function injury, oral intake time, whether or not to receive chemoradiotherapy were analyzed. Results: All tumors in the 12 patients were en bloc removed by TORS. Surgical time ranged from 25 to 80 min with an average of 34.2 min. The blood loss ranged from 10 ml to 50 ml with an average of 20.8 ml. The recovery time for oral intake ranged from 1 day to 30 days with an average of 8.4 days. No patient underwent tracheostomy after TORS. Also, no patient manifested with airway obstruction, bleeding or nerve injury symptoms after operation. All 12 patients reached pathologically negative surgical margins. The patients were followed up for 4 to 22 months, with a median of 12 months. All patients who combined with more advanced than T3 stage, or more advanced than N2 stage were recommended to oncologist, then, followed with radiotherapy or chemoradiotherapy if no relevant contradictions occurred. No local recurrence or distant metastasis case was found. Conclusion: With proper indications, the application of TORS in oropharyngeal cancer is a relatively safe, effective and minimal invasive therapy, which merits more clinical applications.

Nonfuel Antineutrino Contributions in the High Flux Isotope Reactor

Reactor neutrino experiments have seen major improvements in precision in recent years. With the experimental uncertainties becoming lower than those from theory, carefully considering all sources ofν ¯ e is important when making theoretical predictions. One source ofν ¯ e that is often neglected arises from the irradiation of the nonfuel materials in reactors. Theν ¯ e rates and energies from these sources vary widely based on the reactor type, configuration, and sampling stage during the reactor cycle and have to be carefully considered for each experiment independently. In this article, we present a formalism for selecting the possibleν ¯ e sources arising from the neutron captures on reactor and target materials. We apply this formalism to the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory, theν ¯ e source for the the Precision Reactor Oscillation and Spectrum Measurement (PROSPECT) experiment. Overall, we observe that the nonfuelν ¯ e contributions from HFIR to PROSPECT amount to 1% above the inverse beta decay threshold with a maximum contribution of 9% in the 1.8-2.0 MeV range. Nonfuel contributions can be particularly high for research reactors like HFIR because of the choice of structural and reflector material in addition to the intentional irradiation of target material for isotope production. We show that typical commercial pressurized water reactors fueled with low-enriched uranium will have significantly smaller nonfuelν ¯ e contribution.

A high level of serum neopterin is associated with rapidly progressive interstitial lung disease and reduced survival in dermatomyositis

Neopterin is primarily synthesized and released by activated macrophages/monocytes upon stimulation with interferon-γ and is considered as a marker for macrophage activation. This study aimed to analyze the serum levels of neopterin in patients with dermatomyositis (DM) in association with clinical manifestations, laboratory data and patient prognosis. One hundred and eighty-two consecutive DM patients and 30 healthy controls were retrospectively enrolled into the study. Serum levels of neopterin were significantly increased in DM patients compared to healthy controls (P < 0·001). High serum neopterin levels were associated with anti-melanoma differentiation-associated gene (MDA5) antibody, rapidly progressive interstitial lung disease (RP-ILD) and characteristic DM cutaneous involvement. Longitudinal assessment of serum samples revealed that the serum neopterin levels were closely correlated with disease severity (β = 30·24, P < 0·001). In addition, a significant increase in serum neopterin concentration of non-survivors was observed when compared to that of survivors (P < 0·001). Receiver operator characteristic curves showed that serum neopterin could distinguish non-survivors and survivors at an optimal cut-off level of 22·1 nmol/l with a sensitivity and specificity of 0·804 and 0·625, respectively (P < 0·001). Kaplan-Meier survival curves revealed that DM patients with serum neopterin > 22·1 nmol/l had a significantly higher mortality compared to the patient group with serum neopterin < 22·1 nmol/l (log-rank P < 0·001). Multivariate regression analysis identified high serum neopterin concentration to be an independent risk factor for poor prognosis in DM (adjusted hazard ratio = 4·619, 95% confidence interval = 2·092-10·195, P < 0·001). In conclusion, increased serum levels of neopterin were significantly associated with RP-ILD and reduced survival in DM patients, suggesting it as a promising biomarker in disease evaluation of DM.

Small-Molecule Antiviral β-d-N4-Hydroxycytidine Inhibits a Proofreading-Intact Coronavirus with a High Genetic Barrier to Resistance

Coronaviruses (CoVs) have emerged from animal reservoirs to cause severe and lethal disease in humans, but there are currently no FDA-approved antivirals to treat the infections. One class of antiviral compounds, nucleoside analogues, mimics naturally occurring nucleosides to inhibit viral replication. While these compounds have been successful therapeutics for several viral infections, mutagenic nucleoside analogues, such as ribavirin and 5-fluorouracil, have been ineffective at inhibiting CoVs. This has been attributed to the proofreading activity of the viral 3'-5' exoribonuclease (ExoN). β-d-N4-Hydroxycytidine (NHC) (EIDD-1931; Emory Institute for Drug Development) has recently been reported to inhibit multiple viruses. Here, we demonstrate that NHC inhibits both murine hepatitis virus (MHV) (50% effective concentration [EC50] = 0.17 μM) and Middle East respiratory syndrome CoV (MERS-CoV) (EC50 = 0.56 μM) with minimal cytotoxicity. NHC inhibited MHV lacking ExoN proofreading activity similarly to wild-type (WT) MHV, suggesting an ability to evade or overcome ExoN activity. NHC inhibited MHV only when added early during infection, decreased viral specific infectivity, and increased the number and proportion of G:A and C:U transition mutations present after a single infection. Low-level NHC resistance was difficult to achieve and was associated with multiple transition mutations across the genome in both MHV and MERS-CoV. These results point to a virus-mutagenic mechanism of NHC inhibition in CoVs and indicate a high genetic barrier to NHC resistance. Together, the data support further development of NHC for treatment of CoVs and suggest a novel mechanism of NHC interaction with the CoV replication complex that may shed light on critical aspects of replication.IMPORTANCE The emergence of coronaviruses (CoVs) into human populations from animal reservoirs has demonstrated their epidemic capability, pandemic potential, and ability to cause severe disease. However, no antivirals have been approved to treat these infections. Here, we demonstrate the potent antiviral activity of a broad-spectrum ribonucleoside analogue, β-d-N4-hydroxycytidine (NHC), against two divergent CoVs. Viral proofreading activity does not markedly impact sensitivity to NHC inhibition, suggesting a novel interaction between a nucleoside analogue inhibitor and the CoV replicase. Further, passage in the presence of NHC generates only low-level resistance, likely due to the accumulation of multiple potentially deleterious transition mutations. Together, these data support a mutagenic mechanism of inhibition by NHC and further support the development of NHC for treatment of CoV infections.

Whole exome sequencing identified a second pathogenic variant in HOMER2 for autosomal dominant non-syndromic deafness

Hearing loss is one of the most common sensory disorders worldwide, and about half of all occurrences are attributable to genetic factors. Here, we have identified a novel pathogenic variant in HOMER2 in a Chinese family with autosomal dominant, non-syndromic hearing loss. This is the second family reported globally with hearing loss caused by a variant in HOMER2. The pathogenic variant c.840_841insC in HOMER2 (NM_199330), segregating with the hearing-loss phenotype in the family, leads to a premature stop codon producing a truncated protein. The coiled-coil domain in the C-terminal of HOMER2 protein is essential for protein multimerization and HOMER2-CDC42 interaction. We compared the phenotypes in the two families and found that hearing impairment in this Chinese family was more severe. Furthermore, we found that the ability of this insertion mutant type HOMER2 (HOMER2_MU ) to multimerize decreased more significantly than wild-type HOMER2 (HOMER2_WT ) and the reported c.554G>C (NM_004839) mutant HOMER2. HOMER2_MU protein tended to be distributed in a diffuse manner, whereas HOMER2_WT and the reported mutant HOMER2 tended to cluster together. Our research provides a validating second family for variants in HOMER2 causing non-syndromic sensorineural hearing loss. HOMER2 homo-/hetero-multimerization might be the first step in exerting its normal function.

Long non-coding RNA ZFAS1 promotes nasopharyngeal carcinoma through activation of Wnt/β-catenin pathway

OBJECTIVE

To investigate the expression characteristics of long non-coding RNA (lncRNA) ZFAS1 in nasopharyngeal carcinoma (NPC) and to further investigate the role and mechanism of ZFAS1 in the occurrence and development of NPC.

PATIENTS AND METHODS

76 surgical excision samples from newly diagnosed NPC patients and 76 cases of paracancerous tissues were selected. The expression of ZFAS1 was detected by qRT-PCR (quantitative real-time polymerase chain reaction), and the relationship between the expression of ZFAS1 and the clinical prognosis of patients with NPC was analyzed. After the knockdown, the expression of ZFAS1 in nasopharyngeal carcinoma cell line CNE-1 by small interfering RNA, the effect of ZFAS1 on the biological function of NPC cells was analyzed by cell counting kit-8 (CCK8), colony formation assay, flow cytometry and apoptosis assay. The effect of ZFAS1 on the Wnt/β-catenin pathway was analyzed by Western blot.

RESULTS

After analyzing the clinical data of enrolled patients, we found that ZFAS1 was overexpressed in NPC patients, which was closely correlated with tumor size and lymph node metastasis of NPC. Moreover, ZFAS1 was negatively correlated to the survival of NPC patients. After interfering with the expression of ZFAS1, the proliferation of NPC cells was significantly decreased, the cell cycle was inhibited and the apoptosis rate was increased. Western Blot showed that ZFAS1 promoted the occurrence of NPC by activating the Wnt/β-catenin pathway.

CONCLUSIONS

ZFAS1 was overexpressed in NPC and was significantly related to tumor size, lymph node metastasis and poor prognosis of NPC. ZFAS1 could promote NPC by activating Wnt/β-catenin pathway.

[Magnetic resonance imaging characteristics and differential diagnosis of common sellar cystic lesions]

Objective: To investigate magnetic resonance imaging (MRI) characteristic and differential diagnostic keypoints of common sellar regional cystic lesions with the purpose of improving differential diagnostic accuracy. Methods: In total, 174 cases of the pathologically diagnosed cystic lesions in sellar region between March 2016 and June 2019 were included in the current retrospective analysis. These cases included Rathke's cleft cyst (n=68), craniopharyngioma (n=48), pituitary adenoma (n=56) and arachnoid cyst (n=2) in the sellar region. The position, texture and morphology of leisions, signal of cystic and solid part, invasion of surrounding tissues and maximum diameter of cysts on the MRI images were evaluated and compared between different groups. SPSS 25.0 software was used for statistical analysis. Results: There were several specific changes on several MRI sequences in Rathke's cleft cysts, craniopharyngioma and pituitary adenoma groups. For Rathke's cleft cysts, round shape, rare polycystic structure, lack of solid part and maximum diameter of cysts which was significantly less than that of craniopharyngioma and pituitary adenoma groups ((17.37±6.12) mm vs (30.29±13.51) mm vs (28.18±11.13) mm, t value was 6.680, 5.838, respectively, all P<0.05), were favorable diagnostic criteria. While, the intracystic nodules were mostly found in craniopharyngioma. There was no high signal intensity in cystic wall on T1WI and T2WI of pituitary adenoma. MRI signal of arachnoid cyst in sellar region was basically the same as CSF signal, with low signal intensity on T1WI and DWI, high signal intensity on T2WI, without enhanced signal. Conclusions: Common sellar regional cystic lesions showed characteristic manifestations on different MRI sequences. Valuable information in the morphology, MRI signal intensity, maximum diameter measurements may improve accuracy of differential diagnosis for sellar regional cystic lesions.

Phase I study of the checkpoint kinase 1 inhibitor GDC-0575 in combination with gemcitabine in patients with refractory solid tumors

BACKGROUND

Checkpoint kinase 1 (Chk1) inhibition following chemotherapy-elicited DNA damage overrides cell cycle arrest and induces mitotic catastrophe and cell death. GDC-0575 is a highly-selective oral small-molecule Chk1 inhibitor that results in tumor shrinkage and growth delay in xenograft models. We evaluated the safety, tolerability, and pharmacokinetic properties of GDC-0575 alone and in combination with gemcitabine. Antitumor activity and Chk1 pathway modulation were assessed.

PATIENTS AND METHODS

In this phase I open-label study, in the dose escalation stage, patients were enrolled in a GDC-0575 monotherapy Arm (1) or GDC-0575 combination with gemcitabine Arm (2) to determine the maximum tolerated dose. Patients in arm 2 received either i.v. gemcitabine 1000 mg/m2 (arm 2a) or 500 mg/m2 (arm 2b), followed by GDC-0575 (45 or 80 mg, respectively, as RP2D). Stage II enrolled disease-specific cohorts.

RESULTS

Of 102 patients treated, 70% were female, the median age was 59 years (range 27-85), and 47% were Eastern Cooperative Oncology Group PS 0. The most common tumor type was breast (37%). The most frequent adverse events (all grades) related to GDC-0575 and/or gemcitabine were neutropenia (68%), anemia (48%), nausea (43%), fatigue (42%), and thrombocytopenia (35%). Maximum concentrations of GDC-0575 were achieved within 2 hours of dosing, and half-life was ∼23 hours. No pharmacokinetic drug-drug interaction was observed between GDC-0575 and gemcitabine. Among patients treated with GDC-0575 and gemcitabine, there were four confirmed partial responses, three occurring in patients with tumors harboring TP53 mutation. Pharmacodynamic data were consistent with GDC-0575 inhibition of gemcitabine-induced expression of pCDK1/2.

CONCLUSION

GDC-0575 can be safely administered as a monotherapy and in combination with gemcitabine; however, overall tolerability with gemcitabine was modest. Hematological toxicities were frequent but manageable. Preliminary antitumor activity was observed but limited to a small number of patients with a variety of refractory solid tumors treated with GDC-0575 and gemcitabine.

CLINICAL TRIAL NUMBER

NCT01564251.