Clinical and ultrasound features of difficult-to-treat rheumatoid arthritis: A multicenter RA ultrasound cohort study

OBJECTIVE

The optimal strategy for difficult-to-treat (D2T) rheumatoid arthritis (RA) has not been identified, and the ultrasound characteristics of D2T RA have not been reported. We investigated the clinical characteristics and factors contributing to the outcome in D2T RA in a multicentre RA ultrasound observational cohort.

METHOD

We reviewed 307 Japanese patients diagnosed with RA who underwent treatment with biological and targeted synthetic disease-modifying anti-rheumatic drugs (b/tsDMARDs). We compared the differences in patient characteristics between the D2T RA and non-D2T RA groups. We examined the factors contributing to a good response [defined as b/tsDMARD continuation and Clinical Disease Activity Index (CDAI) ≤ 10 at 12 months] in the D2T RA patient group.

RESULTS

Forty-three patients (14%) were categorized as D2T RA and the remaining 264 (86%) as non-D2T RA at baseline. The grey-scale (GS) score, disease duration, and CDAI at the initiation of treatment were significantly higher in the D2T RA group than in the non-D2T RA group. In contrast, the power Doppler (PD) score was not significantly different between the two groups. Of the 43 D2T RA patients, 20 achieved a good response. The introduction of CTLA4-Ig (n = 5) was significantly associated with a good response in analysis based on inverse probability weighting with propensity score. GS and PD scores at baseline were not significantly associated with therapeutic response at 12 months in D2T RA patients.

CONCLUSIONS

Patients with D2T RA had high clinical and ultrasound activity and poor responses to treatment with b/tsDMARDs. CTLA4-Ig was associated with a good response at 12 months in D2T RA patients.

Imaging Microbubbles With Contrast-Enhanced Endobronchial Ultrasound

OBJECTIVE

Endobronchial ultrasound (EBUS) is commonly used to guide transbronchial needle biopsies for the staging of lymph nodes in non-small cell lung cancer patients. Although contrast-enhanced ultrasound (CEUS) and microbubbles (MBs) can improve the diagnostic accuracy in tumors, the ability of contrast-enhanced EBUS (CE-EBUS) to image MBs has not yet been comprehensively evaluated. In this study, we assessed the ability of a CE-EBUS system (Olympus EU-ME2 PREMIER and BF-UC180F bronchoscope) to detect laboratory-synthesized MBs in comparison to clinical (Toshiba Aplio SSA-790A) and pre-clinical (VisualSonics Vevo 2100) CEUS systems in vitro and in vivo, respectively.

METHODS

Agar flow phantoms and reference tissue were used to assess CE-EBUS MB imaging in vitro, and A549 tumor-bearing athymic nude and AE17-OVA tumor-bearing C57BL/6 mice were used to assess MB detectability and perfusion in vivo, respectively.

RESULTS

Results revealed that despite the lower sensitivity of CE-EBUS to MB concentration in comparison to clinical CEUS, CE-EBUS yielded a similar contrast-to-tissue ratio (CTR) in vitro of 28.9 ± 4.5 dB for CE-EBUS, compared with 29.7 ± 2.6 dB for clinical CEUS (p < 0.05). In vivo, CE-EBUS generated a perfusion curve highly correlated with that obtained with the pre-clinical CEUS system (Pearson correlation coefficient = 0.927, p < 0.05). Moreover, CE-EBUS yielded a CTR 2.7 times higher than that obtained with the pre-clinical ultrasound system.

CONCLUSION

These findings together suggest that CE-EBUS can perform contrast imaging comparable to that produced by commercial pre-clinical and clinical ultrasound systems, with potential for clinical characterization of mediastinal lymph nodes in lung cancer patients.

Secondary Mutations of the EGFR Gene That Confer Resistance to Mobocertinib in EGFR Exon 20 Insertion

INTRODUCTION

Approximately 10% of mutations in the EGFR gene in NSCLC are in-frame insertions in exon 20 (X20ins). These tumors usually do not respond to conventional EGFR tyrosine kinase inhibitors (TKIs). Several novel EGFR TKIs active for X20ins are in clinical development, including mobocertinib, which was recently approved by the U.S. Food and Drug Administration. However, acquired resistance during treatment with these TKIs still occurs as in the case of EGFR TKIs of earlier generations.

METHODS

We chronically exposed murine pro-B-cell line cells transduced with the five most common X20ins (A763_Y764insFQEA, V769_D770insASV, D770_N771insSVD, H773_V774insNPH and H773_V774insH) to mobocertinib in the presence of N-ethyl-N-nitrosourea and searched for secondary EGFR mutations. We evaluated the efficacies of several EGFR X20ins inhibitors, including zipalertinib and sunvozertinib, against cells with acquired resistant mutations.

RESULTS

All secondary mutations resulting in acquired resistance to mobocertinib were exclusively C797S in insFQEA and insSVD. However, in the case of other X20ins (insASV, insNPH, and insH), T790M or C797S secondary mutations contributed to acquired resistance to mobocertinib. The emergence of T790M was more frequent in cells treated with lower drug concentrations. Sunvozertinib exhibited good activity against resistant cells with T790M. Cells with C797S were refractory to all EGFR TKIs, except for erlotinib, which was active for insFQEA with C797S.

CONCLUSIONS

T790M or C797S, depending on the original X20ins mutations, conferred acquired resistance to mobocertinib. Sunvozertinib may be the treatment of choice for patients with tumors resistant to mobocertinib because of T790M.

Assessment of effectiveness and safety of thrombolytic therapy to pulmonary emboli by endobronchial ultrasound-guided transbronchial needle injection

Objective

Endobronchial ultrasound-guided transbronchial needle injection (EBUS-TBNI) may effectively treat acute pulmonary embolisms (PEs). Here, we assessed the effectiveness of clot dissolution and safety of tissue plasminogen activator (t-PA) injection using EBUS-TBNI in a 1-week survival study of a porcine PE model.

Methods

Six pigs with bilateral PEs were used: 3 for t-PA injection using EBUS-TBNI (TBNI group) and 3 for systemic administration of t-PA (systemic group). Once bilateral PEs were created, each 25 mg of t-PA injection using EBUS-TBNI for bilateral PEs (a total of 50 mg t-PA) and 100 mg of t-PA systemic administration was performed on day 1. Hemodynamic parameters, blood tests, and contrast-enhanced computed tomography scans were carried out at several time points. On day 7, pigs were humanely killed to evaluate the residual clot volume in the pulmonary arteries.

Results

The average of percent change of residual clot volumes was significantly lower in the TBNI group than in the systemic group (%: systemic group 36.6 ± 22.6 vs TBNI group 9.6 ± 6.1, P < .01) on day 3. Considering the elapsed time, the average decrease of clot volume per hour at pre-t-PA to post t-PA was significantly greater in the TBNI group than in the systemic group (mm3/hour: systemic 68.1 ± 68.1 vs TBNI 256.8 ± 148.1, P < .05). No hemorrhage was observed intracranially, intrathoracically, or intraperitoneally on any contrast-enhanced computed tomography images.

Conclusions

This study revealed that t-PA injection using EBUS-TBNI is an effective and safe way to dissolve clots.

Tests of Light-Lepton Universality in Angular Asymmetries of B^{0}→D^{*-}ℓν Decays

We present the first comprehensive tests of the universality of the light leptons in the angular distributions of semileptonic B^{0}-meson decays to charged spin-1 charmed mesons. We measure five angular-asymmetry observables as functions of the decay recoil that are sensitive to lepton-universality-violating contributions. We use events where one neutral B is fully reconstructed in ϒ(4S)→BB[over ¯] decays in data corresponding to 189  fb^{-1} integrated luminosity from electron-positron collisions collected with the Belle II detector. We find no significant deviation from the standard model expectations.

Precise Measurement of the D_{s}^{+} Lifetime at Belle II

We measure the lifetime of the D_{s}^{+} meson using a data sample of 207  fb^{-1} collected by the Belle II experiment running at the SuperKEKB asymmetric-energy e^{+}e^{-} collider. The lifetime is determined by fitting the decay-time distribution of a sample of 116×10^{3} D_{s}^{+}→ϕπ^{+} decays. Our result is τ_{D_{s}^{+}}=(499.5±1.7±0.9)  fs, where the first uncertainty is statistical and the second is systematic. This result is significantly more precise than previous measurements.

Search for a τ^{+}τ^{-} Resonance in e^{+}e^{-}→μ^{+}μ^{-}τ^{+}τ^{-} Events with the Belle II Experiment

We report the first search for a nonstandard-model resonance decaying into τ pairs in e^{+}e^{-}→μ^{+}μ^{-}τ^{+}τ^{-} events in the 3.6-10  GeV/c^{2} mass range. We use a 62.8  fb^{-1} sample of e^{+}e^{-} collisions collected at a center-of-mass energy of 10.58 GeV by the Belle II experiment at the SuperKEKB collider. The analysis probes three different models predicting a spin-1 particle coupling only to the heavier lepton families, a Higgs-like spin-0 particle that couples preferentially to charged leptons (leptophilic scalar), and an axionlike particle, respectively. We observe no evidence for a signal and set exclusion limits at 90% confidence level on the product of cross section and branching fraction into τ pairs, ranging from 0.7 to 24 fb, and on the couplings of these processes. We obtain world-leading constraints on the couplings for the leptophilic scalar model for masses above 6.5  GeV/c^{2} and for the axionlike particle model over the entire mass range.

Measurement of CP Violation in B^{0}→K_{S}^{0}π^{0} Decays at Belle II

We report a measurement of the CP-violating parameters C and S in B^{0}→K_{S}^{0}π^{0} decays at Belle II using a sample of 387×10^{6}  BB[over ¯] events recorded in e^{+}e^{-} collisions at a center-of-mass energy corresponding to the ϒ(4S) resonance. These parameters are determined by fitting the proper decay-time distribution of a sample of 415 signal events. We obtain C=-0.04_{-0.15}^{+0.14}±0.05 and S=0.75_{-0.23}^{+0.20}±0.04, where the first uncertainties are statistical and the second are systematic.

Clinical Relevance of Patient-Derived Organoid of Surgically Resected Lung Cancer as an In Vitro Model for Biomarker and Drug Testing

Introduction

Lung tumor organoids (LTOs) have attracted attention as in vitro preclinical models; however, their clinical and experimental applications have not been fully established.

Methods

We attempted to establish LTOs from resected specimens of patients with lung cancer who underwent lung resection. Clinicopathologic characteristics related to the establishment of LTOs were evaluated. Histologic assessment and genetic analysis were conducted for both LTOs and their parental tumors. Organoid-derived xenografts were generated in immunocompetent mice. Drug sensitivity was assessed using cell proliferation assays.

Results

We established 53 LTOs from 79 lung cancer samples, including 10 long-term culture models. The establishment rate was significantly lower in squamous cell carcinomas than in other histologic types (48% versus 75%, p = 0.034). Histologic similarities were confirmed among LTOs, the parental tumors, and organoid-derived xenografts. Seven mutations, including two EGFR L858R and one EGFR exon 20 H773delinsYNPY mutations, were detected in both LTO and parental tumors; the other four mutations were detected in either LTO or parental tumors. The extensive culture ability of LTO (passaged >10 times) correlated with poor patient prognosis. LTO9 cells harboring EGFR H773delinsYNPY were sensitive to osimertinib. The parental patient, who had new metastatic lesions, was treated with osimertinib and exhibited a remarkable response.

Conclusions

The establishment and growth rates of LTOs were associated with the histologic subtype and tumor size. LTOs derived from resected specimens have become preclinical models that can be used to predict drug responses and accelerate the development of treatment strategies for patients with rare mutations.

Search for an Invisible Z^{'} in a Final State with Two Muons and Missing Energy at Belle II

The L_{μ}-L_{τ} extension of the standard model predicts the existence of a lepton-flavor-universality-violating Z^{'} boson that couples only to the heavier lepton families. We search for such a Z^{'} through its invisible decay in the process e^{+}e^{-}→μ^{+}μ^{-}Z^{'}. We use a sample of electron-positron collisions at a center-of-mass energy of 10.58 GeV collected by the Belle II experiment in 2019-2020, corresponding to an integrated luminosity of 79.7  fb^{-1}. We find no excess over the expected standard-model background. We set 90%-confidence-level upper limits on the cross section for this process as well as on the coupling of the model, which ranges from 3×10^{-3} at low Z^{'} masses to 1 at Z^{'} masses of 8  GeV/c^{2}.

Prognostic role of preoperative fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography with an image-based harmonization technique: A multicenter retrospective study

Objectives

Despite the prognostic impacts of preoperative fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography examination, fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography-based prognosis prediction has not been used clinically because of the disparity in data between institutions. By applying an image-based harmonized approach, we evaluated the prognostic roles of fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters in clinical stage I non-small cell lung cancer.

Methods

We retrospectively examined 495 patients with clinical stage I non-small cell lung cancer who underwent fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography examinations before pulmonary resection between 2013 and 2014 at 4 institutions. Three different harmonization techniques were applied, and an image-based harmonization, which showed the best-fit results, was used in the further analyses to evaluate the prognostic roles of fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters.

Results

Cutoff values of image-based harmonized fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters, maximum standardized uptake, metabolic tumor volume, and total lesion glycolysis were determined using receiver operating characteristic curves that distinguish pathologic high invasiveness of tumors. Among these parameters, only the maximum standardized uptake was an independent prognostic factor in recurrence-free and overall survivals in univariate and multivariate analyses. High image-based maximum standardized uptake value was associated with squamous histology or lung adenocarcinomas with higher pathologic grades. In subgroup analyses defined by ground-glass opacity status and histology or by clinical stages, the prognostic impact of image-based maximum standardized uptake value was always the highest compared with other fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters.

Conclusions

The image-based fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography harmonization was the best fit, and the image-based maximum standardized uptake was the most important prognostic marker in all patients and in subgroups defined by ground-glass opacity status and histology in surgically resected clinical stage I non-small cell lung cancers.

Search for Lepton-Flavor-Violating τ Decays to a Lepton and an Invisible Boson at Belle II

We search for lepton-flavor-violating τ^{-}→e^{-}α and τ^{-}→μ^{-}α decays, where α is an invisible spin-0 boson. The search uses electron-positron collisions at 10.58 GeV center-of-mass energy with an integrated luminosity of 62.8  fb^{-1}, produced by the SuperKEKB collider and collected with the Belle II detector. We search for an excess in the lepton-energy spectrum of the known τ^{-}→e^{-}ν[over ¯]_{e}ν_{τ} and τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ} decays. We report 95% confidence-level upper limits on the branching-fraction ratio B(τ^{-}→e^{-}α)/B(τ^{-}→e^{-}ν[over ¯]_{e}ν_{τ}) in the range (1.1-9.7)×10^{-3} and on B(τ^{-}→μ^{-}α)/B(τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ}) in the range (0.7-12.2)×10^{-3} for α masses between 0 and 1.6  GeV/c^{2}. These results provide the most stringent bounds on invisible boson production from τ decays.

Observation of e^{+}e^{-}→ωχ_{bJ}(1P) and Search for X_{b}→ωϒ(1S) at sqrt[s] near 10.75 GeV

We study the processes e^{+}e^{-}→ωχ_{bJ}(1P) (J=0, 1, or 2) using samples at center-of-mass energies sqrt[s]=10.701, 10.745, and 10.805 GeV, corresponding to 1.6, 9.8, and 4.7  fb^{-1} of integrated luminosity, respectively. These data were collected with the Belle II detector during special operations of the SuperKEKB collider above the ϒ(4S) resonance. We report the first observation of ωχ_{bJ}(1P) signals at sqrt[s]=10.745  GeV. By combining Belle II data with Belle results at sqrt[s]=10.867  GeV, we find energy dependencies of the Born cross sections for e^{+}e^{-}→ωχ_{b1,b2}(1P) to be consistent with the shape of the ϒ(10753) state. These data indicate that the internal structures of the ϒ(10753) and ϒ(10860) states may differ. Including data at sqrt[s]=10.653  GeV, we also search for the bottomonium equivalent of the X(3872) state decaying into ωϒ(1S). No significant signal is observed for masses between 10.45 and 10.65  GeV/c^{2}.

An Update on Clinicopathological, Imaging, and Genetic Features of Angioleiomyoma

Angioleiomyoma is a benign, pericytic (perivascular) neoplasm that primarily occurs in the subcutis or dermis of the extremities. The lesion typically presents as a small, firm, slow-growing, painful nodule. Magnetic resonance imaging reveals the lesion to be a well-defined, round to oval mass with signal intensity similar to or slightly hyperintense to that of skeletal muscle on T1-weightwed sequences. A dark reticular sign on T2-weighted sequences appears to be a characteristic feature of angioleiomyoma. Prominent enhancement is usually seen after intravenous contrast. Histologically, the lesion consists of well-differentiated smooth muscle cells with many vascular channels. Based on vascular morphologies, angioleiomyoma is classified into three subtypes: solid, venous, and cavernous. By immunohistochemistry, angioleiomyoma is diffusely positive for smooth muscle actin and calponin and variably for h-caldesmon and desmin. Conventional cytogenetic studies have demonstrated relatively simple karyotypes characterized by one or few structural rearrangements or numerical aberrations. In addition, metaphase comparative genomic hybridization analyses have revealed recurrent loss of 22q and gain of Xq. Angioleiomyoma can be successfully treated with simple excision, with a very low recurrence rate. Knowledge of this peculiar neoplasm is important because it can mimic a variety of benign and malignant soft-tissue tumors. This review provides an updated overview of the clinical, radiological, histopathological, cytogenetic, and molecular genetic features of angioleiomyoma.

Measurement of the Λ_{c}^{+} Lifetime

An absolute measurement of the Λ_{c}^{+} lifetime is reported using Λ_{c}^{+}→pK^{-}π^{+} decays in events reconstructed from data collected by the Belle II experiment at the SuperKEKB asymmetric-energy electron-positron collider. The total integrated luminosity of the data sample, which was collected at center-of-mass energies at or near the ϒ(4S) resonance, is 207.2  fb^{-1}. The result, τ(Λ_{c}^{+})=203.20±0.89±0.77  fs, where the first uncertainty is statistical and the second systematic, is the most precise measurement to date and is consistent with previous determinations.

Search for a Dark Photon and an Invisible Dark Higgs Boson in μ^{+}μ^{-} and Missing Energy Final States with the Belle II Experiment

The dark photon A^{'} and the dark Higgs boson h^{'} are hypothetical particles predicted in many dark sector models. We search for the simultaneous production of A^{'} and h^{'} in the dark Higgsstrahlung process e^{+}e^{-}→A^{'}h^{'} with A^{'}→μ^{+}μ^{-} and h^{'} invisible in electron-positron collisions at a center-of-mass energy of 10.58 GeV in data collected by the Belle II experiment in 2019. With an integrated luminosity of 8.34  fb^{-1}, we observe no evidence for signal. We obtain exclusion limits at 90% Bayesian credibility in the range of 1.7-5.0 fb on the cross section and in the range of 1.7×10^{-8}-200×10^{-8} on the effective coupling ϵ^{2}×α_{D} for the A^{'} mass in the range of 4.0  GeV/c^{2}<M_{A^{'}}<9.7  GeV/c^{2} and for the h^{'} mass M_{h^{'}}<M_{A^{'}}, where ϵ is the mixing strength between the standard model and the dark photon and α_{D} is the coupling of the dark photon to the dark Higgs boson. Our limits are the first in this mass range.

Abstract 3255: Probing and overcoming KRASG12C inhibitor resistance by combination with a pan-KRAS SOS1 inhibitor

The recent accelerated approval of the KRASG12C mutant-selective inhibitor sotorasib (AMG 510) for the treatment of 2nd line KRASG12C mutation-positive NSCLC patients marks the first approved targeted therapy for tumors with any KRAS mutation. While KRASG12C inhibitors deliver clinical benefit, most patients who achieved an objective response ultimately progressed. Recent insights into clinical KRASG12C inhibitor resistance identified reactivation of the RAS/MAPK pathway as a common putative driver mechanism of resistance. Multiple ongoing trials seek to augment responses to KRASG12C inhibitors through rational combination strategies, including the pan-KRAS SOS1 inhibitor BI 1701963. Here we use different preclinical experimental approaches to interrogate KRASG12C inhibitor resistance mechanisms with the aim to identify strategies to overcome resistance. To predict on-target resistance, Ba/F3 cells were transduced with KRASG12C, ENU-mutagenized and chronically exposed to KRASG12C inhibitors. Resistant clones were screened for secondary KRAS mutations, highlighting that KRAS G12C/Y96D and Y96S cis mutations did confer resistance to KRASG12C inhibition but could be overcome by MEK inhibitor combination with a SOS1 inhibitor. As second strategy a high-complexity single site variant library of KRASG12C encompassing all possible secondary KRAS mutations was employed to establish Ba/F3 transgenic cell pools. The response of this KRASG12C Ba/F3 clone library harboring a comprehensive set of secondary mutations was tested following treatment with KRASG12C inhibitors alone and in combination with a pan-KRAS SOS1 inhibitor. In parallel, acquired KRASG12C inhibitor resistance was generated in solid cancer cells following long-term MRTX849 treatment. Clones were characterized and their response to KRASG12C inhibition and combination therapy was analyzed. Both in the Ba/F3 cell pool as well as in KRASG12C inhibitor resistant clones combining SOS1 inhibition to KRASG12C inhibition proved to be beneficial. Finally, bringing these findings in vivo, SW837(CRC) tumor-bearing mice were long-term treated with adagrasib until tumors relapsed after initial regression and resistant tumors were randomized for second line treatments. In this KRASG12C inhibitor resistant context, treatment with adagrasib plus cetuximab resulted in tumor stasis and adagrasib plus SOS1i resulted in tumor regression. While more work is currently being undertaken to map the resistance mechanisms in both our in vitro and in vivo settings, all results highlight the benefit of combining a SOS1 inhibitor with a KRASG12C inhibitor to prevent and/or overcome acquired resistance. The pan-KRAS SOS1 inhibitor BI 1701963 is the first direct RAS signaling modifier in phase I clinical trials both as a monotherapy as well as in combination with KRASG12C inhibitors, MEK inhibitors and liposomal irinotecan.

Citation Format: Marco H. Hofmann, Sabine Jurado, Daniel Gerlach, Takamasa Koga, Francesca Trapani, Michael Gmachl, Donat Alpar, Simone Lieb, Astrid Jeschko, Tetsuya Mitsudomi, Norbert Kraut, Mark P. Petronczki. Probing and overcoming KRASG12C inhibitor resistance by combination with a pan-KRAS SOS1 inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3255.

Foretinib can overcome common on-target resistance mutations after capmatinib/tepotinib treatment in NSCLCs with MET exon 14 skipping mutation

Background

Capmatinib and tepotinib are guideline-recommended front-line treatments for non-small-cell lung cancer (NSCLC) patients with MET exon 14 skipping mutations (METex14). However, the emergence of acquired resistance to capmatinib/tepotinib is almost inevitable partially due to D1228X or Y1230X secondary mutations of the MET. In this study, we explored agents that are active against both D1228X and Y1230X MET to propose an ideal sequential treatment after capmatinib/tepotinib treatment failure in NSCLC patients with METex14.

Methods

The inhibitory effects of 300 drugs, including 33 MET-TKIs, were screened in Ba/F3 cells carrying METex14 plus MET D1228A/Y secondary mutations. The screen revealed four-candidate type II MET-TKIs (altiratinib, CEP-40783, foretinib and sitravatinib). Therefore, we performed further growth inhibitory assays using these four MET-TKIs plus cabozantinib and merestinib in Ba/F3 cells carrying MET D1228A/E/G/H/N/V/Y or Y1230C/D/H/N/S secondary mutations. We also performed analyses using Hs746t cell models carrying METex14 (with mutant allele amplification) with/without D1228X or Y1230X in vitro and in vivo to confirm the findings. Furthermore, molecular dynamics (MD) simulations were carried out to examine differences in binding between type II MET-TKIs.

Results

All 6 type II MET-TKIs were active against Y1230X secondary mutations. However, among these 6 agents, only foretinib showed potent activity against D1228X secondary mutations of the MET in the Ba/F3 cell and Hs746t in vitro model and Hs746t in vivo model, and CEP-40783 and altiratinib demonstrated some activity. MD analysis suggested that the long tail of foretinib plays an important role in binding D1228X MET through interaction with a residue at the solvent front (G1163). Tertiary G1163X mutations, together with L1195F/I and F1200I/L, occurred as acquired resistance mechanisms to the second-line treatment foretinib in Ba/F3 cell models.

Conclusions

The type II MET-TKI foretinib may be an appropriate second-line treatment for NSCLCs carrying METex14 after campatinib/tepotinib treatment failure by secondary mutations at residue D1228 or Y1230.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-022-01299-z.

POS1441 INFLUENCE OF ENVIRONMENTAL AND GENETIC FACTORS ON SERUM IGG4 DURING HEALTH CHECKUPS IN NAGASAKI ISLAND STUDY

Background

Although serum IgG4 levels are important for the diagnosis of IgG4-related diseases (IgG4-RD), few studies have validated IgG4 levels in healthy individuals in large resident medical examination cohorts and investigated background factors associated with serum IgG4.

A report on genetic factors shows that HLA loci associate with IgG4-RD found in Japanese nation-wide IgG4-RD registry1). However, environmental and genetic factors related to the elevated serum IgG4 levels, which may closely associate with development of IgG4-RD, have previously been unclear in healthy subjects. The nephelometric immunoassay (NIA) is conventionally used to measure IgG4, but it requires a relatively large amount of serum. The magnetic bead panel assay (MBA), which can evaluate IgG4 levels with only a few ml of serum, has an advantage compared with NIA regarding to required sample volume, but the correlation between the two methods is unclear.

Objectives

First, we attempted to verify the accuracy of the MBA compared to the standard NIA in the first cohort. Next, we examined the relationship between IgG4 measured by the MBA and background information of healthy subjects to identify variables that correlate with serum IgG4 in the second cohort.

Methods

First, Kanazawa University collected 947 samples from the resident health examination, and IgG4 levels were measured by both MBA and NIA, and the correlation between the two was verified using Spearman’s rank correlation coefficient (first cohort). Next (second cohort), serum IgG4 of 3240 samples of Nagasaki Island Study (NaIS), which had started in 2014 collaborating among Nagasaki University and Goto City, Nagasaki Prefecture, intended for research of varying conditions and diseases including IgG4-RD, were then measured by MBA. These subjects were stratified into the two groups as IgG4-high and IgG4-within normal limit using the aforementioned cutoff values, and compared with background information such as age, gender, drinking, smoking, uric acid, serum creatinine, comorbidities and HLA typing, including DRB1*04:06, *04:03, *04:05, *04:10 as disease-susceptibility gene, DRB1*09:01 and DQB1*03:03 as protective gene1).

Results

IgG4 by MBA correlated well with IgG4 by NIA (r=0.94, p-value<0.001) which was determined from Kanazawa samples (N=947). 1,463.6 mg/mL of IgG4 of MBA corresponded to 135 mg/dl, the normal cut-off value for IgG4 by NIA. In the analysis of NaIS samples (N=3240), the overall high IgG4 positivity rate was 6.3%. Multivariable analysis including age, gender, smoking and drinking, led by univariate analysis, showed that gender and smoking were significantly associated with high serum IgG4 positivity (male: odds ratio = 1.8, 95%CI =1.2-2.7, p = 0.009, smoking: odds ratio = 1.7, 95%CI =1.1-2.5, p = 0.012). There was no association between high serum IgG4 level and HLA genotyping.

Conclusion

We concluded that MBA is a good method to measure serum IgG4 even by the very small sample volume. In our study, the prevalence of serum IgG4 positivity was high tendency than previous report2). Our data showed that male and smoking are independent factors associated with high serum IgG4 positivity. There were no association between serum IgG4 level and HLA genotyping in healthy subjects. Further comprehensive investigation is necessary to clarify high risk subjects who will develop IgG4-RD.

References

[1]Terao C, et al. Lancet Rheumatol 2019;1: e14–22.

[2]Carballo I, et al. PLoS One. 2016;11: e0149330.

Disclosure of Interests

None declared

POS0687 INHIBITION OF BONE EROSION, DETERMINED BY HIGH-RESOLUTION PERIPHERAL QUANTITATIVE COMPUTED TOMOGRAPHY (HR-pQCT), IN RHEUMATOID ARTHRITIS PATIENTS RECEIVING A CONVENTIONAL SYNTHETIC DMARD (csDMARD) PLUS DENOSUMAB VS csDMARD THERAPY ALONE: RESULTS OF AN OPEN-LABEL, RANDOMIZED, PARALLEL-GROUP STUDY

Background

Denosumab, a human IgG2 monoclonal antibody with high affinity for RANKL, is approved for treatment of bone erosion (ER) in patients with RA, based on the results of clinical trials. However, its effectiveness in combination with conventional therapy in RA patients has not been fully investigated in clinical practice.

Objectives

This exploratory study aimed to compare, in patients receiving conventional synthetic disease-modifying anti-rheumatic drugs (csDMARD) for treatment of RA, the effectiveness of combined use of csDMARD and denosumab vs csDMARD alone, in terms of inhibition of ER determined by HR-pQCT.

Methods

Detail protocol of this open-label, randomized, parallel-group study has been published previously.1 RA patients with moderate or low disease activity and progressive ER were eligible, and were randomly assigned to receive denosumab in addition to the csDMARD (denosumab) group or to continued use of the csDMARD alone (csDMARD) group. Denosumab was administered every 6 months during the 12-month study period. The primary endpoint was change in ER-depth at the second and third metacarpal bones, determined by HR-pQCT at month 6. For the primary endpoint, a linear mixed effect model analysis was performed using treatment group, sex, anti-cyclic citrullinated peptide (CCP) antibody (positive vs negative), and baseline disease activity (DAS28-ESR) as fixed effects, patients as random effects, and baseline values as covariates. For extension data, measurement time-point and the interaction between treatment group and measurement time-point was further added as fixed effects. The adverse events (AEs) were recorded.

Results

A total of 46 patients were randomized to denosumab and csDMARD groups (both N=23), and baseline characteristics were similar between both groups. Although the difference was not significant, the estimate mean (95%CI) change of ER-depth at month 6 from baseline as the primary endpoint was −0.57 (−1.52, 0.39) in the denosumab group vs −0.22 (−0.97, 0.53) in the csDMARD group, respectively. At months 6 and 12, ER-depth, -width, and -volume (extension data) were numerically lower in the denosumab group than in the csDMARD group (Table 1). Compared with patients in the csDMARD group, those in the denosumab group had significantly higher volumetric bone mineral density (vBMD) at month 12. AEs were reported in 12 (52.2%) and 13 (56.5%) of patients in the denosumab and csDMARD groups, respectively. The most common AEs of denosumab groups was hypocalcemia (reported in 4), and all the events were causally related with denosumab. Serious AEs were reported in 1 (4.3%) and 2 (8.7%) of patients in the denosumab and csDMARD groups, and which were not related to treatment drug.

Table 1.

ER and microstructure in denosumab group vs csDMARD group

MonthDenosumab group (n=21)csDMARDs group (n=22)Difference (Denosumab- csDMARDs)n1Estimate Means [95%CI]n1Estimate Means [95%CI]Estimate Means [95%CI]ER-depth617−0.46 [−1.31, 0.39]25−0.20 [−0.89, 0.49]−0.27 [−0.86, 0.32]1217−0.56 [−1.41, 0.29]22−0.20 [−0.90, 0.49]−0.35 [−0.95, 0.24]ER-width617−0.26 [−1.10, 0.57]25−0.06 [−0.73, 0.61]−0.20 [−0.81, 0.40]1217−0.27 [−1.10, 0.56]22−0.03 [−0.70, 0.64]−0.24 [−0.85, 0.38]ER-volume616−6.21 [−23.89, 11.46]24−1.71 [−16.07, 12.66]−4.51 [−16.67, 7.65]1217−6.25 [−23.94, 11.44]21−3.18 [−17.56, 11.20]−3.07 [−15.32, 9.17]vBMD6426.41 [2.78, 10.03]442.46 [−1.33, 6.24]3.95 [−0.05, 7.94]12389.20 [5.46, 12.95]423.66 [−0.15, 7.46]5.55 [1.46, 9.63]*

These were extension data.

This is the efficacy analysis set which excluded 3 patients from the full analysis set.

*; p<0.01

n, number of patients; n1, number of measurement points

Conclusion

Our results suggest that adding denosumab to csDMARD therapy may help prevent ER, promote ER repair, and improve bone microstructure.

References

[1]Iwamoto N, et al., Trials. 2019;20(1):1–8.

Disclosure of Interests

Naoki Iwamoto Speakers bureau: Daiichi Sankyo Co., Ltd., Grant/research support from: Daiichi Sankyo Co., Ltd., Ko Chiba Speakers bureau: Daiichi Sankyo Co., Ltd., Shuntaro Sato: None declared, Kazuteru Shiraishi: None declared, Konosuke Watanabe: None declared, Nozomi Ohki: None declared, Akitomo Okada: None declared, Tomohiro Koga: None declared, Makiko Kobayashi Employee of: Daiichi Sankyo Co., Ltd. (retired at submission), Kengo Saito Employee of: Daiichi Sankyo Co., Ltd., Naoki Okubo Employee of: Daiichi Sankyo Co., Ltd., Atsushi Kawakami Speakers bureau: Daiichi Sankyo Co., Ltd., Grant/research support from: Daiichi Sankyo Co., Ltd.

Presence of a Ground-glass Opacity Component is the True Prognostic Determinant in Clinical Stage I Non-Small Cell Lung Cancer

Introduction

Recent studies have suggested that including presence or absence of ground-glass opacity (GGO) may improve the tumor descriptor (T descriptor) classification in clinical stage I NSCLC. In this study, we analyzed prognostic implications of presence or absence of GGO, size of the solid component, and predominant histology to identify the true prognostic determinant for early-stage NSCLC.

Methods

We retrospectively examined 384 patients with clinical stage I NSCLC (solid: 242, part solid: 142) who underwent complete resection between 2009 and 2013.

Results

Survival curves of the whole cohort revealed good separation using the current TNM classification. Nevertheless, the part-solid group had a favorable prognosis irrespective of solid component size. Conversely, patients in the solid tumor group with tumors between 3 and 4 cm had a worse prognosis than patients whose tumors were less than or equal to 3 cm. Thus, we propose the following novel T descriptor classification: IA, part-solid tumors; IB, solid tumors less than or equal to 3 cm; and IC, solid tumors between 3 and 4 cm. This novel classification system stratified patient prognosis better than the current classification. On pathologic evaluation, the part-solid group always had better prognoses than the solid group in each subgroup divided by pathologic grade.

Conclusions

These results suggest that presence of GGO is the true prognostic determinant of stage I NSCLC, irrespective of the size of the solid component. Our novel T descriptor classification system could more accurately predict prognoses of clinical stage I NSCLC cases.

Utility of the Ba/F3 cell system for exploring on-target mechanisms of resistance to targeted therapies for lung cancer

Molecular targeted therapies are the standard of care for front‐line treatment of metastatic non‐small‐cell lung cancers (NSCLCs) harboring driver gene mutations. However, despite the initial dramatic responses, the emergence of acquired resistance is inevitable. Acquisition of secondary mutations in the target gene (on‐target resistance) is one of the major mechanisms of resistance. The mouse pro‐B cell line Ba/F3 is dependent on interleukin‐3 for survival and proliferation. Upon transduction of a driver gene, Ba/F3 cells become independent of interleukin‐3 but dependent on the transduced driver gene. Therefore, the Ba/F3 cell line has been a popular system to generate models with oncogene dependence and vulnerability to specific targeted therapies. These models have been used to estimate oncogenicity of driver mutations or efficacies of molecularly targeted drugs. In addition, Ba/F3 models, together with N‐ethyl‐N‐nitrosourea mutagenesis, have been used to derive acquired resistant cells to investigate on‐target resistance mechanisms. Here, we reviewed studies that used Ba/F3 models with EGFR mutations, ALK/ROS1/NTRK/RET fusions, MET exon 14 skipping mutations, or KRAS G12C mutations to investigate secondary/tertiary drug resistant mutations. We determined that 68% of resistance mutations reproducibly detected in clinical cases were also found in Ba/F3 models. In addition, sensitivity data generated with Ba/F3 models correlated well with clinical responses to each drug. Ba/F3 models are useful to comprehensively identify potential mutations that induce resistance to molecularly targeted drugs and to explore drugs to overcome the resistance.

Precise Measurement of the D^{0} and D^{+} Lifetimes at Belle II

We report a measurement of the D^{0} and D^{+} lifetimes using D^{0}→K^{-}π^{+} and D^{+}→K^{-}π^{+}π^{+} decays reconstructed in e^{+}e^{-}→cc[over ¯] data recorded by the Belle II experiment at the SuperKEKB asymmetric-energy e^{+}e^{-} collider. The data, collected at center-of-mass energies at or near the ϒ(4S) resonance, correspond to an integrated luminosity of 72  fb^{-1}. The results, τ(D^{0})=410.5±1.1(stat)±0.8(syst)  fs and τ(D^{+})=1030.4±4.7(stat)±3.1(syst)  fs, are the most precise to date and are consistent with previous determinations.

In vitro validation study of HER2 and HER4 mutations identified in an ad hoc secondary analysis of the LUX-Lung 8 randomized clinical trial

OBJECTIVES

The LUX-Lung 8 randomized trial (LL8) demonstrated a prolonged progression-free survival (PFS) in patients with metastatic squamous cell carcinoma (SCC) of the lung after treatment with afatinib compared with erlotinib. A secondary analysis of the LL8 reported that the presence of rare HER2/HER4 mutations may be partly responsible for this result. Patients with HER2 (hazard ratio [HR] 0.06/p-value 0.02) or HER4 (HR 0.21/p-value unreported) mutations had longer PFS after treatment with afatinib. However, the biological function of these mutations is unclear.

MATERIALS AND METHODS

Ten HER2 and 13 HER4 point mutations that were detected in the secondary analysis were transduced into the mouse pro-B cell line (Ba/F3) to determine changes in interleukin-3 (IL-3) dependence and sensitivity to six EGFR or pan-HER tyrosine kinase inhibitors (TKIs), including afatinib and erlotinib. The efficacy of the six TKIs was compared using a sensitivity index, defined as the 50% inhibitory concentration divided by trough concentration of each drug at clinically recommended doses.

RESULTS

Seven out of 10 Ba/F3 clones expressing HER2 mutations and all 13 Ba/F3 clones expressing HER4 mutations did not grow in the absence of IL-3, indicating these mutations were non-oncogenic. Three Ba/F3 clones expressing the HER2 mutations E395K, G815R, or R929W acquired IL-3-independent growth. The sensitivity indices for afatinib were ≤ one-fifth of those for erlotinib in all three lines. Other second/third-generation (2G/3G) TKIs showed high efficacy against clones expressing these HER2 mutations.

CONCLUSIONS

The majority of HER2/4 mutations detected in lung SCC from LL8 were not oncogenic in the Ba/F3 models, suggesting that the presence of HER2/4 mutations were not responsible for the superior outcomes of afatinib in the LL8 study. However, SCC of the lung in some patients may be driven by rare HER2 mutations, and these patients may benefit from 2G/3G pan-HER-TKI treatment.

Search for B^{+}→K^{+}νν[over ¯] Decays Using an Inclusive Tagging Method at Belle II

A search for the flavor-changing neutral-current decay B^{+}→K^{+}νν[over ¯] is performed at the Belle II experiment at the SuperKEKB asymmetric energy electron-positron collider. The data sample corresponds to an integrated luminosity of 63  fb^{-1} collected at the ϒ(4S) resonance and a sample of 9  fb^{-1} collected at an energy 60 MeV below the resonance. Because the measurable decay signature involves only a single charged kaon, a novel measurement approach is used that exploits not only the properties of the B^{+}→K^{+}νν[over ¯] decay, but also the inclusive properties of the other B meson in the ϒ(4S)→BB[over ¯] event, to suppress the background from other B meson decays and light-quark pair production. This inclusive tagging approach offers a higher signal efficiency compared to previous searches. No significant signal is observed. An upper limit on the branching fraction of B^{+}→K^{+}νν[over ¯] of 4.1×10^{-5} is set at the 90% confidence level.

Activity and mechanism of acquired resistance to tarloxotinib in HER2 mutant lung cancer: an in vitro study

Background

HER2 (ERBB2) activating mutations are present in 2–3% of lung adenocarcinomas; however, no targeted therapy is approved for HER2-altered lung cancers. A novel pan-HER inhibitor, tarloxotinib, is designed to release the active form (tarloxotinib-E) under hypoxic conditions in tumor tissues after being administered as a prodrug. Following the evaluation of the in vitro activity of tarloxotinib-E in HER2-mutant cells, we explored the mechanisms of resistance to tarloxotinib-E in these cells.

Methods

Growth inhibitory assays were performed with tarloxotinib-E and its prodrug using Ba/F3 cells expressing one of six HER2 mutations or wild-type (WT) HER2, in addition to H1781 cells with HER2 exon 20 insertions. Resistant clones were established from N-ethyl-N-nitrosourea (ENU)-treated HER2-mutant Ba/F3 cells and H1781 cells by chronic exposure to tarloxotinib-E.

Results

Tarloxotinib-E showed potent activity against HER2-mutant Ba/F3 cells and H1781 cells. Furthermore, the half maximal inhibitory concentration (IC₅₀) of tarloxotinib (inactive form) for WT HER2 was 180 times higher than that of tarloxotinib-E, indicating a wide therapeutic window of tarloxotinib. We established 30 resistant clones with secondary mutations of HER2 by ENU mutagenesis, all of which harbored C805S in exon 20. In the analysis of H1781 cells that acquired resistance to tarloxotinib-E, we found that increased HER3 expression was the molecular mechanism of tarloxotinib-E resistance.

Conclusions

Tarloxotinib-E exhibited potent activity against cell line models with HER2 mutations. We identified a secondary C805S HER2 mutation and HER3 overexpression as the mechanisms of acquired resistance to tarloxotinib-E.

Ultrasound efficacy of targeted-synthetic disease-modifying anti-rheumatic drug treatment in rheumatoid arthritis: a multicenter prospective cohort study in Japan

OBJECTIVE

This study investigated the effectiveness of treatment with Janus kinase (JAK) inhibitors in rheumatoid arthritis (RA) assessed by ultrasonography (US) activity, and the influence of patient characteristics and previous treatments.

METHOD

This prospective study assessed 60 treatment initiations among 53 Japanese patients diagnosed with RA who underwent treatment with JAK inhibitors during June 2013 to February 2020. Of the 53 patients, seven patients were enrolled in duplicate because they were treated with two different JAK inhibitors at different periods. For each case, the improvement rate on the power Doppler (PD) score was assessed at 6 month follow-up. Median improvement rate of PD score was used to classify cases as either US responders or non-responders, and patient characteristics were compared between the two groups.

RESULTS

All indicators of clinical disease activity and US activity showed a significant improvement at 3 months compared with baseline. Although the JAK inhibitor-cycler group and the interleukin-6 (IL-6) inhibitor inadequate response (IR) group tended to show a later improvement for US activity, all indicators of clinical disease activity and US activity showed a significant improvement at 6 months compared with baseline for both groups. Multivariate analysis showed that concomitant methotrexate use and an IR to the previous biologic or targeted-synthetic disease-modifying anti-rheumatic drug (b/tsDMARD) treatment were independently and significantly associated with US responders.

CONCLUSION

Use of a JAK inhibitor in combination with methotrexate and an absence of IR to any previous b/tsDMARDs demonstrated superior effectiveness for patients with RA.

POS1353 SERUM PROTEOMICS REVEALS INSULIN-LIKE GROWTH FACTOR BINDING PROTEINS-1 AS BIOMARKERS FOR IDIOPATHIC MULTICENTRIC CASTLEMAN’S DISEASE

Background:

Castleman’s disease (CD) is a lymphoproliferative disorder1 and presents as two distinct clinical entities: the localized form, unicentric CD (UCD) and the multicentric form, multicentric CD (MCD)2. MCD without human herpesvirus-8 (HHV-8) infection is defined idiopathic MCD (iMCD)3 and most MCDs in Japan are iMCDs. TAFRO syndrome is a group of disease that present with T: thrombocytopenia, A: anasarca, F: fever, R: reticulin fibrosis/renal dysfunction, O: organomegaly4. iMCD-TAFRO is present in the TAFRO syndrome and it is thought that pathology of lymph node biopsy shows an MCD-like appearance, and some clinical features overlap with MCD5. That do not belong to any of the above categories is classified as iMCD-not otherwise specified (iMCD-NOS). No biomarkers stratifying iMCD-NOS and iMCD-TAFRO have been identified, and no biomarkers defining treatment response have been identified for iMCD.

Objectives:

We will identify biomarkers that discriminate iMCD-NOS and iMCD-TAFRO or predict the treatment responsiveness.

Methods:

We performed a comprehensive analysis of serum proteins using the L-Series Human Antibody Array L-507 on the 4 iMCD-NOS and 2 iMCD-TAFRO patients from which pre- and post-tocilizumab treatment samples were obtained. An analysis by L-507 identified insulin-like growth factor binding proteins-1 (IGFBP-1) as a protein with a high rate of reduction post treatment. Sera from 28 healthy controls, 8 patients with iMCD-NOS, and 6 patients with iMCD-TAFRO were used to validate IGFBP-1 by ELISA. The mean ages of healthy controls, iMCD-NOS, and iMCD-TAFRO used in the validation ELISA were 50, 56, and 47 years, respectively, with no significant differences among the groups. The ratio of male to female was almost 1:1.

Results:

The 4 patients who responded well to treatment with tocilizumab all had a high rate of IGFBP-1 reduction by L-507 serum protein arrays. In ELISA, serum IGFBP-1 was significantly higher (p=0.0016) before the introduction of treatment in iMCD patients than healthy controls. In addition, serum IGFBP-1 level of iMCD-TAFRO was significantly higher than iMCD-NOS (p=0.024). Furthermore, post-treatment serum IGFBP-1 was decreased in many cases.

Conclusion:

Serum IGFBP-1 may play a particularly important role in the pathogenesis of iMCD-TAFRO and may be useful in discriminating between iMCD-NOS and iMCD-TAFRO. In the future, we will accumulate more cases, compare it with other inflammatory diseases, and examine the difference in response to treatment.

References:

[1]CASTLEMAN, et al. 1954. CASE records of the Massachusetts General Hospital Weekly Clinicopathological Exercises: Case 40011. N Engl J Med, 250, 26-30.

[2]WATERSTON, et al. 2004. Fifty years of multicentric Castleman’s disease. Acta Oncol, 43, 698-704.

[3]FAJGENBAUM D, et al. 2014. HHV-8-negative, idiopathic multicentric castleman disease (iMCD): A description of clinical features and therapeutic options through a systematic literature review. Blood (ASH Annual Meeting Abstracts), 124, 4861.

[5]TAKAI K, et al. 2010. Thrombocytopenia with mild bone marrow fibrosis accompanied by fever, pleural effusion, ascites and hepatosplenomegaly [in Japanese]. Rinsho Ketsueki, 51, 320-325.

[6]IWAKI N, et al. 2016. Clinicopathologic analysis of TAFRO syndrome demonstrates a distinct subtype of HHV-8-negative multicentric Castleman disease. Am J Hematol, 91, 220-226.

Disclosure of Interests:

None declared

POS0718 CLINICAL CHARACTERISTICS ASSOCIATED WITH GLANDULAR INVOLVEMENT EVALUATED BY SALIVARY GLAND ULTRASONOGRAPHY IN SJÖGREN’S SYNDROME

Background:

Sjögren’s syndrome (SS) is a systemic autoimmune disease characterized by periductal lymphocytic infiltration of the salivary and lacrimal glands, which results in reduced secretory functions and oral and ocular dryness (1). In addition, patients often have extraglandular manifestations, such as interstitial pneumonia and interstitial nephritis, and the appearance of autoantibodies such as anti-Ro/SS-A and La/SS-B antibodies. Salivary gland ultrasonography (SGUS) is typically used to evaluate the findings of salivary glands; thus, we can evaluate the severity of salivary gland disorders due to SS using SGUS in real time (2).

Objectives:

To identify clinical indices, including disease activity, associated with glandular involvement evaluated using SGUS in patients with SS.

Methods:

We enrolled patients with SS (n=115) and non-SS sicca subjects (n=90) who visited Nagasaki University Hospital between 1995 and 2019. The patients’ SS classifications were based on the 2002 American–European Consensus Group (AECG) SS classification criteria (3). The non-SS sicca subjects exhibited sicca symptoms but did not fulfill the AECG SS classification criteria. SGUS and clinical indices such as age, sex, the focus score (FS), sicca symptoms, the Saxon test results, Schirmer’s test results, anti-SS-A/Ro antibody positivity, anti-SS-B/La antibody positivity, anti-centromere antibody (ACA) positivity, serum immunoglobulin G levels, and the clinical European League Against Rheumatism SS disease activity index were examined. The ultrasonography (US) score was calculated based on SGUS imaging (hypoechoic area, hyperechoic band, and irregular border) (4).

Results:

The US score was significantly higher in patients with SS than that in non-SS sicca subjects. In addition, we found significant correlations between the US score and FS in patients with SS. Multivariate analysis revealed the FS, Saxon test positivity, and ACA positivity as the variables independently associated with the US score in patients with SS. These results were the same in the primary SS patient group (n=96). Patients with ACA positivity had significantly higher US scores compared to those in patients with ACA negativity, whereas the FS was not significantly high. In addition, patients with ACA positivity had significantly greater positivity of hyperechoic bands than that in patients with ACA negativity.

Conclusion:

This study indicated that ACA positivity, which is not reflected in sialadenitis of SS, is associated with the US score in patients with SS. These results suggest that US findings of patients with ACA positivity might show specific changes in salivary glands, such as fibrosis, and not only sialadenitis (5).

References:

[1]Ramos-Casals M, Tzioufas AG, Font J. Primary Sjogren’s syndrome: new clinical and therapeutic concepts. Ann Rheum Dis. 2005;64(3):347-54.

[2]van Ginkel MS, Glaudemans A, van der Vegt B, Mossel E, Kroese FGM, Bootsma H, et al. Imaging in Primary Sjogren’s Syndrome. J Clin Med. 2020;9(8).

[3]Vitali C, Bombardieri S, Jonsson R, Moutsopoulos HM, Alexander EL, Carsons SE, et al. Classification criteria for Sjogren’s syndrome: a revised version of the European criteria proposed by the American-European Consensus Group. Ann Rheum Dis. 2002;61(6):554-8.

[4]Takagi Y, Nakamura H, Sumi M, Shimizu T, Hirai Y, Horai Y, et al. Combined classification system based on ACR/EULAR and ultrasonographic scores for improving the diagnosis of Sjogren’s syndrome. PLoS One. 2018;13(4):e0195113.

[5]Nakamura H, Kawakami A, Hayashi T, Iwamoto N, Okada A, Tamai M, et al. Anti-centromere antibody-seropositive Sjögren’s syndrome differs from conventional subgroup in clinical and pathological study. BMC Musculoskelet Disord. 2010;11:140.

Disclosure of Interests:

None declared

KRAS Secondary Mutations That Confer Acquired Resistance to KRAS G12C Inhibitors, Sotorasib and Adagrasib, and Overcoming Strategies: Insights From In Vitro Experiments

INTRODUCTION

KRAS mutations have been recognized as undruggable for many years. Recently, novel KRAS G12C inhibitors, such as sotorasib and adagrasib, are being developed in clinical trials and have revealed promising results in metastatic NSCLC. Nevertheless, it is strongly anticipated that acquired resistance will limit their clinical use. In this study, we developed in vitro models of the KRAS G12C cancer, derived from resistant clones against sotorasib and adagrasib, and searched for secondary KRAS mutations as on-target resistance mechanisms to develop possible strategies to overcome such resistance.

METHODS

We chronically exposed Ba/F3 cells transduced with KRAS^G12C to sotorasib or adagrasib in the presence of N-ethyl-N-nitrosourea and searched for secondary KRAS mutations. Strategies to overcome resistance were also investigated.

RESULTS

We generated 142 Ba/F3 clones resistant to either sotorasib or adagrasib, of which 124 (87%) harbored secondary KRAS mutations. There were 12 different secondary KRAS mutations. Y96D and Y96S were resistant to both inhibitors. A combination of novel SOS1 inhibitor, BI-3406, and trametinib had potent activity against this resistance. Although G13D, R68M, A59S and A59T, which were highly resistant to sotorasib, remained sensitive to adagrasib, Q99L was resistant to adagrasib but sensitive to sotorasib.

CONCLUSIONS

We identified many secondary KRAS mutations causing resistance to sotorasib, adagrasib, or both, in vitro. The differential activities of these two inhibitors depending on the secondary mutations suggest sequential use in some cases. In addition, switching to BI-3406 plus trametinib might be a useful strategy to overcome acquired resistance owing to the secondary Y96D and Y96S mutations.

Discrepancy between clinical and ultrasound remissions in rheumatoid arthritis: a multicentre ultrasound cohort study in Japan

Objectives: Using multicentre ultrasound (US) cohort data among patients with rheumatoid arthritis (RA), we aimed to identify baseline factors that permit differentiation between two patient cohorts achieving US remission and clinical remission, and to determine the factors contributing to the discrepancy.Method: We reviewed 248 Japanese patients diagnosed with RA who underwent treatment with biological disease-modifying anti-rheumatic drugs at 13 centres. We performed US assessments of the synovia of 22 joints. We assessed the percentages of patients with clinical remission and US remission, defined as total power Doppler scores of 0 at 12 months.Results: The 87 patients who achieved US remission were divided into a group that achieved both clinical and US remission (n = 53) and a group that achieved US remission only (n = 34). Baseline factors that were significantly and independently associated with clinical remission at 12 months among patients who also achieved US remission included short disease duration, the presence of concomitant methotrexate use, and low patient global assessment score (p < 0.05, p < 0.05, and p < 0.005, respectively).Conclusions: RA patients with baseline high patient global assessment scores and long disease duration at baseline were unlikely to achieve clinical remission even after achieving US remission. Objective joint assessments using US provide additional information of potential importance for the management of RA.

Activity of tarloxotinib-E in cells with EGFR exon-20 insertion mutations and mechanisms of acquired resistance

BACKGROUND

Approximately 10% of non-small cell lung cancers (NSCLCs) that harbor epidermal growth factor receptor (EGFR) gene mutations have in-frame insertions in exon 20 of the EGFR gene. These tumors do not usually respond to currently available EGFR-tyrosine kinase inhibitors (TKIs). Tarloxotinib is a novel hypoxia-activated prodrug that releases a potent, irreversible pan-ERBB TKI (tarloxotinib-E) under solid tumor hypoxia.

METHODS

We examined the efficacy of tarloxotinib-E against several types of Ba/F3 cells with introduced EGFR exon 20 mutations (EGFR A763insFQEA, V769insASV, D770insSVD, H773insH and H773insNPH mutations). We assayed growth inhibition for tarloxotinib (prodrug), tarloxotinib-E (active form), poziotinib, afatinib, and osimertinib in Ba/F3 cells with each EGFR exon 20 mutation. We also explored acquired resistance mechanisms to tarloxotinib-E by establishing cells with resistance to tarloxotinib-E via chronic drug exposure after N-ethyl-N-nitrosourea mutagenesis treatment.

RESULTS

Among all tested Ba/F3 cell lines, IC₅₀ was ≥72.1 times higher for tarloxotinib than for tarloxotinib-E, which implies a wide therapeutic window with this prodrug strategy. Tarloxotinib-E was efficacious against all tested Ba/F3 cells except for H773insH, which was less sensitive to all tested EGFR-TKIs. As acquired resistance mechanisms to tarloxotinib-E, we identified either T790M or C797S secondary mutations, depending on the original EGFR exon 20 mutation.

CONCLUSIONS

These findings indicate that tarloxotinib-E could be effective for NSCLC with EGFR exon 20 mutations. Our results also show that T790M or C797S mutations can confer acquired resistance to tarloxotinib-E; and suggest that resistance mechanisms are influenced by the baseline EGFR exon 20 mutations.

Dose-dependence in acquisition of drug tolerant phenotype and high RYK expression as a mechanism of osimertinib tolerance in lung cancer

OBJECTIVE

Emergence of acquired resistance is almost inevitable during EGFR-tyrosine kinase inhibitor therapy for non-small-cell lung cancer (NSCLC) harboring EGFR mutations. Drug tolerance, a reversible state of drug insensitivity in the early phases of tyrosine kinase inhibitor therapy, is considered to serve as the basis of recurrent disease. Therefore, it is important to elucidate the molecular mechanisms of drug tolerance.

MATERIALS AND METHODS

Five EGFR-mutated NSCLC cell lines were used in this study. We established drug-tolerant cells (DTCs) via 72 h treatment with osimertinib (600 nM) or afatinib (60 nM). Acquisition of drug tolerance was evaluated by growth inhibitory assay, and the molecular mechanisms of drug tolerance were analyzed by phospho-RTK array.

RESULTS

DTCs were successfully induced in PC9, HCC4006, and H1975 cells against osimertinib and in PC9 cells against afatinib. We observed that a high drug concentration was required to induce DTCs, and HCC4006 cells become tolerant when a higher dose of afatinib (>180 nM) was used. In the analysis of HCC4006 DTCs against osimertinib, we observed increased receptor-like tyrosine kinase (RYK) expression, and siRNA-mediated RYK knockdown inhibited the proliferation of DTCs.

CONCLUSIONS

These results suggest that induction of DTCs is dose-dependent, and increased RYK expression was the mechanism of drug tolerance in HCC4006 cells against osimertinib.

IL-15 is a biomarker involved in the development of rapidly progressive interstitial lung disease complicated with polymyositis/dermatomyositis

BACKGROUND

Polymyositis/dermatomyositis (PM/DM) is an autoimmune disease that is sometimes complicated with rapidly progressive interstitial lung disease (RPILD). However, serum and lung biomarkers that can predict RPILD development remain unclear.

OBJECTIVES

To determine potential serum and lung biomarkers that can predict RPILD development in patients with PM/DM-ILD.

METHODS

In total, 49 patients with PM/DM-ILD were enrolled. We measured the serum levels of 41 cytokines/chemokines, ferritin and anti-MDA5 antibody, compared them between the RPILD (n = 23) and non-RPILD (n = 26) groups, and ranked them by their importance through random forest analysis. To distinguish the two groups, we determined biomarker combinations by logistic regression analysis. We also measured the bronchoalveolar lavage fluid (BALF) levels of 41 cytokines/chemokines. Using immunohistochemistry, we examined IL-15 expression in lung tissues. The IL-15 production was also investigated using A549 and BEAS-2B cells.

RESULTS

The RPILD group had significantly higher IL-15, IL-1RA, IL-6, CXCL10, VCAM-1, anti-MDA5 antibody and ferritin serum levels than the non-RPILD group, but it had a significantly low CCL22 level. Meanwhile, anti-MDA5 antibody, IL-15, CXCL8, CCL22, IL-1RA and ferritin were the best combination to distinguish the two groups. IL-15 and CCL22 were also predictive marker for RPILD development in anti-MDA5 antibody-positive patients. Additionally, the RPILD group had significantly high IL-15 levels in BALF. The lung tissues expressed IL-15, which increased after cytokine stimulation in the A549 cells.

CONCLUSION

This study identified a combination of biomarkers predicting PM/DM-RPILD progression, and IL-15 is an important cytokine for predicting RPILD development and reflecting ILD severity.

Fluorescence optical imaging in patients with active rheumatoid arthritis: a comparison with ultrasound and an association with biomarkers

Objectives: This study compared indocyanine green (ICG)-enhanced fluorescence optical imaging (FOI) and musculoskeletal ultrasound (MSUS), and explored the significance of the FOI findings based on the association between the FOI and MSUS findings and serum biomarkers in patients with rheumatoid arthritis (RA). The study also explored the association between the FOI findings and patients' joint destruction at the joint-area level.Method: We enrolled 50 consecutive patients with active RA from among the patients hospitalized from May 2014 to March 2016 at Nagasaki University Hospital, Japan. FOI images were acquired with the Xiralite^® fluorescence imaging system and compared with the patients' clinical examination results and MSUS findings. On the same day, the patients' clinical disease activity and levels of serum biomarkers (including vascular endothelial growth factor) were obtained.Results: Although the FOI detected synovitis with high sensitivity, the frequency of positive findings and the diagnostic performance with MSUS as the reference standard for FOI differed considerably among the phases of FOI as well as among the affected joint regions. The FOI scores were positively correlated with clinical disease activity, MSUS scores, and serum biomarkers. The severity of FOI-proven synovitis was associated with the presence of MSUS-proven bone erosion.Conclusion: FOI is effective for detecting joint inflammation in RA patients, with high accuracy. The severity of the FOI score was closely associated with the joint destruction at the joint-area level. However, the significance of positive FOI findings differed depending on not only the phase of FOI but also the affected joint regions.

Search for Axionlike Particles Produced in e^{+}e^{-} Collisions at Belle II

We present a search for the direct production of a light pseudoscalar a decaying into two photons with the Belle II detector at the SuperKEKB collider. We search for the process e^{+}e^{-}→γa, a→γγ in the mass range 0.2<m_{a}<9.7  GeV/c^{2} using data corresponding to an integrated luminosity of (445±3)  pb^{-1}. Light pseudoscalars interacting predominantly with standard model gauge bosons (so-called axionlike particles or ALPs) are frequently postulated in extensions of the standard model. We find no evidence for ALPs and set 95% confidence level upper limits on the coupling strength g_{aγγ} of ALPs to photons at the level of 10^{-3}  GeV^{-1}. The limits are the most restrictive to date for 0.2<m_{a}<1  GeV/c^{2}.

Prognostic implications of preoperative versus postoperative circulating tumor DNA in surgically resected lung cancer patients: a pilot study

Background

Recent studies of advanced lung cancer patients have shown that circulating tumor DNA (ctDNA) analysis is useful for molecular profiling, monitoring tumor burden, and predicting therapeutic efficacies and disease progression. However, the usefulness of ctDNA analysis in surgically resected lung cancers is unclear.

Methods

This study included 20 lung cancer patients with clinical stage IIA–IIIA disease. Preoperative and postoperative (3–12 days) plasma samples were collected for ctDNA analysis. Cancer personalized profiling by deep sequencing, which can detect mutations in 197 cancer-related genes, was used for ctDNA detection. The cohort consisted of 18 men and 2 women with a median age of 69 (range, 37–88) years. Sixteen patients (80%) had a history of smoking. Histologically, there were four squamous cell carcinomas, 13 adenocarcinomas, two adenosquamous cell carcinomas, and one small cell carcinoma.

Results

At the time of data analysis, the 20 patients had been monitored for a median follow-up of 12 months. Eight patients (40%) were positive for preoperative ctDNA, and this was significantly correlated with tumor size (≥5 vs. <5 cm, P=0.018). Four patients (20%) were positive for postoperative ctDNA, and this was significantly correlated with histological grade (3 vs. 1 or 2, P=0.032). Postoperative positivity for ctDNA also predicted shorter recurrence-free survival (RFS) (P=0.015), while pre- and post-operative carcinoembryonic antigen levels (P=0.150 and P=0.533, respectively) and preoperative positivity for ctDNA (P=0.132) were not correlated with RFS.

Conclusions

Detecting ctDNA postoperatively was a poor prognostic factor in surgically resected lung cancer patients that may suggest there is minimal residual disease (MRD).

Inter- and Intratumor Heterogeneity of EGFR Compound Mutations in Non-Small Cell Lung Cancers: Analysis of Five Cases

BACKGROUND

Several clinical and preclinical studies suggest that non-small cell lung cancers (NSCLCs) with EGFR compound mutations were associated with lower efficacies of first-generation EGFR inhibitors than tumors with single EGFR mutation. Some researchers hypothesize that EGFR mutation status is heterogeneous in such tumors and that second-generation EGFR inhibitors may eliminate cancer cells with uncommon EGFR mutations from tumors with EGFR compound mutations. However, this hypothesis is currently unproven; therefore, we performed the current study to determine if tumor cells with EGFR compound mutations are present in heterogeneous or homogeneous manners.

PATIENTS AND METHODS

Multiregion analysis was performed for surgically resected primary NSCLC tumors with EGFR compound mutations to examine the intratumor heterogeneity of EGFR compound mutations. In addition, we evaluated the intertumor heterogeneity of EGFR compound mutations using 2 pleural disseminations obtained from a patient with NSCLC at exploratory thoracotomy and 9 primary or metastatic lesions obtained from 2 autopsied NSCLC patients. Digital polymerase chain reaction, target sequencing, or direct sequencing were used to detect EGFR mutations.

RESULTS

This study included 5 NSCLC cases; their compound mutations were L858R+S768I, G719X+S768I, G719A+R776H, L858R+E709G, and L858R+I759M. Noncancerous pulmonary tissues from each patient did not harbor EGFR mutations, which revealed that all mutations were somatic. We did not detect any intra- or intertumor heterogeneity in these EGFR compound mutations.

CONCLUSION

No intra- or intertumor heterogeneity was observed for EGFR compound mutations. Our results indicate that both EGFR mutations were truncal and selective elimination of cancer cells with uncommon EGFR mutations is unrealistic.

Significance of anti-Ro/SSA antibodies in the response and retention of abatacept in patients with rheumatoid arthritis: a multicentre cohort study

Objective: To determine whether the positivity of baseline anti-Ro/Sjögren's syndrome antigen A (SSA) antibodies influences the response to abatacept, we compared therapeutic responses between anti-Ro/SSA antibody-negative and -positive patients with rheumatoid arthritis (RA) using a multicentre RA ultrasonography prospective cohort. Method: We reviewed Japanese patients with RA who started abatacept as the first biological disease-modifying anti-rheumatic drug between June 2013 and April 2018. We assessed 28-joint Disease Activity Score-erythrocyte sedimentation rate (DAS28-ESR) change between baseline and 6 or 12 months after treatment in RA patients treated with abatacept, and European League Against Rheumatism (EULAR) response at 6 and 12 months. The Global OMERACT-EULAR Synovitis Score (GLOESS) was calculated at baseline and at 6 and 12 months. Results: Overall, 51 patients were enrolled and divided into anti-Ro/SSA antibody-negative and -positive groups of 35 and 16, respectively. Median age at baseline was significantly higher in the anti-Ro/SSA antibody-negative group (p = 0.04). The retention rate and percentage of EULAR good responders at 12 months were significantly higher in the anti-Ro/SSA antibody-negative group (both p = 0.02). Anti-Ro/SSA antibody-negative patients exhibited larger decreases in both DAS28-ESR and DAS28-C-reactive protein at 12 months than anti-Ro/SSA antibody-positive patients (p = 0.02 and 0.04, respectively). GLOESS decreased significantly at 6 months in anti-Ro/SSA antibody-negative patients (p = 0.03). Multivariate analyses showed that anti-Ro/SSA antibody positivity was an independent factor associated with change in the DAS28-ESR at 6 months (p < 0.05). Conclusion: Anti-Ro/SSA antibody positivity predicts a poor response to abatacept and low retention rate.

Spatial heterogeneity of acquired resistance mechanisms to 1st/2nd generation EGFR tyrosine kinase inhibitors in lung cancer

BACKGROUND

Overcoming acquired resistance against targeted therapies to improve outcomes of lung cancer patients harboring driver mutations is a critical issue. While drug therapy oriented to a resistance mechanism appears attractive, spatial heterogeneity of resistance mechanisms in each patient will diminish treatment efficacy. However, the frequency, clinical backgrounds, clinical implications, and patterns of spatial heterogeneity in resistance mechanisms to EGFR tyrosine kinase inhibitors (TKIs) are largely unknown.

PATIENTS AND METHODS

This study included 128 specimens from 24 autopsied patients with lung adenocarcinoma harboring EGFR mutation. Acquired resistance mechanisms reported as relatively frequent in lung cancer, e.g., T790 M and other secondary EGFR mutations, MET and ERBB2 gene amplification, and histological transformation, were retrospectively examined. All patients had received 1st/2nd generation EGFR-TKI and showed acquired resistance to the drug before death. No patient received osimertinib.

RESULTS

No resistance mechanism was identified in two patients. T790M mutation was detected in 20 patients (83 %); however, nine of these patients also had lesions without T790M mutation. Among 22 patients whose resistance mechanisms were identified, ten had spatial heterogeneity of resistance mechanisms (45 %), and these patients had significantly shorter time-to-treatment failure compared with those without heterogeneity (median 4.7 months vs. 14.7 months, p = 0.0004).

CONCLUSION

We observed significant spatial heterogeneity of acquired resistance mechanisms to EGFR-TKIs in lung adenocarcinoma. Our results also indicate that the incidence of resistance mechanisms may vary based on the biopsied tumor locations.

SAT0527 COMBINED EFFECT OF COMMON VARIANTS IN EXON 2 OR EXON 3 AND A PATHOGENIC MUTATION IN EXON 10 OF THE MEDITERRANEAN FEVER GENE ON INFLAMMASOME ACTIVATION IN JAPANESE PATIENTS WITH FAMILIAL MEDITERRANEAN FEVER

Background:

Familial Mediterranean fever (FMF) is an autoinflammatory disease that is caused by Mediterranean fever (MEFV) gene mutations. It is characterized by recurrent and self-limiting febrile attacks within a short period. Although the pathologic significance ofMEFVexon 2 or exon 3 common variants in patients with FMF is modest and these variants are usually associated with less severe clinical presentations of FMF (1, 2), their combined effects with pathogenic mutation in exon 10 remain to be evaluated.

Objectives:

To determine the combined effect of common variants on clinical manifestations and inflammasome activity, we compared the clinical and laboratory characteristics between the coexistence and non-coexistence ofMEFVexon 2 or exon 3 variants in patients with FMF that had a heterozygousMEFVexon 10 mutation.

Methods:

We excluded patients with FMF that had twoMEFVexon 10 mutations in one or more alleles and those withMEFVvariants in exons other than in exons 2, 3, or 10. Finally, we reviewed 131 Japanese patients with FMF that had a heterozygousMEFVexon 10 mutation, and they were divided into the groups with and withoutMEFVexon 2 or exon 3 variants of 34 and 97, respectively. All enrolled patients had only a heterozygous M694I mutation in exon 10 of theMEFVgene. We measured serum IL-18 levels at remission without febrile attacks in the groups with and withoutMEFVexon 2 or exon 3 variants of 9 and 31, respectively.

Results:

In the univariate analysis, the group with variants in exon 2 or exon 3 had significantly earlier onset (16.0 years v.s. 20.5 years, p = 0.04), a higher percentage of thoracic pain with febrile attacks (68% v.s. 44%, p = 0.02), a higher frequency of attack (1.0/month v.s. 0.5/month, p = 0.02), and a higher IL-18 level in the serum at remission (606.3 pg/ml v.s. 168.4 pg/ml, p = 0.04, Figure 1) compared to the group without these variants. Importantly, multivariate analyses showed that the coexistence ofMEFVexon 2 or exon 3 variants and an exon 10 mutation was independently and significantly associated with earlier onset of FMF (p = 0.049) and thoracic pain (p = 0.03).

Figure 1.

Conclusion:

Our results suggest that the coexistence ofMEFVexon 2 or exon 3 variants and aMEFVexon 10 mutation has combined effects on inflammasome activation in the Japanese population.

References:

[1]Migita K, Uehara R, Nakamura Y, et al. Familial Mediterranean fever in Japan. Medicine (Baltimore). 2012 Nov;91(6):337-43.

[2]Shinar Y, Livneh A, Langevitz P, Genotype-phenotype assessment of common genotypes among patients with familial Mediterranean fever. J Rheumatol. 2000;27(7):1703.

Disclosure of Interests:

None declared

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.