Antibody-like proteins that capture and neutralize SARS-CoV-2

To combat severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) and any unknown emerging pathogens in the future, the development of a rapid and effective method to generate high-affinity antibodies or antibody-like proteins is of critical importance. We here report high-speed in vitro selection of multiple high-affinity antibody-like proteins against various targets including the SARS-CoV-2 spike protein. The sequences of monobodies against the SARS-CoV-2 spike protein were successfully procured within only 4 days. Furthermore, the obtained monobody efficiently captured SARS-CoV-2 particles from the nasal swab samples of patients and exhibited a high neutralizing activity against SARS-CoV-2 infection (half-maximal inhibitory concentration, 0.5 nanomolar). High-speed in vitro selection of antibody-like proteins is a promising method for rapid development of a detection method for, and of a neutralizing protein against, a virus responsible for an ongoing, and possibly a future, pandemic.

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.

Emerging MET tyrosine kinase inhibitors for the treatment of non-small cell lung cancer

Introduction MET aberrations, including MET exon 14 skipping mutation and amplification, are present in ~5% of non-small cell lung cancer (NSCLC) cases, and these levels are comparable to the frequency of ALK fusion. MET amplification also occurs as an acquired resistance mechanism in EGFR-mutated NSCLC after EGFR tyrosine kinase inhibitors (TKI) treatment failure. Therefore, the development of therapies for activated MET is urgently needed. Areas covered This review summarizes (1) the mechanisms and frequencies of MET aberrations in NSCLC, (2) the efficacies and toxicities of MET-TKIs under clinical development and (3) the mechanisms of inherent and acquired resistance to MET-TKIs. Expert opinion Type Ia, Ib and II MET-TKIs are currently under clinical development, and phase I/II studies have shown the potent activities of tepotinib, capmatinib and savolitinib; in fact, tepotinib and capmatinib were approved for use by health authorities. However, inherent and acquired resistance through on- and off-target mechanisms has been detected, and strategies to overcome this resistance are being developed.

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.

Internal Delensing of Cosmic Microwave Background Polarization B-Modes with the POLARBEAR Experiment

Using only cosmic microwave background polarization data from the polarbear experiment, we measure B-mode polarization delensing on subdegree scales at more than 5σ significance. We achieve a 14% B-mode power variance reduction, the highest to date for internal delensing, and improve this result to 22% by applying for the first time an iterative maximum a posteriori delensing method. Our analysis demonstrates the capability of internal delensing as a means of improving constraints on inflationary models, paving the way for the optimal analysis of next-generation primordial B-mode experiments.

P93 The usefulness of dual cardiac autonomic nervous modulation assessment for prediction of mortality in patients with relatively preserved left ventricular ejection fraction

Background

Recent guidelines have stated that reduced left ventricular ejection fraction (LVEF) is the gold standard marker for identifying patients at risk for cardiac mortality. Although reduced LVEF identifies patients at an increased risk of cardiac arrest, sudden cardiac deaths (SCDs) occur considerably more often in patients with relatively preserved LVEF. Current guidelines on SCDs risk stratification do not adequately cover this general population pool. Heart rate variability (HRV) and heart rate turbulence (HRT) are non-invasive electrocardiography (ECG)-based techniques capable of providing relevant information on the cardiac autonomic nervous modulation. Although a large body of evidence about autonomic nervous modulation markers has been reported, the usefulness of HRV and HRT parameters for risk stratification in such patients with relatively preserved LVEF has not yet been elucidated.

Purpose

This study aimed to evaluate HRV and HRT parameters for predicting cardiac mortality in patients with structural heart disease (SHD), including ischemic heart disease, dilated cardiomyopathy and valvular heart disease, who have mid-range left ventricular dysfunction (LVD).

Methods

We prospectively enrolled 229 patients (187 men, age 63 ± 13 years) with SHD who have mid-range LVD (LVEF > 40%). HRV and HRT parameters based on 24-hour ambulatory ECG recordings (Fukuda Denshi Co., Ltd., Tokyo, Japan) were evaluated as follows; SDNN, triangular index, high and low frequency HRV, turbulence onset and slope. The primary endpoint was all-cause mortality. Univariate and multivariate Cox regression analysis were used to assess the association between these cardiac autonomic nervous modulation and mortality.

Results

During a mean follow-up of 21 ± 11 months, all-cause mortality was seen in 11 (4.8%) patients. Univariate Cox regression analysis showed that reduced SDNN (<50ms), reduced triangular index (<20ms) and HRT category 2 were significantly associated with the primary endpoint (P < 0.05). When HRT category 2 combined with reduced SDNN, Multivariate Cox regression analysis revealed that this combination more strongly associates with the primary endpoint (hazard ratio =7.91, 95%CI, 1.82-34.2; P = 0.006).

Conclusion

Dual cardiac autonomic nervous modulation assessment which combined HRT and HRV could be a superior technique to predict mortality in patients with relatively preserved LVEF.

P3754Comparison of the transdermal bisoprolol patch with the oral bisoprolol fumarate administration as a therapeutic agent for idiopathic frequent premature ventricular contractions

Background

The transdermal bisoprolol patch (TB) was designed to maintain a sustained concentration of bisoprolol in plasma by higher trough concentration than the oral bisoporolol fumarate administration (OB). It is unclear whether the TB is as effective in treating idiopathic premature ventricular contractions (PVCs) as the OB.

Purpose

We compared the efficacy between the TB and OB in treating idiopathic PVCs while considering their duration of action.

Methods

Among 198 patients with a PVC count of ≥3,000 beats/24 hours, 84 patients were divided into groups treated with TB 4mg (n=50) or OB 2.5mg (n=34). The PVCs were divided into positive heart rate (HR)-dependent PVCs (P-PVCs) and non-positive HR-dependent PVCs (NP-PVCs) based on the relationship between the hourly PVCs density and hourly mean HR. To evaluate the efficacy, PVC counts by 24-hour Holter electrocardiograms were measured at baseline and at 1 month after the initiation of the therapy.

Results

There were no significant between-group differences for the mean HR, PVC count, or type of PVCs. Both the TB (from 16,692±9,737 to 10,442±10,711 beats/24 hours, P<0.001) and OB (from 19,633±16,298 to 9,235±12,124 beats/24 hours, P<0.001) significantly decreased the total PVC count after the initiation of therapy, and a comparison between the two drugs showed no significant difference (P=0.46). In the P-PVC group, both the TB and OB significantly decreased the total PVC count (P<0.001, P=0.022 respectively), PVC count during the day-time (P<0.001, P=0.030 respectively), and PVC count during the night-time (P=0.0038, P=0.022 respectively). In contrast, in the NP-PVC group, neither the TB nor OB made any significantly change in the total PVC count (P=0.079, P=0.10 respectively), PVC count during the day-time (P=0.35, P=0.12 respectively), or PVC count during the night-time (P=0.11, P=0.12 respectively). The TB exhibited a significant reduction during each time period regarding the changes within 24-hours in the P-PVC count from baseline, while the OB did not significantly reduce the P-PVC count from baseline during each time period between 0 and 5 o'clock.

Conclusions

Compared with the OB, the TB could be used with the same efficacy for reducing the PVC count. The TB could be a more useful therapeutic agent for idiopathic P-PVCs during a 24-hour period than the OB.

P6559Long-term follow-up and outcomes of patients with discontinuation of oral anticoagulant therapy after successful ablation procedures for atrial fibrillation

Background

Oral anticoagulant therapy (OAT) is effective for preventing strokes in atrial fibrillation (AF) patients. Currently, there is controversy regarding the discontinuation of OATs in patients with ablation procedures to eliminate AF.

Aim

We investigated the incidence of major bleeding and ischemic strokes/systemic embolisms in low-risk patients that discontinued OATs after successful AF ablation procedures.

Methods

Of 330 consecutive patients that underwent AF ablation procedures and were prescribed one of the direct oral anticoagulants or warfarin, 207 AF patients (158 men, mean age 61±11 years) who discontinued OATs three months after the procedure were enrolled. The average CHADS2 and HAS-BLED scores were 1.0±0.9 and 1.2±1.0, respectively, which meant that most patients had a low risk for strokes.

Results

During follow-up, 31 patients (15%) had recurrences of AF. Those patients underwent a re-ablation procedure and then re-discontinued their OATs three months after the session. During a 60±13 months follow-up, major bleeding was observed in five patients (2.4%) and was associated with a higher HAS-BLED score (2.2±0.4 vs. 1.1±1.0, P=0.027). In contrast, none of the patients experienced ischemic strokes/systemic embolisms.

Conclusions

This prospective study demonstrated that in patients with successful ablation procedures and low risk scores for AF management, OATs could be discontinued three months after the procedure. Unnecessary continuation of OATs may increase the incidence of major bleeding during the follow-up.

Sensitivity and Resistance of MET Exon 14 Mutations in Lung Cancer to Eight MET Tyrosine Kinase Inhibitors In Vitro

BACKGROUND

MNNG HOS transforming gene (MET) exon 14 mutations in lung cancer, including exon 14 skipping and point mutations, have been attracting the attention of thoracic oncologists as new therapeutic targets. Tumors with these mutations almost always acquire resistance, which also occurs in other oncogene-addicted lung cancers. However, the resistance mechanisms and treatment strategies are not fully understood.

METHODS

We generated Ba/F3 cells expressing MET exon 14 mutations by retroviral gene transfer. The sensitivities of these cells to eight MET-tyrosine kinase inhibitors (TKIs) were determined using a colorimetric assay. In addition, using N-ethyl-N-nitrosourea mutagenesis, we generated resistant clones, searched for secondary MET mutations, and then examined the sensitivities of these resistant cells to different TKIs.

RESULTS

Ba/F3 cells transfected with MET mutations grew in the absence of interleukin-3, indicating their oncogenic activity. These cells were sensitive to all MET-TKIs except tivantinib. We identified a variety of secondary mutations. D1228 and Y1230 were common sites for resistance mutations for type I TKIs, which bind the active form of MET, whereas L1195 and F1200 were common sites for type II TKIs, which bind the inactive form. In general, resistance mutations against type I were sensitive to type II, and vice versa.

CONCLUSIONS

MET-TKIs inhibited the growth of cells with MET exon 14 mutations. We also identified mutation sites specific for TKI types as resistance mechanisms and complementary activities between type I and type II inhibitors against those mutations. These finding should provide relevant clinical implication for treating patients with lung cancer harboring MET exon 14 mutations.

Abstract 2200: Potent in vitro activity of Tarloxotinib for EGFR C797S and other mutations refractory to current EGFR tyrosine kinase inhibitors

Introduction: EGFR tyrosine kinase inhibitors (TKIs) are key drugs in the treatment of lung cancers with activating EGFR mutations. However, inherent resistance such as exon 20 insertions and acquired resistance such as T790M / C797S hamper further improvement of treatment outcomes in lung cancer patients with EGFR mutations. In this study, we evaluated efficacy of a novel hypoxia-activated EGFR-TKI, tarloxotinib, for these resistant EGFR mutations using Ba/F3 models.

Methods: Ba/F3 cells with either of exon 20 insertions (A763insFQEA, V769insASV, D770insSVD, or H773insNPH) or Del 19/T790M/C797S in cis (triple mutations) were generated as previously described (Nishino, et al. Lung Cancer, in press). Ba/F3 cells with Del 19 alone was used as sensitive control. Growth inhibitory assays against these Ba/F3 cells were performed for tarloxotinib-E (activated form), tarloxotinib (pro-drug before activation), afatinib, poziotinib, and osimertinib. In vitro kinase assays for various EGFR and HER2 mutations at ATP Km were used to test the potency of Tarloxotinib-E.

Results: Tarloxotinib-E was highly potent across various EGFR and HER2 mutations, including C797S double mutants in the in vitro kinase assays with an IC50 of &lt;0.38 nM. Low nM potency was observed for EGFR C797S triple mutants (d746-750/T790M/C797S, T790M/C797S/L858R). Tarloxotinib showed about 100 times higher IC50 values compared with tarloxotinib-E in all tested Ba/F3 cells, indicating that tarloxotinib-E can selectively inhibit cell growth in lung cancers with EGFR mutations. Poziotinib and tarloxotinib-E were effective against all Ba/F3 cells with exon 20 insertions (IC50 &lt; 10 nM), while afatinib and osimertinib effectively killed only the Ba/F3 cells with A763insFQEA mutation. For Ba/F3 cells with Del19/C797S mutation, afatinib, poziotinib and tarloxtinib-E showed potent activity with an IC50 of 2.8, 1.6 and 5.1 nM respectively. For Ba/F3 cells with Del 19/T790M/C797S, tarloxotinib-E also exhibited activity (IC50 198 nM), while the triple mutations conferred resistance to the other TKIs.

Conclusion: As the hypoxia-activated fragmentation of tarloxotinib into tarloxotinib-E broadens the therapeutic window versus competing small molecule EGFR TKIs, direct IC50 comparisons across agents may not be relevant as tarloxotinib may be dosed higher. These data highlight potential opportunity for tarloxotinib in the treatment of lung cancers with inherent or acquired resistance to current available EGFR-TKIs.

Citation Format: Kenichi Suda, Masaya Nishino, Takamasa Koga, Toshio Fujino, Yoshihisa Kobayashi, Tetsuya Mitsudomi, Avanish Vellanki, Vijaya G. Tirunagaru. Potent in vitro activity of Tarloxotinib for EGFR C797S and other mutations refractory to current EGFR tyrosine kinase inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2200.

Primary pulmonary mucosa-associated lymphoid tissue lymphoma with amyloid light chain-type amyloidosis

BACKGROUND

A total of 75% of patients with Sjögren's syndrome are complicated with pulmonary lesions, of which 12% are lymphoma and 6% are amyloid nodules; the coexistence of both is considered to be rare.

CASE PRESENTATION

A 67-year-old female with Sjögren's syndrome presented with multiple pulmonary nodules on chest computed tomography. Since a definitive diagnosis by transbronchial biopsy was not obtained, wedge resection of the nodules was performed. Pathologic diagnosis revealed eosinophilic deposition that stained positive with Congo red. In addition, lymphoepithelial lesions and lymphocytic infiltration were observed. Lymphocytes with monoclonal proliferation predominantly had κ chain. Based on these findings, the nodules were diagnosed as mucosa-associated lymphoid tissue (MALT) lymphoma with amyloid deposition.

CONCLUSIONS

The combination of these diseases is very rare, and this is the sixth resected case to the best of our knowledge.