Targeted therapeutic options in early and metastatic NSCLC-overview

The complex therapeutic strategy of non-small cell lung cancer (NSCLC) has changed significantly in recent years. Disease-free survival increased significantly with immunotherapy and chemotherapy registered in perioperative treatments, as well as adjuvant registered immunotherapy and targeted therapy (osimertinib) in case of EGFR mutation. In oncogenic-addictive metastatic NSCLC, primarily in adenocarcinoma, the range of targeted therapies is expanding, with which the expected overall survival increases significantly, measured in years. By 2021, the FDA and EMA have approved targeted agents to inhibit EGFR activating mutations, T790 M resistance mutation, BRAF V600E mutation, ALK, ROS1, NTRK and RET fusion. In 2022, the range of authorized target therapies was expanded. With therapies that inhibit KRASG12C, EGFR exon 20, HER2 and MET. Until now, there was no registered targeted therapy for the KRAS mutations, which affect 30% of adenocarcinomas. Thus, the greatest expectation surrounded the inhibition of the KRAS G12C mutation, which occurs in ∼15% of NSCLC, mainly in smokers and is characterized by a poor prognosis. Sotorasib and adagrasib are approved as second-line agents after at least one prior course of chemotherapy and/or immunotherapy. Adagrasib in first-line combination with pembrolizumab immunotherapy proved more beneficial, especially in patients with high expression of PD-L1. In EGFR exon 20 insertion mutation of lung adenocarcinoma, amivantanab was registered for progression after platinum-based chemotherapy. Lung adenocarcinoma carries an EGFR exon 20, HER2 insertion mutation in 2%, for which the first targeted therapy is trastuzumab deruxtecan, in patients already treated with platinum-based chemotherapy. Two orally administered selective c-MET inhibitors, capmatinib and tepotinib, were also approved after chemotherapy in adenocarcinoma carrying MET exon 14 skipping mutations of about 3%. Incorporating reflex testing with next-generation sequencing (NGS) expands personalized therapies by identifying guideline-recommended molecular alterations.

The Relevance of Goodness-of-fit, Robustness and Prediction Validation Categories of OECD-QSAR Principles with Respect to Sample Size and Model Type

We investigated the relevance of the validation principles on the Quantitative Structure Activity Relationship models issued by Organization for Economic and Co-operation and Development. We checked the goodness-of-fit, robustness and predictivity categories in linear and nonlinear models using benchmark datasets. Most of our conclusions are drawn using the sample size dependence of the different validation parameters. We found that the goodness-of-fit parameters misleadingly overestimate the models on small samples. In the case of neural network and support vector models, the feasibility of the goodness-of-fit parameters often might be questioned. We propose to use the simplest y-scrambling method to estimate chance correlation. We found that the leave-one-out and leave-many-out cross-validation parameters can be rescaled to each other in all models and the computationally feasible method should be chosen depending on the model type. We assessed the interdependence of the validation parameters by calculating their rank correlations. Goodness of fit and robustness correlate quite well over a sample size for linear models and one of the approaches might be redundant. In the rank correlation between internal and external validation parameters, we found that the assignment of good and bad modellable data to the training or the test causes negative correlations.

Management of antiplatelet therapy in acute coronary syndrome patients with thrombocytopenia

Összefoglaló. Az akut coronaria szindrómán (ACS) átesett betegek kezelésének alappillére a kettős (aszpirin + klopidogrél ) thrombocytaaggregáció-gátló kezelés. Az immunthrombocytopeniás purpurás (ITP-s) betegek - és különösen azok, akik refrakter ITP miatt thrombopoetinanalóg kezelésben részesülnek - külön elbírálást igényelnek. 50-100 G/l thrombocytaszám közötti és vérzéses szövődménnyel nem rendelkező ACS-s betegeken a gyógyszerkibocsátó stent beültetését követően kettős thrombocytaaggregáció-gátló kezelést csak 1 hónapig kell alkalmazni (ez az időtartam átlagos vérzéses rizikójú betegeken 1 év), majd klopidogrél-monoterápia javasolt. Munkánk során a 2015. január 1. és 2020. október 1. között a Semmelweis Egyetem I. Belgyógyászati Klinikáján kezelt ITP-s betegek körében vizsgáltuk az ACS előfordulását és lefolyását. Klinikánkon az elmúlt 5 évben gondozott, 168 ITP-s beteg közül 3 beteg esetében alakult ki ACS. A refrakter ITP kezelésének részeként mind a 3 beteg thrombopoetinanalóg - (2 beteg romiplosztim-, 1 beteg eltrombopág-) kezelésben részesült. A 3 ITP-s betegünk egyikénél sem alakult ki vérzéses szövődmény a thrombopoetinanalóg-kezelés és a thrombocytaaggregáció-gátlás mellett. Első betegünk esetében 5 év alatt három alkalommal alakult ki ACS (egy ízben fémstentet és két alkalommal gyógyszerkibocsátó stentet kapott). A második betegnél két alkalommal (1 év különbséggel), a harmadik betegnél egy esetben történt gyógyszerkibocsátó stent beültetése. ITP és ACS együttes fennállása esetén az akut és a hosszú távú gyógyszeres kezelés egyéni mérlegelést igényel. Ezen speciális betegcsoport számára a kezelési irányelv kidolgozása megfontolandó. Orv Hetil. 2021; 162(33): 1335-1340. Summary. Dual antiplatelet therapy (DAPT) consisting of aspirin and clopidogrel is essential in the treatment of acute coronary syndrome (ACS). Immune thrombocytopenic purpura (ITP) patients - and especially those receiving thrombopoietin analog (TPO) treatment - deserve special attention. In ACS patients with platelet counts between 50 G/L and 100 G/L and no bleeding symptoms, DAPT is indicated for 1 month after the placement of new generation drug-eluting stents (the length of treatment is 1 year in the case of patients with average bleeding risk) followed by clopidogrel monotherapy. In patients with average bleeding risk, DAPT is recommended for 1 year after the ACS. Our aim was to investigate the incidence and outcome of ACS in ITP patients, who were treated in our clinic between 1st January 2015 and 1st October 2020. Out of 168 patients treated for ITP, 3 patients suffered from ACS in the last 5 years. These patients received TPO treatment (2 patients subcutan romiplostim, 1 patient oral eltrombopag). None of these ITP patients treated with DAPT and with TPO analog suffered from bleeding complications. 1 patient developed ACS three times within the last 5 years (he received bare-metal stent once and drug-eluting stent twice). Drug-eluting stent was placed once in the third, and twice (with 1 year difference) in the second patient. Acute and long-term medication of patients suffering from both ITP and ACS is a challenging task and needs individual evaluation. Establishment of treatment guidelines for this special group is warranted. Orv Hetil. 2021; 162(33): 1335-1340.

Sample-size dependence of validation parameters in linear regression models and in QSAR

The dependence of statistical validation parameters was investigated on the size of the sample taken in fit of multivariate linear curves. We observed that R² and related internal parameters were misleading as they overestimated the goodness-of-fit of models at small sample size. Cross-validation metrics showed correct trends. It was possible to scale the leave-one-out and the leave-many-out results close to identical by correcting the degrees of freedom of the models. y and x-randomized validation parameters were calculated and the methods provided close to identical results. We suggest to use the simplest methods in both cases. The external parameters followed correct trends with respect to the sample size, but their sensitivity differed. We plotted the Roy-Ojha metrics in 2D and we coloured them with respect to other external parameters to provide an easy classification of models. The rank correlations were calculated between the performance parameters. Up to a sample size, goodness-of-fit and robustness were distinguishable, but above a certain sample size, the parameters were redundant. The external-internal pairs were weakly correlated. Our data show that all the three aspects of validation are necessary at small sample sizes, but the internal check of robustness is not informative above a given sample size.

Committor of elementary reactions on multistate systems

In our study, we extend the committor concept on multi-minima systems, where more than one reaction may proceed, but the feasible data evaluation needs the projection onto partial reactions. The elementary reaction committor and the corresponding probability density of the reactive trajectories are defined and calculated on a three-hole two-dimensional model system explored by single-particle Langevin dynamics. We propose a method to visualize more elementary reaction committor functions or probability densities of reactive trajectories on a single plot that helps to identify the most important reaction channels and the nonreactive domains simultaneously. We suggest a weighting for the energy-committor plots that correctly shows the limits of both the minimal energy path and the average energy concepts. The methods also performed well on the analysis of molecular dynamics trajectories of 2-chlorobutane, where an elementary reaction committor, the probability densities, the potential energy/committor, and the free-energy/committor curves are presented.

Diastereomeric ratio determination by high sensitivity band-selective pure shift NMR spectroscopy

An NMR method is reported that allows diastereomeric ratios to be determined even in crowded spectra or where chemical shift differences are small compared to multiplet widths. Band-selective pure shift NMR collapses multiplets to singlets, greatly improving spectral resolution while largely retaining, or even enhancing, signal-to-noise ratio.

Simultaneously enhancing spectral resolution and sensitivity in heteronuclear correlation NMR spectroscopy

BIRD's eye view: Adding periodic BIRD J-refocusing (BIRD=bilinear rotation decoupling) to data acquisition in an HSQC experiment causes broadband homonuclear decoupling, giving a single signal for each proton chemical shift. This pure shift method improves both resolution and signal-to-noise ratio, without the need for special data processing.

Background-free solution boron NMR spectroscopy

The appearance of background signals arising from the NMR probe and tube is a well-known problem of boron NMR spectroscopy. Background suppression may be achieved by using DEPTH, which increases the signal-to-background (S/B) ratio. Although, the quality of such spectra is often adequate, but in the case of rapid relaxation broadened resonances (T(1)  < 1 ms), the residual background signals may still hamper the interpretation of the spectra. It was observed that the background signals are practically invisible in solution (10) B NMR. The unusual isotopic effect on the (S/B) ratio was interpreted as an inherent consequence of the integer versus half-integer spin of (10) B and (11) B, respectively. The practicability of (10/11) B NMR was compared for a selected set of boron compounds covering the typical range of (S/B) ratio. The application of (11) B is more favourable than (10) B as long as it is possible to achieve the desired spectral quality by using DEPTH. Otherwise, the 'background-free' appearance of (10) B NMR spectra makes (10) B a reasonable alternative of (11) B DEPTH. This was found typical for compounds having relaxation broadened resonances. The variable temperature (VT) NMR study of an adduct formation process was also presented here as an example of the advantage of (10) B over (11) B.

Self-association promoted conformational transition of (3R,4S,8R,9R)-9-[(3,5-bis(trifluoromethyl)phenyl))-thiourea](9-deoxy)-epi-cinchonine

The conformational diversity of the (3R,4S,8R,9R)-9-[(3,5-bis(trifluoromethyl)phenyl))-thiourea](9-deoxy)-epi-cinchonine organocatalyst is discussed. Low-temperature NMR experiments confirmed a self-association process, which promotes the quinoline rotation between two intramolecularly hydrogen-bonded monomeric conformers of the catalyst. The balanced population of the coexisting monomeric and dimeric species allowed us to conduct a structural study of a rather complex conformational dynamics of the pure catalyst. The study is extended by a comparison with other members of the bifunctional amine-thiourea organocatalyst family. Changes in the molecular structure of the catalysts influence the interplay between intra- and intermolecular hydrogen bonding, and yield different extent of catalyst self-association. By assessing the conformation of the individual states, we established the thermodynamic model of a self-association promoted conformational transition.

Edge-to-face CH/pi aromatic interaction and molecular self-recognition in epi-cinchona-based bifunctional thiourea organocatalysis

The impact of cooperativity between intermolecular interactions is demonstrated by the molecular self-recognition properties of highly enantioselective epi-cinchona bifunctional thiourea organocatalysts. Low-temperature NMR experiments in inert solvents have revealed two sets of nonequivalent resonances in equal population for thiourea-modified members of the epi-quinine and epi-quinidine families. In solution, the predominance of an asymmetric (C1) dimeric self-assembly with noteworthy structural motifs became evident: simultaneous intra- and intermolecular thiourea hydrogen bonding and a CH/pi interaction were observed. Both the stereochemical and the diverse conformational features of the system favor the observed quinoline T-shaped aromatic pi-pi stacking interaction. The structure findings are supported by quantitative proton-proton distance data that were available from NOE buildup curves. The 3D structure of the dimeric assembly has been modeled in agreement with the H-H distance restraints. Owing to the geometrical preference associated with the dimerization process, the self-assembled bifunctional system is interpreted as a charge-transfer complex with the potential for catalyst self-activation.

Conformational analysis of a helically distorted gold(I) macrocycle derived from xantphos: evidence for the aurophilic Au--Au interaction from NMR

Variable-temperature solution (1)H- and (31)P-NMR experiments are reported for [Au(2)(xantphos)(2)](NO(3))(2) gold(I) complex incorporating a 16-membered Au(2)P(4)C(8)O(2) macrocycle derived from the 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (xantphos) ligand. These NMR studies provide detailed structural information about its solution structure in comparison to the solid-state structure available from single crystal X-ray diffraction. Two-dimensional (1)H-NOESY spectroscopy at low temperatures allowed the full assignment of proton resonances, which are severely exchange-broadened at room temperature. The (1)H--(1)H spatial connectivities of the large number of non-equivalent protons unravel the complete stereochemistry of the gold(I) macrocycle in its symmetrically twisted conformation. Chemical exchange between particular proton pairs has allowed understanding the molecular dynamics and ruled out formation of coordination oligomers. Spectral analysis of the unique phosphorous AA'BB' spin system has revealed three-bond (31)P--(31)P scalar couplings mediated through the Au--Au bond, and has confirmed the existence of the aurophilic contact in low-temperature solutions. The solution (13)C and (31)P spectra are compared to the solid state (31)P-MAS and (13)C--CP/MAS spectra, where signal doubling effects due to the crystal packing have been discovered.

Preparation and structural characterization of trimethyltin(iv) tropolonate. Investigation of a rare methyl-migrational dismutation in the solution, solid and liquid states

The synthesis and structural characterisation, by low temperature X-ray diffraction and solid-state NMR, of the highly reactive monomeric Me(3)Sn(trop) (1) complex has been studied; 1 rearranges into Me(2)Sn(trop)(2) (2) and Me(4)Sn by methyl-transfer dismutation. Based on the NMR kinetic data it appears that complex demethylates faster in the solid and liquid than in dilute CDCl(3) solution, but with a slower rate than in dilute CD(3)OD solution.

Synthesis and Solution- and Solid-State Characterization of Gold(I) Rings with Short Au···Au Interactions. Spontaneous Resolution of a Gold(I) Complex

We report the synthesis and solution- and solid-state characterization of gold(I) rings with short 1,9-transannular Au...Au interactions. The 9- and 16-membered gold(I) rings were prepared by reacting 9,9-dimethyl-4,5-bis(diphenylphosphino)-xanthene and (Me2S)AuCl in the presence of AgNO3 in the molar ratio of 1:0.5:1 and 1:1:1, respectively. X-ray crystallographic measurements in conjunction with solution X-ray diffraction and NMR methods have been used to determine the structure of gold(I) rings, and we also gained insight into the dynamics. The nine-membered gold(I) ring is chiral, and the crystal contains only one of the two enantiomers, either right- or left-handed. To the best of our knowledge this represents the first example of crystallization-induced spontaneous resolution of a binuclear gold(I) cycle. The 16-membered ring with 1,9-transannular Au...Au interaction is in a figure-eight conformation.