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Ataxia telangiectasia and Rad3-related (ATR) kinase protects genome integrity during DNA replication. RP-3500 is a novel, orally bioavailable clinical-stage ATR kinase inhibitor (NCT04497116). RP-3500 is highly potent with IC50 values of 1.0 and 0.33 nmol/L in biochemical and cell-based assays, respectively. RP-3500 is highly selective for ATR with 30-fold selectivity over mammalian target of rapamycin (mTOR) and more than 2,000-fold selectivity over ataxia telangiectasia mutated (ATM), DNA-dependent protein kinase (DNA-PK), and phosphatidylinositol 3-kinase alpha (PI3Kα) kinases. In vivo, RP-3500 treatment results in potent single-agent efficacy and/or tumor regression in multiple xenograft models at minimum effective doses (MED) of 5 to 7 mg/kg once daily. Pharmacodynamic assessments validate target engagement, with dose-proportional tumor inhibition of phosphorylated checkpoint kinase 1 (pCHK1) (IC80 = 18.6 nmol/L) and induction of phosphorylated H2A.X variant histone (γH2AX), phosphorylated DNA-PK catalytic subunit (pDNA-PKcs), and phosphorylated KRAB-associated protein 1 (pKAP1). RP-3500 exposure at MED indicates that circulating free plasma levels above the in vivo tumor IC80 for 10 to 12 hours are sufficient for efficacy on a continuous schedule. However, short-duration intermittent (weekly 3 days on/4 days off) dosing schedules as monotherapy or given concomitantly with reduced doses of olaparib or niraparib, maximize tumor growth inhibition while minimizing the impact on red blood cell depletion, emphasizing the reversible nature of erythroid toxicity with RP-3500 and demonstrating superior efficacy compared with sequential treatment. These results provide a strong preclinical rationale to support ongoing clinical investigation of the novel ATR inhibitor, RP-3500, on an intermittent schedule as a monotherapy and in combination with PARP inhibitors as a potential means of maximizing clinical benefit.

Ataxia telangiectasia and Rad3-related (ATR) kinase protects genome integrity during DNA replication. RP-3500 is a novel, orally bioavailable clinical-stage ATR kinase inhibitor (NCT04497116). RP-3500 is highly potent with IC50 values of 1.0 and 0.33 nmol/L in biochemical and cell-based assays, respectively. RP-3500 is highly selective for ATR with 30-fold selectivity over mammalian target of rapamycin (mTOR) and more than 2,000-fold selectivity over ataxia telangiectasia mutated (ATM), DNA-dependent protein kinase (DNA-PK), and phosphatidylinositol 3-kinase alpha (PI3Kα) kinases. In vivo, RP-3500 treatment results in potent single-agent efficacy and/or tumor regression in multiple xenograft models at minimum effective doses (MED) of 5 to 7 mg/kg once daily. Pharmacodynamic assessments validate target engagement, with dose-proportional tumor inhibition of phosphorylated checkpoint kinase 1 (pCHK1) (IC80 = 18.6 nmol/L) and induction of phosphorylated H2A.X variant histone (γH2AX), phosphorylated DNA-PK catalytic subunit (pDNA-PKcs), and phosphorylated KRAB-associated protein 1 (pKAP1). RP-3500 exposure at MED indicates that circulating free plasma levels above the in vivo tumor IC80 for 10 to 12 hours are sufficient for efficacy on a continuous schedule. However, short-duration intermittent (weekly 3 days on/4 days off) dosing schedules as monotherapy or given concomitantly with reduced doses of olaparib or niraparib, maximize tumor growth inhibition while minimizing the impact on red blood cell depletion, emphasizing the reversible nature of erythroid toxicity with RP-3500 and demonstrating superior efficacy compared with sequential treatment. These results provide a strong preclinical rationale to support ongoing clinical investigation of the novel ATR inhibitor, RP-3500, on an intermittent schedule as a monotherapy and in combination with PARP inhibitors as a potential means of maximizing clinical benefit.

DNA polymerase theta (Polθ) is an attractive synthetic lethal target for drug discovery, predicted to be efficacious against breast and ovarian cancers harboring BRCA-mutant alleles. Here, we describe our hit-to-lead efforts in search of a selective inhibitor of human Polθ (encoded by POLQ). A high-throughput screening campaign of 350,000 compounds identified an 11 micromolar hit, giving rise to the N2-substituted fused pyrazolo series, which was validated by biophysical methods. Structure-based drug design efforts along with optimization of cellular potency and ADME ultimately led to the identification of

Introduction. Des épidémies hospitalières à Burkholderia cepacia à partir d’une source contaminée (solution antiseptique, respirateurs…) ont été décrites. Nous rapportons l’investigation d’une pseudo-épidémie de 14 hémocultures contaminées à B. cepacia chez des enfants dont les prélèvements avaient été réalisés aux urgences pédiatriques. Méthodes. Les 14 cas sont survenus du 12/10/2017 au 3/01/2018, tous aux urgences pédiatriques. L’investigation a inclus : recensement et description des cas, courbe épidémique, analyse des pratiques, enquête environnementale sur les points d’eau, les surfaces, les solutions antiseptiques. Résultats. Deux vagues successives de neuf puis cinq cas, tous considérés comme des contaminations, sont survenues du 12/10/2017 au 02/11/2017 puis du 19/12/2017 au 3/01/2018, toutes sauf une chez de jeunes enfants. Une source environnementale commune a été considérée comme probable, avec trois hypothèses évoquées : contamination de l’antiseptique, contamination des fioles d’hémoculture lors de leur fabrication, contamination du matériel non stérile (entonnoirs ou microtubes) utilisé par les soignants pour la réalisation des hémocultures pour pallier les difficultés de prélèvement, fréquentes chez les jeunes enfants. Les prélèvements n’ont pas retrouvé de B. cepacia dans l’environnement. Discussion-Conclusion. Malgré l’absence de B. cepacia dans l’environnement, l’hypothèse retenue est celle de la contamination, probablement à l’occasion de manipulations, du matériel non stérile utilisé pour la réalisation des hémocultures. Cette investigation illustre les difficultés rencontrées par les équipes de pédiatrie pour certains prélèvements, et l’importance de mettre à leur disposition des procédures et du matériel adaptés.

Background: Ataxia telangiectasia and Rad3-related (ATR) protein kinase is a key mediator of cellular DNA damage repair (DDR) and is activated in response to DNA replication stress. ATR is attractive as a drug target in tumors with loss-of-function alterations in complimentary DDR pathways, including ataxia-telangiectasia mutated (ATM) and BRCA. RESULTS: RP-3500 is a novel, orally bioavailable clinical-stage ATR kinase inhibitor. RP-3500 is highly potent with ATR kinase IC50 values of 1.0 and 0.33 nM in biochemical and cell-based assays, respectively. It is highly selective with >30-fold selectivity over mTOR and >2000-fold selectivity over ATM, DNA-PK and PI3Kα kinases. Preclinical tumor xenograft models harboring synthetic lethal (SNIPRx) gene mutations whose loss of function sensitizes to RP-3500 were selected for in vivo studies. RP-3500 treatment resulted in potent single-agent in vivo efficacy and/or tumor regression in multiple models at minimum effective doses (MED) of 5–7 mg/kg once daily. Pharmacodynamic assessments validated target engagement, with a proportional relationship between tumor pCHK1(Ser345) inhibition and circulating RP-3500 plasma levels (IC80 = 18.6 nM). Circulating free plasma levels of RP-3500 at the MED indicate that exposure above the in vivo tumor pCHK1(Ser345) IC80 for 10–12 hours is sufficient for efficacy and dose proportional phosphorylation of DNA damage markers γ-H2AX, pDNA-PKcs and pKAP1. In vitro, tumor cells with ATM loss exhibited increased susceptibility to RP-3500 and a 3-day compound exposure was sufficient to generate a sustained DNA damage response compared to cells with functional ATM expression. In ATM-deficient mouse models, short-duration intermittent (weekly 3 days on/4 days off or 5 days on/2 days off) dosing schedules maximized tumor growth inhibition while minimizing the impact on hematology parameters, including red blood cell depletion. These results emphasize the reversible nature of erythroid toxicity with RP-3500 and the advantage of intermittent dosing schedules to alleviate anemia. The 3 days on/4 days off intermittent treatment schedule also substantially improved the efficacy and tolerability of RP-3500 and PARP inhibitor combinations compared to continuous treatment schedules. Intermittent treatments of RP-3500 given concomitantly with reduced doses of olaparib or niraparib demonstrated synergistic efficacy in Granta-519 (ATM mutn) and SUM149PT (BRCA1mutn) models with minimal hematological adverse effects and superior efficacy to sequential treatment. CONCLUSIONS: These results provide a strong preclinical rationale to support clinical investigation of the novel ATR inhibitor RP-3500 on an intermittent schedule as a monotherapy and in combination with PARP inhibitors as a means of maximizing clinical benefit. RP-3500 is currently evaluated in the ongoing phase 1 TRESR (Treatment Enabled by SNIPRx) study (NCT04497116). Citation Format: Anne Roulston, Michal Zimmerman, Robert Papp, Alex Skeldon, Charles Pellerin, Émilie Dumas-Bérube, Valerie Dumais, Stephane Dorich, Sara Fournier, Li Li, Marie-Ève Leclaire, Shou Yun Yin, Amandine Chefson, Hunain Alam, William Yang, Chloe Fugère-Desjardins, Sabrina Hammond, Kathryn Skorey, Amina Mulani, Victoria Rimkunas, Artur Veloso, Martine Hamel, Rino Stocco, Yael Mamane, Zuomei Li, Jordan Young, Mike Zinda, Cameron Black. RP-3500: A novel, potent and selective ATR inhibitor that is effective in pre-clinical models as a monotherapy and in combination with PARP inhibitors [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P054.

Radiophotoluminescent (RPL) detectors are used extensively for measurement of γ, X and β radiations. While these detectors show excellent dosimetric properties, we point out behaviors observed in their routine use that can affect the accuracy of their results. There is a radiation-induced darkening of the detector and a background noise limit beyond which the impact of ionizing radiation on the measurement becomes unclear. Tests show that after several measurement-anneal cycles, the RPL detectors reach a threshold value of intrinsic background, which causes measurements of small doses to be unreliable.

Introduction La ventilation non invasive (VNI) est le traitement de reference de l’insuffisance respiratoire chronique hypercapnique, notamment en cas de bronchopneumopathie obstructive (BPCO) et de syndrome obesite-hypoventilation (SOH). L’usage de systemes d’humidification pour lutter contre la secheresse buccale est repandu. Cependant, il n’existe aucune donnee sur la potentielle colonisation microbienne de ces systemes. L’objectif de notre etude etait d’evaluer la prevalence de la contamination microbiologique des reservoirs des ventilateurs non invasifs de domicile, de determiner la prevalence de germes potentiellement pathogenes chez les patients BPCO et SOH. L’objectif secondaire etait d’evaluer le lien la presence de pathogenes et la survenue eventuelle d’une exacerbation dans les 12 mois precedant. Methodes Etude prospective, monocentrique et observationnelle ( NCT03809832 ) incluant les patients appareilles par ventilation non invasive depuis plus de 6 mois, ayant un systeme d’humidification et une observance superieure a 4 heures/jour. Lors de l’evaluation, etaient realises des prelevements microbiologiques de maniere standardisee sur les systemes d’humidification. Un questionnaire systematise sur l’entretien de la ventilation etait administre. Resultats Cinquante-trois patients ont ete inclus: 38 (72%) avec BPCO et 15 (28%) avec SOH. Les analyses microbiologiques ont montre que 50 (94% [95%CI: 84 to 99]) reservoirs etaient contamines par au moins un germe, sans difference entre les deux populations BPCO et SOH (p = 0.55). Un total de 22 (42% [95%CI: 28 to 56]) reservoirs etaient contamines par au moins un germe potentiellement pathogene sur le plan respiratoire, sans difference entre les patients atteints de BPCO et ceux atteints de SOH (p = 0.36). Le score moyen d’observance des mesures d’entretien etaient de 4.9 ± 1.7 sur 7 sans difference entre les deux groupes (p = 0.36). Dans la population BPCO, l’isolement d’un germe potentiellement pathogene dans le reservoir n’etait pas associe a une augmentation du taux d’exacerbations: IRR: 1.17 [95%CI: 0.72 to 1.88] (p = 0.53). Conclusion La contamination microbiologique des reservoirs de ventilateurs non invasifs est extremement frequente. Dans notre etude, nous avons retrouve un taux significatif de germes potentiellement pathogenes sur le plan respiratoire. L’impact clinique de la presence de ces pathogenes reste a determiner.

The design and optimization of a novel isoxazole S(1) linker for renin inhibitor is described herein. This effort culminated in the identification of compound 18, an orally bioavailable, sub-nanomolar renin inhibitor even in the presence of human plasma. When compound 18 was found to inhibit CYP3A4 in a time dependent manner, two strategies were pursued that successfully delivered equipotent compounds with minimal TDI potential.

An oral bioavailability issue encountered during the course of lead optimization in the renin program is described herein. The low F(po) of pyridone analogs was shown to be caused by a combination of poor passive permeability and gut efflux transport. Substitution of pyridone ring for a more lipophilic moiety (logD>1.7) had minimal effect on rMdr1a transport but led to increased passive permeability (P(app)>10 × 10(-6) cm/s), which contributed to overwhelm gut transporters and increase rat F(po). LogD and in vitro passive permeability determination were found to be key in guiding SAR and improve oral exposure of renin inhibitors.

P450 enzymes are of great interest for drug metabolism and as potential biocatalysts. Like most P450s, purified CYP3A4 is normally handled and stored in solution because lyophilization greatly reduces its activity. We show here that colyophilization of this enzyme with sucrose or trehalose, but not mannitol, crown ethers or cyclodextrins, allow recovery of full enzymatic activity after rehydration. Sorbitol was almost as efficient, with 85% retention of the original activity. We also show that similar protection is observed through colyophilization of CYP2D6 with trehalose. This procedure should greatly facilitate handling, storage, or use of these enzymes in anhydrous media.

Avec l’evolution de nos modes de vie ces dernieres decennies (vie de plus en plus en interieur, voyages a travers le monde facilites,…) et l’emergence de nouveaux pathogenes viraux (Ebola, virus Zika…) ou encore bacteriens avec l’apparition des bacteries hautement resistantes aux antibiotiques (BHRe), le risque biologique est en constante evolution. L’exposition de l’homme aux agents biologiques peut comprendre differents risques : les risques toxinique, immuno-allergique, cancerogene et surtout le risque infectieux. L’exposition aux agents microbiens se deroule selon une sequence bien connue. Les germes sont emis a partir d’un reservoir puis vont se transmettre par voie directe ou indirecte a l’hote recepteur. La peau, les muqueuses, les voies digestives ou respiratoires constituent differentes portes d’entree. Les modalites de transmission sont elles aussi bien identifiees : il s’agit soit d’aerosols dont la taille, la vitesse d’emission et la charge infectieuse peuvent varier selon la source ou l’agent infectieux, soit d’un contact direct avec le reservoir notamment par les mains. La prevention consiste a rompre cette chaine de transmission ce qui necessite une bonne connaissance des agents, de leur potentiel infectieux, de leurs reservoirs et de leur mode de survie. Concernant les etablissements de sante, la litterature scientifique nous apporte de nombreux elements nous permettant d’apprehender au mieux le risque biologique pour les professionnels de sante. Cependant, les donnees sont moins nombreuses lorsqu’il s’agit du domicile, du patient comme du professionnel. A l’heure du developpement des techniques ambulatoires et des soins a domicile, la question du risque biologique et de sa prevention ne se posent pas en memes termes qu’a l’hopital. Les germes sont identiques mais l’environnement et les moyens de maitrise different. Nombreux sont les exemples d’infections groupees familiales (virales, alimentaires…). Concernant le risque d’acquisition de bacteries multi-resistantes aux antibiotiques ou de BHRe, de recentes etudes decrivent des reservoirs environnementaux « extra-hospitaliers » mais les risques qu’ils representent ou les mecanismes de transmission ne sont pas encore tous clairement identifies. La possible transmission intrafamiliale de ces germes est cependant confirmee. Face aux nouveaux risques emergents, les autorites et societes savantes ont emis de nombreuses recommandations pour prevenir les risques biologiques dans les etablissements de sante mais l’augmentation de l’ambulatoire et des activites de soins a domicile necessite d’elargir les investigations et les preconisations dans ces « nouveaux » milieux.

The optimization of a novel series of non-nucleoside reverse transcriptase inhibitors (NNRTI) led to the identification of pyridone 36. In cell cultures, this new NNRTI shows a superior potency profile against a range of wild type and clinically relevant, resistant mutant HIV viruses. The overall favorable preclinical pharmacokinetic profile of 36 led to the prediction of a once daily low dose regimen in human. NNRTI 36, now known as MK-1439, is currently in clinical development for the treatment of HIV infection.

The discovery and SAR of a novel series of spirocyclic renin inhibitors are described herein. It was found that by restricting the northern aromatic plate to the bioactive conformation through spirocyclization, increase in renin potency and decrease in hERG affinity could both be realized. When early members of this series were found to be potent time-dependent CYP3A4 inhibitors, two distinct strategies to address this liability were explored and this effort culminated in the identification of compound 31 as an optimized renin inhibitor.

An SAR campaign aimed at decreasing the overall lipophilicity of renin inhibitors such as 1 is described herein. It was found that replacement of the northern appendage in 1 with an N-methyl pyridone and subsequent re-optimization of the benzyl amide handle afforded compounds with in vitro and in vivo profiles suitable for further profiling. An unexpected CV toxicity in dogs observed with compound 20 led to the employment of a time and resource sparing rodent model for in vivo screening of key compounds. This culminated in the identification of compound 31 as an optimized renin inhibitor.

Des médicaments injectables sont conservés, manipulés et perfusés quotidiennement dans les unités de soins du CHU de Grenoble. À chacune de ces étapes, ils sont susceptibles d'être exposés à la lumière. Certains principes actifs vont alors connaître un mécanisme de photodégradation, pouvant aboutir à une perte de stabilité du médicament, et ainsi à une toxicité, une perte d'efficacité ou une modification de leur aspect. Cette photodégradation peut évoluer dans certains cas très rapidement, au point de nécessiter une protection de la lumière même le temps d'une perfusion. Alors que les notices précisent lorsque un médicament doit être conservé à l'abri de la lumière, il devient en revanche difficile de savoir lorsque l'administration doit également être faite à l'obscurité. Une enquête de pratique au CHU de Grenoble a en effet révélé des difficultés dans le choix du matériel de perfusion, transparent ou photoprotecteur, et des différences d'administration pour un même médicament entre les unités de soins, ce qui n'est pas en accord avec les actuels objectifs d'assurance qualité et d'accréditations. Ainsi, cette liste de médicaments nécessitant du matériel photoprotecteur est faite pour apporter une aide aux infirmières, une meilleure harmonisation des modalités d'administration entre les services, et ainsi une meilleure sécurité aux patients. De plus, le matériel photoprotecteur étant bien plus onéreux que le matériel transparent, la liste permettra d'éviter leur utilisation trop importante par principe de précaution.

The impact on patients' attitudes of quality report cards on infection control in hospitals has never previously been studied. In 2006, the French government implemented a mandatory report card on infection control activity (ICALIN) in all hospitals. This approach was aimed at encouraging professionals to change their routine practices in case they should lose patients due to a low ICALIN score. Our objective was to assess what impact ICALIN could have on patients' attitude as regards hospital choice. We performed a survey of patients and visitors in 14 randomly selected hospitals of various ICALIN scores. A convenience sample of 381 patients and visitors completed an anonymous questionnaire on ICALIN, their reasons for choosing a hospital and attitude in the event of a low ICALIN score. Factors associated with interest in ICALIN and impact of ICALIN on hospital choice were assessed by logistic regression. Our results showed that 77% of participants were interested in ICALIN. ICALIN was ranked sixth as a reason for choosing a hospital. In the case of a low ICALIN, 24.1% of participants would refuse admission and 54.9% would seek advice from their general practitioner. Sociodemographic factors had no influence on patients' attitude. In conclusion, our survey suggests that patients take note of poor performance on infection control report cards. As most patients rely on their general practitioner to interpret these report cards, there is a definite need for further communication with general practitioners on this issue.

P450 enzymes have attracted the attention of chemists for decades because of their impressive ability to catalyze the hydroxylation of inactivated C--H bonds. However, their use for synthesis in aqueous systems is limited. We report here a survey of the activity of purified human CYP3A4 in the presence of organic solvents or ionic liquids. We show that CYP3A4 tolerates only small amounts (15 %) of water-miscible organic cosolvents or ionic liquids before its activity toward testosterone drops below detection. [BMIM][PF(6)] in a biphasic system was less detrimental to enzyme activity, with 20 % of the activity remaining in the presence of 15 % of this ionic liquid. CYP3A4 activity in the absence of buffer was onlyor=10 % in solvents of the alkane series, with a minimum of 0.85 % water, and with the addition of sucrose and testosterone before enzyme lyophilization. Biphasic solvent systems were more promising, with approximately 85 % of the activity retained.

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