Metabolism-driven in vitro/in vivo disconnect of an oral ERɑ VHL-PROTAC.

Targeting the estrogen receptor alpha (ERα) pathway is validated in the clinic as an effective means to treat ER+ breast cancers. Here we present the development of a VHL-targeting and orally bioavailable proteolysis-targeting chimera (PROTAC) degrader of ERα. In vitro studies with this PROTAC demonstrate excellent ERα degradation and ER antagonism in ER+ breast cancer cell lines. However, upon dosing the compound in vivo we observe an in vitro-in vivo disconnect. ERα degradation is lower in vivo than expected based on the in vitro data. Investigation into potential causes for the reduced maximal degradation reveals that metabolic instability of the PROTAC linker generates metabolites that compete for binding to ERα with the full PROTAC, limiting degradation. This observation highlights the requirement for metabolically stable PROTACs to ensure maximal efficacy and thus optimisation of the linker should be a key consideration when designing PROTACs.

Multi-center, pragmatic, cluster-randomized, controlled trial of standardized peritoneal dialysis (PD) training versus usual care on PD-related infections (the TEACH-PD trial): trial protocol.

BACKGROUND: Peritoneal dialysis (PD)-related infections, such as peritonitis, exit site, and tunnel infections, substantially impair the sustainability of PD. Accordingly, PD-related infection is the top-priority research outcome for patients and caregivers. While PD nurse trainers teach patients to perform their own PD, PD training curricula are not standardized or informed by an evidentiary base and may offer a potential approach to prevent PD infections. The Targeted Education ApproaCH to improve Peritoneal Dialysis outcomes (TEACH-PD) trial evaluates whether a standardized training curriculum for PD nurse trainers and incident PD patients based on the International Society for Peritoneal Dialysis (ISPD) guidelines reduces PD-related infections compared to usual training practices. METHODS: The TEACH-PD trial is a registry-based, pragmatic, open-label, multi-center, binational, cluster-randomized controlled trial. TEACH-PD will recruit adults aged 18 years or older who have not previously undergone PD training at 42 PD treatment units (clusters) in Australia and New Zealand (ANZ) between July 2019 and June 2023. Clusters will be randomized 1:1 to standardized TEACH-PD training curriculum or usual training practice. The primary trial outcome is the time to the first occurrence of any PD-related infection (exit site infection, tunnel infection, or peritonitis). The secondary trial outcomes are the individual components of the primary outcome, infection-associated catheter removal, transfer to hemodialysis (greater than 30 days and 180 days), quality of life, hospitalization, all-cause death, a composite of transfer to hemodialysis or all-cause death, and cost-effectiveness. Participants are followed for a minimum of 12 months with a targeted average follow-up period of 2 years. Participant and outcome data are collected from the ANZ Dialysis and Transplant Registry (ANZDATA) and the New Zealand Peritoneal Dialysis (NZPD) Registry. This protocol follows the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) guidelines. DISCUSSION: TEACH-PD is a registry-based, cluster-randomized pragmatic trial that aims to provide high-certainty evidence about whether an ISPD guideline-informed standardized PD training curriculum for PD nurse trainers and adult patients prevents PD-related infections. TRIAL REGISTRATION: ClinicalTrials.gov NCT03816111. Registered on 24 January 2019.

The PARP1 Inhibitor AZD5305 Impairs Ovarian Adenocarcinoma Progression and Visceral Metastases in Patient-derived Xenografts Alone and in Combination with Carboplatin.

PARP inhibitors (PARPi) have changed the management of patients with ovarian cancer and their effectiveness has been demonstrated especially in homologous recombination repair-deficient tumors. These first-generation drugs target PARP1, but also PARP2 and other family members potentially responsible for adverse effects that limit their therapeutic potential and restrict their use in combination with chemotherapeutic agents. We investigated ovarian cancer patient-derived xenografts (OC-PDXs) to assess whether malignant progression could be impaired by a novel inhibitor selective for PARP1 (AZD5305) and to assess the potential of its combination with carboplatin (CPT), the standard-of-care for patients with ovarian cancer. In BRCA-mutated OC-PDXs, AZD5305 achieved greater tumor regressions and longer duration of response as well as a superior impairment of visceral metastasis and improved survival benefit compared with the first-generation dual PARP1/2 inhibitors. The combination of AZD5305 plus CPT was more efficacious than single agents. Subcutaneously growing tumors experienced regression that persisted after therapy stopped. Combination efficacy was greater against tumors that did not respond well to platinum, even at a dose at which AZD5305 monotherapy was ineffective. The combination therapy impaired metastatic dissemination and significantly prolonged the lifespan of mice bearing OC-PDXs in their abdomen. This combination benefit was evident even when CPT was used at suboptimal doses, and was superior to full-dose platinum treatment. These preclinical studies demonstrate that the PARP1-selective inhibitor AZD5305 retains and improves the therapeutic benefit of the first-generation PARPi, providing an opportunity to maximize benefits for this class of anticancer agents. Significance: Selective PARP1i AZD5305 can exceed the efficacy of first-generation PARPi, which target both PARP1 and PARP2, and potentiates the efficacy of CPT when given in combination. AZD5305 alone or in combination with platinum delayed visceral metastasis, ultimately extending the lifespan of OC-PDX-bearing mice. These preclinical models mimic the progression of the disease occurring in patients after debulking surgery, and are translationally relevant.

Ferric Derisomaltose Evaluation in Patients with Non-Dialysis-Dependent Chronic Kidney Disease or Peritoneal Dialysis.

Background: Iron deficiency anemia is common in patients with advanced chronic kidney disease (CKD). Ferric derisomaltose (FDI) enables iron repletion in a single dose, unlike other forms of iron for IV administration, which require multiple doses. Protocols are commonly used with other IV irons, but there are limited Canadian data for FDI, and no protocol exists. Objectives: To evaluate the efficacy and safety of FDI for patients with CKD and to ascertain information related to its use in Canadian provinces. Methods: This retrospective cohort study involved patients with non-dialysis-dependent CKD (NDD-CKD) and patients undergoing peritoneal dialysis (PD) who received FDI in a tertiary hospital in Nova Scotia between June 2020 and May 2021. Each patient was followed for a minimum of 6 months. The efficacy outcomes were the changes from baseline in hemoglobin, transferrin saturation (TSAT), and ferritin after the first dose of FDI and at 3 and 6 months. The safety outcomes were the frequency and types of adverse reactions to FDI. Electronic surveys were sent to 33 Canadian renal pharmacists to gather information about FDI use, dosing, administration, monitoring, funding, and safety in their respective organizations. Results: A total of 52 infusions were administered to 35 patients during the study period. The median times between doses 1 and 2 and between doses 2 and 3 were 19.1 and 6.6 weeks, respectively. The median change from baseline to first post-FDI follow-up blood work was significant for hemoglobin (9.0 g/L, p = 0.023), TSAT (11 percentage points, p < 0.001), and ferritin (271.4 µg/L, p < 0.001). Median darbepoetin doses decreased from baseline to 6 months (p < 0.001). Three adverse reactions occurred. At least 15 (65%) of the 23 survey respondents reported that FDI was funded by their province or was listed on their hospital drug formulary. Conclusion: This study provides evidence that FDI is an effective and safe treatment for anemia in NDD-CKD and PD patients.

Contexte: L'anémie ferriprive est fréquente chez les patients atteints d'insuffisance rénale chronique avancée (IRC). Une seule dose de dérisomaltose ferrique (FDI) permet au niveau de fer de se rétablir, contrairement à d'autres formes de fer administrées par IV qui nécessitent, elles, plusieurs doses. Des protocoles sont couramment utilisés avec d'autres fers administrés par IV, mais les données canadiennes sur le FDI sont limitées et il n'existe aucun protocole. Objectifs: Évaluer l'efficacité et l'innocuité du FDI chez les patients atteints d'IRC et vérifier les informations relatives à son utilisation dans les provinces du Canada. Méthodes: Cette étude de cohorte rétrospective comprenait des patients atteints d'IRC sans dialyse (NDD-IRC) et des patients sous dialyse péritonéale (DP) ayant reçu du FDI dans un hôpital de soins tertiaires de la Nouvelle-Écosse entre juin 2020 et mai 2021. Chaque patient a fait l'objet d'un suivi pendant au moins 6 mois. Les résultats d'efficacité étaient les changements par rapport à la base de trois mesures après la première dose de FDI et à 3 et 6 mois, soit l'hémoglobine, la saturation de la transferrine (TSAT) et la ferritine. Les résultats d'innocuité étaient la fréquence et les types de réactions indésirables au FDI. Des sondages ont été envoyés par voie électronique à 33 pharmaciens canadiens spécialisés en néphrologie afin de recueillir des renseignements sur l'utilisation, le dosage, l'administration, la surveillance, le financement et l'innocuité du FDI dans leurs organismes respectifs. Résultats: Au total, 52 perfusions ont été administrées à 35 patients au cours de la période d'étude. Les délais médians entre les doses 1 et 2, et entre les doses 2 et 3 étaient respectivement de 19,1 et 6,6 semaines. Le changement médian entre la base et le premier bilan sanguin de suivi post-FDI était important pour l'hémoglobine (9,0 g/L, p = 0,023), le TSAT (11 points de pourcentage, p < 0,001) et la ferritine (271,4 µg/L, p < 0,001). Les doses médianes de darbépoétine ont diminué par rapport à la base à 6 mois (p < 0,001). Trois effets indésirables se sont produits. Au moins 15 des 23 répondants au sondage (65 %) ont déclaré que le FDI était financé par leur province ou figurait sur les listes de médicaments des hôpitaux. Conclusion: Cette étude fournit des preuves que le FDI est un traitement efficace et sûr de l'anémie chez les patients NDD-IRC et PD.

Development and Validation of Patient Education Tools for Deprescribing in Patients on Hemodialysis.

Background: Deprescribing is a patient-centered solution to reducing polypharmacy in patients on hemodialysis (HD). In a deprescribing pilot study, patients were hesitant to participate due to limited understanding of their own medications and their unfamiliarity with the concept of deprescribing. Therefore, patient education materials designed to address these knowledge gaps can overcome barriers to shared decision-making and reduce hesitancy regarding deprescribing. Objective: To develop and validate a medication-specific, patient education toolkit (bulletin and video) that will supplement an upcoming nationwide deprescribing program for patients on HD. Methods: Patient education tools were developed based on the content of previously validated deprescribing algorithms and literature searches for patients' preferences in education. A preliminary round of validation was completed by 5 clinicians to provide feedback on the accuracy and clarity of the education tools. Then, 3 validation rounds were completed by patients on HD across 3 sites in Vancouver, Winnipeg, and Toronto. Content and face validity were evaluated on a 4-point and 5-point Likert scale, respectively. The content validity index (CVI) score was calculated after each round, and revisions were made based on patient feedback. Results: A total of 105 patients participated in the validation. All 10 education tools achieved content and face validity after 3 rounds. The CVI score was 1.0 for most of the tools, with 0.95 being the lowest value. Face validity ranged from 72% to 100%, with majority scoring above 90%. Conclusion: Ten patient education tools on deprescribing were developed and validated by patients on HD. These validated, medication-specific education tools are the first of its kind for patients on HD and will be used in a nationwide implementation study alongside the validated deprescribing algorithms developed by our research group.

Contexte: La déprescription est une solution axée sur le patient pour réduire la polypharmacie chez les patients sous hémodialyse (HD). Dans une étude pilote sur la déprescription, les patients ont hésité à participer en raison de leur compréhension limitée de leurs propres médicaments et de leur manque de connaissance du concept de déprescription. Par conséquent, du matériel éducatif conçu pour combler ces lacunes dans les connaissances des patients pourrait surmonter les obstacles à la prise de décision partagée et réduire les hésitations à l'égard de la déprescription. Objectifs: Développer et valider une trousse d'information (bulletin et vidéo) pour les patients portant sur les médicaments. Cette trousse viendra compléter un futur programme national de déprescription pour les patients sous HD. Méthodologie: Des outils d'éducation pour les patients ont été développés à partir du contenu d'algorithmes de déprescription validés précédemment et de recherches documentaires sur les préférences des patients en matière d'éducation. Une ronde préliminaire de validation a été complétée par cinq cliniciens afin d'obtenir des commentaires sur l'exactitude et la clarté des outils d'éducation. Trois cycles de validation ont ensuite été réalisés par des patients sous HD dans trois sites: Vancouver, Winnipeg et Toronto. La validité du contenu et la validité apparente ont été évaluées à l'aide d'échelles de Likert à 4 et 5 points, respectivement. L'indice de validité du contenu (IVC) a été calculé après chaque ronde et des révisions ont été effectuées en fonction des commentaires des patients. Résultats: En tout, 105 patients ont participé à la validation. La validité du contenu et la validité apparente ont été atteintes pour les dix outils d'éducation après trois rondes auprès des patients. L'IVC s'établissait à 1,0 pour la plupart des outils évalués; 0,95 était la valeur d'indice la plus faible. La validité apparente variait entre 72% et 100%, la majorité des outils ayant obtenu un score supérieur à 90%. Conclusion: Dix outils d'éducation pour les patients portant sur la déprescription ont été développés et validés par des patients sous HD. Ces outils d'éducation validés portant spécifiquement sur les médicaments sont les premiers du genre conçus pour les patients sous HD. Ils seront utilisés dans le cadre d'une étude nationale de mise en œuvre, parallèlement aux algorithmes validés de déprescription qui ont été développés par notre groupe de recherche.

Hyperkalemia: Prevalence, Predictors and Emerging Treatments.

It is well established that an elevated potassium level (hyperkalemia) is associated with a risk of adverse events including morbidity, mortality and healthcare system cost. Hyperkalemia is commonly encountered in many chronic conditions including kidney disease, diabetes and heart failure. Furthermore, hyperkalemia may result from the use of renin-angiotensin-aldosterone system inhibitors (RAASi), which are disease-modifying treatments for these conditions. Therefore, balancing the benefits of optimizing treatment with RAASi while mitigating hyperkalemia is crucial to ensure patients are optimally treated. In this review, we will briefly discuss the definition, causes, epidemiology and consequences of hyperkalemia. The majority of the review will be focused on management of hyperkalemia in the acute and chronic setting, emphasizing contemporary approaches and evolving data on the relevance of dietary restriction and the use of novel potassium binders.

Community pharmacists' perspectives on assessing kidney function and medication dosing for patients with advanced chronic kidney disease: A qualitative study using the theoretical domains framework.

Background: The kidneys are responsible for the elimination of many drugs. Chronic kidney disease (CKD) is common, and medications may require adjustment to avoid adverse outcomes. Despite the availability of kidney drug dosing resources, people with CKD are at risk of inappropriate drug prescribing. Community pharmacists are in the ideal position to mitigate harm from inappropriate prescribing in this population. Methods: In this qualitative study, community pharmacists were interviewed on their perspective on kidney function assessment and dose adjustment in people with advanced CKD (estimated glomerular filtration rate <30 mL/min/1.73 m2). The theoretical domains framework for targeting behavioural change was used to inform the interview guide and analysis. Purposeful sampling was employed until data saturation. Semistructured virtual interviews were audio-recorded, transcribed verbatim and uploaded into NVIVO 12 Pro to facilitate thematic analysis. Deductive and inductive iterative coding approaches were employed to determine categories and themes. Results: Twelve pharmacists were interviewed, with a mean age of 42 years and 16 years of experience. Four themes comprising 10 categories were identified to influence kidney function assessment and dosing, including resources (information access, technology, references), environment (pharmacy infrastructure, practice setting), reflection (triggers, experience and training, collaboration) and leadership and governance (pharmacist role, advocacy). Feedback on an optimal CKD tool was collected, and enabling themes (categories) for implementation included knowledge and skills (education, training) and reflection (role, support, integration). Conclusions: Findings will inform the interventions needed to improve implementation of kidney assessment and dosing of high-risk medications in people with kidney impairment into community pharmacy practice. Can Pharm J (Ott) 2023;156:xx-xx.

Preclinical Characterization of AZD5305, A Next-Generation, Highly Selective PARP1 Inhibitor and Trapper.

PURPOSE: We hypothesized that inhibition and trapping of PARP1 alone would be sufficient to achieve antitumor activity. In particular, we aimed to achieve selectivity over PARP2, which has been shown to play a role in the survival of hematopoietic/stem progenitor cells in animal models. We developed AZD5305 with the aim of achieving improved clinical efficacy and wider therapeutic window. This next-generation PARP inhibitor (PARPi) could provide a paradigm shift in clinical outcomes achieved by first-generation PARPi, particularly in combination. EXPERIMENTAL DESIGN: AZD5305 was tested in vitro for PARylation inhibition, PARP-DNA trapping, and antiproliferative abilities. In vivo efficacy was determined in mouse xenograft and PDX models. The potential for hematologic toxicity was evaluated in rat models, as monotherapy and combination. RESULTS: AZD5305 is a highly potent and selective inhibitor of PARP1 with 500-fold selectivity for PARP1 over PARP2. AZD5305 inhibits growth in cells with deficiencies in DNA repair, with minimal/no effects in other cells. Unlike first-generation PARPi, AZD5305 has minimal effects on hematologic parameters in a rat pre-clinical model at predicted clinically efficacious exposures. Animal models treated with AZD5305 at doses ≥0.1 mg/kg once daily achieved greater depth of tumor regression compared to olaparib 100 mg/kg once daily, and longer duration of response. CONCLUSIONS: AZD5305 potently and selectively inhibits PARP1 resulting in excellent antiproliferative activity and unprecedented selectivity for DNA repair deficient versus proficient cells. These data confirm the hypothesis that targeting only PARP1 can retain the therapeutic benefit of nonselective PARPi, while reducing potential for hematotoxicity. AZD5305 is currently in phase I trials (NCT04644068).

Influence of the methyl group in isoprene epoxides on reactivity compared to butadiene epoxides: Biological significance.

Reactions of the epoxides of 1,3-butadiene and isoprene (2-methyl-1,3-butadiene) with oxygen, nitrogen and sulfur nucleophiles have been compared to enable a better molecular understanding of the relative human toxicities of these epoxides. Hydrolysis of rac.-ethenyloxirane in (18O)water gave 77% (2-18O)but-3-ene-1,2-diol and 23% (1-18O)but-3-ene-1,2-diol. The R:S ratio for but-3-ene-1,2-diol from hydrolysis of (S)-ethenyloxirane was 75:25. Hence, hydrolysis of ethenyloxirane occurs by competing SN2 attack at C-2 and C-3 in 3:1 ratio, with no SN1 component. Hydrolysis of rac.-2-ethenyl-2-methyloxirane gave 2-hydroxy-2-methylbut-3-en-1-ol (73%) and 27% of a 2:1 mixture of the E- and Z-isomers of 4-hydroxy-2-methylbut-2-en-1-ol. In (18O)water (2-18O)2-hydroxy-2-methylbut-3-en-1-ol was obtained. Formation of these products occurs via SN1 ionisation to resonance-stabilised allylic cations which are captured by water. Reaction of rac.-ethenyloxirane with l-valine methyl ester gave diastereoisomeric adducts from SN2 attack of the valine amino at both C-2 (substituted position) and C-3 of the oxirane. The corresponding reaction of rac.-2-methyl-2-ethenyloxirane gave diastereoisomeric adducts, (R, S)- and (S, S)-N-(2-hydroxy-2-methyl-3-buten-1-yl)-l-valine methyl ester, from SN2 attack of the valine amino solely at C-3. Reactions of rac.-2-ethenyl-2-methyloxirane with cysteine derivatives occurred at C-2 in neutral polar media (SN1 reaction) or at C-3 in basic media (SN2), whereas for ethenyloxirane products arose from attack at both C-2 and C-3. Reaction of meso-butadiene diepoxide (meso-2,2'-bioxirane) with l-valine methyl ester gave mainly 2:1 adducts, dimethyl 2,2'-(((2R,3S)-2,3-dihydroxybutane-1,4-diyl)bis(azanediyl))-(2S,2'S)-bis(3-methyl-butanoates), whereas 2-methyl-2,2'-bioxirane gave a mixture of 1:1 [methyl 2-(3,4-dihydroxy-3-methylpyrrolidin-1-yl)-3-methylbutanoates] and 2:1 adducts. Meso-2,2'-bioxirane reacted with N-acetylcysteine methyl ester in methanol to afford meso-thiolane-3,4-diol, by elimination of N-acetyldehydroalanine methyl ester from a precursor cyclic adduct. Similarly, 2-methyl-2,2'-bioxirane gave solely 3-methylthiolane-3,4-diols. Thus, the methyl group of isoprene has a subtle effect on the reactivity of its epoxides relative to those of butadiene and therefore, in the context of their toxicology, could abrogate crosslinking of nitrogen functions in biomolecules related to mutagenicity and carcinogenicity.

Multi-modal molecular imaging maps the correlation between tumor microenvironments and nanomedicine distribution.

Gaining insight into the heterogeneity of nanoparticle drug distribution within tumors would improve both design and clinical translation of nanomedicines. There is little data showing the spatio-temporal behavior of nanomedicines in tissues as current methods are not able to provide a comprehensive view of the nanomedicine distribution, released drug or its effects in the context of a complex tissue microenvironment. Methods: A new experimental approach which integrates the molecular imaging and bioanalytical technologies MSI and IMC was developed to determine the biodistribution of total drug and drug metabolite delivered via PLA-PEG nanoparticles and to overlay this with imaging of the nanomedicine in the context of detailed tumor microenvironment markers. This was used to assess the nanomedicine AZD2811 in animals bearing three different pre-clinical PDX tumors. Results: This new approach delivered new insights into the nanoparticle/drug biodistribution. Mass spectrometry imaging was able to differentiate the tumor distribution of co-dosed deuterated non-nanoparticle-formulated free drug alongside the nanoparticle-formulated drug by directly visualizing both delivery approaches within the same animal or tissue. While the IV delivered free drug was uniformly distributed, the nanomedicine delivered drug was heterogeneous. By staining for multiple biomarkers of the tumor microenvironment on the same tumor sections using imaging mass cytometry, co-registering and integrating data from both imaging modalities it was possible to determine the features in regions with highest nanomedicine distribution. Nanomedicine delivered drug was associated with regions higher in macrophages, as well as more stromal regions of the tumor. Such a comparison of complementary molecular data allows delineation of drug abundance in individual cell types and in stroma. Conclusions: This multi-modal imaging solution offers researchers a better understanding of drug and nanocarrier distribution in complex tissues and enables data-driven drug carrier design.

The DNA-PK Inhibitor AZD7648 Sensitizes Patient-Derived Ovarian Cancer Xenografts to Pegylated Liposomal Doxorubicin and Olaparib Preventing Abdominal Metastases.

Ovarian cancer is the deadliest gynecologic cancer, with a 5-year survival rate of 30%, when the disease has spread throughout the peritoneal cavity. We investigated the efficacy to delay disease progression by the DNA-dependent protein kinase (DNA-PK) inhibitor AZD7648, administered in combination with two of the therapeutic options for patient management: either pegylated liposomal doxorubicin (PLD) or the PARP inhibitor olaparib. Patient-derived ovarian cancer xenografts (OC-PDX) were transplanted subcutaneously to evaluate the effect of treatment on tumor growth, or orthotopically in the peritoneal cavity to evaluate the effect on metastatic spread. AZD7648 was administered orally in combination with PLD (dosed intravenously) or with olaparib (orally). To prove the inhibition of DNA-PK in the tumors, we measured pDNA-PKcs, pRPA32, and γH2AX, biomarkers of DNA-PK activity. AZD7648 enhanced the therapeutic efficacy of PLD in all the OC-PDXs tested, regardless of their BRCA status or sensitivity to cisplatin or PLD. The treatment caused disease stabilization, which persisted despite therapy discontinuation for tumors growing subcutaneously, and significantly impaired the abdominal metastatic dissemination, prolonging the lifespan of mice implanted orthotopically. AZD7648 potentiated the efficacy of olaparib in BRCA-deficient OC-PDXs but did not sensitize BRCA-proficient OC-PDXs to olaparib, despite an equivalent inhibition of DNA-PK, suggesting the need of a preexisting olaparib activity to benefit from the addition of AZD7648. This work suggests that AZD7648, an inhibitor of DNA-PK, dosed in combination with PLD or olaparib is an exciting therapeutic option that could benefit patients with ovarian cancer and should be explored in clinical trials.

Method To Visualize the Intratumor Distribution and Impact of Gemcitabine in Pancreatic Ductal Adenocarcinoma by Multimodal Imaging.

Gemcitabine (dFdC) is a common treatment for pancreatic cancer; however, it is thought that treatment may fail because tumor stroma prevents drug distribution to tumor cells. Gemcitabine is a pro-drug with active metabolites generated intracellularly; therefore, visualizing the distribution of parent drug as well as its metabolites is important. A multimodal imaging approach was developed using spatially coregistered mass spectrometry imaging (MSI), imaging mass cytometry (IMC), multiplex immunofluorescence microscopy (mIF), and hematoxylin and eosin (H&E) staining to assess the local distribution and metabolism of gemcitabine in tumors from a genetically engineered mouse model of pancreatic cancer (KPC) allowing for comparisons between effects in the tumor tissue and its microenvironment. Mass spectrometry imaging (MSI) enabled the visualization of the distribution of gemcitabine (100 mg/kg), its phosphorylated metabolites dFdCMP, dFdCDP and dFdCTP, and the inactive metabolite dFdU. Distribution was compared to small-molecule ATR inhibitor AZD6738 (25 mg/kg), which was codosed. Gemcitabine metabolites showed heterogeneous distribution within the tumor, which was different from the parent compound. The highest abundance of dFdCMP, dFdCDP, and dFdCTP correlated with distribution of endogenous AMP, ADP, and ATP in viable tumor cell regions, showing that gemcitabine active metabolites are reaching the tumor cell compartment, while AZD6738 was located to nonviable tumor regions. The method revealed that the generation of active, phosphorylated dFdC metabolites as well as treatment-induced DNA damage primarily correlated with sites of high proliferation in KPC PDAC tumor tissue, rather than sites of high parent drug abundance.

ALT neuroblastoma chemoresistance due to telomere dysfunction-induced ATM activation is reversible with ATM inhibitor AZD0156.

Cancers overcome replicative immortality by activating either telomerase or an alternative lengthening of telomeres (ALT) mechanism. ALT occurs in ~25% of high-risk neuroblastomas, and progression in patients with ALT neuroblastoma during or after front-line therapy is frequent and often fatal. Temozolomide + irinotecan is commonly used as salvage therapy for neuroblastoma. Patient-derived cell lines and xenografts established from patients with relapsed ALT neuroblastoma demonstrated de novo resistance to temozolomide + irinotecan [SN-38 in vitro, P < 0.05; in vivo mouse event-free survival (EFS), P < 0.0001] vs. telomerase-positive neuroblastomas. We observed that ALT neuroblastoma cells manifested constitutive ataxia-telangiectasia mutated (ATM) activation due to spontaneous telomere dysfunction which was not observed in telomerase-positive neuroblastoma cells. We demonstrated that induction of telomere dysfunction resulted in ATM activation that, in turn, conferred resistance to temozolomide + SN-38 (4.2-fold change in IC50, P < 0.001). ATM knockdown (shRNA) or inhibition using a clinical-stage small-molecule inhibitor (AZD0156) reversed resistance to temozolomide + irinotecan in ALT neuroblastoma cell lines in vitro (P < 0.001) and in four ALT xenografts in vivo (EFS, P < 0.0001). AZD0156 showed modest to no enhancement of temozolomide + irinotecan activity in telomerase-positive neuroblastoma cell lines and xenografts. Ataxia telangiectasia and Rad3 related (ATR) inhibition using AZD6738 did not enhance temozolomide + SN-38 activity in ALT neuroblastoma cells. Thus, ALT neuroblastoma chemotherapy resistance occurs via ATM activation and is reversible with ATM inhibitor AZD0156. Combining AZD0156 with temozolomide + irinotecan warrants clinical testing for neuroblastoma.

AZD0364 Is a Potent and Selective ERK1/2 Inhibitor That Enhances Antitumor Activity in KRAS-Mutant Tumor Models when Combined with the MEK Inhibitor, Selumetinib.

The RAS-regulated RAF-MEK1/2-ERK1/2 (RAS/MAPK) signaling pathway is a major driver in oncogenesis and is frequently dysregulated in human cancers, primarily by mutations in BRAF or RAS genes. The clinical benefit of inhibitors of this pathway as single agents has only been realized in BRAF-mutant melanoma, with limited effect of single-agent pathway inhibitors in KRAS-mutant tumors. Combined inhibition of multiple nodes within this pathway, such as MEK1/2 and ERK1/2, may be necessary to effectively suppress pathway signaling in KRAS-mutant tumors and achieve meaningful clinical benefit. Here, we report the discovery and characterization of AZD0364, a novel, reversible, ATP-competitive ERK1/2 inhibitor with high potency and kinase selectivity. In vitro, AZD0364 treatment resulted in inhibition of proximal and distal biomarkers and reduced proliferation in sensitive BRAF-mutant and KRAS-mutant cell lines. In multiple in vivo xenograft models, AZD0364 showed dose- and time-dependent modulation of ERK1/2-dependent signaling biomarkers resulting in tumor regression in sensitive BRAF- and KRAS-mutant xenografts. We demonstrate that AZD0364 in combination with the MEK1/2 inhibitor, selumetinib (AZD6244 and ARRY142886), enhances efficacy in KRAS-mutant preclinical models that are moderately sensitive or resistant to MEK1/2 inhibition. This combination results in deeper and more durable suppression of the RAS/MAPK signaling pathway that is not achievable with single-agent treatment. The AZD0364 and selumetinib combination also results in significant tumor regressions in multiple KRAS-mutant xenograft models. The combination of ERK1/2 and MEK1/2 inhibition thereby represents a viable clinical approach to target KRAS-mutant tumors.

Preclinical Comparison of the Blood-brain barrier Permeability of Osimertinib with Other EGFR TKIs.

PURPOSE: Osimertinib is a potent and selective EGFR tyrosine kinase inhibitor (EGFR-TKI) of both sensitizing and T790M resistance mutations. To treat metastatic brain disease, blood-brain barrier (BBB) permeability is considered desirable for increasing clinical efficacy. EXPERIMENTAL DESIGN: We examined the level of brain penetration for 16 irreversible and reversible EGFR-TKIs using multiple in vitro and in vivo BBB preclinical models. RESULTS: In vitro osimertinib was the weakest substrate for human BBB efflux transporters (efflux ratio 3.2). In vivo rat free brain to free plasma ratios (Kpuu) show osimertinib has the most BBB penetrance (0.21), compared with the other TKIs (Kpuu ≤ 0.12). PET imaging in Cynomolgus macaques demonstrated osimertinib was the only TKI among those tested to achieve significant brain penetrance (C max %ID 1.5, brain/blood Kp 2.6). Desorption electrospray ionization mass spectroscopy images of brains from mouse PC9 macrometastases models showed osimertinib readily distributes across both healthy brain and tumor tissue. Comparison of osimertinib with the poorly BBB penetrant afatinib in a mouse PC9 model of subclinical brain metastases showed only osimertinib has a significant effect on rate of brain tumor growth. CONCLUSIONS: These preclinical studies indicate that osimertinib can achieve significant exposure in the brain compared with the other EGFR-TKIs tested and supports the ongoing clinical evaluation of osimertinib for the treatment of EGFR-mutant brain metastasis. This work also demonstrates the link between low in vitro transporter efflux ratios and increased brain penetrance in vivo supporting the use of in vitro transporter assays as an early screen in drug discovery.

Development and Validation of Nine Deprescribing Algorithms for Patients on Hemodialysis to Decrease Polypharmacy.

BACKGROUND: Polypharmacy is ubiquitous in patients on hemodialysis (HD), and increases risk of adverse events, medication interactions, nonadherence, and mortality. Appropriately applied deprescribing can potentially minimize polypharmacy risks. Existing guidelines are unsuitable for nephrology clinicians as they lack specific instructions on how to deprescribe and which safety parameters to monitor. OBJECTIVE: To develop and validate deprescribing algorithms for nine medication classes to decrease polypharmacy in patients on HD. DESIGN: Questionnaires and materials sent electronically. PARTICIPANTS: Nephrology practitioners across Canada (nephrologists, nurse practitioners, renal pharmacists). METHODS: A literature search was performed to develop the initial algorithms via Lynn's method for development of content-valid clinical tools. Content and face validity of the algorithms was evaluated over three interview rounds using Lynn's method for determining content validity. Canadian nephrology clinicians each evaluated three algorithms (15 clinicians per round, 45 clinicians in total) by rating each algorithm component on a four-point Likert scale for relevance; face validity was rated on a five-point scale. After each round, content validity index of each component was calculated and revisions made based on feedback. If content validity was not achieved after three rounds, additional rounds were completed until content validity was achieved. RESULTS: After three rounds of validation, six algorithms achieved content validity. After an additional round, the remaining three algorithms achieved content validity. The proportion of clinicians rating each face validity statement as "Agree" or "Strongly Agree" ranged from 84% to 95% (average of all five questions, across three rounds). LIMITATIONS: Algorithm development was guided by existing deprescribing protocols intended for the general population and the expert opinions of our study team, due to a lack of background literature on HD-specific deprescribing protocols. There is no universally accepted method for the validation of clinical decision-making tools. CONCLUSIONS: Nine medication-specific deprescribing algorithms for patients on HD were developed and validated by clinician review. Our algorithms are the first medication-specific, patient-centric deprescribing guidelines developed and validated for patients on HD.

CONTEXTE: La polypharmacie est très répandue chez les patients hémodialysés et augmente le risque d'événements indésirables, d'interactions médicamenteuses, d'inobservance au traitement et de mortalité. La déprescription, appliquée de façon appropriée, peut réduire les risques associés à la polypharmacie. Les directives de déprescription existantes ne conviennent cependant pas aux cliniciens en néphrologie puisqu'elles ne renferment aucune indication spécifique sur la manière de procéder ni sur les paramètres de sécurité à surveiller. OBJECTIF: Développer et valider des algorithmes de déprescription pour neuf classes de médicaments en vue de réduire la polypharmacie chez les patients hémodialysés. CONCEPTION: Des questionnaires et des documents envoyés par voie électronique. PARTICIPANTS: Des praticiens en néphrologies de partout au Canada (néphrologues, infirmières-praticiennes, pharmaciens spécialisés en néphrologie). MÉTHODOLOGIE: Une recherche bibliographique a été effectuée pour développer les algorithmes initiaux avec la méthode de Lynn pour le développement d'outils cliniques à contenu validé. Le contenu et la validité apparente des algorithmes ont été évalués au cours de trois cycles d'interviews par la méthode de Lynn pour déterminer la validité d'un contenu. Les praticiens interviewés (15 par cycle, pour un total de 45) ont chacun évalué trois algorithmes en classant la pertinence de leurs composants sur une échelle de Likert en quatre points, et en classant leur validité apparente sur une échelle en cinq points. Après chaque cycle, l'indice de validité du contenu a été calculé pour chaque composant et des correctifs ont été apportés en fonction de la rétroaction. Si la validité du contenu n'était pas atteinte après trois cycles, des cycles supplémentaires étaient effectués jusqu'à ce que celle-ci soit atteinte. RÉSULTATS: Six algorithmes ont atteint la validité après trois cycles de validation. Les trois algorithmes restants l'ont atteint après un cycle supplémentaire. La proportion de cliniciens ayant attribué la mention de validité apparente « d'accord ¼ ou « tout à fait d'accord ¼ se situait entre 84 et 95 % (moyenne des cinq questions, sur trois cycles). LIMITES: Le développement des algorithmes repose sur les protocoles de déprescription existants, destinés à la population générale, et sur l'avis des experts de notre équipe d'étude puisque la documentation portant sur des protocoles de déprescription spécifiques aux patients hémodialysés est insuffisante. Il n'existe aucune méthode universellement acceptée pour valider les outils de décision clinique. CONCLUSION: Neuf algorithmes de déprescription spécifiques aux patients hémodialysés ont été développés et validés par révision des cliniciens. Nos algorithmes sont les premiers guides de déprescription développés et validés spécifiquement pour les médicaments des patients hémodialysés. ENREGISTREMENT DE L'ESSAI: Sans objet ­ il s'agit d'une série de questionnaires.

AZD7648 is a potent and selective DNA-PK inhibitor that enhances radiation, chemotherapy and olaparib activity.

DNA-dependent protein kinase (DNA-PK) is a critical player in the DNA damage response (DDR) and instrumental in the non-homologous end-joining pathway (NHEJ) used to detect and repair DNA double-strand breaks (DSBs). We demonstrate that the potent and highly selective DNA-PK inhibitor, AZD7648, is an efficient sensitizer of radiation- and doxorubicin-induced DNA damage, with combinations in xenograft and patient-derived xenograft (PDX) models inducing sustained regressions. Using ATM-deficient cells, we demonstrate that AZD7648, in combination with the PARP inhibitor olaparib, increases genomic instability, resulting in cell growth inhibition and apoptosis. AZD7648 enhanced olaparib efficacy across a range of doses and schedules in xenograft and PDX models, enabling sustained tumour regression and providing a clear rationale for its clinical investigation. Through its differentiated mechanism of action as an NHEJ inhibitor, AZD7648 complements the current armamentarium of DDR-targeted agents and has potential in combination with these agents to achieve deeper responses to current therapies.

Postoperative pyoderma gangrenosum after spinal fusion with instrumentation: case report.

Pyoderma gangrenosum (PG) is a rare inflammatory dermatosis that is most often associated with inflammatory bowel disease, but which can occur as a pathergic reaction around surgical incisions. The authors report the case of a patient who developed postoperative PG over the course of several months after undergoing extensive spinal instrumentation between the T4 and iliac levels. This is only the second such case occurring after spine surgery to be reported. The authors additionally review the literature to characterize treatment approaches and outcomes for this condition. The case highlights a potentially severe adverse effect of surgery that can be difficult to recognize and causes delays in effective treatment. It also demonstrates the importance of multidisciplinary collaboration in the effective care of patients.