Development of a Clinical Prediction Model for In-hospital Mortality from the South African Cohort of the African Surgical Outcomes Study.

BACKGROUND: Data on the factors that influence mortality after surgery in South Africa are scarce, and neither these data nor data on risk-adjusted in-hospital mortality after surgery are routinely collected. Predictors related to the context or setting of surgical care delivery may also provide insight into variation in practice. Variation must be addressed when planning for improvement of risk-adjusted outcomes. Our objective was to identify the factors predicting in-hospital mortality after surgery in South Africa from available data. METHODS: A multivariable logistic regression model was developed to identify predictors of 30-day in-hospital mortality in surgical patients in South Africa. Data from the South African contribution to the African Surgical Outcomes Study were used and included 3800 cases from 51 hospitals. A forward stepwise regression technique was then employed to select for possible predictors prior to model specification. Model performance was evaluated by assessing calibration and discrimination. The South African Surgical Outcomes Study cohort was used to validate the model. RESULTS: Variables found to predict 30-day in-hospital mortality were age, American Society of Anesthesiologists Physical Status category, urgent or emergent surgery, major surgery, and gastrointestinal-, head and neck-, thoracic- and neurosurgery. The area under the receiver operating curve or c-statistic was 0.859 (95% confidence interval: 0.827-0.892) for the full model. Calibration, as assessed using a calibration plot, was acceptable. Performance was similar in the validation cohort as compared to the derivation cohort. CONCLUSION: The prediction model did not include factors that can explain how the context of care influences post-operative mortality in South Africa. It does, however, provide a basis for reporting risk-adjusted perioperative mortality rate in the future, and identifies the types of surgery to be prioritised in quality improvement projects at a local or national level.

Half-life extension of peptidic APJ agonists by N-terminal lipid conjugation.

Agonism of the endothelial receptor APJ (putative receptor protein related to AT1; AT1: angiotensin II receptor type 1) has the potential to ameliorate congestive heart failure by increasing cardiac output without inducing hypertrophy. Although the endogenous agonist, pyr-apelin-13 (1), has shown beneficial APJ-mediated inotropic effects in rats and humans, such effects are short-lived given its extremely short half-life. Here, we report the conjugation of 1 to a fatty acid, providing a lipidated peptide (2) with increased stability that retains inotropic activity in an anesthetized rat myocardial infarction (MI) model. We also report the preparation of a library of 15-mer APJ agonist peptide-lipid conjugates, including adipoyl-γGlu-OEG-OEG-hArg-r-Q-hArg-P-r-NMeLeuSHK-G-Oic-pIPhe-P-DBip-OH (17), a potent APJ agonist with high plasma protein binding and a half-life suitable for once-daily subcutaneous dosing in rats. A correlation between subcutaneous absorption rate and lipid length/type of these conjugates is also reported.

Potent complement C3a receptor agonists derived from oxazole amino acids: Structure-activity relationships.

Potent ligands for the human complement C3a receptor (C3aR) were developed from the almost inactive tripeptide Leu-Ala-Arg corresponding to the three C-terminal residues of the endogenous peptide agonist C3a. The analogous Leu-Ser-Arg was modified by condensing the serine side chain with the leucine carbonyl with elimination of water to form leucine-oxazole-arginine. Subsequent elaboration with a variety of N-terminal amide capping groups produced agonists as potent as human C3a itself in stimulating Ca(2+) release from human macrophages. Structure-activity relationships are discussed.

Discovery of 5-(1H-indol-5-yl)-1,3,4-thiadiazol-2-amines as potent PIM inhibitors.

PIM kinases are a family of Ser/Thr kinases that are implicated in tumorigenesis. The discovery of a new class of PIM inhibitors, 5-(1H-indol-5-yl)-1,3,4-thiadiazol-2-amines, is discussed with optimized compounds showing excellent potency against all three PIM isoforms.

The discovery of novel 3-(pyrazin-2-yl)-1H-indazoles as potent pan-Pim kinase inhibitors.

The three Pim kinases are a small family of serine/threonine kinases regulating several signaling pathways that are fundamental to tumorigenesis. As such, the Pim kinases are a very attractive target for pharmacological inhibition in cancer therapy. Herein, we describe our efforts toward the development of a potent, pan-Pim inhibitor. The synthesis and hit-to-lead SAR development from a 3-(pyrazin-2-yl)-1H-indazole derived hit 2 to the identification of a series of potent, pan-Pim inhibitors such as 13o are described.

The discovery and optimization of aminooxadiazoles as potent Pim kinase inhibitors.

High levels of Pim expression have been implicated in several hematopoietic and solid tumor cancers. These findings suggest that inhibition of Pim signaling by a small molecule Pim-1,2 inhibitor could provide patients with therapeutic benefit. Herein, we describe our progress towards this goal starting from the highly Pim-selective indole-thiadiazole compound (1), which was derived from a nonselective hit identified in a high throughput screening campaign. Optimization of this compound's potency and its pharmacokinetic properties resulted in the discovery of compound 29. Cyclopropane 29 was found to exhibit excellent enzymatic potency on the Pim-1 and Pim-2 isoforms (Ki values of 0.55nM and 0.28nM, respectively), and found to inhibit the phosphorylation of BAD in the Pim-overexpressing KMS-12 cell line (IC50=150nM). This compound had moderate clearance and bioavailability in rat (CL=2.42L/kg/h; %F=24) and exhibited a dose-dependent inhibition of p-BAD in KMS-12 tumor pharmacodynamic (PD) model with an EC50 value of 6.74µM (18µg/mL) when dosed at 10, 30, 100 and 200mg/kg po in mice.

Phosphoinositide-3-kinase inhibitors: evaluation of substituted alcohols as replacements for the piperazine sulfonamide portion of AMG 511.

Replacement of the piperazine sulfonamide portion of the PI3Kα inhibitor AMG 511 (1) with a range of aliphatic alcohols led to the identification of a truncated gem-dimethylbenzylic alcohol analog, 2-(5-(4-amino-6-methyl-1,3,5-triazin-2-yl)-6-((5-fluoro-6-methoxypyridin-3-yl)amino)pyridin-3-yl)propan-2-ol (7). This compound possessed good in vitro efficacy and pharmacokinetic parameters and demonstrated an EC50 of 239 ng/mL in a mouse liver pharmacodynamic model measuring the inhibition of hepatocyte growth factor (HGF)-induced Akt Ser473 phosphorylation in CD1 nude mice 6 h post-oral dosing.

Imidazolone as an Amide Bioisostere in the Development of ß-1,3-N-Acetylglucosaminyltransferase 2 (B3GNT2) Inhibitors.

B3GNT2 is responsible for elongation of cell surface long-chain polylactosamine, which influences the regulation of the immune response, making it an attractive target for immunomodulation. In the development of amide containing B3GNT2 inhibitors guided by structure-based drug design, imidazolones were found to successfully serve as amide bioisosteres. This novel imidazolone isosteric strategy alleviated torsional strain of the amide bond on binding to B3GNT2 and improved potency, isoform selectivity, as well as certain physicochemical and pharmacokinetic properties. Herein, we present the synthesis, SAR, X-ray cocrystal structures, and in vivo PK properties of imidazol-4-ones in the context of B3GNT2 inhibition.

Isoform-selective thiazolo[5,4-b]pyridine S1P1 agonists possessing acyclic amino carboxylate head-groups.

Replacement of the azetidine carboxylate of an S1P(1) agonist development candidate, AMG 369, with a range of acyclic head-groups led to the identification of a novel, S1P(3)-sparing S1P(1) agonist, (-)-2-amino-4-(3-fluoro-4-(5-(1-phenylcyclopropyl)thiazolo[5,4-b]pyridin-2-yl)phenyl)-2-methylbutanoic acid (8c), which possessed good in vivo efficacy and pharmacokinetic properties. A 0.3mg/kg oral dose of 8c produced a statistically significant reduction in blood lymphocyte counts 24h post-dosing in female Lewis rats.

Quinolinone-based agonists of S1P1: use of a N-scan SAR strategy to optimize in vitro and in vivo activity.

We reveal how a N-scan SAR strategy (systematic substitution of each CH group with a N atom) was employed for quinolinone-based S1P(1) agonist 5 to modulate physicochemical properties and optimize in vitro and in vivo activity. The diaza-analog 17 displays improved potency (hS1P(1) RI; 17: EC(50)=0.020 µM, 120% efficacy; 5: EC(50)=0.070 µM, 110% efficacy) and selectivity (hS1P(3) Ca(2+) flux; 17: EC(50) >25 µM; 5: EC(50)=1.5 µM, 92% efficacy), as well as enhanced pharmacokinetics (17: CL=0.15 L/h/kg, V(dss)=5.1L/kg, T(1/2)=24h, %F=110; 5: CL=0.93L/h/kg, V(dss)=11L/kg, T(1/2)=15 h, %F=60) and pharmacodynamics (17: 1.0mg/kg po, 24h PLC POC=-67%; 5: 3mg/kg po, 24h PLC POC=-51%) in rat.

Discovery of a Covalent Inhibitor of KRASG12C (AMG 510) for the Treatment of Solid Tumors.

KRASG12C has emerged as a promising target in the treatment of solid tumors. Covalent inhibitors targeting the mutant cysteine-12 residue have been shown to disrupt signaling by this long-"undruggable" target; however clinically viable inhibitors have yet to be identified. Here, we report efforts to exploit a cryptic pocket (H95/Y96/Q99) we identified in KRASG12C to identify inhibitors suitable for clinical development. Structure-based design efforts leading to the identification of a novel quinazolinone scaffold are described, along with optimization efforts that overcame a configurational stability issue arising from restricted rotation about an axially chiral biaryl bond. Biopharmaceutical optimization of the resulting leads culminated in the identification of AMG 510, a highly potent, selective, and well-tolerated KRASG12C inhibitor currently in phase I clinical trials (NCT03600883).

Hemodynamic effects of ephedrine, phenylephrine, and the coadministration of phenylephrine with oxytocin during spinal anesthesia for elective cesarean delivery.

BACKGROUND: Hemodynamic responses to vasopressors used during spinal anesthesia for elective Cesarean delivery, have not been well described. This study compared the effects of bolus phenylephrine and ephedrine on maternal cardiac output (CO). The hypothesis was that phenylephrine, but not ephedrine, decreases CO when administered in response to hypotension during spinal anesthesia. METHODS: Forty-three patients were randomized to receive 80 microg of phenylephrine or 10 mg of ephedrine. Both pulse wave form analysis and transthoracic bioimpedance changes were used to estimate stroke volume in each patient. Hemodynamic responses to spinal anesthesia and oxytocin were also recorded. A subgroup of 20 patients was randomized to receive oxytocin compared with oxytocin plus 80 microg of phenylephrine after delivery. RESULTS: Mean CO and maximum absolute response in CO were significantly lower during the 150 s after phenylephrine administration than after ephedrine (6.2 vs. 8.1 l/min, P = 0.001, and 5.2 vs. 9.0 l/min, P < 0.0001, respectively for pulse wave form analysis, and 5.2 vs. 6.3 l/min, P = 0.01 and 4.5 vs. 6.7 l/min, P = 0.0001, respectively for bioimpedance changes). CO changes correlated with heart rate changes. Coadministration of phenylephrine obtunded oxytocin-induced decreases in systemic vascular resistance and increases in heart rate and CO. Trends in CO change were similar using either monitor. CONCLUSIONS: Bolus phenylephrine reduced maternal CO, and decreased CO when compared with ephedrine during elective spinal anesthesia for Cesarean delivery. CO changes correlated with heart rate changes after vasopressor administration, emphasizing the importance of heart rate as a surrogate indicator of CO. Coadministered phenylephrine obtunded hemodynamic responses to oxytocin.

Discovery of ( R)-8-(6-Methyl-4-oxo-1,4,5,6-tetrahydropyrrolo[3,4- b]pyrrol-2-yl)-3-(1-methylcyclopropyl)-2-((1-methylcyclopropyl)amino)quinazolin-4(3 H)-one, a Potent and Selective Pim-1/2 Kinase Inhibitor for Hematological Malignancies.

Pim kinases are a family of constitutively active serine/threonine kinases that are partially redundant and regulate multiple pathways important for cell growth and survival. In human disease, high expression of the three Pim isoforms has been implicated in the progression of hematopoietic and solid tumor cancers, which suggests that Pim kinase inhibitors could provide patients with therapeutic benefit. Herein, we describe the structure-guided optimization of a series of quinazolinone-pyrrolodihydropyrrolone analogs leading to the identification of potent pan-Pim inhibitor 28 with improved potency, solubility, and drug-like properties. Compound 28 demonstrated on-target Pim activity in an in vivo pharmacodynamic assay with significant inhibition of BAD phosphorylation in KMS-12-BM multiple myeloma tumors for 16 h postdose. In a 2-week mouse xenograft model, daily dosing of compound 28 resulted in 33% tumor regression at 100 mg/kg.

Hemodynamic changes associated with spinal anesthesia for cesarean delivery in severe preeclampsia.

BACKGROUND: Hemodynamic responses to spinal anesthesia (SA) for cesarean delivery in patients with severe preeclampsia are poorly understood. This study used a beat-by-beat monitor of cardiac output (CO) to characterize the response to SA. The hypothesis was that CO would decrease from baseline values by less than 20%. METHODS: Fifteen patients with severe preeclampsia consented to an observational study. The monitor employed used pulse wave form analysis to estimate nominal stroke volume. Calibration was by lithium dilution. CO and systemic vascular resistance were derived from the measured stroke volume, heart rate, and mean arterial pressure. In addition, the hemodynamic effects of phenylephrine, the response to delivery and oxytocin, and hemodynamics during recovery from SA were recorded. Hemodynamic values were averaged for defined time intervals before, during, and after SA. RESULTS: Cardiac output remained stable from induction of SA until the time of request for analgesia. Mean arterial pressure and systemic vascular resistance decreased significantly from the time of adoption of the supine position until the end of surgery. After oxytocin administration, systemic vascular resistance decreased and heart rate and CO increased. Phenylephrine, 50 mug, increased mean arterial pressure to above target values and did not significantly change CO. At the time of recovery from SA, there were no clinically relevant changes from baseline hemodynamic values. CONCLUSIONS: Spinal anesthesia in severe preeclampsia was associated with clinically insignificant changes in CO. Phenylephrine restored mean arterial pressure but did not increase maternal CO. Oxytocin caused transient marked hypotension, tachycardia, and increases in CO.

National priorities for perioperative research in South Africa.

BACKGROUND: Perioperative research is currently unco-ordinated in South Africa (SA), with no clear research agenda. OBJECTIVE: To determine the top ten national research priorities for perioperative research in SA. METHODS: A Delphi technique was used to establish consensus on the top ten research priorities. RESULTS: The top ten research priorities were as follows: (i) establishment of a national database of (a) critical care outcomes, and (b) critical care resources; (ii) a randomised controlled trial of preoperative B-type natriuretic peptide-guided medical therapy to decrease major adverse cardiac events following non-cardiac surgery; (iii) a national prospective observational study of the outcomes associated with paediatric surgical cases; (iv) a national observational study of maternal and fetal outcomes following operative delivery in SA; (v) a stepped-wedge trial of an enhanced recovery after surgery programme for (a) surgery, (b) obstetrics, (c) emergency surgery, and (d) trauma surgery; (vi) a stepped-wedge trial of a surgical safety checklist on patient outcomes in SA; (vii) a prospective observational study of perioperative outcomes after surgery in district general hospitals in SA; (viii) short-course interventions to improve anaesthetic skills in rural doctors; (ix) studies of the efficacy of simulation training to improve (a) patient outcomes, (b) team dynamics, and (c) leadership; and (x) development and validation of a risk stratification tool for SA surgery based on the South African Surgical Outcomes Study (SASOS) data. CONCLUSIONS: These research priorities provide the structure for an intermediate-term research agenda.

Discovery and Optimization of Macrocyclic Quinoxaline-pyrrolo-dihydropiperidinones as Potent Pim-1/2 Kinase Inhibitors.

The identification of Pim-1/2 kinase overexpression in B-cell malignancies suggests that Pim kinase inhibitors will have utility in the treatment of lymphoma, leukemia, and multiple myeloma. Starting from a moderately potent quinoxaline-dihydropyrrolopiperidinone lead, we recognized the potential for macrocyclization and developed a series of 13-membered macrocycles. The structure-activity relationships of the macrocyclic linker were systematically explored, leading to the identification of 9c as a potent, subnanomolar inhibitor of Pim-1 and -2. This molecule also potently inhibited Pim kinase activity in KMS-12-BM, a multiple myeloma cell line with relatively high endogenous levels of Pim-1/2, both in vitro (pBAD IC50 = 25 nM) and in vivo (pBAD EC50 = 30 nM, unbound), and a 100 mg/kg daily dose was found to completely arrest the growth of KMS-12-BM xenografts in mice.

Discovery and Optimization of Quinazolinone-pyrrolopyrrolones as Potent and Orally Bioavailable Pan-Pim Kinase Inhibitors.

The high expression of proviral insertion site of Moloney murine leukemia virus kinases (Pim-1, -2, and -3) in cancers, particularly the hematopoietic malignancies, is believed to play a role in promoting cell survival and proliferation while suppressing apoptosis. The three isoforms of Pim protein appear largely redundant in their oncogenic functions. Thus, a pan-Pim kinase inhibitor is highly desirable. However, cell active pan-Pim inhibitors have proven difficult to develop because Pim-2 has a low Km for ATP and therefore requires a very potent inhibitor to effectively block the kinase activity at cellular ATP concentrations. Herein, we report a series of quinazolinone-pyrrolopyrrolones as potent and selective pan-Pim inhibitors. In particular, compound 17 is orally efficacious in a mouse xenograft model (KMS-12 BM) of multiple myeloma, with 93% tumor growth inhibition at 50 mg/kg QD upon oral dosing.