Fragment-Based Discovery of Allosteric Inhibitors of SH2 Domain-Containing Protein Tyrosine Phosphatase-2 (SHP2).

The ubiquitously expressed protein tyrosine phosphatase SHP2 is required for signaling downstream of receptor tyrosine kinases (RTKs) and plays a role in regulating many cellular processes. Genetic knockdown and pharmacological inhibition of SHP2 suppresses RAS/MAPK signaling and inhibit the proliferation of RTK-driven cancer cell lines. Here, we describe the first reported fragment-to-lead campaign against SHP2, where X-ray crystallography and biophysical techniques were used to identify fragments binding to multiple sites on SHP2. Structure-guided optimization, including several computational methods, led to the discovery of two structurally distinct series of SHP2 inhibitors binding to the previously reported allosteric tunnel binding site (Tunnel Site). One of these series was advanced to a low-nanomolar lead that inhibited tumor growth when dosed orally to mice bearing HCC827 xenografts. Furthermore, a third series of SHP2 inhibitors was discovered binding to a previously unreported site, lying at the interface of the C-terminal SH2 and catalytic domains.

Activated 4-Factor Prothrombin Complex Concentrate as a Hemostatic Adjunct for Neonatal Cardiac Surgery: A Propensity Score-Matched Cohort Study.

BACKGROUND: Prothrombin complex concentrates are an emerging "off-label" therapy to augment hemostasis after cardiopulmonary bypass (CPB), but data supporting their use for neonatal cardiac surgery are limited. METHODS: We retrospectively reviewed neonates undergoing open heart surgery with first-time sternotomy between May 2014 and December 2018 from a hospital electronic health record database. Neonates who received activated 4-factor prothrombin complex concentrate (a4FPCC) after CPB were propensity score matched (PSM) to neonates who did not receive a4FPCC (control group). The primary efficacy outcome was total volume (mL/kg) of blood products transfused after CPB, including the first 24 hours on the cardiovascular intensive care unit (CVICU). The primary safety outcome was the incidence of 7- and 30-day postoperative thromboembolism. Secondary outcomes included 24 hours postoperative chest tube output, time to extubation, duration of CVICU stay, duration of hospital stay, 30-day mortality, and incidence of acute kidney injury on postoperative day 3. We used linear regression modeling on PSM data for the primary efficacy outcome. For the primary safety outcome, we tested for differences using McNemar test on PSM data. For secondary outcomes, we used linear regression, Fisher exact test, or survival analyses as appropriate, with false discovery rate-adjusted P values. RESULTS: A total of 165 neonates were included in the final data analysis: 86 in the control group and 79 in the a4FPCC group. After PSM, there were 43 patients in the control group and 43 in the a4FPCC group. We found a statistically significant difference in mean total blood products transfused for the a4FPCC group (47.5 mL/kg) compared with the control group (63.7 mL/kg) for PSM patients (adjusted difference, 15.3; 95% CI, 29.4-1.3; P = .032). We did not find a statistically significant difference in 7- or 30-day thromboembolic rate, postoperative chest tube output, time to extubation, incidence of postoperative acute kidney injury (AKI), or 30-day mortality between the groups. The a4FPCC group had a significantly longer length of intensive care unit stay (32.9 vs 13.3 days; adjusted P = .049) and hospital stay (44.6 vs 24.1 days; adjusted P = .049) compared with the control group. CONCLUSIONS: We found that the use of a4FPCC as a hemostatic adjunct for post-CPB bleeding in neonatal cardiac surgery was associated with a decrease in mean total blood products transfused after CPB without an increased rate of 7- or 30-day postoperative thromboembolism. Our findings suggest that a4FPCCs can be considered as part of a hemostasis pathway for refractory bleeding in neonatal cardiac surgery.

The use of prothrombin complex concentrate as a warfarin reversal agent in pediatric patients undergoing orthotopic heart transplantation.

BACKGROUND: Patients supported with a ventricular assist device are predisposed to severe bleeding at the time of orthotopic heart transplant due to several risk factors including anticoagulation with vitamin K antagonists. Kcentra, a four-factor prothrombin complex concentrate, has been approved by the FDA for warfarin reversal in adults prior to urgent surgery. There is a lack of published data on the preoperative use of four-factor prothrombin complex concentrates in pediatric patients undergoing cardiacsurgery. METHODS: This is a single-center retrospective analysis of pediatric patients with a continuous-flow ventricular assist device who underwent heart transplant, comparing patients who received Kcentra for anticoagulation reversal with a historical patient cohort who did not. Consecutive patients from January 2013 to December 2017 were analyzed. The primary outcome was volume of blood product transfusion prior to cardiopulmonary bypass initiation. Secondary outcomes include blood product transfusion after cardiopulmonary bypass intraoperatively and up to 24 hours postoperatively, chest tube output within 24 hours of surgery, time to extubation, incidence of thromboembolism, and post-transplant length ofstay. RESULTS: From 2013 to 2017, 31 patients with continuous-flow ventricular assist devices underwent heart transplant, with 27 patients included in the analysis. Fifteen patients received Kcentra compared with 12 patients who received fresh-frozen plasma for anticoagulation reversal. Compared with the control group, patients who received Kcentra had less packed red blood cells, fresh-frozen plasma, and platelets transfused prior to cardiopulmonary bypass initiation. The Kcentra group also received less packed red blood cells on bypass and less packed red blood cells after cardiopulmonary bypass termination. There were no differences in chest tube output, time to extubation, intensive care unit length of stay, or overall hospital length of stay. Neither group had thromboembolic complications detected during the first seven postoperative days. CONCLUSION: This small retrospective study indicates that preoperative warfarin reversal with Kcentra reduces blood product exposure in pediatric patients with ventricular assist devices undergoing heart transplant.

Fibrinogen Concentrate as an Alternative to Cryoprecipitate in a Postcardiopulmonary Transfusion Algorithm in Infants Undergoing Cardiac Surgery: A Prospective Randomized Controlled Trial.

BACKGROUND: Infants undergoing cardiac surgery are at risk for bleeding and massive transfusion due to an immature coagulation system, complex surgeries, and cardiopulmonary bypass (CPB) effects. Hemodilution from CPB promotes an acquired hypofibrinogenemia that results in impaired fibrin formation, inadequate clot formation, and increased bleeding. In North America, the current standard of care to supplement fibrinogen is cryoprecipitate. An alternative option is the off-label use of fibrinogen concentrate (FC; RiaSTAP; CSL Behring, Marburg, Germany), a purified fibrinogen. Because perioperative allogenic transfusions are associated with increased morbidity and mortality, we sought to determine whether FC would be an acceptable alternative to cryoprecipitate in a post-CPB transfusion algorithm in infants undergoing open-heart surgery. METHODS: We randomized 60 infants (<12 months) undergoing nonemergent cardiac surgery with CPB at 2 tertiary care children's hospitals to receive either cryoprecipitate or FC in a post-CPB transfusion algorithm. Infants underwent a stratified randomization based on institution and surgical complexity. The primary outcome was the difference in number of intraoperative allogenic blood product transfusions. Secondary outcomes included 24-hour chest tube output (CTO), mechanical ventilation time, adverse events (AEs), intensive care unit (ICU) length of stay (LOS), hospital LOS, postoperative thrombosis, and death within 30 days of surgery. The primary analysis followed the intent-to-treat (ITT) principle and was performed using linear regression adjusted for institution and complexity of surgery. A per-protocol (PP) analysis was also performed. RESULTS: Between June 2016 and January 2018, we enrolled 60 patients with complete data available for 25 patients who received cryoprecipitate and 29 patients who received FC. Patients in the cryoprecipitate group (median age: 4 months [2-6 months]) received 5.5 (4.0-7.0) allogeneic blood units in the ITT analysis and 6.0 units (5.0-7.0 units) in the PP analysis. Patients in the FC group (median age: 4 months [2-5]) received 4 units (3.0-5.0 units) in the ITT analysis and 4.0 units (3.0-5.0 units) in the PP analysis. In the adjusted ITT analysis, the FC group received 1.79 units (95% confidence interval [CI], 0.64-2.93; P = .003) less than the cryoprecipitate group. In the adjusted PP analysis, the FC group received 2.67 units (95% CI, 1.75-3.59; P < .001) less than the cryoprecipitate group. There were no significant differences in secondary outcomes or AEs. CONCLUSIONS: Our findings suggest that FC may be considered as an alternative to cryoprecipitate for the treatment of hypofibrinogenemia in infants with bleeding after CPB. Although we found no significant differences between secondary outcomes or AEs, further studies are needed to assess safety.

Evolving pediatric epidural practice: An institution's clinical experience over 20 years-A retrospective observational cohort study.

BACKGROUND AND OBJECTIVES: Epidural analgesia is an effective, established perioperative intervention in all age-groups. In children, however, epidural-related data are limited compared to the adult population. The aim of this study was to examine the use of pediatric epidural analgesia in our institution and, thereby, add to the existing data pool. METHODOLOGY: Patients who received epidural analgesia as part of their perioperative management between 1996 and 2016 at Great Ormond Street Hospital, London, UK, were studied to determine how epidural practice has changed over time, associated incidence of serious adverse events, complications, and patient/parent satisfaction. Epidural use and monitoring were in accordance with standard hospital protocols. Data were prospectively collected and entered into a secure database by trained personnel. These data were subsequently extracted for retrospective analysis. RESULTS: A total of 3876 patients were included. The median age was 4.4 years (range 1 day to 20 years), and the median weight was 20.3 kg. Across all age-groups, the lumbar region was the most common site of epidural insertion while urology (42.2%) and general surgery (37.3%) were the specialities for which it was most utilized. Over the study period, the number of epidurals performed declined while the number of surgical procedures performed simultaneously increased. The infusate most commonly used was local anesthetic with preservative-free morphine (71.9%). In 923 (23.2%) patients, systemic opioids were additionally used for analgesic management by means of patient-controlled analgesia or nurse-controlled analgesia. There was one serious adverse event in the form of permanent nerve injury, giving an overall incidence of approximately 1:3800. Other complications included postoperative nausea and vomiting (35.9%), urinary retention (4.4%), and pruritus (31%). Overall global satisfaction with the service was generally high, with 95% providing a rating of "very good" or "good." CONCLUSION: This study evaluated two decades of epidural practice in our institution. Epidural analgesia remains a safe, effective option for postoperative analgesia, but its use has declined over time, and this trend is likely to continue. Rates of serious adverse events and complications were low and comparable to those published in other similar studies. Global satisfaction among patients/parents remains high.

STAC3 variants cause a congenital myopathy with distinctive dysmorphic features and malignant hyperthermia susceptibility.

SH3 and cysteine-rich domain-containing protein 3 (STAC3) is an essential component of the skeletal muscle excitation-contraction coupling (ECC) machinery, though its role and function are not yet completely understood. Here, we report 18 patients carrying a homozygous p.(Trp284Ser) STAC3 variant in addition to a patient compound heterozygous for the p.(Trp284Ser) and a novel splice site change (c.997-1G > T). Clinical severity ranged from prenatal onset with severe features at birth, to a milder and slowly progressive congenital myopathy phenotype. A malignant hyperthermia (MH)-like reaction had occurred in several patients. The functional analysis demonstrated impaired ECC. In particular, KCl-induced membrane depolarization resulted in significantly reduced sarcoplasmic reticulum Ca2+ release. Co-immunoprecipitation of STAC3 with CaV 1.1 in patients and control muscle samples showed that the protein interaction between STAC3 and CaV 1.1 was not significantly affected by the STAC3 variants. This study demonstrates that STAC3 gene analysis should be included in the diagnostic work up of patients of any ethnicity presenting with congenital myopathy, in particular if a history of MH-like episodes is reported. While the precise pathomechanism remains to be elucidated, our functional characterization of STAC3 variants revealed that defective ECC is not a result of CaV 1.1 sarcolemma mislocalization or impaired STAC3-CaV 1.1 interaction.

Epoprostenol Therapy for a Pediatric Patient With Subacute Heparin-Induced Thrombocytopenia and a Ventricular Assist Device Undergoing Heart Transplant: A Case Report.

Concerns remain regarding the use of direct thrombin inhibitors for cardiopulmonary bypass anticoagulation in pediatric patients with heparin-induced thrombocytopenia undergoing complex cardiac surgery. We describe the safe and effective use of epoprostenol sodium as an alternative therapy before heparin exposure for a pediatric patient with subacute heparin-induced thrombocytopenia and a ventricular assist device undergoing heart transplant.

Current use of factor concentrates in pediatric cardiac anesthesia.

Excessive bleeding following pediatric cardiopulmonary bypass is associated with increased morbidity and mortality, both from the effects of hemorrhage and the therapies employed to achieve hemostasis. Neonates and infants are especially at risk because their coagulation systems are immature, surgeries are often complex, and cardiopulmonary bypass technologies are inappropriately matched to patient size and physiology. Consequently, these young children receive substantial amounts of adult-derived blood products to restore adequate hemostasis. Adult and pediatric data demonstrate associations between blood product transfusions and adverse patient outcomes. Thus, efforts to limit bleeding after pediatric cardiopulmonary bypass and minimize allogeneic blood product exposure are warranted. The off-label use of factor concentrates, such as fibrinogen concentrate, recombinant activated factor VII, and prothrombin complex concentrates, is increasing as these hemostatic agents appear to offer several advantages over conventional blood products. However, recognizing that these agents have the potential for both benefit and harm, well-designed studies are needed to enhance our knowledge and to determine the optimal use of these agents. In this review, our primary objective was to examine the evidence regarding the use of factor concentrates to treat bleeding after pediatric CPB and identify where further research is required. PubMed, MEDLINE/OVID, The Cochrane Library and the Cochrane Central Register of Controlled Trials (CENTRAL) were systematically searched to identify existing studies.

Persistent postsurgical pain in children and young people: prediction, prevention, and management.

Ensuring optimum preoperative and postoperative pain management should always be a priority in children.

NMR backbone resonance assignment and solution secondary structure determination of human NSD1 and NSD2.

Proteins of the NSD family are histone-methyl transferases with critical functions in the regulation of chromatin structure and function. NSD1 and NSD2 are homologous proteins that function as epigenetic regulators of transcription through their abilities to catalyse histone methylation. Misregulation of NSD1 and NSD2 expression or mutations in their genes are linked to a number of human diseases such as Sotos syndrome, and cancers including acute myeloid leukemia, multiple myeloma, and lung cancer. The catalytic domain of both proteins contains a conserved SET domain which is involved in histone methylation. Here we report the backbone resonance assignments and secondary structure information of the catalytic domains of human NSD1 and NSD2.

Perioperative management of pediatric en-bloc combined heart-liver transplants: a case series review.

BACKGROUND: Combined heart and liver transplantation (CHLT) in the pediatric population involves a complex group of patients, many of whom have palliated congenital heart disease (CHD) involving single ventricle physiology. OBJECTIVE: The purpose of this study was to describe the perioperative management of pediatric patients undergoing CHLT at a single institution and to identify management strategies that may be used to optimize perioperative care. METHODS: We did a retrospective database review of all patients receiving CHLT at a children's hospital between 2006 and 2014. Information collected included preoperative characteristics, intraoperative management, blood transfusions, and postoperative morbidity and mortality. RESULTS: Five pediatric CHLTs were performed over an 8-year period. All patients had a history of complex CHD with multiple sternotomies, three of whom had failing Fontan physiology. Patient age ranged from 7 to 23 years and weight from 29.5 to 68.5 kg. All CHLTs were performed using an en-bloc technique where both the donor heart and liver were implanted together on cardiopulmonary bypass (CPB). The median operating room time was 14.25 h, median CPB time was 3.58 h, and median donor ischemia time was 4.13 h. Patients separated from CPB on dopamine, epinephrine, and milrinone infusions and two required inhaled nitric oxide. All patients received a massive intraoperative blood transfusion post CPB with amounts ranging from one to three times the patient's estimated blood volume. The patient who required the most transfusions was in decompensated heart and liver failure preoperatively. Four of the five patients received an antifibrinolytic agent as well as a procoagulant (prothrombin complex concentrate or recombinant activated Factor VII) to assist with hemostasis. There were no 30-day thromboembolic events detected. Postoperatively the median length of mechanical ventilation, ICU stay and stay to hospital discharge was 4, 8, and 37 days, respectively. All patients are alive and free from allograft rejection at this time. CONCLUSION: Combined heart and liver transplantation in the pediatric population involves a complex group of patients with unique perioperative challenges. Successful management starts with thorough preoperative planning and communication and involves strategies to deal with massive intraoperative hemorrhage and coagulopathy in addition to protecting and supporting the transplanted heart and liver and meticulous surgical technique. An integrated multidisciplinary team approach is the cornerstone for successful outcomes.

1H, 15N and 13C backbone assignments of GDP-bound human H-Ras mutant G12V.

Harvey Ras (H-Ras) is a membrane-associated GTPase with critical functions in cell proliferation and differentiation. The G12V mutant of H-Ras is one of the most commonly encountered oncoproteins in human cancer. This mutation disrupts the GTPase activity of H-Ras, leading to constitutive activation and aberrant downstream signalling. Here we report the backbone resonance assignments of human H-Ras mutant G12V lacking the C-terminal membrane attachment domain.

The prevalence of pain at home and its consequences in children following two types of short stay surgery: a multicenter observational cohort study.

BACKGROUND: The potential for pain at home in children following day case surgery has long been recognized. Pain has also been associated with behavioral disturbances and sleep disruption in children following surgery and may also impact negatively on recovery, parental and patient satisfaction, family life, healthcare use, and have an economic cost. AIM: To investigate the prevalence of pain at home, and its consequences, in children following two types of short stay surgery across eight pediatric centers in the UK in an observational cohort study. Reporting of the study was done in adherence with STROBE guidelines. METHOD: Two hundred and forty-one children undergoing either Tonsillectomy with or without Adenoidectomy (T's ± A's) or Orchidopexy surgery (either by Open or Laparoscopic) were recruited. Data collection was via three structured telephone interviews [Day (D) 2, 7 and 14] conducted from a clinical research facility. The normal clinical practices of the centers involved in the study were not altered in any way. Outcomes studied were (i) Pain incidence and severity; (ii) Associated consequences-incidence of psychological disturbances, unplanned use of healthcare services, and social/economic cost to families; and (iii) Comparative pain and associated outcomes for two types of surgery (T's ± A's vs Orchidopexy). RESULTS: The incidence of pain following both operative models was high though it differed between the two groups. In the T's ± A's group, the incidence of pain was high throughout the study period (D2 90.1%, D3-7 88.1%, D8-14 61.8%). The Orchidopexy group demonstrated a similar pattern, though with decreased rates (D2 70.4%, D3-7 34.7%, D8-14 17.1%). Both groups showed similar patterns for the rates of behavioral disturbances (T's & A's: D2 76%, D3-7 73%, D8-14 30% and Orchidopexy: D2 37%, D3-7 20%, D8-14 10%). Seventy percent of the families reported unplanned healthcare use with pain the primary reason in 79% of these. CONCLUSIONS: The prevalence of pain at home, and its potential associated consequences, is high following short stay surgery in children in the UK. In both groups, high incidences were seen for longer periods than is commonly perceived. These findings were consistent between the centers involved suggesting that this is a significant national healthcare issue with potential short- and long-term consequences for the child, their family, and health services.

Fragment-Based Drug Discovery Targeting Inhibitor of Apoptosis Proteins: Discovery of a Non-Alanine Lead Series with Dual Activity Against cIAP1 and XIAP.

Inhibitor of apoptosis proteins (IAPs) are important regulators of apoptosis and pro-survival signaling pathways whose deregulation is often associated with tumor genesis and tumor growth. IAPs have been proposed as targets for anticancer therapy, and a number of peptidomimetic IAP antagonists have entered clinical trials. Using our fragment-based screening approach, we identified nonpeptidic fragments binding with millimolar affinities to both cellular inhibitor of apoptosis protein 1 (cIAP1) and X-linked inhibitor of apoptosis protein (XIAP). Structure-based hit optimization together with an analysis of protein-ligand electrostatic potential complementarity allowed us to significantly increase binding affinity of the starting hits. Subsequent optimization gave a potent nonalanine IAP antagonist structurally distinct from all IAP antagonists previously reported. The lead compound had activity in cell-based assays and in a mouse xenograft efficacy model and represents a highly promising start point for further optimization.

Exploring weak ligand-protein interactions by long-lived NMR states: improved contrast in fragment-based drug screening.

Ligands that have an affinity for protein targets can be screened very effectively by exploiting favorable properties of long-lived states (LLS) in NMR spectroscopy. In this work, we describe the use of LLS for competitive binding experiments to measure accurate dissociation constants of fragments that bind weakly to the ATP binding site of the N-terminal ATPase domain of heat shock protein 90 (Hsp90), a therapeutic target for cancer treatment. The LLS approach allows one to characterize ligands with an exceptionally wide range of affinities, since it can be used for ligand concentrations [L] that are several orders of magnitude smaller than the dissociation constants K(D). This property makes the LLS method particularly attractive for the initial steps of fragment-based drug screening, where small molecular fragments that bind weakly to a target protein must be identified, which is a difficult task for many other biophysical methods.

Development and implementation of a new data registry in congenital cardiac anesthesia.

A new multisite registry for congenital cardiac anesthesia patients has now been incorporated into The Society of Thoracic Surgeons Congenital Heart Surgery Database. This new registry, "The Joint Congenital Cardiac Anesthesia Society-Society of Thoracic Surgeons Congenital Cardiac Anesthesia Database," is part of the Congenital Cardiac Anesthesia Society's commitment to patient care and research on outcomes improvement. This report will review the planning and funding of the initial start-up as well as the data elements being used in the registry. Patients in the registry include not only cardiac surgical patients but also those with congenital heart disease undergoing procedures in locations other than the operating room, including in the cardiac catheterization laboratory, intensive care unit, general operating room, and radiology suite. Initial results from the first data harvests are reported, including site participation, patient population submitted, and adverse outcomes observed. These initial results validate the concept and serve as a benchmark for further development and implementation of the registry. Because of the relative infrequency of anesthesia-related events in this low-volume procedure, a multisite data harvest is the most reasonable approach to capture a sufficient number of patient encounters in a timely manner to support outcomes analysis, quality assessment, and quality improvement.

Case report: airway and concurrent hemodynamic management in a neonate with oculo-auriculo-vertebral (Goldenhar) syndrome, severe cervical scoliosis, interrupted aortic arch, multiple ventricular septal defects, and an unstable cervical spine.

We report the challenging case of a 1-week-old, term, 2.4 kg neonate with Goldenhar syndrome (including microcephaly, left microtia, left facial palsy, dextro-scoliosis of the cervical spine, and cervico-thoracic levoscoliosis), multiple ventricular septal defects, a type B interrupted aortic arch, a large patent ductus arteriosis, and radiographic and clinical signs concerning for an unstable cervical spine. Our anesthesia team was consulted for perioperative management of this patient during her surgical repair. This case report describes the use of the Air-Q size 1 laryngeal airway (LA) to assist fiberoptic intubation in an ASA 4 neonate with cardiac disease, an anticipated difficult airway with the addition of an unstable cervical spine, as well as the anesthetic techniques used to maintain hemodynamic stability while the airway was secured.

Review of the off-label use of recombinant activated factor VII in pediatric cardiac surgery patients.

In recent years the off-label use of recombinant activated factor VII (rFVIIa) has markedly increased, particularly in pediatric cardiac surgery patients, and practitioners differ widely in their usage of the drug. In 2009, the Congenital Cardiac Anesthesia Society (CCAS) assembled a task force to review the literature on rFVIIa administration to pediatric cardiac surgery patients. The goal of the CCAS Task Force was to assess current practices and make recommendations about rFVIIa therapy to enhance quality of care, improve patient outcomes, reduce costs, and develop future research. In this review we summarized the important topics on current administration of rFVIIa to pediatric cardiac surgery patients including indications for use, efficacy, safety, dosing, and monitoring. All pediatric and pertinent adult literature regarding the administration of rFVIIa to cardiac surgical patients and published since 2000 were selected and studied. Of the 40 pediatric publications reviewed for this report, only 1 was a prospective randomized controlled trial thus making determinations of efficacy difficult. There is no substantive evidence to support the efficacy of rFVIIa as prophylactic or routine therapy during pediatric cardiac surgery. It may prove reasonable as rescue therapy because current observational evidence suggests that potential benefits of rFVIIa for this indication might outweigh the risks. Rescue therapy is appropriate for bleeding that is massive, potentially life-threatening, and refractory to conventional therapy. Nevertheless, extreme caution is advised when considering the administration of rFVIIa to patients who are at risk for thromboembolic complications because rates for clinical and subclinical thrombosis secondary to rFVIIa therapy are unknown at this time. This review is designed to aid practitioners in deciding when and how to administer rFVIIa to pediatric cardiac surgery patients; it is not intended to determine standard-of-care or practice guidelines. There are insufficient data to make evidence-based recommendations. Randomized controlled trials are needed to assess the efficacy of rFVIIa as prophylactic, routine, or rescue therapy and to determine the drug's safety profile particularly with regard to thrombosis. The CCAS rFVIIa Task Force will continue to monitor the literature, gather data, and make updates as more information becomes available.

Fragment-Based Discovery of 7-Azabenzimidazoles as Potent, Highly Selective, and Orally Active CDK4/6 Inhibitors.

Herein, we describe the discovery of potent and highly selective inhibitors of both CDK4 and CDK6 via structure-guided optimization of a fragment-based screening hit. CDK6 X-ray crystallography and pharmacokinetic data steered efforts in identifying compound 6, which showed >1000-fold selectivity for CDK4 over CDKs 1 and 2 in an enzymatic assay. Furthermore, 6 demonstrated in vivo inhibition of pRb-phosphorylation and oral efficacy in a Jeko-1 mouse xenograft model.