HCC screening with ultrasound: assessment of quality using ultrasound LI-RADS score.

PURPOSE: To describe ultrasound (US) quality for hepatocellular carcinoma (HCC) screening/surveillance using the US LI-RADS scoring system, and to assess predictive factors of worse US quality scores. METHODS: This retrospective study included adult patients (n = 470; M/F 264/206, median age 59y) at risk for HCC that underwent US for HCC screening/surveillance. US examinations were independently reviewed by 2 radiologists that assigned a visualization score (A: no/minimal, B: moderate, C: severe limitation) and US diagnostic category (US LI-RADS 1: negative, US LI-RADS 2: subthreshold, US LI-RADS 3: positive) to each study. A generalized linear mixed model was used to assess the predictive factors of worse visualization score using OR (odds ratio) statistics. Simple Kappa coefficient (K) assessed inter-reader agreement. RESULTS: For readers 1 and 2, 295/320 (62.8%/68.1%) cases were scored A, 153/134 (32.6%/28.5%) were scored B, and 22/16 (4.6%/3.4%) were scored C, respectively. There was moderate inter-reader agreement for US LI-RADS visualization score (K = 0.478) and 100% concordance for US diagnostic category (K = 1), with 30 (6.4%) cases scored as positive (US LI-RADS 3). Cirrhosis and obesity were significant independent predictors of worse visualization scores (B/C) (cirrhosis: OR 10.4 confidence intervals: [4.25-25.48], p < 0.001; obesity: OR 3.61 [2.11-6.20], p < 0.001). Of the 30 lesions scored as US LI-RADS 3, 9 were characterized as probable or definite HCC on confirmatory CT/MRI, yielding a PPV of 30% (9/30) and a false-positive rate of 70% (21/30). CONCLUSION: Moderate to severe limitations in quality of US performed for HCC screening/surveillance was observed in approximately one-third of patients. Patients with cirrhosis and/or elevated BMI have poorer quality US studies and may benefit from other screening modalities such as CT or MRI.

Comparative assessment of standard and immune response criteria for evaluation of response to PD-1 monotherapy in unresectable HCC.

PURPOSE: To assess response to programmed death-1 (PD-1) monotherapy (nivolumab) in hepatocellular carcinoma (HCC) patients using RECIST1.1, modified RECIST (mRECIST), and immune RECIST (iRECIST). A secondary objective was to identify clinicolaboratory and imaging variables predictive of progressive disease (PD) and overall survival (OS). METHODS: Patients with HCC treated with nivolumab at a single institution from 5/2016 to 12/2019 with MRI or CT performed ≥ 4 weeks post treatment were retrospectively assessed. Patients who received concurrent locoregional, radiation, or other systemic therapies were excluded. Response was assessed by 2 observers in consensus using RECIST1.1, mRECIST, and iRECIST at 3/6/9/12-month time points. Time to progression (TTP) and OS were recorded. Clinicolaboratory and imaging variables were evaluated as predictors of PD and OS using uni-/multivariable and Cox regression analyses. RESULTS: Fifty-eight patients (42M/16F) were included. 118 target lesions (TL) were identified before treatment. Baseline mean TL size was 49.1 ± 43.5 mm (range 10-189 mm) for RECIST1.1/iRECIST and 46.3 ± 42.3 mm (range 10-189 mm) for mRECIST. Objective response rate (ORR) was 21% for mRECIST/iRECIST/RECIST1.1, with no cases of pseudoprogression. Median OS and median TTP were 717 days and 127 days for RECIST1.1/mRECIST/iRECIST-iUPD (unconfirmed PD). Older age, MELD/Child-Pugh scores, AFP, prior transarterial radioembolization (TARE), and larger TL size were predictive of PD and/or poor OS using mRECIST/iRECIST. The strongest predictor of PD (HR = 2.49, 95% CI 1.29-4.81, p = 0.007) was TARE. The strongest predictor of poor OS was PD by mRECIST/iRECIST at 3 months (HR = 2.26, 95% CI 1.00-5.10, p = 0.05) with borderline significance. CONCLUSION: Our results show ORR of 21%, equivalent for mRECIST, iRECIST, and RECIST1.1 in patients with advanced HCC clinically treated with nivolumab.

Outcomes assessment in intrahepatic cholangiocarcinoma using qualitative and quantitative imaging features.

BACKGROUND: To assess the performance of imaging features, including radiomics texture features, in predicting histopathologic tumor grade, AJCC stage, and outcomes [time to recurrence (TTR) and overall survival (OS)] in patients with intrahepatic cholangiocarcinoma (ICC). METHODS: Seventy-three patients (26 M/47F, mean age 63y) with pre-operative imaging (CT, n = 37; MRI, n = 21; CT and MRI, n = 15] within 6 months of resection were included in this retrospective study. Qualitative imaging traits were assessed by 2 observers. A 3rd observer measured tumor apparent diffusion coefficient (ADC), enhancement ratios (ERs), and Haralick texture features. Blood biomarkers and imaging features were compared with histopathology (tumor grade and AJCC stage) and outcomes (TTR and OS) using log-rank, generalized Wilcoxon, Cox proportional hazards regression, and Fisher exact tests. RESULTS: Median TTR and OS were 53.9 and 79.7 months. ICC recurred in 64.4% (47/73) of patients and 46.6% (34/73) of patients died. There was fair accuracy for some qualitative imaging features in the prediction of worse tumor grade (maximal AUC of 0.68 for biliary obstruction on MRI, p = 0.032, observer 1) and higher AJCC stage (maximal AUC of 0.73 for biliary obstruction on CT, p = 0.002, observer 2; and AUC of 0.73 for vascular involvement on MRI, p = 0.01, observer 2). Cox proportional hazards regression analysis showed that CA 19-9 [hazard ratio (HR) 2.44/95% confidence interval (CI) 1.31-4.57/p = 0.005)] and tumor size on imaging (HR 1.13/95% CI 1.04-1.22/p = 0.003) were significant predictors of TTR, while CA 19-9 (HR 4.08/95% CI 1.75-9.56, p = 0.001) and presence of metastatic lymph nodes at histopathology (HR 2.86/95% CI 1.35-6.07/p = 0.006) were significant predictors of OS. On multivariable analysis, satellite lesions on CT (HR 2.79/95%CI 1.01-7.15/p = 0.032, observer 2), vascular involvement on MRI (HR 0.10/95% CI 0.01-0.85/p = 0.032, observer 1), and texture feature MRI variance (HR 0.55/95% CI 0.31-0.97, p = 0.040) predicted TTR once adjusted for the independent predictors CA 19-9 and tumor size on imaging. Several qualitative and quantitative features demonstrated associations with TTR, OS, and AJCC stage at univariable analysis (range: HR 0.35-19; p < 0.001-0.045), however none were predictive of OS at multivariable analysis when adjusted for CA 19-9 and metastatic lymph nodes (p > 0.088). CONCLUSIONS: There was reasonable accuracy in predicting tumor grade and higher AJCC stage in ICC utilizing certain qualitative and quantitative imaging traits. Serum CA 19-9, tumor size, presence of metastatic lymph nodes, and qualitative imaging traits of satellite lesions and vascular involvement are predictors of patient outcomes, along with a promising predictive ability of certain quantitative texture features.

Drug therapies for chronic hepatitis C infection: a cost-effectiveness analysis.

BACKGROUND: Before 2011, pegylated interferon plus ribavirin was the standard therapy for chronic hepatitis C. Interferon-free direct-acting antiviral agents were then approved. Although these treatments appear to be more effective, they are substantially more expensive. In anticipation of the need for information regarding the comparative cost-effectiveness of new regimens in a recent therapeutic review, we conducted the analysis to inform listing decision in Canada. METHODS: A state-transition model was developed in the form of a cost-utility analysis. Regimens included in the analysis were comprehensive. The cohort under consideration had a mean age of 50 years. The cohort was defined by treatment status and cirrhosis status. Inputs for the model were derived from published sources and validated by clinical experts. RESULTS: For each genotype 1 population, at least 1 of the interferon-free agents appeared to be economically attractive compared with pegylated interferon-ribavirin, at a willingness-to-pay of $50 000 per quality-adjusted life-year. The drug that was the most cost-effective varied by population. For genotype 2-4 population, the direct-acting antiviral therapies appeared not to be economically attractive compared with pegylated interferon-ribavirin for the treatment-naive; however, there were direct-acting antiviral therapies that appeared to be attractive when compared with no treatment for the treatment-experienced. INTERPRETATION: Public health policy should be informed by consideration of health benefit, social and ethical values, feasibility and cost-effectiveness. Our analysis assists the development of reimbursements and policies for interferon-free direct-acting antiviral agent regimens for chronic hepatitis C infection by informing the last criterion. Considering the rapid development of treatments for chronic hepatitis C, further update and expanded reviews will be necessary.

Hepatocellular carcinoma: IVIM diffusion quantification for prediction of tumor necrosis compared to enhancement ratios.

PURPOSE: To correlate intra voxel incoherent motion (IVIM) diffusion parameters of liver parenchyma and hepatocellular carcinoma (HCC) with degree of liver/tumor enhancement and necrosis; and to assess the diagnostic performance of diffusion parameters vs. enhancement ratios (ER) for prediction of complete tumor necrosis. PATIENTS AND METHODS: In this IRB approved HIPAA compliant study, we included 46 patients with HCC who underwent IVIM diffusion-weighted (DW) MRI in addition to routine sequences at 3.0 T. True diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion fraction (PF) and apparent diffusion coefficient (ADC) were quantified in tumors and liver parenchyma. Tumor ER were calculated using contrast-enhanced imaging, and degree of tumor necrosis was assessed using post-contrast image subtraction. IVIM parameters and ER were compared between HCC and background liver and between necrotic and viable tumor components. ROC analysis for prediction of complete tumor necrosis was performed. RESULTS: 79 HCCs were assessed (mean size 2.5 cm). D, PF and ADC were significantly higher in HCC vs. liver (p < 0.0001). There were weak significant negative/positive correlations between D/PF and ER, and significant correlations between D/PF/ADC and tumor necrosis (for D, r 0.452, p < 0.001). Among diffusion parameters, D had the highest area under the curve (AUC 0.811) for predicting complete tumor necrosis. ER outperformed diffusion parameters for prediction of complete tumor necrosis (AUC > 0.95, p < 0.002). CONCLUSION: D has a reasonable diagnostic performance for predicting complete tumor necrosis, however lower than that of contrast-enhanced imaging.

Lymph nodes can accurately be measured on PET-CT for lymphoma staging/restaging without a concomitant contrast enhanced CT scan.

Dual imaging with both contrast enhanced CT scan and PET-CT is recommended for evaluation of lymphoma. We compared the performance in identification and size measurements of involved lymph nodes in FDG-avid lymphomas on the low dose non-contrast enhanced CT of a PET-CT scan with those on a diagnostic contrast enhanced CT scan. The size of FDG-avid lymph nodes was measured in both the short and long axis on both the low dose non-contrast CT of the PET-CT and the contrast enhanced CT by two independent readers. A total of 307 FGD avid lymph nodes were identified in 52 patients. There was no statistically significant differences in the measured size of the nodes on the non-contrast and contrast enhanced scans (p=0.21). Baseline staging and restaging of FDG-avid lymphomas can be performed with one test, PET-CT, without an accompanying contrast enhanced CT scan, with no effect on the measured nodal size.

Phase 2 trial of the topoisomerase II inhibitor, amrubicin, as second-line therapy in patients with metastatic urothelial carcinoma.

PURPOSE: The purpose of this investigator-initiated multicenter phase II study was to determine the activity of the third-generation synthetic anthracycline, amrubicin, administered as second-line therapy in patients with advanced urothelial carcinoma. METHODS: Patients with progressive metastatic urothelial cancer despite first-line chemotherapy were eligible for enrollment. Amrubicin was initially administered at a dose of 40 mg/m(2)/day daily × 3 every 21 days, and the dose was subsequently reduced to 35 mg/m(2)/day daily × 3 every 21 days. Prophylactic granulocyte colony-stimulating factor was administered to all patients, and prophylactic antibiotics were administered to patients at high risk of febrile neutropenia. Treatment was administered for up to six cycles in the absence of intolerable toxicity or disease progression. The primary endpoint was the objective response rate. RESULTS: A total of 22 patients were enrolled. Among the first three patients enrolled, all developed grade 4 neutropenia and one patient died of neutropenic sepsis. The starting dose of amrubicin was subsequently reduced, there were no further episodes of febrile neutropenia, and only one patient required a subsequent dose reduction. The most common adverse events were hematologic; grade ≥3 neutropenia occurred in 27 %, and other grade ≥3 adverse events were uncommon. Partial responses were achieved in three patients [13.6, 95 % confidence interval (CI) 0-28 %), while stable disease was the best response in 12 patients (54.5, 95 % CI 33.7-75.3 %). The trial was closed prematurely due to a development decision by the funder. CONCLUSIONS: Amrubicin as second-line therapy in advanced urothelial carcinoma is associated with modest single-agent activity. While there remains a role for the introduction of novel cytotoxic agents in the management of metastatic urothelial cancer, optimal development of such therapies will likely require patient selection biomarkers.

Yttrium-90 Glass-Based Microsphere Radioembolization in the Treatment of Hepatocellular Carcinoma Secondary to the Hepatitis B Virus: Safety, Efficacy, and Survival.

PURPOSE: To evaluate outcomes of yttrium-90 radioembolization performed with glass-based microspheres in the treatment of hepatocellular carcinoma (HCC) secondary to the hepatitis B virus (HBV). MATERIALS AND METHODS: A total of 675 patients treated between January 2006 and July 2014 were reviewed, of which 45 (age 62 y ± 10; 91% male) received glass-based radioembolization for HCC secondary to HBV. All patients were stratified according to previous therapy (naive, n = 14; 31.1%), Child-Pugh class (class A, n = 41; 91%), Eastern Cooperative Oncology Group (ECOG) performance status (PS; < 1, n = 21; 47%), solitary (n = 26; 58%) and unilobar (n = 37; 82%) tumor distribution, tumor size < 5 cm (n = 29; 64%), portal vein thrombosis (n = 14; 31%), α-fetoprotein level > 400 ng/mL (n = 17; 38%), and Barcelona Clinic Liver Cancer stage (A, n = 8; B, n = 9; C, n = 28). RESULTS: A total of 50 radioembolization treatments were performed, with a 100% technical success rate (median target dose, 120 Gy). Clinical toxicities included pain (16%), fatigue (12%), and nausea (4%). Grade 3/4 laboratory toxicities included bilirubin (8%) and aspartate aminotransferase (4%) toxicities. Observed toxicities were independent of treatment dose. The objective response rates were 55% per modified Response Evaluation Criteria In Solid Tumors and 21% per World Health Organization criteria, and the disease control rate was 63%. Disease progression was secondary to new, nontarget HCC in 45% of cases. Median time to progression and overall survival were 6.0 mo (95% confidence interval [CI], 4.4-8.0 mo) and 19.3 mo (95% CI, 11.2-22.7 mo), respectively. Multivariate analysis demonstrated ECOG PS ≥ 1 and AFP level > 400 ng/mL to be independent predictors of inferior overall survival. CONCLUSIONS: Glass-based radioembolization for HCC secondary to HBV can be safely performed, with favorable target lesion response and overall survival.

Reimbursement-Based Economics--What Is It and How Can We Use It to Inform Drug Policy Reform?

BACKGROUND: In Ontario, approximately $3.8 billion is spent annually on publicly funded drug programs. The annual growth in Ontario Public Drug Program (OPDP) expenditure has been limited to 1.2% over the course of 3 years. Concurrently, the Ontario Drug Policy Research Network (ODPRN) was appointed to conduct drug class review research relating to formulary modernization within the OPDP. Drug class reviews by ODPRN incorporate a novel methodological technique called reimbursement-based economics, which focuses on reimbursement strategies and may be particularly relevant for policy-makers. OBJECTIVES: To describe the reimbursement-based economics approach. METHODS: Reimbursement-based economics aims to identify the optimal reimbursement strategy for drug classes by incorporating a review of economic literature, comprehensive budget impact analyses, and consideration of cost-effectiveness. This 3-step approach is novel in its focus on the economic impact of alternate reimbursement strategies rather than individual therapies. RESULTS: The methods involved within the reimbursement-based approach are detailed. To facilitate the description, summary methods and findings from a recent application to formulary modernization with respect to the drug class tryptamine-based selective serotonin receptor agonists (triptans) used to treat migraine headaches are presented. CONCLUSIONS: The application of reimbursement-based economics in drug policy reforms allows policy-makers to consider the cost-effectiveness and budget impact of different reimbursement strategies allowing consideration of the trade-off between potential cost savings vs increased access to cost-effective treatments.

Phase Ib/II trial of gemcitabine, cisplatin, and lenalidomide as first-line therapy in patients with metastatic urothelial carcinoma.

BACKGROUND: Outcomes with current chemotherapy in metastatic urothelial carcinoma (MUC) remain poor. Lenalidomide, an antiangiogenic and immunomodulatory agent, enhances the effects of chemotherapy in preclinical studies. In this phase Ib/II study, we sought to determine a tolerable dose of lenalidomide in combination with gemcitabine and cisplatin (GCL) in patients with MUC and to explore the safety and activity of this regimen. METHODS: Patients with chemotherapy-naïve MUC received gemcitabine 1,000 mg/m(2) on days 1 and 8 and cisplatin 70 mg/m(2) on day 1 every 21 days. In phase Ib, there were four planned escalating dose levels of lenalidomide (10, 15, 20, and 25 mg) daily on days 1-14. RESULTS: Seven patients received GCL in phase Ib. The dose of lenalidomide was not escalated beyond 10 mg because of cytopenias requiring repeated dose delays and reductions. Two additional patients were enrolled in phase II, but the study was ultimately terminated due to poor tolerability and slow accrual. The most frequent grade ≥ 3 adverse events were cytopenias and diarrhea. Three of the nine patients experienced an objective response (one complete response, two partial responses). CONCLUSION: Chronic administration of the GCL regimen was poorly tolerated because of additive and cumulative myelosuppression.

Phase Ib study of dovitinib in combination with gemcitabine plus cisplatin or gemcitabine plus carboplatin in patients with advanced solid tumors.

PURPOSE: Dovitinib is a small molecule kinase inhibitor with activity against the fibroblast growth factor and vascular endothelial growth factor receptor families. The purpose of this phase Ib study was to define the recommended phase 2 dose of the combinations of gemcitabine and cisplatin or gemcitabine and carboplatin plus dovitinib. METHODS: Patients with advanced solid tumors were enrolled in two parallel dose escalation arms (cisplatin- or carboplatin-based regimens). Treatment was administered with gemcitabine (1,000 mg/m(2) on days 1 and 8), cisplatin (70 mg/m(2)), or carboplatin (AUC 5) on day 1, and dovitinib (orally on days 1-5, 8-12, and 15-19), every 21 days. The starting dose of dovitinib was 300 mg and was dose escalated in successive cohorts using 3 + 3 dose escalation rules. RESULTS: Fourteen patients with advanced solid tumors were enrolled, five to the cisplatin arm and nine to the carboplatin arm. Patients enrolled in the cisplatin arm received a median of two cycles of treatment (range 1-5), and patients enrolled in the carboplatin arm received a median of one cycle of treatment (range 1-4). There were no protocol-defined dose-limiting toxicities in the cisplatin arm. However, the cohort was closed due to the need for frequent dose delays and/or reductions and two patients experiencing severe thromboembolic events. There were two dose-limiting toxicities in the carboplatin arm at the starting dose level of dovitinib (both prolonged neutropenia), and the dose of dovitinib was de-escalated to 200 mg. Two additional dose-limiting toxicities (prolonged neutropenia and febrile neutropenia) occurred in the lower dose cohort, and the study was closed. No patients achieved an objective response to treatment. CONCLUSIONS: Dovitinib in combination with gemcitabine plus cisplatin or gemcitabine plus carboplatin was poorly tolerated due to myelosuppression.

Comparative health systems research among Kaiser Permanente and other integrated delivery systems: a systematic literature review.

CONTEXT: Because of rising health care costs, wide variations in quality, and increased patient complexity, the US health care system is undergoing rapid changes that include payment reform and movement toward integrated delivery systems. Well-established integrated delivery systems, such as Kaiser Permanente (KP), should work to identify the specific system-level factors that result in superior patient outcomes in response to policymakers' concerns. Comparative health systems research can provide insights into which particular aspects of the integrated delivery system result in improved care delivery. OBJECTIVE: To provide a baseline understanding of comparative health systems research related to integrated delivery systems and KP. DESIGN: Systematic literature review. METHODS: We conducted a literature search on PubMed and the KP Publications Library. Studies that compared KP as a system or organization with other health care systems or across KP facilities internally were included. The literature search identified 1605 articles, of which 65 met the study inclusion criteria and were examined by 3 reviewers. RESULTS: Most comparative health systems studies focused on intra-KP comparisons (n = 42). Fewer studies compared KP with other US (n = 15) or international (n = 12) health care systems. Several themes emerged from the literature as possible factors that may contribute to improved care delivery in integrated delivery systems. CONCLUSIONS: Of all studies published by or about KP, only a small proportion of articles (4%) was identified as being comparative health systems research. Additional empirical studies that compare the specific factors of the integrated delivery system model with other systems of care are needed to better understand the "system-level" factors that result in improved and/or diminished care delivery.

Budget impact analysis-principles of good practice: report of the ISPOR 2012 Budget Impact Analysis Good Practice II Task Force.

BACKGROUND: Budget impact analyses (BIAs) are an essential part of a comprehensive economic assessment of a health care intervention and are increasingly required by reimbursement authorities as part of a listing or reimbursement submission. OBJECTIVES: The objective of this report was to present updated guidance on methods for those undertaking such analyses or for those reviewing the results of such analyses. This update was needed, in part, because of developments in BIA methods as well as a growing interest, particularly in emerging markets, in matters related to affordability and population health impacts of health care interventions. METHODS: The Task Force was approved by the International Society for Pharmacoeconomics and Outcomes Research Health Sciences Policy Council and appointed by its Board of Directors. Members were experienced developers or users of BIAs; worked in academia and industry and as advisors to governments; and came from several countries in North America and South America, Oceania, Asia, and Europe. The Task Force solicited comments on the drafts from a core group of external reviewers and, more broadly, from the membership of the International Society for Pharmacoeconomics and Outcomes Research. RESULTS: The Task Force recommends that the design of a BIA for a new health care intervention should take into account relevant features of the health care system, possible access restrictions, the anticipated uptake of the new intervention, and the use and effects of the current and new interventions. The key elements of a BIA include estimating the size of the eligible population, the current mix of treatments and the expected mix after the introduction of the new intervention, the cost of the treatment mixes, and any changes expected in condition-related costs. Where possible, the BIA calculations should be performed by using a simple cost calculator approach because of its ease of use for budget holders. In instances, however, in which the changes in eligible population size, disease severity mix, or treatment patterns cannot be credibly captured by using the cost calculator approach, a cohort or patient-level condition-specific model may be used to estimate the budget impact of the new intervention, accounting appropriately for those entering and leaving the eligible population over time. In either case, the BIA should use data that reflect values specific to a particular decision maker's population. Sensitivity analysis should be of alternative scenarios chosen from the perspective of the decision maker. The validation of the model should include at least face validity with decision makers and verification of the calculations. Data sources for the BIA should include published clinical trial estimates and comparator studies for the efficacy and safety of the current and new interventions as well as the decision maker's own population for the other parameter estimates, where possible. Other data sources include the use of published data, well-recognized local or national statistical information, and, in special circumstances, expert opinion. Reporting of the BIA should provide detailed information about the input parameter values and calculations at a level of detail that would allow another modeler to replicate the analysis. The outcomes of the BIA should be presented in the format of interest to health care decision makers. In a computer program, options should be provided for different categories of costs to be included or excluded from the analysis. CONCLUSIONS: We recommend a framework for the BIA, provide guidance on the acquisition and use of data, and offer a common reporting format that will promote standardization and transparency. Adherence to these good research practice principles would not necessarily supersede jurisdiction-specific BIA guidelines but may support and enhance local recommendations or serve as a starting point for payers wishing to promulgate methodology guidelines.

A positive feedback loop links opposing functions of P-TEFb/Cdk9 and histone H2B ubiquitylation to regulate transcript elongation in fission yeast.

Transcript elongation by RNA polymerase II (RNAPII) is accompanied by conserved patterns of histone modification. Whereas histone modifications have established roles in transcription initiation, their functions during elongation are not understood. Mono-ubiquitylation of histone H2B (H2Bub1) plays a key role in coordinating co-transcriptional histone modification by promoting site-specific methylation of histone H3. H2Bub1 also regulates gene expression through an unidentified, methylation-independent mechanism. Here we reveal bidirectional communication between H2Bub1 and Cdk9, the ortholog of metazoan positive transcription elongation factor b (P-TEFb), in the fission yeast Schizosaccharomyces pombe. Chemical and classical genetic analyses indicate that lowering Cdk9 activity or preventing phosphorylation of its substrate, the transcription processivity factor Spt5, reduces H2Bub1 in vivo. Conversely, mutations in the H2Bub1 pathway impair Cdk9 recruitment to chromatin and decrease Spt5 phosphorylation. Moreover, an Spt5 phosphorylation-site mutation, combined with deletion of the histone H3 Lys4 methyltransferase Set1, phenocopies morphologic and growth defects due to H2Bub1 loss, suggesting independent, partially redundant roles for Cdk9 and Set1 downstream of H2Bub1. Surprisingly, mutation of the histone H2B ubiquitin-acceptor residue relaxes the Cdk9 activity requirement in vivo, and cdk9 mutations suppress cell-morphology defects in H2Bub1-deficient strains. Genome-wide analyses by chromatin immunoprecipitation also demonstrate opposing effects of Cdk9 and H2Bub1 on distribution of transcribing RNAPII. Therefore, whereas mutual dependence of H2Bub1 and Spt5 phosphorylation indicates positive feedback, mutual suppression by cdk9 and H2Bub1-pathway mutations suggests antagonistic functions that must be kept in balance to regulate elongation. Loss of H2Bub1 disrupts that balance and leads to deranged gene expression and aberrant cell morphologies, revealing a novel function of a conserved, co-transcriptional histone modification.

Separate domains of fission yeast Cdk9 (P-TEFb) are required for capping enzyme recruitment and primed (Ser7-phosphorylated) Rpb1 carboxyl-terminal domain substrate recognition.

In fission yeast, discrete steps in mRNA maturation and synthesis depend on a complex containing the 5'-cap methyltransferase Pcm1 and Cdk9, which phosphorylates the RNA polymerase II (Pol II) carboxyl-terminal domain (CTD) and the processivity factor Spt5 to promote transcript elongation. Here we show that a Cdk9 carboxyl-terminal extension, distinct from the catalytic domain, mediates binding to both Pcm1 and the Pol II CTD. Removal of this segment diminishes Cdk9/Pcm1 chromatin recruitment and Spt5 phosphorylation in vivo and leads to slow growth and hypersensitivity to cold temperature, nutrient limitation, and the IMP dehydrogenase inhibitor mycophenolic acid (MPA). These phenotypes, and the Spt5 phosphorylation defect, are suppressed by Pcm1 overproduction, suggesting that normal transcript elongation and gene expression depend on physical linkage between Cdk9 and Pcm1. The extension is dispensable, however, for recognition of CTD substrates "primed" by Mcs6 (Cdk7). On defined peptide substrates in vitro, Cdk9 prefers CTD repeats phosphorylated at Ser7 over unmodified repeats. In vivo, Ser7 phosphorylation depends on Mcs6 activity, suggesting a conserved mechanism, independent of chromatin recruitment, to order transcriptional CDK functions. Therefore, fission yeast Cdk9 comprises a catalytic domain sufficient for primed substrate recognition and a multivalent recruitment module that couples transcription with capping.

Using effectiveness and cost-effectiveness to make drug coverage decisions: a comparison of Britain, Australia, and Canada.

CONTEXT: National public insurance for drugs is often based on evidence of comparative effectiveness and cost-effectiveness. This study describes how that evidence has been used across 3 jurisdictions (Australia, Canada, and Britain) that have been at the forefront of evidence-based coverage internationally. OBJECTIVES: To describe how clinical and cost-effectiveness evidence is used in coverage decisions both within and across jurisdictions and to identify common issues in the process of evidence-based coverage. DESIGN, SETTING, AND PARTICIPANTS: Descriptive analysis of retrospective data from the Common Drug Review (CDR) of Canada, National Institute for Health and Clinical Excellence (NICE) in Britain, and Pharmaceutical Benefits Advisory Committee (PBAC) of Australia. All publicly available information as of December 31, 2008, was gathered from each committee's Web site (data set begins in January 2004 [CDR], February 2001 [NICE], and July 2005 [PBAC]). MAIN OUTCOME MEASURE: Listing recommendations for each drug by disease indication. RESULTS: NICE recommended 87.4% (174/199) of submissions for listing compared with a listing rate of 49.6% (60/121) and 54.3% (153/282) for the CDR and PBAC, respectively. Significant uncertainty around clinical effectiveness, typically resulting from inadequate study design or the use of inappropriate comparators and unvalidated surrogate end points, was identified as a key issue in coverage decisions. Recommendations varied considerably across countries, possibly because of differences in the medications reviewed; different agency processes, including the willingness to negotiate on price; and the approach to "me too" drugs. The data suggest that the 3 agencies make recommendations that are consistent with evidence on effectiveness and cost-effectiveness but that other factors are often important. CONCLUSIONS: NICE, PBAC, and CDR face common issues with respect to the quality and strength of the experimental evidence in support of a clinically meaningful effect. However, comparative effectiveness and cost-effectiveness, along with other relevant factors, can be used by national agencies to support drug decision making. The results of the evaluation process in different countries are influenced by the context, agency processes, ability to engage in price negotiation, and perhaps differences in social values.

Brc1-mediated rescue of Smc5/6 deficiency: requirement for multiple nucleases and a novel Rad18 function.

Smc5/6 is a structural maintenance of chromosomes complex, related to the cohesin and condensin complexes. Recent studies implicate Smc5/6 as being essential for homologous recombination. Each gene is essential, but hypomorphic alleles are defective in the repair of a diverse array of lesions. A particular allele of smc6 (smc6-74) is suppressed by overexpression of Brc1, a six-BRCT domain protein that is required for DNA repair during S-phase. This suppression requires the postreplication repair (PRR) protein Rhp18 and the structure-specific endonucleases Slx1/4 and Mus81/Eme1. However, we show here that the contribution of Rhp18 is via a novel pathway that is independent of PCNA ubiquitination and PRR. Moreover, we identify Exo1 as an additional nuclease required for Brc1-mediated suppression of smc6-74, independent of mismatch repair. Further, the Apn2 endonuclease is required for the viability of smc6 mutants without extrinsic DNA damage, although this is not due to a defect in base excision repair. Several nucleotide excision repair genes are similarly shown to ensure viability of smc6 mutants. The requirement for excision factors for the viability of smc6 mutants is consistent with an inability to respond to spontaneous lesions by Smc5/6-dependent recombination.

A new SUMO ligase in the DNA damage response.

SUMO is a small ubiquitin-like protein that is attached to target proteins, altering their localization and function. The condensin and cohesin-related Smc5/6 complex has been linked to DNA repair and checkpoint responses, but details of its molecular function have remained obscure. Recent reports show one subunit of the complex is a SUMO ligase, providing another link between protein sumoylation and DNA damage responses.

Brc1-mediated DNA repair and damage tolerance.

The structural maintenance of chromosome (SMC) proteins are key elements in controlling chromosome dynamics. In eukaryotic cells, three essential SMC complexes have been defined: cohesin, condensin, and the Smc5/6 complex. The latter is essential for DNA damage responses; in its absence both repair and checkpoint responses fail. In fission yeast, the UV-C and ionizing radiation (IR) sensitivity of a specific hypomorphic allele encoding the Smc6 subunit, rad18-74 (renamed smc6-74), is suppressed by mild overexpression of a six-BRCT-domain protein, Brc1. Deletion of brc1 does not result in a hypersensitivity to UV-C or IR, and thus the function of Brc1 relative to the Smc5/6 complex has remained unclear. Here we show that brc1Delta cells are hypersensitive to a range of radiomimetic drugs that share the feature of creating lesions that are an impediment to the completion of DNA replication. Through a genetic analysis of brc1Delta epistasis and by defining genes required for Brc1 to suppress smc6-74, we find that Brc1 functions to promote recombination through a novel postreplication repair pathway and the structure-specific nucleases Slx1 and Mus81. Activation of this pathway through overproduction of Brc1 bypasses a repair defect in smc6-74, reestablishing resolution of lesions by recombination.