Renin-Angiotensin Inhibition and Outcomes in HFrEF and Advanced Kidney Disease.

BACKGROUND: Renin-angiotensin system inhibitors improve outcomes in patients with heart failure with reduced ejection fraction (HFrEF). However, less is known about their effectiveness in patients with HFrEF and advanced kidney disease. METHODS: In the Medicare-linked Organized Program to Initiate Lifesaving Treatment in Hospitalized Patients with Heart Failure (OPTIMIZE-HF), 1582 patients with HFrEF (ejection fraction ≤40%) had advanced kidney disease (estimated glomerular filtration rate <30 mL/min/1.73 m2). Of these, 829 were not receiving angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) prior to admission, of whom 214 were initiated on these drugs prior to discharge. We calculated propensity scores for receipt of these drugs for each of the 829 patients and assembled a matched cohort of 388 patients, balanced on 47 baseline characteristics (mean age 78 years; 52% women; 10% African American; 73% receiving beta-blockers). Hazard ratios (HR) and 95% confidence intervals (CI) were estimated comparing 2-year outcomes in 194 patients initiated on ACE inhibitors or ARBs to 194 patients not initiated on those drugs. RESULTS: The combined endpoint of heart failure readmission or all-cause mortality occurred in 79% and 84% of patients initiated and not initiated on ACE inhibitors or ARBs, respectively (HR associated with initiation, 0.79; 95% CI, 0.63-0.98). Respective HRs (95% CI) for the individual endpoints of - Respective HRs (95% CI) for the individual endpoints of all-cause mortality and heart failure readmission were 0.81 (0.63-1.03) and 0.63 (0.47-0.85). CONCLUSIONS: The findings from our study add new information to the body of cumulative evidence that suggest that renin-angiotensin system inhibitors may improve clinical outcomes in patients with HFrEF and advanced kidney disease. These hypothesis-generating findings need to be replicated in contemporary patients.

Metabolomic assessment of mechanisms underlying anti-renal fibrosis properties of petroleum ether extract from Amygdalus mongolica.

CONTEXT: The petroleum ether extract (PET) of Amygdalus mongolica (Maxim.) Ricker (Rosaceae) has an ameliorative effect on renal fibrosis (RF). OBJECTIVE: To evaluate the antifibrotic effects of A. mongolica seeds PET on RF by serum metabolomics, biochemical and histopathological analyses. MATERIALS AND METHODS: Sixty male Sprague-Dawley rats were randomly divided into the sham-operated, RF model, benazepril hydrochloride-treated model (1.5 mg/kg) and PET-treated (1.75, 1.25, 0.75 g/kg) groups, and the respective drugs were administered intragastrically for 21 days. Biochemical indicators including BUN, Scr, HYP, SOD, and MDA were measured. Haematoxylin and eosin and Masson staining were used for histological examination. The serum metabolomic profiles were determined by UPLC-Q-TOF/MS and metabolism network analysis. Acute toxicity test was performed to validate biosafety. RESULTS: The PET LD50 was >23.9 g/kg in rats. PET significantly alleviated fibrosis by reducing the levels of Scr (from 34.02 to 32.02), HYP (from 403.67 to 303.17) and MDA (from 1.84 to 1.73), and increasing that of SOD (from 256.42 to 271.85). Metabolomic profiling identified 10 potential biomarkers, of which three key markers were significantly associated with RF-related pathways including phenylalanine, tyrosine and tryptophan biosynthesis, amino sugar and nucleotide sugar metabolism and tyrosine metabolism. In addition, three key biomarkers were restored to baseline levels following PET treatment, with the medium dose showing optimal effect. CONCLUSIONS: These findings revealed the mechanism of A. mongolica PET antifibrotic effects for RF rats on metabolic activity and provided the experimental basis for the clinical application.

Assessment of renal fibrosis and anti-fibrotic agents using a novel diagnostic and stain-free second-harmonic generation platform.

Current histological measurement techniques for interstitial collagen, the basis of interstitial fibrosis, are semi-quantitative at best and only provide a ratio of collagen levels within tissues. The Genesis200 imaging system and supplemental image analysis software, FibroIndex from HistoIndex, is a novel, automated platform that uses second-harmonic generation (SHG) for imaging and characterization of interstitial collagen deposition and additional characteristics, in the absence of any staining. However, its ability to quantify renal fibrosis requires investigation. This study compared SHG imaging of renal fibrosis in mice with unilateral ureteric obstruction (UUO), to that of Masson's trichrome staining (MTS) and immunohistochemistry (IHC) of collagen I. Additionally, the platform generated data on collagen morphology and distribution patterns. While all three methods determined that UUO-injured mice underwent significantly increased renal fibrosis after 7 days, the HistoIndex platform additionally determined that UUO-injured mice had a significantly increased collagen-to-tissue cross reticulation ratio (all P < .001 vs sham group). Furthermore, in UUO-injured mice treated with the relaxin family peptide receptor-1 agonists, relaxin (0.5 mg/kg/day) or B7-33 (0.25 mg/kg/day), or angiotensin converting enzyme-inhibitor, perindopril (1 mg/kg/day) over the 7-day period, only the HistoIndex platform determined that the drug-induced prevention of renal fibrosis correlated with significantly reduced collagen fiber thickness and collagen-to-tissue cross reticulation ratio, but increased collagen fiber counts. Relaxin or B7-33 treatment also increased renal matrix metalloproteinase-2 and reduced tissue inhibitor of metalloproteinase-1 levels (all P < .01 vs UUO alone). This study demonstrated the diagnostic value of the HistoIndex platform over currently used staining techniques.

Quantitative Benefit-Risk Assessment of P-gp-Mediated Drug-Drug Interactions of Dabigatran Coadministered With Pharmacokinetic Enhancers in Patients With Renal Impairment.

Drug-drug interactions (DDIs) between dabigatran and ritonavir/cobicistat are of major concern in people living with HIV, particularly in those with impaired renal function, because they can result in increased dabigatran exposure and thus an increased risk of major bleeding events. However, the extent of this interaction and subsequent need for dose adjustment in subjects with varying degrees of renal function is currently not yet fully understood. To close this knowledge gap, we conducted an integrated population physiologically-based pharmacokinetic/pharmacodynamic analysis linking changes in dabigatran exposure due to DDIs and varying degrees of renal function to the probability of experiencing an ischemic stroke or major bleeding event within 1 year. The results of our analysis suggest that coadministration of dabigatran etexilate (dabigatran prodrug) and ritonavir/cobicistat should be avoided in subjects with severe renal impairment. A 2-hour dose separation or dabigatran etexilate dose reduction to 110 mg b.i.d. (twice daily) should be considered in subjects with moderate renal impairment when coadministered with ritonavir, while the dabigatran etexilate dose should be further reduced to 75 mg b.i.d. when coadministered with cobicistat. No dabigatran etexilate dose adjustment is needed in subjects with normal renal function receiving ritonavir, but dabigatran etexilate dose reduction to 110 mg b.i.d. should be considered when coadministered with cobicistat.

Quality assessment and cost saving of renal dosing recommendation by clinical pharmacists at medical wards in Thailand.

Background Renal dosage adjustment for patients with reduced kidney function is a common function of clinical pharmacy service. Assessment of pharmacist's intervention in the aspect of quality and economic impact should be conducted to evaluate the benefit of this service. Objective This study aimed to assess the quality and cost saving of clinical pharmacists' recommendation on renal dosage adjustment among patients with reduced kidney function. Setting Eight medical wards of the Siriraj Hospital, a tertiary-care hospital in Bangkok, Thailand. Method A retrospective study was conducted using medical records and clinical pharmacist's intervention database. All patients admitted to the study wards whose estimated creatinine clearance were less than 60 mL/min or presented with acute kidney injury on admission during October 2016-December 2017 were included. The targeted medications were antimicrobial agents. Main outcome measure Percentage of the concordance between pharmacists' recommendation compared to standard dosing references and related cost saving. Results Among 158 patients, pharmacists provided 190 recommendations, including 151 (79.1%) dose reduction, 17 (8.9%) dose increase and 22 (11.5%) recommendations to provide supplemental dose after dialysis. These recommendations were 90.5% consistent with standard references. Physician accepted and complied with 89.5% of pharmacists' recommendations. Average direct cost saving was €5,114.11 while cost avoidance was €863.47. Conclusion Trained clinical pharmacists were able to provide high-quality recommendation on dosage adjustment in these patients in accordance to standard dosing guidelines. In addition, dosage adjustment also led to a significant direct cost saving and cost avoidance from prevention of adverse drug reactions.

Semi-solid phase assay for the alternative complement pathway activity assessment (AP100).

Since the introduction of the most expensive drug in the world (Eculizumab) in the therapeutic arsenal of many diseases involving the alternative complement pathway (ACP) in their pathophysiology, the unmet need to perform simple ACP assays affordable for all countries has become one of the major challenges of the contemporary medicine. The assay currently used is AH50, despite it still challenging for several laboratories. This educational chapter consists of a detail protocol of standardized hemolytic assay AP100 and aims to help clinical laboratories over the world and especially those of the developing and low income countries to perform it. The procedure is essentially the same as for the timed lysis assay and dilution methods (AP50) except the concentration of ACP buffer and the chicken erythrocyte density used to make the gels. In clinical field, AP100 has at least nine applications in disease diagnosis and follow-up. AP100 has many advantages over the AH50 as it is more reliable for the Eculizumab monitoring and more practical with a purpose to be stored and transported for several weeks. AP100 is a portable and easy to use device both at the bedside and in the companion medical care.

Comparison of health state utility estimates from instrument-based and vignette-based methods: a case study in kidney disease.

OBJECTIVE: We take advantage of a rare occurrence when two different studies report on the estimation of quality of life utilities for the same health states to assess convergence of the reported measures. Health state utilities are important inputs into health economic models that estimate the impact of new medical technologies using a common metric of health gain-the quality adjusted life-year. RESULTS: We find low concordance between the two measures which is concerning in that this could have important ramifications for health care decision making based on estimated cost-effectiveness. We explore possible reasons for the discrepancy between the two measures and draw implications for the design of future studies.

Optical Metabolic Imaging for Assessment of Radiation-Induced Injury to Rat Kidney and Mitigation by Lisinopril.

The kidney is one of the most radiosensitive organs; it is the primary dose-limiting organ in radiotherapies for upper abdominal cancers. The role of mitochondrial redox state in the development and treatment of renal radiation injury, however, remains ill-defined. This study utilizes 3D optical cryo-imaging to quantify renal mitochondrial bioenergetics dysfunction after 13 Gy leg-out partial body irradiation (PBI). Furthermore, the mitigating effects of lisinopril (lisino), an anti-hypertensive angiotensin converting enzyme inhibitor, is assessed in renal radiation-induced injuries. Around day 150 post-irradiation, kidneys are harvested for cryo-imaging. The 3D images of the metabolic indices (NADH, nicotinamide adenine dinucleotide, and FAD, flavin adenine dinucleotide) are acquired, and the mitochondrial redox states of the irradiated and irradiated + lisino kidneys are quantified by calculating the volumetric mean redox ratio (NADH/FAD). PBI oxidized renal mitochondrial redox state by 78%. The kidneys from the irradiated + lisino rats showed mitigation of mitochondrial redox state by 93% compared to the PBI group. The study provides evidence for an altered bioenergetics and energy metabolism in the rat model of irradiation-induced kidney damage. In addition, the results suggest that lisinopril mitigates irradiation damage by attenuating the oxidation of mitochondria leading to increase redox ratio.

Assessment of treatment efficacy using surface-enhanced Raman spectroscopy analysis of urine in rats with kidney transplantation or kidney disease.

BACKGROUND: Individuals who have kidney disease or kidney transplants need routine assessment of their kidney damage and function, which are largely measured based on histological examination of kidney biopsies, blood test, and urinalysis. These methods are practically difficult or inconvenient, and expensive. The objective of this study was to develop a model to estimate the kidney damage and function by surface-enhanced Raman spectroscopy (SERS). METHODS: Urine samples were collected from two previous studies: renal allograft recipient Lewis rats receiving anti-TGF-ß antibody or control antibody treatment and obese diabetic ZSF1 rats with kidney disease fed with whole grape powder-containing chow or control chow. Silver nanoparticle-based SERS spectra of urine were measured. SERS spectra were analyzed using principal component analysis (PCA) combined with linear discriminant analysis (LDA) and partial least squires (PLS) analysis. RESULTS: PCA/LDA separated anti-TGF-ß antibody-treated group from control group with 90% sensitivity and 70% specificity in kidney transplants, and grape-fed group from controls with 72.7% sensitivity and 60% specificity in diabetic kidneys. The receiver operating characteristic curves showed that the integration area under the curve was 0.850 ± 0.095 (p = 0.008) in kidney transplant groups and 0.800 ± 0.097 (p = 0.02) in diabetic kidney groups. PLS predicted the biochemical parameters of kidney function using the SERS spectra, resulting in R2 = 0.8246 (p < 0.001,urine protein), R2 = 0.8438 (p < 0.001, urine creatinine), R2 = 0.9265 (p < 0.001, urea), R2 = 0.8719 (p < 0.001, serum creatinine), and R2 = 0.6014 (p < 0.001, urine protein to creatinine ratio). CONCLUSION: Urine SERS spectral analysis suggesting that it may become a convenient method for rapid assessment of renal impairment.

Cost-effectiveness of rivaroxaban versus warfarin for treatment of nonvalvular atrial fibrillation in patients with worsening renal function.

BACKGROUND: Nonvalvular atrial fibrillation (NVAF) is highly prevalent and increases the risks of cardiovascular events. In a recent subgroup analysis, treatment response was shown to vary for patients exhibiting worsening renal function (WRF) on-treatment. It is important to understand the cost-effectiveness of novel oral anticoagulant (NOAC) use in this population. METHODS: A cost-effectiveness analysis (CEA) was conducted using a Markov model to determine whether NOAC rivaroxaban treatment is cost-effective relative to warfarin in NVAF patients with on-treatment WRF. Input parameters were sourced from clinical literature including a multicenter clinical trial and subgroup analysis. We studied elderly US male patients at increased risk for stroke (CHADS2 score ≥ 2) undergoing treatment for NVAF and exhibiting WRF. Main outcome measures included total healthcare costs in 2017 US dollars (societal perspective), total quality-adjusted life years (QALYs), incremental cost-effectiveness ratio (ICER), and incremental net monetary benefits (INMB) per-patient. RESULTS: The remaining lifetime use of rivaroxaban is associated with 5.69 QALYs at a cost of $66,075 per patient, while warfarin produced 5.22 QALYs with costs of $78,504 per patient. At a willingness-to-pay (WTP) of $150,000 per QALY, incremental net monetary benefits (INMB) per patient are $83,590. In our population, treatment with warfarin was dominated by rivaroxaban in 99.4% of 10,000 simulations. CONCLUSIONS: Rivaroxaban is likely a dominant treatment over warfarin in elderly US male NVAF patients exhibiting WRF, providing increased QALYs at a decreased overall cost. Application of these findings may require healthcare providers to predict which patients are likely to exhibit WRF.

Budget Impact Analysis of a Renal Point-of-Care Test in Dutch Community Pharmacies to Prevent Antibiotic-Related Hospitalizations.

OBJECTIVES: Medication errors that lead to adverse drug reactions are a key cause of unintentional patient harm and subsequent economic burden. To prevent this, measurement of renal function could be considered. The aim of this study was to determine the budget impact of obtaining and evaluating renal function in community pharmacies in the Netherlands to prevent antibiotic-related hospitalizations. METHODS: A decision model was built to simulate the process of antibiotic prescriptions in community pharmacies with and without the use of a point-of-care test (PoCT) in patients aged 65 years and older. By using a PoCT, the number of patients with renal function values available increases, leading to the possibility of dose adjustment when necessary. In turn, this might avoid hospitalizations. For this study, real-life patient data were used from 351 community pharmacies. Direct costs of renal function screening, antibiotic treatments, and medical care due to antibiotic-related hospitalization were included. RESULTS: The budget impact analysis showed annual cost-savings of €86 per patient through the availability of renal function values in Dutch community pharmacies. Savings were mostly due to avoided hospitalizations. CONCLUSION: Obtaining and evaluating renal function in community pharmacies by point of care tests is expected to be cost-saving in the Netherlands.

Renal Pre-Competitive Consortium (RPC2): discovering therapeutic targets together.

Despite significant effort, patients with kidney disease have not seen their outcomes improved significantly over the past two decades. This has motivated clinicians and researchers to consider alternative methods to identifying risk factors, disease progression markers, and effective therapies. Genome-scale data sets from patients with renal disease can be used to establish a platform to improve understanding of the molecular basis of disease; however, such studies require expertise and resources. To overcome these challenges, we formed an academic-industry consortium to share molecular target identification efforts and expertise across academia and the pharmaceutical industry. The Renal Pre-Competitive Consortium (RPC2) aims to accelerate novel drug development for kidney diseases through a systems biology approach. Here, we describe the rationale, philosophy, establishment, and initial results of this strategy.

History of Erythropoiesis-Stimulating Agents, the Development of Biosimilars, and the Future of Anemia Treatment in Nephrology.

BACKGROUND: Exogenous replacement of erythropoietin (EPO) by recombinant human EPO has been considered a standard of care for the treatment of anemia in patients with chronic kidney disease for more than 20 years. Genetically engineered biologic proteins derived from human, animal, or microorganism sources are a major area of growth in modern medical care, accounting for one-third of new drug approvals in the past decade. Despite benefit to patients, the use of biologics comes at a significant cost, representing one of the fastest growing segments of strained healthcare budgets around the world. SUMMARY: Biosimilars, or biologic drugs that are designed to be highly similar to approved reference biologic drugs, have been available in Europe for more than 10 years with no unusual or unexpected effects compared to their reference biologics whose patents have expired. Given the success of the biosimilar approval pathway pioneered in Europe, it has served as a global reference for other regulatory authorities to establish and implement biosimilar licensure frameworks, including the United States (US), the largest pharmaceutical market in the world. Given 10 of the top 25 drugs sold in 2014 were biologics, and considering the rising costs of healthcare, biosimilars have the potential to become a significant part of the US market. Key Messages: For the nephrology community, the recent patent expiries for epoetin alfa (Epogen®, Amgen and Procrit®, Johnson & Johnson) have created the opportunity to develop biosimilar EPOs. And while no biosimilar in this therapeutic class is approved in the US, there are proposed biosimilars in development.

Orphan drug policies and use in pediatric nephrology.

Orphan drugs designed to treat rare diseases are often overpriced per patient. Novel treatments are sometimes even more expensive for patients with ultra-rare diseases, in part due to the limited number of patients. Pharmaceutical companies that develop a patented life-saving drug are in a position to charge a very high price, which, at best, may enable these companies to further develop drugs for use in rare disease. However, is there a limit to how much a life-saving drug should cost annually per patient? Government interventions and regulations may opt to withhold a life-saving drug solely due to its high price and cost-effectiveness. Processes related to drug pricing, reimbursement, and thereby availability, vary between countries, thus having implications on patient care. These processes are discussed, with specific focus on three drugs used in pediatric nephrology: agalsidase beta (for Fabry disease), eculizumab (for atypical hemolytic uremic syndrome), and cysteamine bitartrate (for cystinosis). Access to and costs of orphan drugs have most profound implications for patients, but also for their physicians, hospitals, insurance policies, and society at large, particularly from financial and ethical standpoints.

Glomerular Diseases: Registries and Clinical Trials.

Nephrology has conducted few high-quality clinical trials, and the trials that have been conducted have not resulted in the approval of new treatments for primary or inflammatory glomerular diseases. There are overarching process issues that affect the conduct of all clinical trials, but there are also some specialty-specific issues. Within nephrology, primary glomerular diseases are rare, making adequate recruitment for meaningful trials difficult. Nephrologists need better ways, beyond histopathology, to phenotype patients with glomerular diseases and stratify the risk for progression to ESRD. Rigorous trial design is needed for the testing of new therapies, where most patients with glomerular diseases are offered the opportunity to enroll in a clinical trial if standard therapies have failed or are lacking. Training programs to develop a core group of kidney specialists with expertise in the design and implementation of clinical trials are also needed. Registries of patients with glomerular disease and observational studies can aid in the ability to determine realistic estimates of disease prevalence and inform trial design through a better understanding of the natural history of disease. Some proposed changes to the Common Rule, the federal regulations governing the ethical conduct of research involving humans, and the emerging use of electronic health records may facilitate the efficiency of initiating multicenter clinical trials. Collaborations among academia, government scientific and regulatory agencies, industry, foundations, and patient advocacy groups can accelerate therapeutic development for these complex diseases.

Influence of kidney disease on drug disposition: An assessment of industry studies submitted to the FDA for new chemical entities 1999-2010.

In 1998, the United States Food and Drug Administration (FDA) released the first guidance for industry regarding pharmacokinetic (PK) studies in renally impaired patients. This study aimed to determine if the FDA renal PK guidance influenced the frequency and rigor of renal studies conducted for new chemical entities (NCEs). FDA-approved package inserts (APIs) and clinical pharmacology review documents were analyzed for 194 NCEs approved from 1999 to 2010. Renal studies were conducted in 71.6% of NCEs approved from 1999 to 2010, a significant increase over the 56.3% conducted from 1996 to 1997 (P = .0242). Renal studies were more likely to be completed in highly renally excreted drugs (fe ≥ 30%) compared with drugs with low renal excretion, fe < 30% (89.6% vs 65.8%, P = .0015). PK studies to assess the impact of dialysis were conducted for 31.7% of NCEs that had a renal study: a greater proportion of high fe NCEs were studied (44.2% vs 26.0%, P = .0335). No significant change in frequency or rigor of PK studies was detected over time. The majority of NCEs (76.3%) with a renal study provided specific dosing recommendations in the API. The adoption of the 1998 FDA guidance has resulted in improved availability of PK and drug-dosing recommendations, particularly for high fe drugs.

The use of surrogate endpoints in regulating medicines for cardio-renal disease: opinions of stakeholders.

AIM: There is discussion whether medicines can be authorized on the market based on evidence from surrogate endpoints. We assessed opinions of different stakeholders on this topic. METHODS: We conducted an online questionnaire that targeted various stakeholder groups (regulatory agencies, pharmaceutical industry, academia, relevant public sector organisations) and medical specialties (cardiology or nephrology vs. other). Participants were enrolled through purposeful sampling. We inquired for conditions under which surrogate endpoints can be used, the validity of various cardio-renal biomarkers and new approaches for biomarker use. RESULTS: Participants agreed that surrogate endpoints can be used when the surrogate is scientifically valid (5-point Likert response format, mean score: 4.3, SD: 0.9) or when there is an unmet clinical need (mean score: 3.8, SD: 1.2). Industry participants agreed to a greater extent than regulators and academics. However, out of four proposed surrogates (blood pressure (BP), HbA1c, albuminuria, CRP) for cardiovascular outcomes or end-stage renal disease, only use of BP for cardiovascular outcomes was deemed moderately accurate (mean: 3.6, SD: 1.1). Specialists in cardiology or nephrology tended to be more positive about the use of surrogate endpoints. CONCLUSION: Stakeholders in drug development do not oppose to the use of surrogate endpoints in drug marketing authorization, but most surrogates are not considered valid. To solve this impasse, increased efforts are required to validate surrogate endpoints and to explore alternative ways to use them.

The incidence, management, and evolution of rapamycin-related side effects in kidney transplant recipients.

Conversion from a calcineurin-inhibitor-based immunosuppression to a rapamycin-based immunosuppression may preserve kidney graft function. The side effects of rapamycin can limit its usefulness, but their management and evolution are rarely reported in clinical trials. We performed a retrospective cohort study in patients transplanted before December 31, 2008 and who received rapamycin to replace calcineurin inhibitors. In 219 patients studied, 98% presented ≥1 side effects after starting rapamycin. Side effects occurring in ≥10% of patients were dyslipidemia (52%, 95% confidence interval (CI): 45-59%), peripheral edema (37%, 95%CI: 31-43%), cytopenia (36%, 95% CI: 30-42%), acne (29%, 95% CI: 23-35%), proteinuria (23%, 95% CI: 17-29%), and oral ulcers 14% (95% CI: 10-18%). Proteinuria, ulcers, and edema were difficult to manage and were more likely to cause cessation of rapamycin. Rapamycin was discontinued in 46% of patients (95% CI: 40-52%). Age (odds ratio [OR] per 10-yr increase: 1.29, 95% CI: 1.05-1.59) and obesity (OR: 2.57, 95% CI: 1.10-6.01) were independently associated with cessation of rapamycin. We conclude that successful control of dyslipidemia and cytopenia can be achieved without discontinuing rapamycin. Most other side effects are harder to manage. Leaner and younger patients are less likely to discontinue rapamycin due to side effects.

Drug discovery in renal disease--towards a more efficient framework.

The time and cost involved in bringing new drugs to the market hamper their approval. This problem is especially apparent in the case of renal diseases. Efficient drug research requires an a priori understanding of disease pathophysiology, target validation, rational and efficient drug discovery strategies and early testing of the physiological and pharmacological effects of the new agent in humans. Drug development initiated by academia benefits from international research networks and relies on internationally acceptable high-quality nonclinical data packages and bulk investigational drugs. Academics should, therefore, better understand pharmaceutical practice regulations and novel, efficient drug-development strategies. Many researchers remain unfamiliar with these areas and should collaborate with regulatory authorities to discover and validate surrogate markers for use in drug development, and to efficiently and effectively maximize the benefits and minimize the adverse effects of new drugs. The Japanese government and regulatory authorities have implemented a framework to encourage such collaborations; extension of this framework beyond its current reach is envisaged.

Vitamin D and proteinuria: a critical review of molecular bases and clinical experience.

Proteinuria is the main predictor of chronic kidney disease progression. Drugs that block the renin-angiotensin-aldosterone (RAA) system reduce proteinuria and slow down the progression of the disease. However, their effect is suboptimal, and residual proteinuria persists as an important predictor of renal impairment. Vitamin D has pleiotropic effects that could have an impact on these parameters. In this study, we critically review the molecular and experimental bases that suggest an antiproteinuric effect of vitamin D receptor (VDR) activation and the available evidence on its antiproteinuric effect in clinical practice. In animal models, we have observed the antiproteinuric effect of VDR activation, which could be due to direct protective action on the podocyte or other pleiotropic effects that slow down RAA system activation, inflammation and fibrosis. Clinical trials have generally been conducted in patients with a vitamin D deficiency or insufficiency and the main trial (VITAL) did not demonstrate that paricalcitol improved the study's primary endpoint (decrease in the urine albumin to creatinine ratio). In this sense, the information available is insufficient to advise the use of native vitamin D or VDR activators as renoprotective antiproteinuric drugs beyond the experimental level. Two Spanish clinical trials and one Italian trial attempted to determine the effect of paricalcitol and vitamin D on residual proteinuria in various clinical circumstances (PALIFE, NEFROVID and PROCEED).