EP2906955A1 - Dosage de néphropathie chronique - Google Patents

Dosage de néphropathie chronique

Info

Publication number
EP2906955A1
EP2906955A1 EP13780189.0A EP13780189A EP2906955A1 EP 2906955 A1 EP2906955 A1 EP 2906955A1 EP 13780189 A EP13780189 A EP 13780189A EP 2906955 A1 EP2906955 A1 EP 2906955A1
Authority
EP
European Patent Office
Prior art keywords
value
patient
risk
flc
serum
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP13780189.0A
Other languages
German (de)
English (en)
Inventor
Stephen Harding
Paul Cockwell
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Binding Site Group Ltd
Original Assignee
Binding Site Group Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Binding Site Group Ltd filed Critical Binding Site Group Ltd
Publication of EP2906955A1 publication Critical patent/EP2906955A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
    • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
    • G01N33/68—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving proteins, peptides or amino acids
    • G01N33/6893—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving proteins, peptides or amino acids related to diseases not provided for elsewhere
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2800/00—Detection or diagnosis of diseases
    • G01N2800/34—Genitourinary disorders
    • G01N2800/347—Renal failures; Glomerular diseases; Tubulointerstitial diseases, e.g. nephritic syndrome, glomerulonephritis; Renovascular diseases, e.g. renal artery occlusion, nephropathy
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2800/00—Detection or diagnosis of diseases
    • G01N2800/50—Determining the risk of developing a disease

Definitions

  • the invention relates to methods of identifying patients with reduced risk of requiring renal replacement therapy and assays for use in such methods.
  • Antibodies comprise heavy chains and light chains. They usually have a two-fold symmetry and are composed of two identical heavy chains and two identical light chains, each containing variable and constant region domains. The variable domains of each light- chain/heavy-chain pair combine to form an antigen-binding site, so that both chains contribute to the antigen-binding specificity of the antibody molecule.
  • Light chains are of two types, ⁇ and ⁇ . There are approximately twice as many ⁇ as ⁇ molecules produced in humans, but this is different in some mammals. Usually the light chains are attached to heavy chains. However, some unattached "free light chains" are detectable in the serum or urine of individuals.
  • FLC may be specifically identified by raising antibodies against the surface of the free light chain that is normally hidden by the binding of the light chain to the heavy chain. In FLC this surface is exposed, allowing it to be detected immunologically.
  • kits for the detection of ⁇ or ⁇ FLC include, for example, "FreeliteTM", manufactured by The Binding Site Group Limited, Birmingham, United Kingdom. The Applicants have previously identified that measuring the amount of free ⁇ , free ⁇ and/or free ⁇ /free ⁇ ratios, allows the detection of monoclonal gammopathies in patients.
  • an increase in one of the ⁇ or ⁇ light chains is looked for.
  • multiple myelomas result from the monoclonal multiplication of a malignant plasma cell, resulting in an increase in a single type of cell producing a single type of immunoglobulin.
  • This increase in concentration may be determined, and usually the ratio of the free ⁇ to free ⁇ is determined and compared with the normal range. This aids in the diagnosis of monoclonal disease.
  • the FLC assays may also be used for the following of treatment of the disease in patients. Prognosis of, for example, patients after treatment for AL amyloidosis may be carried out.
  • the Applicants had identified that assaying for FLC and especially total or combined FLC (cFLC) can be used to predict long-term survival of individuals over a period of a number of years, even when the individual is an apparently healthy subject. They have found that FLC concentration is statistically, significantly linked to long-term survival. Moreover, this link appears to be similar or better than the link for existing long-term survival prognostic markers such as cholesterol, creatinine, cystatin C and C-reactive protein.
  • cFLC total or combined FLC
  • CKD chronic kidney disease
  • Elevated cFLC in samples of serum in patients referred to a haematology unit have been shown to correlate to increased frequency of death in patients after 100 days (Basu S et al J Clin Pathol (2012) doi: 10.1136/jclinpath-2012-200910).
  • RRT renal replacement therapy
  • CKD stages 3b-5 are monitored in secondary care by follow-up appointments often in the specialist renal units at hospitals.
  • eGFR estimated glomerular filtration rates
  • eGFR estimated glomerular filtration rates
  • That model looked at a variety of factors including age, sex, eGFR, albuminuria, serum calcium, serum phosphate, serum bicarbonate and serum albumin concentrations to produce a model which produces a probability of renal failure expressed as a percentage over time. This can be used as a guide to indicate those at more or less risk of renal failure over 5 years. It does not provide specific guidance on interpretation of the data in regards to individual patient management.
  • the Applicant has now assessed the risk of RRT by looking at free light chains and other markers or risk factors to produce an improved, easier to use, scoring system.
  • the invention provides a method of identifying the risk of a patient with chronic kidney disease (CKD) requiring renal replacement therapy (RRT) within a predetermined period of time comprising determining a value of free light chains (FLC) in a sample from the patient, comparing the value to a predetermined value and assigning a risk score to that value of FLC in the sample to indicate the risk of the patient requiring RRT.
  • the time period of time may be at least 6, 8 or 10 or approximately 12 months or 361 days, or 2, 3, 4 or 5 years.
  • the risk stage of CKD may be any risk stage. It may be, for example, risk stage 3b-5 or 4.
  • One or more additional risk factors may be determined selected from.
  • the presence of diabetes in a patient the eGFR value, serum phosphate value, serum calcium value, serum cystatin C value, ACR value; ethnicity of the patient, underlying renal diagnosis of the patient, sodium value, potassium value, bicarbonate value, creatinine value, C reactive protein (CRP) value, an albumin value and a parathyroid hormone (PTH) value.
  • eGFR value serum phosphate value
  • serum calcium value serum cystatin C value
  • ACR value ethnicity of the patient
  • ethnicity of the patient underlying renal diagnosis of the patient
  • sodium value, potassium value, bicarbonate value creatinine value
  • C reactive protein (CRP) value an albumin value
  • PTH parathyroid hormone
  • Table 1 shows regression values associated with risk of progression to RRT.
  • the method may typically determine one or more additional risk factors in the patient by determining whether the patient has diabetes by measuring the eGFR value for the patient, measuring a serum phosphate value for the patient, and/or measuring an albumin/creatinine ratio (ACR) value for the patient.
  • eGFR value for the patient
  • serum phosphate value for the patient
  • ACR albumin/creatinine ratio
  • all of these risk factors are determined, though alternatively only one or two may be determined.
  • at least FLC, eGFR, serum phosphate, and ACR, and optionally diabetes levels, values and scores are determined.
  • a risk score may be assigned for each risk factor. For example, the or each value determined for the patient may be compared to a predetermined value to identify a risk score associated with the value. That risk may be expressed as a positive or negative or zero risk, or for example if the value is above a particular level and shows a risk then a score of +1 is given, or below that level a score of zero is given. Similarly if the patient has diabetes then a positive risk, or +1 score is given, or if the patient does not have diabetes a negative or zero score is given.
  • a risk score is typically determined for FLC, eGFR, serum phosphate and ACR and optionally diabetes for the patient.
  • the FLC may be kappa or lambda FLC. However, preferably the total FLC concentration is measured as detecting kappa FLC or lambda FLC alone may miss, for example abnormally high levels of one or other FLC produced for example monoclonally in the patient.
  • Combined FLC means the total amount of free kappa plus free lambda light chains in a sample.
  • total free light chains means the amount of ⁇ and ⁇ free light chains in the sample from the subject.
  • the sample is typically a sample of serum from the subject. However, whole blood, plasma or urine may be used. Serum may also be used to determine serum phosphate for example, and the ACR value determined in urine.
  • the FLC such as total FLC
  • the FLC is determined by immunoassay, such as ELISA assays or utilising fluorescently labelled beads, such as LuminexTM beads.
  • immunoassay such as ELISA assays or utilising fluorescently labelled beads, such as LuminexTM beads.
  • fluorescently labelled beads such as LuminexTM beads.
  • it may be used in the form of a lateral flow point of care test kit generally known in the art.
  • ELISA for example uses antibodies to detect specific antigens.
  • One or more of the antibodies used in the assay may be labelled with an enzyme capable of converting a substrate into a detectable analyte.
  • enzymes include horseradish peroxidase, alkaline phosphatase and other enzymes known in the art.
  • other detectable tags or labels may be used instead of, or together with, the enzymes.
  • radioisotopes include radioisotopes, a wide range of coloured and fluorescent labels known in the art, including fluorescein, Alexa fluor, Oregon Green, BODIPY, rhodamine red, Cascade Blue, Marina Blue, Pacific Blue, Cascade Yellow, gold; and conjugates such as biotin (available from, for example, Invitrogen Ltd, United Kingdom).
  • Dye sols, metallic sols, chemilumine scent labels or coloured latex may also be used.
  • One or more of these labels may be used in the ELISA assays according to the various inventions described herein, or alternatively in the other assays, labelled antibodies or kits described herein.
  • ELISA-type assays The construction of ELISA-type assays is itself well known in the art.
  • a "binding antibody” specific for the FLC is immobilised on a substrate.
  • the "binding antibody” may be immobilised onto the substrate by methods which are well known in the art.
  • FLC in the sample are bound by the "binding antibody” which binds the FLC to the substrate via the "binding antibody”.
  • Unbound immunoglobulins may be washed away.
  • the presence of bound immunoglobulins may be determined by using a labelled "detecting antibody” specific to a different part of the FLC of interest than the binding antibody.
  • Flow cytometry may be used to detect the binding of the FLC of interest. This technique is well known in the art for, e.g. cell sorting. However, it can also be used to detect labelled particles, such as beads, and to measure their size. Numerous text books describe flow cytometry, such as Practical Flow Cytometry, 3rd Ed. (1994), H. Shapiro, Alan R. Liss, New York, and Flow Cytometry, First Principles (2nd Ed.) 2001, A.L. Given, Wiley Liss.
  • One of the binding antibodies such as the antibody specific for FLC
  • a bead such as a polystyrene or latex bead.
  • the beads are mixed with the sample and the second detecting antibody.
  • the detecting antibody is preferably labelled with a detectable label, which binds the FLC to be detected in the sample. This results in a labelled bead when the FLC to be assayed is present.
  • Other antibodies specific for other analytes described herein may also be used to allow the detection of those analytes.
  • cFLC levels above 50mg/L in serum may identify patients at risk of needing RRT, for example within 12 months more typically above 80, 90, 96.3, 100, 104 mg/L, above 120mg/L or above 150 mg/L may be used as the cut off, above which a positive risk factor is shown and a score may be recorded for the FLC value in the sample.
  • Diabetes may optionally be used. It increases the risk of RRT. Hence it may produce a positive or +1 risk value eGFR may be calculated using the 4-variable modification of diet in renal disease (MDRD) comprised of gender, age, ethnicity and serum creatinine (Vervoot 2002, Nephrol Dial Transplant. 17(11): 1909- 13).
  • MDRD 4-variable modification of diet in renal disease
  • Urine albumin creatine ratio may be measured on Roche Modular analysers. Urine Albumin is measured by automated immunoturbidimetry using antibody against human albumin. Urine creatinine is measured by a compensated version of the Jaffe reaction using alkaline picrate. eGFR levels of below 25, typically below 20 or below 15 ml/min/1.73m indicates a risk of progression to RRT. Hence below such a value may be given a positive or +1 risk value.
  • serum phosphate levels above 1.3, typically above 1.36 or above 1.4mmol/L; and/or the presence of albuminuria, either micro, typically ACR ratios above 2.5, 3 or 3.5, or macro, typically ACR ratios above 25, 28 typically above 30 or 35mg/mmol indicate risks of factors for requiring RRT and may then be given a positive or +1 risk value.
  • Figure 1 shows Kaplan-Meier patient progression to RRT based on zero, one, two or three (top to bottom lines) of positive risk factors.
  • Figure 2 shows further analysis of data discussed below.
  • Risk factors included eGFR ⁇ 20ml/min/1.73ni2, ACR>30mg/mmol, phosphate>1.4mmol/L and cFLC>120mg/L
  • cFLC cut-off was ROC determined.
  • eGFR cut-off is the median for CKD stage 4
  • the optimal cut-off for risk assessment of progression using combined FLC (cFLC) was 96.3mg/L.
  • cFLC combined FLC
  • an optimal model was developed which classified patients by the number of risk factors that they were positive for. These risk factors included: Diabetes (Yes/No), eGFR ⁇ 20ml/min/1.73m , serum phosphate>1.36mmol/L, albumin/creatinine ratio (ACR) >30 (i.e. marco-albuminuria), and serum cFLC >104mg/L.
  • This model was further improved by using the following risk factors: cFLC > 120 mg/L, ACR > 30, eGFR ⁇ 20 mL/min/1.73m" and serum phosphate > 1.4 mmol/L. This has been found to classify patients without the need to determine whether diabetes is present in the patient, though this may still optionally be determined.
  • Table 6 shows cross-tabulation of patients from the development population who progressed to RRT over the duration of patient follow-up and within the first year of follow-up. Patients were scored by the number of risk factors for which they were positive; risk factors included eGFR ⁇ 20ml/min/1.73m 2 , ACR>30mg/mmol, phosphate>1.4mmol/L and cFLC>120mg/L. Kaplan Meier analysis of this data is shown in Figures 2(a) and (b).

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  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Molecular Biology (AREA)
  • Chemical & Material Sciences (AREA)
  • Biomedical Technology (AREA)
  • Urology & Nephrology (AREA)
  • Hematology (AREA)
  • Immunology (AREA)
  • Biotechnology (AREA)
  • Microbiology (AREA)
  • Cell Biology (AREA)
  • Proteomics, Peptides & Aminoacids (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Pathology (AREA)
  • Investigating Or Analysing Biological Materials (AREA)

Abstract

La présente invention concerne un procédé permettant d'identifier le risque d'un patient présentant une néphropathie chronique (CKD) nécessitant une transplantation rénale (RRT) dans une période de temps prédéfinie et comprenant les étapes consistant à déterminer une valeur de chaînes légères libres (FLC), de préférence des FLC combinées, dans un échantillon provenant d'un patient, à comparer la valeur avec une valeur prédéfinie et à attribuer une note de risque à cette valeur de FLC dans l'échantillon pour indiquer le risque du patient ayant besoin d'une RRT sur une durée prédéfinie.
EP13780189.0A 2012-10-10 2013-10-09 Dosage de néphropathie chronique Withdrawn EP2906955A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB201218137A GB201218137D0 (en) 2012-10-10 2012-10-10 Chronic kidney disease assay
PCT/GB2013/052628 WO2014057263A1 (fr) 2012-10-10 2013-10-09 Dosage de néphropathie chronique

Publications (1)

Publication Number Publication Date
EP2906955A1 true EP2906955A1 (fr) 2015-08-19

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP13780189.0A Withdrawn EP2906955A1 (fr) 2012-10-10 2013-10-09 Dosage de néphropathie chronique

Country Status (3)

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EP (1) EP2906955A1 (fr)
GB (1) GB201218137D0 (fr)
WO (1) WO2014057263A1 (fr)

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Publication number Priority date Publication date Assignee Title
CN109642907A (zh) * 2016-03-30 2019-04-16 松森昭 用于测定糖尿病罹患的方法

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GB0914535D0 (en) * 2009-08-19 2009-09-30 Binding Site Group The Ltd Prognosis assay
GB2478520A (en) * 2010-03-02 2011-09-14 Binding Site Group Ltd Kidney prognostic assay

Non-Patent Citations (1)

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Title
See references of WO2014057263A1 *

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GB201218137D0 (en) 2012-11-21
WO2014057263A1 (fr) 2014-04-17

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