ESENSOR WARFARIN SENSITIVITY AND XT-8 INSTRUMENT

K073720 · Osmetech Molecular Diagnostics · ODW · Jul 17, 2008 · Clinical Toxicology

Device Facts

• Record ID: K073720
• Device Name: ESENSOR WARFARIN SENSITIVITY AND XT-8 INSTRUMENT
• Applicant: Osmetech Molecular Diagnostics
• Product Code: ODW · Clinical Toxicology
• Decision Date: Jul 17, 2008
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 862.3360
• Device Class: Class 2

Intended Use

The eSensor® Warfarin Sensitivity Test is an in vitro diagnostic for the detection and genotyping of the *2 and * 3 alleles of the cytochrome P450 (CYP450) 2C9 gene locus and the Vitamin K epoxide reductase C1 (VKORC1) gene promoter polymorphism (-1639G>A) from genomic DNA extracted from fresh whole blood samples preserved with EDTA, as an aid in the identification of patients at risk for increased warfarin sensitivity. The eSensor® Warfarin Sensitivity Test is for Rx only professional use within the confines of a licensed laboratory, as defined by the Clinical Laboratory Improvement Amendments (CLIA) of 1988. The eSensor® XT-8 Instrument is an in vitro diagnostic device intended for genotyping multiple mutations or polymorphisms in an amplified DNA sample utilizing electrochemical detection technology.

Device Story

System performs in vitro genotyping of DNA samples; utilizes bench-top XT-8 workstation and single-use disposable cartridges. Input: genomic DNA extracted from EDTA-preserved whole blood; amplified via PCR and treated with exonuclease to generate single-stranded targets. Process: hybridization of target DNA to capture probes on electrode array; sandwich assay with ferrocene-labeled signal probes. Detection: voltammetry measures oxidation potential of ferrocene labels to identify alleles. Output: automated genotype report provided to clinician. Used in clinical laboratory settings by trained personnel. Benefits: aids identification of patients at risk for increased warfarin sensitivity, supporting personalized dosing decisions.

Clinical Evidence

Bench testing only. Reproducibility study (3 sites, 5 days, 3 lots) showed 100% agreement with DNA sequencing after resolving initial operator/manufacturing errors. Method comparison study (157 samples) showed 100% agreement with bi-directional DNA sequencing (95% LCB 98.1% per-sample; 99.4% per-SNP). Limit of detection established at 0.1 ng to 1000 ng DNA. No interference observed from common blood substances (bilirubin, triglycerides, hemoglobin, warfarin, heparin, etc.).

Technological Characteristics

Solid-phase electrochemical detection; sandwich hybridization assay. Materials: disposable cartridge with EEPROM chip, electrode array with synthetic oligonucleotide capture probes and ferrocene-labeled signal probes. Energy: electrical (voltammetry). Connectivity: standalone instrument with 1-3 processing towers. Software: C# application software, embedded firmware (C/DSP). Sterilization: N/A (disposable). Standards: CLSI EP7-A2.

Indications for Use

Indicated for patients requiring warfarin therapy to identify those at risk for increased warfarin sensitivity by genotyping CYP2C9 (*2, *3 alleles) and VKORC1 (-1639G>A promoter polymorphism) from EDTA-preserved whole blood genomic DNA.

Regulatory Classification

Identification

A drug metabolizing enzyme genotyping system is a device intended for use in testing deoxyribonucleic acid (DNA) extracted from clinical samples to identify the presence or absence of human genotypic markers encoding a drug metabolizing enzyme. This device is used as an aid in determining treatment choice and individualizing treatment dose for therapeutics that are metabolized primarily by the specific enzyme about which the system provides genotypic information.

Special Controls

The special control is FDA's guidance document entitled "Class II Special Controls Guidance Document: Drug Metabolizing Enzyme Genotyping System."

*Classification.* Class II (special controls). The special control is FDA's guidance document entitled “Class II Special Controls Guidance Document: Drug Metabolizing Enzyme Genotyping Test System.” See § 862.1(d) for the availability of this guidance document.

Predicate Devices

• Verigene® Warfarin Metabolism Nucleic Acid Test (k070804)

Submission Summary (Full Text)

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K073720

# 510(k) Summary

#

This summary of the 510(k) safety and effectiveness information is being submitted in accordance with the requirements of SMDA 1900 and CFR 807.92

| 510(k) number | |
|--------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Summary<br>Preparation<br>Date | July 15, 2008 |
| Submitted by | Osmetech Molecular Diagnostics<br>757 South Raymond Ave.<br>Pasadena, CA 91105<br>Phone: [phone]<br>Fax: [phone] |
| Contact | Robert Dicheck, Vice President of Quality & Regulatory Affairs (Official Correspondent)<br>Michael Reed, Ph.D., Director of Product Development & Project Manager |
| Proprietary<br>names and<br>classifications | For the assay:<br>eSensor® Warfarin Sensitivity Test<br>Regulations: 21CFR §862.3360 - Drug Metabolism Enzyme Genotyping Test<br>21CFR §864.7750 - Prothrombin Time Test<br>Panels: 91 Toxicology & 81 Hematology<br>Classification: II<br>Product Codes: ODW Cytochrome P450 2C9 (CYP450 2C9) Drug Metabolizing Enzyme Genotyping<br>System<br>ODV Vitamin K epoxide reductase complex subunit 1 (VKORC1) Genotyping<br>System<br>For the instrument:<br>eSensor® XT-8 System<br>Regulation: 21CFR §862.2570 - Instrument for Clinical Multiplex Test Systems<br>Panel: 75 Clinical Chemistry<br>Classification: II<br>Product Code: NSU Instrumentation for Clinical Multiplex Test Systems |
| Common<br>names | For the Assay:<br>Warfarin Sensitivity Test (CYP2C9*2, CYP2C9*3, VKORCI)<br>For the Instrument.<br>Bench-top molecular diagnostics workstation |
| Intended uses | • The eSensor® Warfarin Sensitivity Test is an <i>in vitro</i> diagnostic for the detection and genotyping of the *2<br>and * 3 alleles of the cytochrome P450 (CYP450) 2C9 gene locus and the Vitamin K epoxide reductase<br>C1 (VKORC1) gene promoter polymorphism (-1639G>A) from genomic DNA extracted from fresh whole<br>blood samples preserved with EDTA, as an aid in the identification of patients at risk for increased<br>warfarin sensitivity. The eSensor® Warfarin Sensitivity Test is for Rx only professional use within the<br>confines of a licensed laboratory, as defined by the Clinical Laboratory Improvement Amendments (CLIA)<br>of 1988.<br>• The eSensor® XT-8 Instrument is an <i>in vitro</i> diagnostic device intended for genotyping multiple mutations<br>or polymorphisms in an amplified DNA sample utilizing electrochemical detection technology. |
| Special<br>conditions for<br>use<br>statement(s) | The eSensor® Warfarin Sensitivity Test is for Rx only professional use within the confines of a licensed<br>laboratory, as defined by the Clinical Laboratory Improvement Amendments (CLIA) of 1988. |
| Predicate<br>devices | Nanosphere Verigene® Warfarin Metabolism Nucleic Acid Test and Verigene® System |

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| Device<br>descriptions | The eSensor® XT-8 System is an <i>in vitro</i> diagnostic device for performing hybridization and genotyping of<br>multiple mutations and/or polymorphisms in an amplified DNA sample. The XT-8 Instrument is configured<br>with one to three processing towers which perform up to 8 simultaneous tests per tower. The XT-8 System<br>uses a single-use, disposable test cartridge to perform hybridization and genotyping in approximately 30<br>minutes per sample. The cartridge contains an EEPROM chip which transmits the cartridge lot number,<br>expiration date and protocol identity to the instrument. | | |
|--------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------|
| | The analysis process for each sample consists of three steps: 1) Genomic DNA isolated from whole blood<br>obtained using EDTA as anti-coagulant is combined with PCR Mix and Taq polymerase enzyme and is<br>subjected to amplification of target sequences by PCR using a thermal cycler. 2) Amplified DNA is treated<br>with exonuclease enzyme to generate single-stranded target DNA. 3) Single-stranded, amplified target DNA<br>is mixed with hybridization and genotyping reagents and transferred to an eSensor® Warfarin Sensitivity<br>Test cartridge, and the cartridge is inserted in the eSensor® XT-8 Instrument. The instrument controls the<br>circulation of the sample inside the cartridge containing to allow hybridization at a controlled temperature,<br>and then detects and genotypes the sample by voltammetry. | | |
| | Genotyping of the test panel polymorphisms is achieved by a sandwich assay principle: 1) Each pair of<br>electrodes contains a different synthetic oligonucleotide capture probe which is complementary to one of<br>the target DNA fragments. 2) The hybridization reagents contain pairs of ferrocene-labeled synthetic<br>oligonucleotide signal probes; one member of each pair is complementary to the major allele sequence of<br>the target polymorphism, while the second member of the pair is complementary to the minor allele<br>sequence. Each member of the probe pair has a ferrocene label with a different oxidation potential for each<br>allele. 3) Single-stranded, amplified target DNA hybridizes to its specific capture probe, and in turn<br>hybridizes to the allele-specific, ferrocene-labeled signal probe. 4) Each electrode of the array is analyzed<br>by voltammetry; the target polymorphism is determined by the location of the electrode containing the<br>capture probe, and the genotype is identified by the ratio of signals from the allele-specific ferrocene labels.<br>The array also includes positive and negative controls to confirm the hybridization reaction and detect non-<br>specific signals.<br>Upon completion of the test, the EEPROM chip on the cartridge contains information that prevents its re-<br>use with a new sample. The instrument analyzes the results and provides a report of the test results. The<br>operator removes the used cartridge from the slot of the XT-8 Instrument, and that slot is ready to accept a<br>new test. | | |
| Comparison to<br>technological<br>features of the<br>predicate<br>device | The following is a comparison of the Osmetech Molecular Diagnostics eSensor® Warfarin Sensitivity Test<br>and XT-8 System to the Nanosphere, Inc. Verigene® Warfarin Metabolism Nucleic Acid Test and<br>Verigene® System. | | |
| | Characteristic | Verigene® Warfarin Metabolism<br>Nucleic Acid Test and Verigene®<br>System | eSensor® Warfarin Sensitivity<br>Test and XT-8 System |
| | Test type | Qualitative genetic test for single<br>nucleotide polymorphism detection | Same as predicate |
| | Sample Type | Genomic DNA obtained from a human<br>whole blood sample | Same as predicate |
| | Target of detection | Single-nucleotide polymorphism | Same as predicate |
| | DNA extraction | Performed off-line | Same as predicate |
| | Genes | Cytochrome P450 2C9 and VKORC1 | Same as predicate |
| | Number of Loci<br>genotyped | 3 | Same as predicate |
| | Genotyping reaction<br>location | Test cartridge | Same as predicate |
| | Genotyping principle | Sandwich hybridization test | Same as predicate |
| | User interface | Graphical user interface with touch<br>screen | Same as predicate |
| | Instrument operating<br>system | Random access compatible with<br>multiple simultaneous test types | Same as predicate |
| | Assay results | Assay signal results are interpreted by a<br>software program and are assigned a<br>genotype that is presented to the end-<br>user in a report format | Same as predicate |

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| Performance<br>characteristics | Reproducibility:<br>Site to Site, Operator to Operator, Lot to Lot, Day to Day and Run to Run reproducibility<br>A reproducibility study was performed at three sites, two external and one internal. Five genomic DNA samples covering all possible genotypes for all three alleles in the Warfarin Sensitivity Test were tested in duplicate runs on a daily basis by the same operator for 5 days at 3 different sites. One site performed the same reproducibility testing twice each day, using two different operators and the same testing materials. Three kit lots were randomized throughout the study. An additional run using the same kit lot and sample as for the first-pass test were performed for test that gave a no-call result.<br>The data were evaluated after first-pass results and following the additional run for no-calls. All samples gave 100% agreement with DNA sequencing. There were 9 first-pass no-calls: one was due to a cartridge manufacturing assembly error, and the remaining eight were due to operator error in set-up of the exonuclease reaction The following tables summarize the percent agreement between results obtained at each of the sites and DNA sequencing, before (first-pass) and after additional testing of no-calls (final): | | | | | | | |
|------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------|--------------------------|--------------------------|---------------------|-----------------------|-----------------------|-----------------------|
| Summary of Inter-laboratory and Inter-Operator Reproducibility Results | | | | | | | | |
| Site | Operator | Allele | Total tests | First-pass correct calls | First-pass no-calls | Final correct calls | Final incorrect calls | % Agreement (95% LCB) |
| 1 | 1 | 2C9*2 | 50 | 42 | 8 | 50 | 0 | 100% (94.2%) |
| | | 2C9*3 | 50 | 42 | 8 | 50 | 0 | 100% (94.2%) |
| | | VKORC1 | 50 | 42 | 8 | 50 | 0 | 100% (94.2%) |
| 1 | 2 | 2C9*2 | 50 | 49 | 1 | 50 | 0 | 100% (94.2%) |
| | | 2C9*3 | 50 | 49 | 1 | 50 | 0 | 100% (94.2%) |
| | | VKORC1 | 50 | 49 | 1 | 50 | 0 | 100% (94.2%) |
| 2 | 3 | 2C9*2 | 50 | 50 | 0 | 50 | 0 | 100% (94.2%) |
| | | 2C9*3 | 50 | 50 | 0 | 50 | 0 | 100% (94.2%) |
| | | VKORC1 | 50 | 50 | 0 | 50 | 0 | 100% (94.2%) |
| 3 | 4 | 2C9*2 | 50 | 50 | 0 | 50 | 0 | 100% (94.2%) |
| | | 2C9*3 | 50 | 50 | 0 | 50 | 0 | 100% (94.2%) |
| | | VKORC1 | 50 | 50 | 0 | 50 | 0 | 100% (94.2%) |
| All | | 2C9*2 | 200 | 191 | 9 | 200 | 0 | 100% (98.5%) |
| All | | 2C9*3 | 200 | 191 | 9 | 200 | 0 | 100% (98.5%) |
| All | | VKORC1 | 200 | 191 | 9 | 200 | 0 | 100% (98.5%) |
| Summary of Reproducibility Results sorted by sample and genotype. | | | | | | | | |
| Sample | Genotype | Total Tests | First-pass correct calls | First-pass no-calls | Final correct calls | Final Incorrect calls | % Agreement (95% LCB) | |
| 01 | 2C9 *1/*1 VKORC1 G/G | 40 | 37 | 3 | 40 | 0 | 100% (92.8%) | |
| 02 | 2C9 *2/*3 VKORC1 G/A | 40 | 38 | 2 | 40 | 0 | 100% (92.8%) | |
| 03 | 2C9 *2/*2 VKORC1 G/G | 40 | 39 | 1 | 40 | 0 | 100% (92.8%) | |
| 04 | 2C9 *3/*3 VKORC1 G/G | 40 | 39 | 1 | 40 | 0 | 100% (92.8%) | |
| 05 | 2C9 *1/*3 VKORC1 A/A | 40 | 38 | 2 | 40 | 0 | 100% (92.8%) | |

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#### Genomic DNA extraction reproducibility

Three different sites extracted 7 whole blood samples of different genotypes in triplicate and tested them using the eSensor® Warfarin Sensitivity Test. Each site used a different commercially available extraction method, which yielded DNA with A260/280 ratios of 1.7 to 3.3. First pass results were in 100% agreement with DNA sequencing, as shown in the following tables:

Summary of Inter-laboratory Extraction Reproducibility Results

| Site | Allele | # Total Tests | Correct Calls | Incorrect Calls | No Calls | % Agreement (95% LCB) |
|------|--------|---------------|---------------|-----------------|----------|----------------…