Dextramer® CMV Kit is a semi-quantitative assay intended for the identification and enumeration of cytomegalovirus (CMV)-specific CD8+ T cells in anticoagulated (Na Heparin) whole blood specimens by flow cytometry.

Dextramer® CMV Kit is indicated for assessment of CMV-specific immune status and risk of CMV reactivation in adult human stem cell transplant patients following immunosuppression and used in conjunction with other laboratory and clinical findings.

The kit cannot be used to measure CMV infection or disease.

The kit is limited to individuals with the following HLA types: A0101, A0201, B0702, B0801, B*3501.

Special instrument requirements:

FACSCanto II flow cytometer (Becton Dickinson).

Device Description

The Dextramer® CMV Kit comprises 5 CMV Dextramers, Negative control as well as 3 antibodies recognizing CD3, CD4, and CD8. The Dextramer® CMV Kit accurately enumerates CMV-specific T cells in blood samples. This involves a two-step procedure followed by analysis by flow cytometry:

Step 1: Determination of the percentage of CMV-specific CD3CD8 T cells in the sample (Tube A)

Step 2: Determination of the absolute number of CD3CD8 T-cells in the sample (Tube C)

The absolute number of CMV-specific CD3CD8 T cells/ul blood is then determined.

AI/ML Overview

This document is a 510(k) summary for the Immudex Dextramer® CMV Kit, detailing its substantial equivalence to a predicate device and presenting performance characteristics from non-clinical and clinical studies.

Here's a breakdown of the requested information:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state "acceptance criteria" in the traditional sense (e.g., a specific threshold that must be met for approval for each metric). Instead, it presents performance characteristics. For comparative studies, substantial equivalence based on statistical metrics (slope, intercept, r-value) is used. For clinical studies, a statistically significant risk ratio is the performance indicator.

Performance Characteristic	Acceptance Criteria (Implicit)	Reported Device Performance
Non-clinical studies
Analytical sensitivity	Lowest concentration measurable with acceptable CV% (e.g., <20%)	1 cell/uL (CV% below 20%)
Analytical specificity	CMV seronegative samples should be below the functional assay sensitivity.	100% (35/35) CMV seronegative samples showed 0.00 - 0.06 cells/ul, below 1 cell/ul.
Inter-lab reproducibility	Acceptable CV% range	CV ranged between 6% and 18%
Intra-lab reproducibility	Acceptable CV% range	CV ranged between 5% and 14%
Linearity - Recovery	Linearity demonstrated across a specified range with acceptable slope and recovery.	Linearity between 1-107 CMV-specific T cells/ul with slope 0.98-1.08. Recovery 73-134%.
Interference	No significant interference from tested cell populations.	No significant interference from monocytes (2x normal), granulocytes (3x normal), platelets (3x normal), and red blood cells (2x normal).
Cross-reaction	No significant cross-reaction with allele mismatching CMV Dextramer reagents; results should be below functional assay sensitivity.	All results from 4 blood samples with HLA mis-matched CMV Dextramer were within 0.00 - 0.11 cells/ul, below 1 cell/ul.
Comparison with predicate	Substantial equivalence based on Deming regression for both CD8+ T-cells and CMV-specific T-cells (slope close to 1, intercept close to 0, high r).	CD8+ T-cells: Slope 0.984 (95% CI: 0.92 to 1.05), Intercept -0.4406 (95% CI: -8.47 to 7.59), r 0.905.
		CMV-specific T-cells: Slope 1.010 (95% CI: 0.89 to 1.13), Intercept 0.39 (95% CI: 0.09 to 0.69), r 0.952.
Clinical studies
Risk of antigenemia	Statistically significant correlation between CMV-specific T-cell status and risk of CMV antigenemia.	Relative Risk of developing antigenemia is 3.4 (95% CI: 1.57 - 7.46) for patients with < 7 cells/uL CMV-specific CD8+ T cells compared to patients with ≥ 7 cells/uL (at Day 100 post-transplant). Only Day 100 showed significant association.

2. Sample Size Used for the Test Set and the Data Provenance

Non-clinical (Analytical specificity, Cross-reaction):
- Analytical specificity: 35 routine blood specimens.
- Cross-reaction: 4 blood samples.
- Provenance: Not specified, but generally analytical studies are conducted in a controlled lab environment.
Non-clinical (Comparison with predicate):
- 117 MHC multimer measurements from blood specimens of stem cell transplant recipients.
- Provenance: Not specified, but likely from clinical sites or blood banks.
Clinical Studies:
- Test set: 120 allogeneic SCT patients were followed. The specific numbers used for the 2x2 table for "Risk of developing CMV antigenemia after Day 100" are:
  - < 7 cells/ul: 10 patients (9 Yes, 1 No)
  - ≥ 7 cells/ul: 19 patients (5 Yes, 14 No)
  - Total for this specific analysis: 29 patients.
- Data Provenance: Prospective study with allogeneic SCT patients. Country of origin not specified.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and the Qualifications of Those Experts

The document does not mention the use of experts to establish ground truth for the device's performance directly.

For the non-clinical studies, the ground truth for cell counts and specificities would be based on validated laboratory methods and reference standards.
For the clinical study, the "ground truth" for CMV antigenemia was based on "recurrence of CMV infection and determination of numbers of CMV-specific CD8+ T cells" and "CMV antigenemia," which are clinical outcomes or standard laboratory diagnoses. No expert panel for ground truth adjudication is indicated.

4. Adjudication Method for the Test Set

Not applicable. There is no indication of an adjudication method by experts for establishing ground truth in this submission. The outcomes (CMV antigenemia, cell counts) are measured or clinically diagnosed.

5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was Done, If So, What was the Effect Size of How Much Human Readers Improve with AI vs without AI assistance

Not applicable. This device is a semi-quantitative assay (a laboratory kit for flow cytometry), not an AI-assisted diagnostic imaging or interpretation tool for human readers. There is no mention of human reader performance or AI assistance.

6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was Done

The device itself is a standalone laboratory assay (kit) that is used with a flow cytometer. The performance characteristics described are for the kit's ability to identify and enumerate CMV-specific T cells, which is essentially its "standalone" performance. There isn't an "algorithm" in the typical sense of AI, but the kit and its associated flow cytometry analysis constitute the device's standalone operation.

7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc)

Non-clinical studies: The ground truth for analytical performance (sensitivity, specificity, reproducibility, linearity, cross-reactivity) is inherently based on the known quantities/characteristics of the samples used in the experiments. For the "Comparison with predicate," the predicate device's results are used as a reference point for substantial equivalence.
Clinical studies: The ground truth for the clinical correlation (risk of antigenemia) is clinical outcomes data (development of CMV antigenemia) and the enumeration of CMV-specific CD8+ T cells by the device itself and the predicate. CMV antigenemia is a laboratory-confirmed clinical event.

8. The Sample Size for the Training Set

The document does not detail a separate "training set" for the Dextramer CMV Kit, as it is a laboratory assay kit and not a machine learning algorithm that typically undergoes a distinct training phase. The development and validation of such a kit would involve internal experiments and optimization, but these are not typically referred to as a "training set" in the context of device approval documents like this.

9. How the Ground Truth for the Training Set Was Established

Not applicable, as a distinct "training set" in the context of machine learning and its associated ground truth establishment is not described for this device. The kit's components and methodology are based on established scientific principles in immunology and flow cytometry.

Summary

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Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002

March 2, 2017

Immudex Aps Liselotte Brix Chief Operating Officer Fruebjergvej 3 Copenhagen, DK 2100

Re: K153538

Trade/Device Name: Dextramer CMV Kit Regulation Number: 21 CFR 864.5220 Regulation Name: Automated differential cell counter Regulatory Class: II Product Code: GKZ Dated: February 22, 2017 Received: February 24, 2017

Dear Dr. Brix:

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food. Drug. and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA). it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Parts 801 and 809); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

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If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and 809), please contact the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address

http://www.fda.gov/MedicalDevices/Resourcesfor You/Industry/default.htm. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to

http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.

You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address

http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.

Sincerely,

Kelly Oliner -S

FOR

Leonthena R. Carrington, MS, MBA, MT (ASCP) Director Division of Immunology and Hematology Devices Office of In Vitro Diagnostics and Radiological Health Center for Devices and Radiological Health

Enclosure

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DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration

Indications for Use

Form Approved: OMB No. 0910-0120 Expiration Date: January 31, 2017 See PRA Statement below.

510(k) Number (if known) K153538

Device Name

Dextramer® CMV Kit

Indications for Use (Describe)

The kit cannot be used to measure CMV infection or disease.

The kit is limited to individuals with the following HLA types: A0101, A0201, B0702, B3501.

Special instrument requirements:

FACSCanto II flow cytometer (Becton Dickinson).

Type of Use (Select one or both, as applicable)

区 Prescription Use (Part 21 CFR 801 Subpart D)

Over-The-Counter Use (21 CFR 801 Subpart C)

CONTINUE ON A SEPARATE PAGE IF NEEDED.

This section applies only to requirements of the Paperwork Reduction Act of 1995.

DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW.

The burden time for this collection of information is estimated to average 79 hours per response, including the time to review instructions, search existing data sources, gather and maintain the data needed and complete and review the collection of information. Send comments regarding this burden estimate or any other aspect of this information collection, including suggestions for reducing this burden, to:

Department of Health and Human Services Food and Drug Administration Office of Chief Information Officer Paperwork Reduction Act (PRA) Staff PRAStaff@fda.hhs.gov

"An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB number."

FORM FDA 3881 (8/14)

Page 1 of 1

PSC Publishing Services (301) 443-6740

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D. 510(k) Summary

Image /page/3/Picture/1 description: The image shows the logo for "Immudex", a company focused on immunology. The word "Immudex" is written in a bold, sans-serif font, with the first two letters in orange and the rest in blue. Below the company name is the tagline "Immunology Taken to a Higher Level", written in a smaller, sans-serif font.

1. Applicant:

Immudex ApS Fruebjergvej 3 DK-2100 København Ø DENMARK

2. Contact Person:

Liselotte Brix Phone: +45 39179772 / +45 40910121 E-mail: lb@immudex.com

3. Summary Preparation Date:

February 28, 2017

4. Device Name and Classification:

Trade Name (proprietary name): Dextramer® CMV Kit

Common Name (usual name): None

Classification: Class II

Product code: GKZ, Counter, differential cell

Panel: Hematology

Regulation section: 21 CFR § 864.5220, Automated differential cell counter

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5. Substantial Equivalence Information:

Predicate name(s) and predicate 510(k) number(s):

Predicate Device Name(s)	Manufacturer	510(k) number(s)
iTAg MHC Tetramer CMV Kit	Beckman Coulter	K051122

Comparison with Predicate:

	Device	Predicate
Name	Dextramer® CMV Kit	iTAg MHC Tetramer CMV Kit
Intended Use	Identification and enumeration ofcytomegalovirus (CMV)-specificCD8+ T cells in anticoagulatedvenous whole bloodin adult human stem cell transplantpatients by flow cytometry.	Same
Kitcomponents&AccessoryReagents	Anti-CD8/FITCAnti-CD4/PEAnti-CD3/PerCPDextramer CMV Set of 5 individualMHC Dextramers labeled with PE.FACS Lysing Solution	Anti-CD8/FITCAnti-CD4/PEAnti-CD3/PC5CMV Tetramer Set of 5 individualMHC Tetramers labeled with PE.iTAg Lyse Reagent
Instrument	TruCountFlow cytometer	Flow-Count™ Fluorospheres
Sample type	Whole blood	Same
Anti-coagulant	Heparin	EDTA
Cell typedetected	CMV-specific CD8 + T cellsHuman T lymphocytes (CD3+),suppressor/cytotoxic (CD3+CD8+)T-lymphocyte subsets, andhelper/inducer (CD3+CD4+) T-lymphocyte subsets	Same
Detectionmethod	Multimers of MHC moleculesdisplaying CMV-specific peptideAntibodies bound to CD3, CD4 andCD8	Same
MHCMultimerbackbone	Dextran	Streptavidin
HLA types(peptidesequence)	HLA-A0101 (VTEHDTLLY)HLA-A0201 (NLVPMVATV)	SameSame
	HLA-B*0702 (TPRVTGGGAM)	Same

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Controls	HLA-B*0801 (ELRRKMMYM)Same
	HLA-B*3501 (IPSINVHHY)Same
	Negative controlSimilar
Negative control aboveSame
Control cellsIMMUNO-TROL Control Cells

6. Device Description:

The Dextramer® CMV Kit comprises 5 CMV Dextramers, Negative control as well as 3 antibodies recognizing CD3, CD4, and CD8:

Dextramer reagents

HLA-A*0101 / VTEHDTLLY / PE	25 tests/0.25 ml	Cat. No. CA2131-PE
HLA-A*0201 / NLVPMVATV / PE	50 tests/0.50 ml	Cat. No. CB2132-PE
HLA-B*0702 / TPRVTGGGAM / PE	25 tests/0.25 ml	Cat. No. CH2136-PE
HLA-B*0801 / ELRRKMMYM / PE	25 tests/0.25 ml	Cat. No. CI2137-PE
HLA-B*3501 / IPSINVHHY / PE	25 tests/0.25 ml	Cat. No. CK2138-PE
Negative control / PE	150 tests/1.50 ml	Cat. No. CI3233-PE

Antibodies

Anti-CD8/FITC	2 ml	Cat. No. A-CD8-FITC
Anti-CD3/PerCP	2 ml	Cat. No. A-CD3-PerCP
Anti-CD4/PE	2 ml	Cat. No. A-CD4-PE

The Dextramer® CMV Kit accurately enumerates CMV-specific T cells in blood samples. This involves a two-step procedure followed by analysis by flow cytometry:

Step 1: Determination of the percentage of CMV-specific CD3CD8 T । cells in the sample (Tube A)

Step 2: Determination of the absolute number of CD3CD8 T-cells in the sample (Tube C)

The absolute number of CMV-specific CD3CD8 T cells/ul blood is then determined.

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7. Intended use(s):

The kit cannot be used to measure CMV infection or disease.

The kit is limited to individuals with the following HLA types: A0101, A0201, B0702, B0801, B*3501.

Special instrument requirements:

FACSCanto II flow cytometer (Becton Dickinson).

8. Indication(s) for use:

The kit cannot be used to measure CMV infection or disease.

The kit is limited to individuals with the following HLA types: A0101, A0201, B0702, B0801, B*3501.

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Special instrument requirements:

FACSCanto II flow cvtometer (Becton Dickinson).

9. Performance Characteristics:

Non-clinical studies

Analytical sensitivity

The functional assay sensitivity is 1 cells/ul as determined by the lowest concentration of cells (cells/ul) that can be determined with a CV% below 20%.

Analytical specificity

100% (35/35) routine blood specimens from CMV seronegative stem cell transplant recipients showed 0.00 - 0.06 cells/ul and thus below the functional assay sensitivity of 1 cell/ul.

Inter-lab reproducibility

The inter-lab reproducibility CV ranged between 6% and 18%.

Intra-lab reproducibility

The intra-lab reproducibility CV ranged between 5% and 14%.

Linearity - Recovery

The Dextramer CMV assay showed linearity in the range of 1-107 CMV-specific T cells/ul with a slope ranging from 0.98-1.08. Recovery was 73-134%.

Interference

There was no significant interference from the tested cell populations equivalent to 2x normal level for monocytes, equivalent to 3x normal level for granulocytes, equivalent to 3x normal level for platelets, and equivalent to 2x normal level for red blood cells.

Cross-reaction

No significant cross-reaction with allele mismatching CMV Dextramer reagents. All results from analysis of 4 blood samples with CMV-specific T cells with HLA mis-matched CMV Dextramer were within 0.00 - 0.11 cells/ul and thus below the functional assay sensitivity of 1 cell/ul.

Comparison with predicate

Analysis of blood specimens from stem cell transplant recipients representing 5 alleles for a total of 117 MHC multimer measurements using iTAq MHC Tetramer CMV Kit and Dextramer CMV Kit showed substantial equivalence based on

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Deming regression for enumeration of the subset of CD8+ T-cells and CMVspecific T-cells.

	Slope	95% CI	Intercept	95% CI	r
CD8+ T-cells	0.984	0.92 to 1.05	-0.4406	-8.47 to 7.59	0.905
CMV-specific T-cells	1.010	0.89 to 1.13	0.39	0.09 to 0.69	0.952

Clinical studies

A prospective study with 120 allogeneic SCT patients followed for up to one year for recurrence of CMV infection and determination of numbers of CMV-specific CD8+ T cells using the CMV Dextramer Kit. Dextramer analysis were performed pre-transplant at day 30, 100 and 360 and included the alleles HLA-A0101, A0201, B0702, B0801 and B*3501.

68 patients were CMV seropositive (recipient and/or donor) prior to transplantation of which 34 patients developed antigenimia.

2x2 tables are provided for each time point posttransplant showing correlation of CMV-specific T-cell and occurance of CMV antigenimia and used for calculation of the risk of CMV infection/antigenimia after Day 100

Risk of developing CMV antigenemia after Day 100

Risk is defined as risk of patients with less than 7 cells/ul of developing CMV infection post Day 100 compared to patients with more than 7 cells/ul.

Day 100	Development of antigenemia (post Day 100)
# CMV+ T cells	Yes	No	Total
<7 cells/ul	9	1	10
≥7 cells/ul	5	14	19
Total	14	15	29
Risk	3.4 (95% CI: 1.57 – 7.46)

Dextramer results were evaluated at Day 30, 100, and Day 365 post-transplant. Only day 100 shows significant association between CMV-specific CD8+ T cells status (<7 cells/µL or ≥ 7 cells/µL) and development of antigenemia. Results summarized in the table above show that the relative risk in developing antigenemia is 3.4 (95% Cl: 1.57 - 7.46) for patients with < 7 cells/µL CMVspecific CD8+ T cells determined by the Dextramer CMV kit, as compared to patients with ≥ 7 cells/uL CMV-specific CD8+ T cells.

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10. Conclusion:

The Dextramer® CMV Kit has similar intended use and indications as the predicates iTAg MHC Tetramer CMV Kit.

The performance of the Dextramer CMV Kit is substantially equivalent to the performances of iTAg MHC Tetramer CMV Kit.

Clinical data support the use of Dextramer® CMV Kit for assessment of CMVspecific immune status and risk of CMV reactivation in adult human stem cell transplant patients following immunosuppression and for use in conjunction with other laboratory and clinical findings.

Regulation Number and Section

§ 864.5220 Automated differential cell counter.

(a)
Identification. An automated differential cell counter is a device used to identify one or more of the formed elements of the blood. The device may also have the capability to flag, count, or classify immature or abnormal hematopoietic cells of the blood, bone marrow, or other body fluids. These devices may combine an electronic particle counting method, optical method, or a flow cytometric method utilizing monoclonal CD (cluster designation) markers. The device includes accessory CD markers.(b)
Classification. Class II (special controls). The special control for this device is the FDA document entitled “Class II Special Controls Guidance Document: Premarket Notifications for Automated Differential Cell Counters for Immature or Abnormal Blood Cells; Final Guidance for Industry and FDA.”