QUALICODE B. BURGDORFERI IGM WESTERN BLOT KIT, MODEL DK-C062-024

K991062 · Immunetics, Inc. · LSR · Sep 21, 1999 · Microbiology

Device Facts

• Record ID: K991062
• Device Name: QUALICODE B. BURGDORFERI IGM WESTERN BLOT KIT, MODEL DK-C062-024
• Applicant: Immunetics, Inc.
• Product Code: LSR · Microbiology
• Decision Date: Sep 21, 1999
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.3830
• Device Class: Class 2

Intended Use

The Immunetics QualiCode™ B. burgdorferi IgM Western Blot Kit is intended for use in testing human serum samples which have demonstrated positive or equivocal responses using EIA or IFA test procedures to provide supportive evidence of infection with Borrelia burgdorferi. The QualiCode B. burgdorferi IgM Western Blot Kit can be used to test human sera for IgM antibodies during the acute phase of disease, within one month of infection, in accordance with CDC/ASTPHLD guidelines. During this period, patients may not yet have developed a detectable IgG response. Beyond one month from infection, an IgG Western Blot test is recommended. Patients should not be tested solely for IgM antibodies at this stage due to the higher probability of false positive results. Symptomatic patients showing IgM but not IgG antibodies at an early stage in infection should be re-tested for IgG antibodies 2-4 weeks later.

Device Story

QualiCode B. burgdorferi IgM Western Blot Kit is an in vitro diagnostic assay for detecting human IgM antibodies against B. burgdorferi. Input: human serum samples previously screened via ELISA or IFA. Process: Borrelia proteins are fractionated via SDS-polyacrylamide gel electrophoresis and transferred to nitrocellulose strips. Patient serum is incubated with these strips; human IgM antibodies bind to specific antigens. Bound antibodies are detected using anti-human IgM conjugated with alkaline phosphatase, which reacts with a substrate to produce a visible colored product. Output: qualitative visual assessment of band reactivity compared to controls. Used in clinical laboratories by trained personnel. Results provide supplemental evidence of infection to aid Lyme disease diagnosis. Benefits: higher specificity than screening assays, assisting in confirming early-stage infection.

Clinical Evidence

Clinical trial data evaluated 602 samples for specificity and 186 samples for sensitivity. Specificity: 96% overall (95% CI 93-97%), with 95% in endemic and 96% in non-endemic normal populations; 87% in cross-reactive panel. Sensitivity: 91% for samples <1 month post-onset (n=76), 83% for 1-2 months (n=23), 63% for 3-12 months (n=16), and 47% for >12 months (n=17). Reproducibility studies showed 80% inter-lot, 85% inter-run, and 93% inter-reader agreement.

Technological Characteristics

Western Blot assay using polyacrylamide gel electrophoresis (SDS-PAGE) and nitrocellulose membrane transfer. Detection via alkaline phosphatase-conjugated anti-human IgM and colorimetric substrate reaction. Manual visual interpretation of band reactivity against defined controls.

Indications for Use

Indicated for human patients suspected of Lyme disease who have tested positive or equivocal on initial EIA or IFA screening. Used for IgM antibody detection during the acute phase (within one month of infection). Not indicated for patients beyond one month post-infection (IgG testing recommended) or as a sole diagnostic test.

Regulatory Classification

Identification

Treponema pallidum treponemal test reagents are devices that consist of the antigens, antisera and all control reagents (standardized reagents with which test results are compared) which are derived from treponemal sources and that are used in the fluorescent treponemal antibody absorption test (FTA-ABS), the Treponema pallidum immobilization test (T.P.I.), and other treponemal tests used to identify antibodies to Treponema pallidum directly from infecting treponemal organisms in serum. The identification aids in the diagnosis of syphilis caused by bacteria belonging to the genus Treponema and provides epidemiological information on syphilis.

Submission Summary (Full Text)

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# 510(k) Safety and Effectiveness Summary

# Submitted by:

Immunetics, Inc. 63 Rogers Street Cambridge, MA 02142

### Contact Person:

Andrew E. Levin, Ph.D. Scientific Director

(617) 492 - 5416

# Date of Preparation:

September 9, 1999

# 1. Name and Address of Owner/Operator and Manufacturer

Immunetics, Inc. 63 Rogers Street Cambridge, MA 02142

# 2. Product Name

Trade Name: QualiCode™ B. burgdorferi IgM Western Blot Kit

Common Name: B. burgdorferi IgM Western Blot Kit

# 3. Claim of Substantial Equivalence

The characterized samples used for the establishment of Substantial Equivalence were obtained from patients with a clinical diagnosis of Lyme Disease in accordance with the CDC case definition, i.e. based on the presence of EM (erythema migrans) or the presentation of late Lyme clinical manifestations (e.g., arthritic, cardiac, or neurological symptoms). Infection was confirmed by culture of Borrelia from biopsies in many examples.

Each of the clinical trial sites provided specimens that were well characterized by the site using Lyme-specific serological analyses, including EIA and/or Western Blot testing. In particular, specimens selected for the trial were required to have tested positive or indeterminate on a B. burgdorferi screening assay, typically an ELISA, in accordance with the two-tier testing protocol recommended by CDC/ASTPHLD (CDC (1995) "Recommendations for test performance and interpretation from the Second

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National Conference on Serologic Diagnosis of Lyme Disease", Morbid. Mort. Weekly Rep. 44:590-591.).

Substantial equivalence of this device is based on the assessment of performance of the device in these clinical trials in which the well-characterized, archived Lyme Disease specimens, the Centers for Disease Control Lyme Disease Serum Panel, normal donor specimens (from endemic and non-endemic regions), and samples from diverse disease conditions were analyzed.

#### 4. Description

The device is a Western Blot assay. Proteins and other antigenic components of the Borrelia spirochete are fractionated by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The separated proteins are electrophoretically transferred from the gel to nitrocellulose membranes. which are subsequently blocked to minimize non-specific binding and cut into strips. These nitrocellulose strips with resolved Borrelia burgdorferi antigens are then reacted with diluted serum and controls (positive and negative sera of defined reactivity).

During the incubation period, human antibodies specific to the B, burgdorferi antigens, if present in the sample or control, will bind to the antigen to which they have affinity. Unbound serum and non-specific antibodies are washed from the strip. Detection of bound IgM antibodies is accomplished by reacting and incubating the strips with a solution containing anti-human IgM antibodies conjugated with alkaline phosphatase. Unbound conjugate antibodies are removed by washing. The qualitative assessment of the detected IgM antibodies is then accomplished by the reaction of the alkaline phosphatase with a chemical substrate, which is cleaved into a colored, insoluble product that can be visualized. The determination of the reactivity of each unknown specimen is accomplished by comparison of the identified, visualized bands to the Band Identifying and Band Intensity Controls.

#### 5. Intended use

The QualiCode™ B. burgdorferi IgM Western Blot Kit is an in vitro qualitative assay for the detection of human IgM antibodies reactive with Borrelia burgdorferi antigens present on a membrane strip. The QualiCode™ B. burgdorferi IgM Western Blot Kit is intended for supplemental testing of human serum specimens which yield positive or equivocal results on B. burgdorferi ELISA or IFA screening assays. QualiCode test results can provide additional, more specific evidence of infection with B. burgdorferi which may be useful in the diagnosis of Lyme disease.

The QualiCode™ B. burgdorferi IgM Western Blot Kit can be used to test human sera for IgM antibodies during the acute phase of disease, within one month of infection, in accordance with CDC/ASTPHLD guidelines. During this period, patients may not yet have developed a detectable IgG response. Beyond one month from infection, an IgG Western Blot test is recommended. Patients should not be tested solely for IgM

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antibodies at this stage due to the higher probability of false-positive results. Symptomatic patients showing IgM but not IgG antibodies at an early stage in infection should be re-tested for IgG antibodies 2-4 weeks later.

#### Summary of Performance 6.

From a summary of the clinical trial data, the following performance characteristics are described:

# Expected values

Three (3) investigational sites, including Immunetics and two (2) independent off-site investigators, assayed samples from the following patient populations:

- 1. Normal population (n=430) comprised of samples from Lyme disease endemic (n=279) and non-endemic (n=151) regions.
- 2. Cross Reactive Panel (n=172) comprised of samples from patients with diseases other than Lyme disease that may be cross - reactive.
- 3. Lyme Disease Panel (n=186) comprised of samples from patients with a clinical diagnosis of Lyme disease, based on presence of erythema migrans or one or more symptoms of late Lyme disease, and which tested positive or equivocal on ELISA or other screening assays for B. burgdorferi antibodies.

# Specificity

Specificity of the device was determined from analysis of results of testing normal donor specimens from endemic and non-endemic regions and potentially cross reactive disease specimens (602 total samples). The specificity values derived from testing each population are shown in the table below in the "% Negative" column:

| Sample Type | n | % Positive | % Negative | 95% CI |
|-----------------------------|-----|------------|------------|---------|
| Normal - endemic region | 279 | 5% | 95% | 92-97 % |
| Normal - non-endemic region | 151 | 4% | 96% | 92-98 % |
| Normal - overall | 430 | 4% | 96% | 93-97 % |
| Cross - Reactive Panel | 172 | 13% | 87% | 88-96% |

# Sensitivity

Sensitivity of the device was determined by testing a total of 186 well-characterized sera from patients with Lyme disease, which had been drawn at different times after onset of disease. Sensitivity for each time after onset category is shown in the table below in the "% Positive" column:

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# Sensitivity of the Immunetics, Inc. QualiCode™ B. burgdorferi IgM Western Blot Kit vs. Time after Onset

| Draw Time (months) | n | % Positive | % Negative | 95% CI |
|--------------------|----|------------|------------|---------|
| Unknown | 54 | 74% | 26% | 60-85 % |
| <1 | 76 | 91% | 9% | 82-96 % |
| 1-2 | 23 | 83% | 17% | 61-94 % |
| 3-12 | 16 | 63% | 37% | 35-82 % |
| >12 | 17 | 47% | 53% | 25-72 % |

# Reproducibility

Inter-lot reproducibility was determined by assaying a panel of 20 specimens, including positive, weakly reactive and negative sera, on three lots of the Immunetics QualiCode™ kit. There was 80% agreement between interpretations from the three kit lots. The reproducibility of scoring of individual bands between the three lots varied from 80% to 100%, averaging 88%.

Inter-run reproducibility was determined by assaying the 20 specimen panel twice, on separate days, at each of three sites. There was 85% agreement overall between interpretations from the two runs averaged over all three sites. The reproducibility of individual band scoring between the two runs averaged over all three sites varied between 75% and 93%, with an average of 85% over all three bands.

Inter-reader reproducibility was determined by assaying the 20 specimen panel twice, on separate days, at each of three sites, with each strip interpreted by two indevendent readers. There was 93% agreement overall between interpretations from the two readers averaged over the three sites. Band scoring reproducibility varied between 97% and 98% averaged over the three sites, with an average of 97% over all three bands.

| Study | n | % Interpretation Agreement |
|--------------|----|----------------------------|
| Inter-lot | 20 | 80 |
| Inter-run | 20 | 85 |
| Inter-reader | 20 | 93 |

# 7. Conclusions

Based on the clinical performance, this device has been shown to be safe and effective for the intended use in the qualitative detection of human Immunoglobulin M (IgM) antibodies in serum or plasma to Borrelia burgdorferi antigens, and as a supplemental, more specific, test to aid in the diagnosis of infection or exposure to Borrelia burgdorferi, the causative agent of Lyme disease.

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SEP 2 1 1999

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

Andrew E. Levin. Ph.D. Scientific Director Immunetics, Inc. 63 Rogers Street Cambridge, Massachusetts 02142

Re: K991062

Trade Name: QualiCode™ B. burgdorferi IgM Western Blot Kit Regulatory Class: II Product Code: LSR Dated: July 8, 1999 Received: July 9, 1999

Dear Dr. Levin:

We have reviewed your Section 510(k) notification of intent to market the device referenced above and we 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). 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.

If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the Current Good Manufacturing Practice requirements, as set forth in the Quality System Regulation (OS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic OS inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition. FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or regulations.

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Page 2

Under the Clinical Laboratory Improvement Amendments of 1988 (CLIA-88), this device may require a CLIA complexity categorization. To determine if it does, you should contact the Centers for Disease Control and Prevention (CDC) at [phone].

This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at [phone]. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at [phone]. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll free number [phone] or at [phone] or at its internet address "http://www.fda.gov/cdrh/dsmamain.html"

Sincerely yours,

Steven Autman

Steven I. Gutman, M.D., M.B.A. Director Division of Clinical Laboratory Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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510(k) Number (if known):

Device Name: QualiCode B. burgdorferi IgM Western Blot Kit

Indications For Use:

The Immunetics QualiCode" B. burgdorferi IgM Western Blot Kit is intended for use in testing human serum samples which have demonstrated positive or eguivocal responses using EIA or IFA test procedures to provide supportive evidence of infection with Borrelia burgdorferi.

The QualiCode B. burgdorferi IgM Western Blot Kit can be used to test human sera for IqM antibodies during the acute phase of disease, within one month of infection, in accordance with CDC/ASTPHLD During this period, patients may not yet have developed quidelines. a detectable IgG response. Beyond one month from infection, an IgG Western Blot test is recommended. Patients should not be tested solely for IgM antibodies at this stage due to the higher probability of false positive results. Symptomatic patients showing IgM but not IqG antibodies at an early stage in infection should be re-tested for IgG antibodies 2-4 weeks later.

(PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON ANOTHER PAGE IF NEEDED)

Concurrence of CDRH, Office of Device Evaluation (ODE)

Woody Dubres

Prescription Use
(Per 21 CFR 801.109)

OR

Over-The-Counter Use

(Optional format 1-2-96)