(635 days)
Estrogen Receptor Clone 6F11 (ER 6F11) Mouse Monoclonal antibody is intended for laboratory use to qualitatively identify estrogen receptor (ER) antigen in sections of formalin fixed, paraffin embedded breast cancer tissue by immunohistochemistry methods. Estrogen Receptor Clone 6F11 specifically binds to the ER antigen located in the nucleus of ER positive normal and neoplastic cells.
Estrogen Receptor Clone 6F1 I is indicated as an aid in the management, prognosis and predication of therapy outcome of breast cancer. The clinical interpretation of any staining or its absence should be complemented by morphological studies using proper controls and should be evaluated within the context of the patient's clinical history and other diagnostic tests by qualified pathologist.
Estrogen Receptor Clone 6F11 Ready-to-Use Primary Antibody for Bond™ and the Estrogen Receptor Clone 6F11 Liquid Concentrate Primary Antibody, Novocastra™ are optimized for use on the Leica Biosystems Bond III staining platform using the Bond Polymer Refine Detection Kit.
Estrogen Receptor Clone 6F11 is a mouse anti-human monoclonal antibody produced as a tissue culture supernatant. This antibody is utilized to perform a semi-quantitative immunohistochemical (IHC) assay to identify estrogen receptor (ER) expression in human breast cancer tissue routinely processed and paraffin-embedded for histological examination.
Estrogen Receptor Clone 6F11 primary antibody is provided in two formats, a Bond™ Ready-to-Use format (product code PA0151 (7mL) and PA0009 (30 mL)) and a concentrated liquid format (product code NCL-L-ER-6F11 (1mL) and is optimally diluted for use on the automated Bond System (Bond III ) in combination with Bond Polymer Refine Detection kit.
Total protein concentration for Estrogen Receptor clone 6F11 is approximately 3.8 g/L. The immunoglobulin concentration is approximately 75 mg/L.
The Estrogen Receptor Clone 6F11 Liquid Concentrate Primary Antibody, Novocastra" is recommended for use at a dilution of 1 in 50 when diluted in Bond Antibody Diluent (AR9352).
The Estrogen Receptor Clone 6F11 Ready-to-Use Primary Antibody for Bond™ is a tissue culture supernatant prepared at a working immunoglobulin concentration of 0.88 µg/mL. It is supplied in Tris buffered saline with carrier protein, containing 0.35% ProClin™ 950 as a preservative.
Acceptance Criteria and Device Performance for Estrogen Receptor Clone 6F11
The Leica Biosystems Estrogen Receptor Clone 6F11 (ER 6F11) primary antibody, in both Ready-to-Use (PA0151) and Liquid Concentrate (NCL-L-ER-6F11) formats, demonstrated performance across several studies to meet acceptance criteria for its intended use in immunohistochemistry for ER antigen identification in breast cancer tissue.
1. Table of Acceptance Criteria and Reported Device Performance
The provided document details various performance studies rather than explicit, pre-defined acceptance criteria with specific thresholds for each metric. However, the data presented strongly implies what would be considered acceptable performance for a device seeking governmental approval, particularly regarding reproducibility and correlation with existing methods and clinical outcomes.
Based on the studies, the implicit acceptance criteria for the device revolve around demonstrating high agreement in various precision and reproducibility studies, and acceptable clinical performance (sensitivity, specificity, PPV, NPV) when compared to a "gold standard."
Summary Table of Reported Device Performance against Implicit Acceptance Criteria:
| Study Type / Metric | Implicit Acceptance Criteria (Indicative) | Reported Device Performance (Leica Device) | Formats Studied |
|---|---|---|---|
| Clinical Outcome Study (Calgary Cohort) | Ready-to-Use (PA0151) | ||
| Inter-observer Kappa (ER Status) | High agreement (e.g., Kappa > 0.6) | 0.67 to 0.83 ("almost perfect agreement") | Ready-to-Use (PA0151) |
| Intra-observer Kappa (ER Status) | High agreement (e.g., Kappa > 0.8) | 0.91 ("almost perfect agreement") | Ready-to-Use (PA0151) |
| Univariate Kaplan-Meier HR (ER Status) | Statistically significant difference in survival between ER+ and ER- groups (p 0.90) | 0.97 (Figure 4) | Ready-to-Use (PA0151) |
| Specificity (vs. LBA Gold Standard) | Adequate (e.g., > 0.40) | 0.44 (Figure 4) | Ready-to-Use (PA0151) |
| PPV (vs. LBA Gold Standard) | High (e.g., > 0.90) | 0.96 (Figure 4) | Ready-to-Use (PA0151) |
| NPV (vs. LBA Gold Standard) | Adequate (e.g., > 0.60) | 0.70 (Figure 4) | Ready-to-Use (PA0151) |
| Precision Studies (TMA) | Overall, Positive, and Negative Percent Agreement with high confidence intervals (e.g., > 90%) | All precision studies reported 100% OPA, PPA, NPA with tight 95% CIs (e.g., 97-100% range) | Both formats |
| Between Observer Precision (TMA) | High Overall Percent Agreement (OPA) (e.g., > 90%) | 95% (PA0151, Obs1-Obs2/Obs3), 100% (PA0151, Obs2-Obs3), 98.33% (PA0151, All Obs) | Both formats |
| 89.47% (NCL-L-ER-6F11, Obs1-Obs2), 94.74% (NCL-L-ER-6F11, Obs1-Obs3/Obs2-Obs3), 96.49% (NCL-L-ER-6F11, All Obs) | Left panel for PA0151, right for NCL-L-ER-6F11 | ||
| Reproducibility Studies (Whole Tissue Sections) | Overall, Positive, and Negative Percent Agreement with high confidence intervals (e.g., > 90%) | Varies by site/comparison, generally high (e.g., 88.89% - 100% OPA), but some lower bounds on CIs (e.g., 72.71% NPA for Site A PA0151 overall) | Both formats |
| Inter-Platform Comparison Study | High Overall, Positive, and Negative Percent Agreement when compared to the reference standard device | Overall PA: 96.73%, Positive PA: 98.37%, Negative PA: 90.16% (95% CI reported) | Liquid Concentrate (NCL-L-ER-6F11) vs. Ready-to-Use (PA0151) |
| Stability Studies | Intensity Score and Proportion Score identical to control for variable ER expression in breast cancer cases. | Reported with 18 months shelf-life via accelerated testing, ongoing real-time testing. | All three product formats |
2. Sample Size Used for the Test Set and Data Provenance
The document describes several distinct test sets:
- Clinical Outcome Study (Calgary Cohort):
- Sample Size: n=532 breast cancer patients (retrospectively analyzed); n=473 for univariate analysis; n=363 for multivariate analysis.
- Data Provenance: Retrospective, Calgary-based patient cohort (Canada), diagnosed between 1985 and 2000.
- Precision and Reproducibility Studies (TMA and Whole Tissue Sections): These studies used unspecified "breast cancer cases."
- Within-Run Precision (PA0151): 108 test data points (presumably cases or samples).
- Within-Instrument Precision (PA0151): 321 test data points.
- Between-Run Precision (PA0151): 180 test data points.
- Between Laboratory Precision (PA0151): 101 test data points from 3 investigational sites.
- Lot to Lot Precision (PA0151): 100 test data points using 3 reagent lots.
- Between Observer Precision (PA0151 & NCL-L-ER-6F11): 20 whole section breast cancer cases for each format (total 40 cases if both studies were distinct).
- Inter-Site Reproducibility (PA0151 & NCL-L-ER-6F11): 18 cases evaluated at 3 sites over 5 days (9 replicates per case).
- Lot to Lot Reproducibility (PA0151 & NCL-L-ER-6F11): 18 cases using 3 reagent lots.
- Inter-Platform Comparison Study:
- Sample Size: 306 invasive breast cancer specimens. An additional 452 cases were assessed to enrich the cohort, but the final reported results are for the 306 cases.
- Data Provenance: Clinical archives, from three independent US-based testing facilities. Specimens were formalin-fixed, paraffin-embedded.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
- Clinical Outcome Study (Calgary Cohort):
- Number of Experts: 3 observers scored slides (likely pathologists, though specific qualifications were not given beyond "observers").
- Qualifications: Not explicitly stated, but clinical outcome studies involving immunohistochemistry interpretation typically involve experienced pathologists.
- Precision, Reproducibility, and Inter-Platform Comparison Studies:
- Number of Experts: 3 observers/investigational sites are mentioned for between-observer and inter-site studies.
- Qualifications: Not explicitly stated beyond "observers" and "investigational sites." It's implied these are expert professionals (e.g., pathologists) involved in diagnostic interpretation.
4. Adjudication Method for the Test Set
- Clinical Outcome Study (Calgary Cohort): The scoring method was the "Allred scoring method." Cohen's Kappa statistic was used to quantify inter- and intra-observer reproducibility. While individual observer scores were compared, there is no explicit mention of an adjudication process (e.g., 2+1, 3+1) to establish a consensus ground truth solely among the experts for this specific test set. The ground truth for comparative effectiveness was primarily based on ligand-binding assay (LBA) and patient progression on tamoxifen.
- Precision, Reproducibility, and Inter-Platform Comparison Studies: For these studies, the "ground truth" often refers to a reference standard against which the test device is compared. For observer agreement studies, the "adjudication method" is the direct comparison of observer scores without necessarily establishing a final adjudicated truth.
- In the inter-platform comparison study, the "reference standard device" (Estrogen Receptor Clone 6F11 Ready-to-Use Primary Antibody for Bond™ on the Bond III) effectively served as the de facto ground truth against which the Liquid Concentrate format was compared.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, And the Effect Size of How Much Human Readers Improve with AI vs. Without AI Assistance
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done in the context of human readers with vs. without AI assistance.
This document describes the validation of an immunohistochemistry (IHC) assay and its accompanying primary antibody, not an AI or digital pathology device meant to assist human readers. The studies focus on the performance and reproducibility of the IHC staining method itself.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
No, a standalone performance study in the context of an algorithm only was not done.
As noted above, this submission is for an IHC primary antibody and its associated staining platform, which is interpreted by human observers (pathologists). There is no mention of an algorithm or AI component in this device.
7. The Type of Ground Truth Used
The ground truth varied depending on the specific study:
- Clinical Outcome Study (Calgary Cohort):
- Ligand-binding assay (LBA): Used as a "gold standard" for calculating sensitivity, specificity, PPV, and NPV of the device.
- Patient progression on tamoxifen: Used as another "gold standard" for calculating diagnostic performance metrics, indicating real clinical outcome.
- Precision and Reproducibility Studies: For these studies, the "ground truth" was often the consensus or established score from a reference method or a designated expert, against which other measurements/observers were compared. For the between-observer studies, direct comparison of observer agreement served as the assessment.
- Inter-Platform Comparison Study: The Estrogen Receptor Clone 6F11 Ready-to-Use Primary Antibody for Bond™ on the Bond III (the existing, approved format) served as the "reference standard test" or ground truth against which the Liquid Concentrate format was evaluated.
- Stability Studies: A "control score" for Intensity Score and Proportion Score was used as the ground truth.
8. The Sample Size for the Training Set
The document does not describe a "training set" in the context of a machine learning model, as the submission concerns an IHC assay and antibody, not an AI device.
9. How the Ground Truth for the Training Set Was Established
Not applicable, as no training set for an AI model is described.
§ 864.1860 Immunohistochemistry reagents and kits.
(a)
Identification. Immunohistochemistry test systems (IHC's) are in vitro diagnostic devices consisting of polyclonal or monoclonal antibodies labeled with directions for use and performance claims, which may be packaged with ancillary reagents in kits. Their intended use is to identify, by immunological techniques, antigens in tissues or cytologic specimens. Similar devices intended for use with flow cytometry devices are not considered IHC's.(b)
Classification of immunohistochemistry devices. (1) Class I (general controls). Except as described in paragraphs (b)(2) and (b)(3) of this section, these devices are exempt from the premarket notification requirements in part 807, subpart E of this chapter. This exemption applies to IHC's that provide the pathologist with adjunctive diagnostic information that may be incorporated into the pathologist's report, but that is not ordinarily reported to the clinician as an independent finding. These IHC's are used after the primary diagnosis of tumor (neoplasm) has been made by conventional histopathology using nonimmunologic histochemical stains, such as hematoxylin and eosin. Examples of class I IHC's are differentiation markers that are used as adjunctive tests to subclassify tumors, such as keratin.(2) Class II (special control, guidance document: “FDA Guidance for Submission of Immunohistochemistry Applications to the FDA,” Center for Devices and Radiologic Health, 1998). These IHC's are intended for the detection and/or measurement of certain target analytes in order to provide prognostic or predictive data that are not directly confirmed by routine histopathologic internal and external control specimens. These IHC's provide the pathologist with information that is ordinarily reported as independent diagnostic information to the ordering clinician, and the claims associated with these data are widely accepted and supported by valid scientific evidence. Examples of class II IHC's are those intended for semiquantitative measurement of an analyte, such as hormone receptors in breast cancer.
(3) Class III (premarket approval). IHC's intended for any use not described in paragraphs (b)(1) or (b)(2) of this section.
(c)
Date of PMA or notice of completion of a PDP is required. As of May 28, 1976, an approval under section 515 of the Federal Food, Drug, and Cosmetic Act is required for any device described in paragraph (b)(3) of this section before this device may be commercially distributed. See § 864.3.