(298 days)
The OSDI HER-2/neu Assay is an in vitro, diagnostic device intended for use in the quantitative determination of serum HER-2/neu in women with metastatic breast cancer who have an initial value of 15 ng/ml or greater. HER-2/neu values obtained may be used in the follow-up and monitoring of patients with metastatic breast cancer. HER-2/neu values should be used in conjunction with information available from clinical and other diagnostic procedures in the management of breast cancer. The clinical utility of the serum measurement of HER-2/neu as a prognostic indicator for early recurrence and in the management of patients on immunotherapy regiments has not been fully established.
The HER-2/neu ELISA is a sandwich enzyme immunoassay, which utilizes two monoclonal antibodies to quantitate the extracellular domain (ECD) of the HER-2/neu protein in serum. The capture antibody (NB-3) has been immobilized on the interior surface of the microtiter plate wells. To perform the assay, an appropriate volume of serum is incubated in the coated well to allow binding of the antigen by the capture antibody. The captured HER-2/neu ECD is then reacted with a different anti-HER-2/neu antibody designated TA-1. The TA-1 antibody is biotinylated. The detection of the ECD of HER-2/neu is with a streptavidin horseradish peroxidase conjugate, which then catalyzes the conversion of the chromogenic substrate o-phenylenediamine into a colored product. The colored reaction product is quantitated by spectrophotometry (read absorbance at 490 mm) and is related to the amount of the HER-2/neu ECD in the serum sample. Six prepared HER-2/neu standards (0, 2.5, 7.5, 15, 25 and 35 ng/ml) allow construction of a standard curve for subsequent quantification of HER-2/neu in serum samples. Also available from OSDI is a set of HER-2/neu controls (10-CVX) designed to be used in conjunction with the ELISA for quality monitoring of assay performance. This control set consists of three (3) control levels at 2.9, 9.1 and 24.0 ng/mL HER-2/neu protein.
The Oncogene Science Diagnostics, Inc. (OSDI) Manual HER-2/neu Microtiter ELISA is an in vitro diagnostic assay intended for the quantitative measurement of the extracellular domain of HER-2/neu protein in human serum. It is used in the follow-up and monitoring of patients with metastatic breast cancer whose initial serum level of HER-2/neu is 15 ng/mL or greater, in conjunction with other clinical and diagnostic procedures.
Here's an analysis of the acceptance criteria and the study proving the device meets those criteria:
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are not explicitly stated in a quantitative table within the document but can be inferred from the performance metrics described for various aspects of the assay. The "reported device performance" are the results from the non-clinical and clinical studies.
| Acceptance Criteria (Inferred) | Reported Device Performance |
|---|---|
| Specificity: Interference | "None of the potential endogenous or exogenous interferents demonstrated any significant interfering effects on HER-2/neu recovery." (Page 6) |
| Specificity: Cross-Reactivity | "The maximum effect seen with [Human Epidermal Growth Factor Receptor (HER-1)] cross-reactant was not significant (≤1%)... no cross-reactivity with HER-3." (Page 7) |
| Specificity: Heterophilic Antibodies and HAMA Interference | "HAMA and rheumatoid factors do not cause false negative or false positive results in the present assay format" when detector diluent contained Normal Mouse Serum (NMS). (Page 7) |
| Linearity | "When observed HER-2/neu concentration was plotted versus expected concentration, the slope and correlation coefficient of each data set were close to the optimum of 1, indicating linearity within the dynamic range of the assay." (Page 7) |
| Spike and Recovery (Matrix Effect) | "The total average percent recovery of all spiked serum samples in all three kit lots was 103%, indicating no effect of matrix on the ability of the ELISA to accurately measure HER-2/neu protein in serum." (Page 8) |
| Hook Effect (Antigen Excess) | "Separation of sample and reagent addition by washes prevents high-dose hook effect in this device." (Page 8) |
| Parallelism (Dilution Studies) | "Recoveries were evaluated at each of the dilution points for mean and standard deviation and were comparable for all three ELISA kit lots. Serum samples diluted in kit Sample Diluent result in accurate recovery of analyte at a range of concentrations in human samples." (Page 8) |
| End-to-End Variation (Robustness to timing) | "The expected variance in timing during normal use by skilled individuals should fall well short of these extended times tested and recoveries should be unaffected." (Page 9 - small increase/decrease (15%) observed only when times extended well beyond normal usage) |
| Plate Coating Variations | "Serum sample recovery, and therefore antibody coating, is consistent throughout plates and kit lots with 4.7-7.6 % CV." (Page 9) |
| Reproducibility (Intra- and Inter-assay) | OSDI Site, All Microtiter ELISA Lots Combined (Table 4.3-1): |
- Control 1 (24.2 ng/mL): Within Run %CV 3.8, Total %CV 7.8
- Control 2 (9.5 ng/mL): Within Run %CV 4.7, Total %CV 9.1
- Control 3 (2.9 ng/mL): Within Run %CV 7.8, Total %CV 10.6
- Control 4 (9.2 ng/mL): Within Run %CV 4.5, Total %CV 8.3
Three Sites and Three Kit Lots Combined (Table 4.3-2): - Control 1 (24.5 ng/mL): Within Run %CV 6.0, Total %CV 10.7
- Control 2 (9.8 ng/mL): Within Run %CV 7.0, Total %CV 10.4
- Control 3 (3.3 ng/mL): Within Run %CV 10.2, Total %CV 17.7
- Control 4 (9.5 ng/mL): Within Run %CV 6.9, Total %CV 10.8
"Within run CV's of 6-7% and total CV's of 10-11% for clinically relevant controls... well within acceptable limits for an assay of this type and for its intended use." (Page 9) |
| Sensitivity (Detection Limit) | "An MDD of 1.5 ng/mL was observed when assaying 232 replicates of Sample Diluent alone in three HER-2/neu ELISA kit lots. This MDD is acceptable for the intended use of this assay, where the lowest normal patient was 4.23 ng/ml and the cutoff determined in this study for elevated HER-2/neu values was 1.5 ng/ml." (Page 10) |
| Clinical Utility (Correspondence between HER-2/neu changes and clinical course) | Table 4.4-1: Correspondence of Metastatic Breast Cancer Patient Disease Status with Changes in Serum HER-2/neu: Visit-by-Visit - Change in HER-2/neu ≥20% ↑: 52 cases of Progression, 33 cases of No Progression (Total 85)
- Change in HER-2/neu
§ 866.6010 Tumor-associated antigen immunological test system.
(a)
Identification. A tumor-associated antigen immunological test system is a device that consists of reagents used to qualitatively or quantitatively measure, by immunochemical techniques, tumor-associated antigens in serum, plasma, urine, or other body fluids. This device is intended as an aid in monitoring patients for disease progress or response to therapy or for the detection of recurrent or residual disease.(b)
Classification. Class II (special controls). Tumor markers must comply with the following special controls: (1) A guidance document entitled “Guidance Document for the Submission of Tumor Associated Antigen Premarket Notifications (510(k)s) to FDA,” and (2) voluntary assay performance standards issued by the National Committee on Clinical Laboratory Standards.