Clinical and health economic outcomes of alternative HER2 test strategies for guiding adjuvant trastuzumab therapy

HER2 testing across practices-Have we come to a consensus on the ideal method of testing? A systematic literature review

Human epidermal growth factor (HER2) is an oncogene that codes for HER2 protein. The gene is amplified, and protein is overexpressed in 20% of patients and carries a poor prognosis. HER2-positive tumors tend to be more aggressive and highly proliferative. In 2006, trastuzumab, a monoclonal antibody targeting HER2, was approved for use with chemotherapy as an adjuvant treatment for women with HER2-positive breast cancer. The drug has shown improved survival rates for women with HER2-positive breast cancer. As promised for survival in HER2-positive patients continues with new research, and as novel drug approvals emerge, HER2 assessment plays a significant role in adjuvant and in metastatic setting. HER2 assays approved by the US Food and Drug administration include immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), and bright field dual in situ hybridization (DISH). Accuracy of HER2 testing across laboratories has an impact on treatment as false-negative testing can deprive the patients of trastuzumab therapy. The current review will focus on the variability of HER2 testing across laboratories and the potential impact on treatment.

Cost-utility analyses of drug therapies in breast cancer: a systematic review

The economic evaluation (EE) of health care products has become a necessity. Their quality must be high in order to trust the results and make informed decisions. While cost-utility analyses (CUAs) should be preferred to cost-effectiveness analyses in the oncology area, the quality of breast cancer (BC)-related CUA has been given little attention so far. Thus, firstly, a systematic review of published CUA related to drug therapies for BC, gene expression profiling, and HER2 status testing was performed. Secondly, the quality of selected CUA was assessed and the factors associated with a high-quality CUA identified. The systematic literature search was conducted in PubMed, MEDLINE/EMBASE, and Cochrane to identify published CUA between 2000 and 2014. After screening and data extraction, the quality of each selected CUA was assessed by two independent reviewers, using the checklist proposed by Drummond et al. The analysis of factors associated with a high-quality CUA (defined as a Drummond score ≥7) was performed using a two-step approach. Our systematic review was based on 140 CUAs and showed a wide variety of methodological approaches, including differences in the perspective adopted, the time horizon, measurement of cost and effectiveness, and more specially health-state utility values (HSUVs). The median Drummond score was 7 [range 3-10]. Only one in two of the CUA (n = 74) had a Drummond score ≥7, synonymous of "high quality." The statistically significant predictors of a high-quality CUA were article with "gene expression profiling" topic (p = 0.001), consulting or pharmaceutical company as main location of first author (p = 0.004), and articles with both incremental cost-utility ratio and incremental cost-effectiveness ratio as outcomes of EE (p = 0.02). Our systematic review identified only 140 CUAs published over the past 15 years with one in two of high quality. It showed a wide variety of methodological approaches, especially focused on HSUVs. A critical appraisal of utility values is necessary to better understand one of the main difficulties encountered by authors and propose areas for improvement to increase the quality of CUA. Since the last 5 years, there is a tendency toward an improvement in the quality of these studies, probably coupled with economic context, a better and widely spreading of recommendations and thus appropriation by medical practitioners. That being said, there is an urgent need for mandatory use of European and international recommendations to ensure quality of such approaches and to allow easy comparison.

The Lifetime Economic Burden of Inaccurate HER2 Testing: Estimating the Costs of False-Positive and False-Negative HER2 Test Results in US Patients with Early-Stage Breast Cancer

BACKGROUND

Patients with breast cancer whose tumors test positive for human epidermal growth factor receptor 2 (HER2) are treated with HER2-targeted therapies such as trastuzumab, but limitations with HER2 testing may lead to false-positive (FP) or false-negative (FN) results.

OBJECTIVES

To develop a US-level model to estimate the effect of tumor misclassification on health care costs and patient quality-adjusted life-years (QALYs).

METHODS

Decision analysis was used to estimate the number of patients with early-stage breast cancer (EBC) whose HER2 status was misclassified in 2012. FP results were assumed to generate unnecessary trastuzumab costs and unnecessary cases of trastuzumab-related cardiotoxicity. FN results were assumed to save money on trastuzumab, but with a loss of QALYs and greater risk of disease recurrence and its associated costs. QALYs were valued at $100,000 under a net monetary benefit approach.

RESULTS

Among 226,870 women diagnosed with EBC in 2012, 3.12% (n = 7,070) and 2.18% (n = 4,955) were estimated to have had FP and FN test results, respectively. Approximately 8400 QALYs (discounted, lifetime) were lost among women not receiving trastuzumab because of FN results. The estimated incremental per-patient lifetime burden of FP or FN results was $58,900 and $116,000, respectively. The implied incremental losses to society were $417 million and $575 million, respectively.

CONCLUSIONS

HER2 tests result in misclassification and nonoptimal treatment of approximately 12,025 US patients with EBC annually. The total economic societal loss of nearly $1 billion suggests that improvements in HER2 testing accuracy are needed and that further clinical and economic studies are warranted.

HER2 gene and protein expression status of breast carcinoma can be reliably tested on a single slide

Human epidermal growth factor receptor 2 (HER2) status in breast carcinomas serves as a predictor of benefit from anti-HER2 therapy. In providing clinicians with the information necessary to decide whether or not to treat with targeted therapy, it might be necessary to choose between methods assessing HER2 protein overexpression or gene amplification. A new diagnostic approach could be a combination of both tests on the same slide. If accurate and reproducible, this approach might optimize patient stratification for therapy. In this study, formalin-fixed paraffin-embedded tumor samples from 77 breast cancer patients were examined for HER2 by immunohistochemistry (IHC) and silver in situ hybridization (SISH) using HER2 IHC (clone 4B5), HER2/CEN17SISH, and combined IHC and SISH assay, called gene protein (GP). Cases were selected to ensure a sufficient number of borderline cases on the basis of IHC scores (0, 1+, 2+, 3+), obtained during diagnostic histopathological workup. The concordance between the HER2 IHC score obtained during diagnostic histopathological workup and GP was 93 %. Discordances had no influence on therapy decisions. The concordance between ISH results using dual ISH (DISH) and GP was 96 %. Of the 77 cases studied by GP, three cases with a ratio close to 2 would have been called amplified by DISH. The use of GP reduced the time for slide reading for a trained pathologist by up to 25 %, relative to sequential reading of IHC followed by SISH. For cases with an IHC score of 2+, the final result was obtained in 1 day, while the sequential technique would have required retesting by ISH on a second day. In conclusion, assessment of HER2 status by GP is an improvement for pathologists and facilitates clinical decision-making for breast cancer management.

Reagent and labor cost optimization through automation of fluorescence in situ hybridization (FISH) with the VP 2000: an Italian case study

In the modern molecular diagnostic laboratory, cost considerations are of paramount importance. Automation of complex molecular assays not only allows a laboratory to accommodate higher test volumes and throughput but also has a considerable impact on the cost of testing from the perspective of reagent costs, as well as hands-on time for skilled laboratory personnel. The following study tracked the cost of labor (hands-on time) and reagents for fluorescence in situ hybridization (FISH) testing in a routine, high-volume pathology and cytogenetics laboratory in Treviso, Italy, over a 2-y period (2011-2013). The laboratory automated FISH testing with the VP 2000 Processor, a deparaffinization, pretreatment, and special staining instrument produced by Abbott Molecular, and compared hands-on time and reagent costs to manual FISH testing. The results indicated significant cost and time saving when automating FISH with VP 2000 when more than six FISH tests were run per week. At 12 FISH assays per week, an approximate total cost reduction of 55% was observed. When running 46 FISH specimens per week, the cost saving increased to 89% versus manual testing. The results demonstrate that the VP 2000 processor can significantly reduce the cost of FISH testing in diagnostic laboratories.

Biomarker testing for breast, lung, and gastroesophageal cancers at NCI designated cancer centers

BACKGROUND

Molecular biomarkers, a cornerstone of precision oncology, are critical in breast, gastroesophageal, and non-small cell lung cancer management (BC, GEC, NSCLC). Testing practices are intensely debated, impacting diagnostic quality and affecting pathologists, oncologists and patients. However, little is known about testing approaches used in practice. Our study described biomarker practices in BC, GEC, and NSCLC at the leading US cancer centers.

METHODS

We conducted a survey of the National Cancer Institute (NCI) designated centers on BC, GEC, and NSCLC biomarker testing. We used simple frequencies to describe practices, two-sided Fisher's exact test and two-sided McNemar's test for cross-cancer comparison. All statistical tests were two-sided.

RESULTS

For BC human epidermal growth factor receptor 2 (HER2), 39% of centers combine guidelines by using in situ hybridization (ISH) and immunohistochemistry (IHC) concurrently, and 21% reflex-test beyond guideline-recommended IHC2+. For GEC HER2, 44% use ISH and IHC concurrently, and 28% reflex-test beyond IHC2+. In NSCLC, the use of IHC is limited to 4% for epidermal growth factor receptor (EGFR) and 7% for anaplastic lymphoma kinase (ALK). 43.5% test NSCLC biomarkers on oncologist order; 34.5% run all biomarkers upfront, and 22% use a sequential protocol. NSCLC external testing is statistically significantly higher than BC (P < .0001) and GEC (P < .0001). NSCLC internally developed tests are statistically significantly more common than BC (P < .0001) and GEC (P < .0001).

CONCLUSIONS

At the NCI cancer centers, biomarker testing practices vary, but exceeding guidelines is a common practice for established biomarkers and emerging practice for newer biomarkers. Use of internally developed tests declines as biomarkers mature. Implementation of multibiomarker protocols is lagging. Our study represents a step toward developing a biomarker testing practice landscape.

Detection of ALK expression in non-small-cell lung cancer with ALK gene rearrangements--comparison of multiple immunohistochemical methods

AIM

Testing for ALK rearrangements in advanced, non-squamous non-small-cell lung cancers that are wild-type for activating EGFR mutation has become standard care. Fluorescence in-situ hybridization is considered the gold standard for this evaluation. Pre-screening with immunohistochemistry has been suggested, to reduce testing costs and to make testing more widely available. By analysing the sensitivity and specificity of different ALK immunohistochemical assays, we aimed to identify the most reliable assay to detect ALK rearrangement.

METHODS AND RESULTS

ALK screening performed by FISH analysis was compared with three different immunohistochemical assays, in which two ALK antibody clones (5A4 and D5F3) were used on two detection platforms (Dako AutostainerLink 48 and Ventana Benchmark GX). Data from 30 ALK FISH-positive cases show that the sensitivity of the immunohistochemical assays varies from 93.3% to 96.6%. Head-to-head comparison of the 5A4 and D5F3 ALK antibody clones demonstrates similar staining potency. In general, homogeneous, intermediate to strong staining of the ALK-positive samples was obtained.

CONCLUSIONS

ALK immunohistochemistry can be considered as a pre-screen method if one accepts a sensitivity of 93.3-96.6%. Because ALK immunohistochemical staining needs to be performed close to the detection limit of the assay, vigilant quality control monitoring is required to guarantee trustworthy results.

What do providers, payers and patients need from comparative effectiveness research on diagnostics? The case of HER2/Neu testing in breast cancer

AIMS

Comparing effectiveness of diagnostic tests is one of the highest priorities for comparative effectiveness research (CER) set by the Institute of Medicine. Our study aims to identify what information providers, payers and patients need from CER on diagnostics, and what challenges they encounter implementing comparative information on diagnostic alternatives in practice and policy.

MATERIALS & METHODS

Using qualitative research methods and the example of two alternative protocols for HER2 testing in breast cancer, we conducted interviews with 45 stakeholders: providers (n = 25) from four academic and eight nonacademic institutions, executives (n = 13) from five major US private payers and representatives (n = 7) from two breast cancer patient advocacies.

RESULTS

The need for additional scientific evidence to determine the preferred HER2 protocol was more common for advocates than payers (100 vs 54%; p = 0.0515) and significantly more common for advocates than providers (100 vs 40%; p = 0.0077). The availability of information allowing assessment of the implementation impact from alternative diagnostic protocols on provider institutions may mitigate the need for additional scientific evidence for some providers and payers (24 and 46%, respectively). The cost-effectiveness of alternative protocols from the societal perspective is important to payers and advocates (69 and 71%, respectively) but not to providers (0%; p = 0.0001 and p = 0.0001). The lack of reporting laboratory practices is a more common implementation challenge for payers and advocates (77 and 86%, respectively) than for providers (32%). The absence of any mechanism for patient involvement was recognized as a challenge by payers and advocates (69 and 100%, respectively) but not by providers (0%; p = 0.0001 and p = 0.0001).

CONCLUSION

Comparative implementation research is needed to inform the stakeholders considering diagnostic alternatives. Transparency of laboratory practices is an important factor in enabling implementation of CER on diagnostics in practice and policy. The incongruent views of providers versus patient advocates and payers on involving patients in diagnostic decisions is a concerning challenge to utilizing the results of CER.

A gene-protein assay for human epidermal growth factor receptor 2 (HER2): brightfield tricolor visualization of HER2 protein, the HER2 gene, and chromosome 17 centromere (CEN17) in formalin-fixed, paraffin-embedded breast cancer tissue sections

BACKGROUND

The eligibility of breast cancer patients for human epidermal growth factor receptor 2 (HER2)-directed therapies is determined by the HER2 gene amplification and/or HER2 protein overexpression status of the breast tumor as determined by in situ hybridization (ISH) or immunohistochemistry (IHC), respectively. Our objective was to combine the US Food and Drug Administration (FDA)-approved HER2 & chromosome 17 centromere (CEN17) brightfield ISH (BISH) and HER2 IHC assays into a single automated HER2 gene-protein assay allowing simultaneous detection of all three targets in a single tissue section.

METHODS

The HER2 gene-protein assay was optimized using formalin-fixed, paraffin-embedded (FFPE) samples of the xenograft tumors MCF7 [HER2 negative (non-amplified gene, protein negative)] and Calu-3 [HER2 positive (amplified gene, protein positive)]. HER2 IHC was performed using a rabbit monoclonal anti-HER2 antibody (clone 4B5) and a conventional 3,3'-diaminobenzidine IHC detection. The HER2 & CEN17 BISH signals were visualized using horseradish peroxidase-based silver and alkaline phosphatase-based red detection systems, respectively with a cocktail of 2,4-dinitrophenyl-labeled HER2 and digoxigenin-labeled CEN17 probes. The performance of the gene-protein assay on tissue microarray slides containing 189 randomly selected FFPE clinical breast cancer tissue cores was compared to that of the separate HER2 IHC and HER2 & CEN17 BISH assays.

RESULTS

HER2 protein detection was optimal when the HER2 IHC protocol was used before (rather than after) the BISH protocol. The sequential use of HER2 IHC and HER2 & CEN17 BISH detection steps on FFPE xenograft tumor sections appropriately co-localized the HER2 protein, HER2 gene, and CEN17 signals after mitigating the silver background staining by using a naphthol phosphate-containing hybridization buffer for the hybridization step. The HER2 protein and HER2 gene status obtained using the multiplex HER2 gene-protein assay demonstrated high concordance with those obtained using the separate HER2 IHC and HER2 & CEN17 BISH assays, respectively.

CONCLUSIONS

We have developed a protocol that allows simultaneous visualization of the HER2 IHC and HER2 & CEN17 BISH targets. This automated protocol facilitated the determination of HER2 protein and HER2 gene status in randomly selected breast cancer samples, particularly in cases that were equivocal or exhibited tumor heterogeneity. The HER2 gene-protein assay produced results virtually equivalent to those of the single FDA-approved HER2 IHC and HER2 & CEN17 BISH assays.

VIRTUAL SLIDES

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2041964038705297.