A Companion Diagnostic With Significant Clinical Impact in Treatment of Breast and Gastric Cancer.

The development of trastuzumab (Herceptin®) was one of the most significant cancer drug development projects of the 20th century. Not only was it a scientific and medical achievement but it also paved the way for the drug-diagnostic codevelopment model, where a predictive biomarker assay is developed in parallel to the drug. One of the challenges in the development of trastuzumab was to select the right patient population likely to respond and here, it was critical to have access to an accurate, robust and reliable assay for detection of HER2 overexpression in tumors. In the clinical development of trastuzumab, a clinical trial assay (CTA), developed by Genentech, was used for selection of HER2 positive patients. However, during the phase III trial with trastuzumab, a new optimized IHC assay, HercepTest™ was designed and developed by Dako. In the final stage of its development, a comparative study with the CTA was conducted in order to show concordance between the two assays. In September 1998, the Food and Drug Administration (FDA) simultaneously granted approval to trastuzumab and HercepTest™. The assay has been used for patient selection in a number of significant breast cancer clinical trials such as the HERA, CLEOPATRA, EMILIA and more. In these trials, HercepTest™ demonstrated its clinical utility in the neoadjuvant, adjuvant, and metastatic setting as well as in relation to different types of HER2 targeted therapies. Likewise, the assay was used for selection of HER2 positive gastric cancer patients in the important ToGA trail. HercepTest™ was the first companion diagnostic ever approved by the FDA, and more than 20 years of use has documented its clinical impact.

Development of a Diagnostic Programmed Cell Death 1-Ligand 1 Immunohistochemistry Assay for Nivolumab Therapy in Melanoma.

Nivolumab is a monoclonal antibody that blocks the interaction between programmed cell death 1 (PD1) and programmed cell death 1-ligand 1 (PD-L1), resulting in enhanced antitumor activity by the immune system. Nivolumab is currently approved by the US Food and Drug Administration (FDA) for melanoma, non-small cell lung cancer (NSCLC), renal cell carcinoma, classical Hodgkin lymphoma, squamous cell carcinoma of the head and neck, and urothelial carcinoma. PD-L1 IHC 28-8 pharmDx is FDA-approved as a complementary diagnostic for immunohistochemical (IHC) detection of PD-L1 in non-squamous NSCLC and melanoma. We report validation of PD-L1 IHC 28-8 pharmDx for PD-L1 detection on formalin-fixed, paraffin-embedded human melanoma specimens using Autostainer Link 48. A prevalence assessment of 104 melanoma specimens indicated that PD-L1 was detected across the full expression level range (0% to 100% of tumor cells). Assay robustness and precision studies were conducted at Agilent Technologies, with additional reproducibility studies performed at 3 external laboratories. Precision studies evaluated at ≥1% and ≥5% expression levels revealed a range of average negative agreement from 89.5%, 95% CI (83.2, 93.6) to 100%, 95% CI (97.3, 100), and average positive agreement from 85.5%, 95% CI (77.6, 90.9) to 100%, 95% CI (97.9, 100). For external reproducibility, precise results were obtained. These results demonstrate PD-L1 IHC 28-8 pharmDx is a precise, robust, and reproducible assay for determining PD-L1 expression in melanoma. This is the first PD-L1 IHC test to receive FDA approval as a complementary diagnostic in melanoma patients whereby positive PD-L1 expression is correlated with the magnitude of nivolumab treatment effect.

High concordance between two companion diagnostics tests: a concordance study between the HercepTest and the HER2 FISH pharmDx kit.

The present study was done to investigate the concordance between the HER2 status measured by immunohistochemical analysis (HercepTest, DAKO, Carpinteria, CA) and fluorescence in situ hybridization (FISH; HER2 FISH pharmDx, DAKO) in a large study cohort (n = 681) of patients with high-risk breast cancer. A high agreement between immunohistochemical and FISH results was demonstrated. For the whole study population, the agreement between the 2 assays was 93.1% with a corresponding κ coefficient of 0.85. When the equivocal immunohistochemical 2+ cases were excluded from the analysis (n = 79), the agreement increased to 95.0% with a κ coefficient of 0.90. When the cutoff value for amplified/nonamplified cases in the HER2 FISH assay was increased from 2.0 to 2.2 as recommended in the American Society of Clinical Oncology/College of American Pathologists guidelines, the concordance between the 2 assays was 94.3% with a κ coefficient of 0.87 in the whole study population. When the equivocal immunohistochemical 2+ cases were excluded from this analysis, the concordance is similar (95.7% with a κ coefficient of 0.91).

The new era of personalized medicine: 10 years later.

The interest in personalized medicine has increased considerably over the last 10 years with an almost exponential growth in the number of publications since 1999 when the first article discussing the subject appeared. However, the foundation of what we perceive today as personalized medicine had already been created in the 1960s with the discovery of the estrogen receptor, and later on, with the development of the selective estrogen receptor modulator drug - tamoxifen. The key driver in today's personalized medicine is molecular diagnostics, but the need to improve the current pharmacotherapy also plays a very important role. Many of the frequently used drugs are not as effective and safe as they should be. The efficacy rate of drugs within major disease areas such as asthma, cancer, psychiatric illnesses and cardiovascular diseases are in the range of 25-60%. Drug safety is another critical issue which imposes burdens on both patients and society. In the European Union, it is estimated that 5% of all hospital admissions are due to side effects related to pharmacotherapy, thus resulting in nearly 200,000 deaths per year. The total cost related to side effects from therapeutic drugs in the European Union is €79 billion per year. This situation needs to be improved, and this can be achieved by taking differences in the individual patient's biologies into consideration when the drugs are dispensed. A more individualized pharmacotherapy by the implementation of pharmacodiagnostic testing will be an important aid in improving efficacy and reducing the frequency of serious side effects in the future. However, there are obstacles to be overcome with regard to the implementation of personalized medicine, and besides scientific and economic issues, it will be a challenge to address other aspects, such as regulatory requirements, reimbursement, education and logistics.

Development of a real-time RT-PCR assay for detecting EGFRvIII in glioblastoma samples.

PURPOSE: Epidermal growth factor receptor variant III (EGFRvIII) is an oncogenic, constitutively active mutant form of the EGFR that is commonly expressed in glioblastoma and is also detected in a number of epithelial cancers. EGFRvIII presents a unique antigenic target for anti-EGFRvIII vaccines and it has been shown to modulate response to EGFR kinase inhibitor therapy. Thus, detection in clinical samples may be warranted. Existing patents preclude the use of anti-EGFRvIII antibodies for clinical detection. Further, frozen tissue is not routinely available, particularly for patients treated in the community. Thus, detection of EGFRvIII in formalin-fixed paraffin-embedded (FFPE) clinical samples is a major challenge. EXPERIMENTAL DESIGN: We developed a real-time reverse transcription-PCR (RT-PCR) assay for detecting EGFRvIII in FFPE samples and analyzed 59 FFPE glioblastoma clinical samples with paired frozen tissue from the same surgical resection. We assessed EGFRvIII protein expression by immunohistochemistry using two distinct specific anti-EGFRvIII antibodies and examined EGFR gene amplification by fluorescence in situ hybridization. RESULTS: The FFPE RT-PCR assay detected EGFRvIII in 16 of 59 (27%) samples, exclusively in cases with EGFR amplification, consistent with the expected frequency of this alteration. The FFPE RT-PCR assay was more sensitive and specific for detecting EGFRvIII than either of the two antibodies alone, or in combination, with a sensitivity of 93% (95% confidence interval, 0.78-1.00) and a specificity of 98% (95% confidence interval, 0.93-1.00). CONCLUSION: This assay will facilitate accurate assessment of EGFRvIII in clinical samples and may aid in the development of strategies for stratifying patients for EGFRvIII-directed therapies.

Characterization of anti-TIMP-1 monoclonal antibodies for immunohistochemical localization in formalin-fixed, paraffin-embedded tissue.

The aim of this study was to evaluate seven anti-TIMP-1 (tissue inhibitor of metalloproteinase-1) monoclonal antibodies by immunohistochemical (IHC) staining of formalin-fixed, paraffin-embedded (FFPE) tissue. Detection of the TIMP-1 protein was studied by IHC in FFPE human archival normal and neoplastic samples. Indirect IHC technique was used, and the seven antibodies (clones VT1, VT2, VT4, VT5, VT6, VT7, and VT8) were tested in various concentrations using different pretreatment protocols. All seven VT antibodies specifically immunostained the cytoplasm of islets of Langerhans cells in normal pancreas, epithelial cells of hyperplastic prostate, tumor cells of medullary thyroid carcinoma, and fibroblast-like cells of malignant melanoma. Specificity of the anti-TIMP-1 antibodies was confirmed by several controls, e.g., Western blotting on proteins extracted from FFPE tissue showed that the VT7 antibody reacted specifically with a protein band of approximately 28 kDa, corresponding to the molecular mass of TIMP-1. However, sensitivity varied with the different antibodies. Use of heat-induced epitope retrieval (HIER) and the VT7 clone applied at low concentrations demonstrated more intense immunoreactivity with the TIMP-1-positive cell types compared to the other six clones. Furthermore, when tested on a range of normal and neoplastic endocrine tissues, the VT7 clone demonstrated immunoreactivity with all neuroendocrine cell types. In conclusion, all seven antibodies detected TIMP-1 protein in various normal and neoplastic FFPE tissues, but one clone, VT7, was superior for IHC staining of TIMP-1 in FFPE tissue sections when using HIER.

Prodefensins are matrix proteins of specific granules in human neutrophils.

Defensins are potent antimicrobial and proinflammatory peptides. The human neutrophil defensins human neutrophil peptide (HNP)-1-3 are synthesized as 94 amino acide (aa) preproHNPs, which are converted to 75 aa proHNPs by cotranslational removal of a 19 aa endoplasmic reticulum signal peptide. At the promyelocytic stage of myelopoiesis, proHNPs are further proteolytically modified and accumulate in azurophil granules as 29-30 aa HNPs. In contrast, proHNPs produced by more mature myeloid cells are not subjected to proteolytic cleavage and undergo a high degree of constitutive exocytosis. The proHNPs are devoid of antimicrobial potential, and the significance of their secretion is unknown. To investigate whether mature neutrophils contain proHNPs, we developed antibodies against proHNP-1 by DNA immunization of rabbits. In addition, antibodies against the 45 aa proHNP pro-piece were raised by conventional immunization procedures. These antibodies allowed detection of proHNPs in homogenates of peripheral blood neutrophils. The proHNPs were isolated by affinity chromatography, and their identity was confirmed by mass spectrometry and N-terminal aa sequence analysis. Finally, the neutrophil proHNPs were identified as novel matrix proteins of specific granules by subcellular fractionation experiments, release studies, and immunoelectron microscopy. Thus, human neutrophils not only store large amounts of mature defensins in azurophil granules but also contain a more easily mobilized reservoir of unprocessed prodefensins in specific granules.

Immunohistochemical detection of EGFR in paraffin-embedded tumor tissues: variation in staining intensity due to choice of fixative and storage time of tissue sections.

The epidermal growth factor receptor (EGFR) is highly expressed in a variety of solid malignant tumors and its expression has been correlated with disease progression and poor survival. With the advent of targeted therapies, especially IMC-C225 (Cetuximab), a monoclonal antibody (MAb) directed against the EGFR, there is an increasing interest in immunohistochemistry (IHC)-based EGFR screening methods using paraffin-embedded tumor specimens to select cancer patients eligible for treatment with Cetuximab. With the EGFRpharmDX kit, a complete assay for demonstration of EGFR is now available. Because no information about the preservation of the EGFR under various conditions of fixation is available, we performed a prospective study on a panel of commonly used fixatives to determine optimal tissue preservation protocols. The stability of the epitope on cut tissue sections stored for a period up to 24 month was also tested using material originating from patients with head and neck cancer, non-small-cell lung carcinomas, and colorectal adenocarcinomas. Depending on the fixative used and the time of storage of cut tissue sections, a variation in the determined level of EGFR expression was demonstrated compared with the most optimal fixation procedure.