Budget Impact of Switching to Biosimilar Trastuzumab (CT-P6) for the Treatment of Breast Cancer and Gastric Cancer in 28 European Countries

BACKGROUND

As the economic burden of treating cancer patients has been soaring in European countries, performing a budget impact analysis is becoming one of the requirements for payers' application dossiers.

OBJECTIVE

The objective of this study was to estimate the budgetary impact of introducing the biosimilar trastuzumab (CT-P6) from the payer's perspective and to determine the number of additional patients who could be treated with resulting savings in 28 European countries.

METHODS

A budget impact model was developed to analyze the financial impact of switching from originator trastuzumab to biosimilar CT-P6 in the treatment of early and metastatic breast cancer and metastatic gastric cancer with a time horizon of 1-5 years. Budgetary savings and the number of patients potentially affected were measured based on epidemiological and sales volume data. The base-case analysis assumed that the price of CT-P6 is 70% of the originator price, the switching rate of originator to CT-P6 in the first year is 20%, and the annual growth in the switching rate for each subsequent year is 5%.

RESULTS

For analyses using the base-case scenario following CT-P6 introduction, the total estimated budgetary savings over a 5-year period (depending on the scenario) ranged from €1.13 billion to €2.27 billion based on epidemiological data, or from €0.91 billion to €1.82 billion based on sales volume data. In the first year only, the projected budgetary savings ranged from €58 million to €136 million, and the number of additional patients who could be treated using the savings ranged from 3503 to 7078 by sensitivity analysis.

CONCLUSIONS

The conducted budget impact analysis assessing a switch from originator trastuzumab to biosimilar CT-P6 in 28 European countries indicates that budget savings could be between €0.91 billion and €2.27 billion over the next 5 years. These savings could be used to help improve patient access to local biologics in their respective countries while simultaneously strengthening the overall public health landscape across the European Union.

HER2 amplification in gastroesophageal adenocarcinoma: correlation of two antibodies using gastric cancer scoring criteria, H score, and digital image analysis with fluorescence in situ hybridization

We assessed 103 resected gastroesophageal adenocarcinomas for HER2 amplification by fluorescence in situ hybridization (FISH) and 2 commercial immunohistochemical assays. Of 103, 30 (29%) were FISH-amplified. Both immunohistochemical assays had greater than 95% concordance with FISH. However, as a screening test for FISH amplification, the Ventana Medical Systems (Tucson, AZ) 4B5 antibody demonstrated superior sensitivity (87%) compared with the DAKO (Carpinteria, CA) A0485 (70%). Of the cases, 28 were immunohistochemically 3+ or immunohistochemically 2+/FISH-amplified with the 4B5 assay compared with only 22 cases with the A0485 assay, representing a large potential difference in patient eligibility for anti-HER2 therapy. Cases with low-level FISH amplification (HER2/CEP17, 2.2-4.0) express lower levels of HER2 protein compared with cases with high-level amplification (HER2/CEP17, ≥4.0), raising the possibility of a differential response to anti-HER2 therapy. The H score and digital image analysis may have a limited role in improving HER2 test performance.

HER2 status in gastro-oesophageal adenocarcinomas assessed by two rabbit monoclonal antibodies (SP3 and 4B5) and two in situ hybridization methods (FISH and SISH)

AIMS

HER2 gene amplification has been detected in 10-20% of gastric adenocarcinomas. In view of the recently demonstrated clinical benefit of the anti-human epidermal growth factor receptor 2 (HER2) drug trastuzumab in the treatment of advanced gastric cancer, reliable HER2 testing is of key importance. The aim of this study was to examine HER2 status in gastro-oesophageal adenocarcinomas comparing SP3 and 4B5 immunohistochemistry (IHC) with dual probe HER2 [fluorescence in situ hybridization (FISH) and silver in situ hybridization (SISH)].

METHODS AND RESULTS

IHC and SISH were carried out on biopsy specimens of 146 patients with adenocarcinomas of the oesophagus and stomach. All SP3-IHC-positive cases and 91% of 4B5-IHC-positive cases were amplified. Sensitivity of SP3-IHC-positivity and 4B5-IHC-positivity for amplification was 77% and 96%, respectively. Results of FISH performed in 42 cases were identical to SISH. Amplification was heterogeneous in 73% of the adenocarcinomas; 24% of the oesophago-gastric carcinomas and 7% of distal stomach tumours were amplified.

CONCLUSIONS

HER2-positivity is present in a significant proportion of oesophago-gastric adenocarcinomas (24%), but at a lower rate in the distal stomach (7%). Sensitivity for amplification is higher with 4B5 IHC than with SP3. FISH and SISH yield identical results, but assessment is much easier with SISH. Our findings provide important guidance for HER2-testing in gastro-oesophageal adenocarcinomas for patients in whom anti-HER2 treatment is considered.

Gastric cancer in the era of molecularly targeted agents: current drug development strategies

Gastric cancer is the second most common cause of cancer death worldwide with approximately one million cases diagnosed annually. Despite considerable improvements in surgical techniques, innovations in clinical diagnostics and the development of new chemotherapy regimens, the clinical outcome for patients with advanced gastric cancer and cancer of the GEJ is generally poor with 5-year survival rates ranging between 5 and 15%. The understanding of cancer relevant events has resulted in new therapeutic strategies, particularly in developing of new molecular targeted agents. These agents have the ability to target a variety of cancer relevant receptors and downstream pathways including the epidermal growth factor receptor (EGFR), the vascular endothelial growth factor receptor (VEGFR), the insulin-like growth factor receptor (IGFR), the c-Met pathway, cell-cycle pathways, and down-stream signalling pathways such as the Akt-PI3k-mTOR pathway. In the era of new molecularly targeted agents this review focuses on recent developments of targeting relevant pathways involved in gastric cancer and cancer of the GEJ.