Within the scope of the GANNET53 trial, blood will be drawn routinely during your treatment. In addition to that, extra blood samples are taken for scientific laboratory tests. Since these additional blood samples are taken together with the routine blood samples, it will not be necessary to puncture the vein more often. If it is required or already planned due to complaints to collect abdominal fluid (ascites), the removed abdominal fluid can also be used for scientific laboratory tests with your consent only. If you consent, the recurred tumour is biopsied (on a voluntary basis) and the extracted tumour tissue is examined scientifically in the laboratory.
By examination of blood, abdominal fluid and tumour tissue (biomaterials), the particular tumour biology as well as possible factors influencing the prognosis and response to the therapy are analysed. These factors are called biomarkers and they can serve as indicators for measuring the disease. The aim is to investigate if these factors are decision-making aids for future treatments and if the patients’ course of disease can thereby be improved. You should know that these examinations of biomaterials are done without direct reference to you personally. This means that these test results are not applied for planning or supervising your current treatment. The extracted samples are used to better understand pathological processes or to gain deeper insights into the effect of the new treatment form. This is crucial for the medical progress. Future patients with the same disease as yours could benefit from these scientific laboratory analyses.
What exactly is analysed? The emphasis of the scientific laboratory analyses lies on the exact determination of the so-called p53 status of ovarian cancer:
There are different types of ovarian cancers, type I and type II tumours. More than 70% of all ovarian cancers are type II tumours. Almost all cases of these type II tumours (96%) are characterised by a change (mutation) in a protein (p53). This protein usually has a protective function by regulating the division, repair, ageing and death of cells.
However, when it mutates, it loses its protective function so that damaged cells can divide uncontrollably. This can lead to the occurrence of cancer. Therefore, it is our aim to collect as much information as possible on the p53 status of tumours of trial participants in GANNET53. For this reason, the obtained tissue samples are analysed for changed (mutant) p53 in the laboratory.
Examinations at the University Medical Centre in Göttingen, Germany, have shown that mutant p53 molecules depend on the existence of a so-called heat-shock protein, hsp90. Together these molecules build a complex, leading to a strong accumulation of changed (mutant) p53 protein in the cell. In our clinical trial, a new pharmaceutical called ganetespib is used. This pharmaceutical breaks off the complex between the heat-shock protein hsp90 and the mutant p53 protein. As a consequence the cell is then capable of breaking down the mutant, bad p53 protein, again.
Apart from p53, other factors (biomarkers) that possibly influence the course of disease are analysed as well.
The aim of these scientific laboratory analyses is to develop laboratory tests that can be used to better control and predict how patients respond to the new therapy form.