New treatment successfull in therapy resistant ovarian cancer

Chemotherapy is a known and potent treatment that not only damages cancer cells, but also healthy cells. As a consequence the treatment leads to side effects like hair loss and fatigue. In contrast, an antibody-drug-conjugate (ADC) is a relatively new type of medicine consisting of an antibody with an attached chemotherapy molecule. In contrast to standard chemotherapy this treatment reaches specifically the tumour cells.

Prof. dr. Toon Van Gorp, head of the department of gynacological oncology of UZ Leuven and principal investigator of the trial, explains: “The antibody binds to certain proteins on the outer membrane of the cell. Like a Trojan horse the cancer cell will internalize the ADC and degrade it. This releases the chemotherapy which will attack the cancer cell. Due to the targeted therapy possible with an ADC we see less general side effects while we can eliminate the cancer cells more selectively.

Breakthrough

The international trial was performed between February 2020 and March 2023. In 21 countries worldwide 453 patients with platinum-resistant ovarian cancer were randomized to either treatment with the ADC ‘mirvetuximab soravtansine’, or to the standard chemotherapy. In the group treated with mirvetuximab soravtansine the disease could be controlled for a longer period of time and the treatment was generally tolerated better.

Prof. dr. Toon Van Gorp: “Ovarian cancer is usually effectively treated with platinum-based chemotherapy, but over time nearly all patients relapse because the tumour cells become resistant. Once ovarian cancer is no longer sensitive to platinum-based chemotherapy the disease becomes difficult to treat. This new treatment gives new hope to our patients. This is the first time in over thirty years that a new drug shows a better survival in chemotherapy resistant disease.”

This new trial is a major step in the right direction in the treatment of ovarian cancer. It remains the gynaecological cancer with the highest mortality rate.

ADC's

The first ADCs were developed 20 years ago for the treatment of haematological cancers. This type of cancer is easily attacked with antibodies that circulate in the blood stream. Afterwards they were developed for breast cancer. In the past five years the evolution really took off; with one ADC after another being developed and tested. Not all ADC’s are successful and reach phase 3 trials, but those that do seem to be more effective than chemotherapy.