Genasense

Genasense is a medicine containing the active substance oblimersen. It is made up into a solution that is given as an intravenous infusion (drip into a vein).

Genasense was to be used to treat patients with melanoma (a type of skin cancer affecting cells called ‘melanocytes’) whose disease is advanced (it cannot be removed by surgery alone) or metastatic (has spread to other parts of the body). Genasense was to be used in combination with dacarbazine (another anticancer medicine).

The active substance in Genasense, oblimersen, is an antineoplastic medicine. It is thought to work by preventing cells from producing the protein Bcl-2. This protein normally allows skin cancer cells to stay alive by preventing them from committing suicide (apoptosis). By blocking the production of Bcl-2, Genasense was expected to make the cancer cells more sensitive to factors that cause cell death, including anticancer medicines such as dacarbazine. This was expected to slow down the growth of the tumour.
Oblimersen is an ‘anti-sense oligonucleotide’ medicine. It attaches to the ‘messenger RNA’ (mRNA) that normally instructs the cell how to make Bcl-2. This stimulates the cell to destroy the mRNA, blocking the production of the protein.

The effects of Genasense were first tested in experimental models before being studied in humans.

Genasense has also been studied in 771 patients with advanced or metastatic melanoma. The effects of Genasense in combination with dacarbazine were compared with those of dacarbazine taken alone. The main measure of effectiveness was survival.

In the main study of patients with melanoma, survival rates were very similar in the patients receiving Genasense with dacarbazine and those receiving dacarbazine alone. Therefore, the study did not demonstrate that Genasense was effective in treating melanoma. There were side effects associated with treatment with Genasense.

At that point in time, the CHMP was of the opinion that the benefits of Genasense in the treatment of advanced or metastatic melanoma did not outweigh its risks. Hence, the CHMP recommended that Genasense be refused marketing authorisation. The CHMP refusal was confirmed after re-examination.

The company informed the CHMP that there are no consequences for patients currently included in clinical trials or compassionate use programmes with Genasense. If you are in a clinical trial or compassionate use programme and need more information about your treatment, contact the doctor who is giving it to you.