There is evidence that two novel mesothelioma medications may work better than some of the most commonly used drug treatments.
Researchers in Stockholm, Sweden treated six mesothelioma cell lines with six different drugs, some of which are already commonly used to treat the asbestos-linked cancer. The drugs tested include carboplatin, pemetrexed, doxorubicin and gemcitabine, all of which have been used to fight mesothelioma. The new drugs included in the tests were selenite (a form of selenium) and bortezomib (a proteasome inhibitor). The researchers tested the drugs alone and in various combinations to see which were most effective.
“As a single agent, selenite was effective on four out of six cell lines and, in combination with bortezomib, yielded the greatest response in the studied mesothelioma cell lines,” the authors conclude in a report on PLoS One, a peer-reviewed online journal. They point out that, one of the reasons for mesothelioma’s resistance to conventional treatments is the fact that a single tumor can contain several different types of cells, each of which can be susceptible to different drugs.
In the study, epithelioid mesothelioma cells were more sensitive to all of the drugs tested than cells of sarcomatoid variety. In addition, a number of biomarkers were found to predict which cells would respond best to which drugs. Mesothelioma cells with higher levels of the protein MRP-1 appeared to be more sensitive to treatment with carboplatin and cells with higher levels of xCT responded best to pemetrexed.
Although the selenite/bortezomib combination was the most effective across all mesothelioma cell lines tested, the authors point out that the tendency of mesothelioma tumors to contain cells of varying sensitivity (called heterogeneity) “highlights the need for more individualized therapy.” But individualized mesothelioma therapy, they observe, will depend on the development of new tests to predict the drug sensitivity of cells. In the meantime, they are calling for further clinical testing of selenite and bortezomib as “future treatment regime components.”
Szulkin, A et al, “Variation in drug sensitivity of malignant mesothelioma cell lines with substantial effects of selenite and bortezomib, highlights the need for individualized therapy”, PLoS One, June 2013.