Delivering an encapsulated form of the chemotherapy drug pemetrexed (Alimta) directly into the pleural cavity where mesothelioma starts, may offer a more effective way to slow mesothelioma tumor growth.
Scientists in Japan have just added a new study to the growing body of research on liposomal pemetrexed, a form of pemetrexed that encloses molecules of the drug in tiny bubble-like structures called liposomes.
Liposomal Pemetrexed for Greater Impact, Fewer Side Effects
Although pemetrexed is the number one mesothelioma chemotherapy drug, only about four in ten malignant pleural mesothelioma patients respond to it.
Liposomal pemetrexed, on the other hand, allows more of the pemetrexed to get into mesothelioma tumors where it can do the most damage to the cancer cells without harming as many healthy cells.
The result is a more effective mesothelioma treatment with fewer toxic side effects.
Two Kinds of Mesothelioma Treatment Approaches
In the latest study of liposomal pemetrexed for mesothelioma treatment, researchers at Tokushima University tested versions of pemetrexed encapsulated in either a cholesterol-containing liposome or a cholesterol-free liposome.
Both kinds of pemetrexed were injected into the pleural cavities of mice infected with malignant pleural mesothelioma.
The team reports that the cholesterol-free version of pemetrexed “drastically inhibited the tumor growth in the pleural cavity” while uncoated or cholesterol-coated pemetrexed barely affected the mesothelioma tumors.
Why Liposomal Pemetrexed for Mesothelioma Chemotherapy?
The greatest challenge with any mesothelioma drug is how to kill as many cancer cells as possible while minimizing the impact on healthy cells. Although pemetrexed is an effective killer of mesothelioma cells, the high doses needed to achieve the most impact can cause deadly side effects.
The process of encapsulating a toxic chemotherapy drug like pemetrexed in a liposomal coating potentially creates a mesothelioma treatment that is both safer and more effective.
Targeted Drug Delivery Makes for More Effective Mesothelioma Treatment
Administering the liposomal pemetrexed directly into the pleural cavity ensures that more of the drug reaches its intended mesothelioma tumor target. The cholesterol-free pemetrexed not only stayed in the pleural cavity longer than other versions, but also released more of the drug.
“This therapeutic strategy of direct intrapleural administration of liposomal pemetrexed…might be a promising therapeutic approach to conquering the poor prognosis for malignant pleural mesothelioma,” writes study author Hidenori Ando of the Institute of Biomedical Sciences at Tokushima University.
The new study on mesothelioma treatment with liposomal pemetrexed appears in the Journal of Controlled Release.
Ando, H, et al, “Advanced therapeutic approach for the treatment of malignant pleural mesothelioma via the intrapleural administration of liposomal pemetrexed”, October 14, 2015, Journal of Controlled Release, Epub ahead of print