Abraxane, a drug approved in the US since 2005 and the EU since 2008, may have its use expanded after new research suggests it has a previously unknown secondary effect on cancer cells.
In a study by researchers at the New York University Langone Medical Center, Abraxane was found to ‘re-activate’ immune cells involved in the growth of cancer, switching them from cells that dampen the immune response to those that amplify it.
Abraxane is an albumin-bound form of paclitaxel used to treat breast, lung and pancreatic cancer. Unbound paclitaxel prevents the breakdown of molecules in cancer cells called microtubules which is an essential step for cancer cells to continue to multiply.
The addition of albumin to paclitaxel increase the efficacy of paclitaxel, however, the reason behind this effect has been unconfirmed since its discovery – until now.
In cancer cell line experiments, the NYU team found that albumin enhanced the uptake of paclitaxel by immune cells called macrophages. Past studies have shown these cells to switch into an immunosuppressive mode in certain cancers, preventing the effective destruction of tumours by immune cells.
In mouse models of pancreatic tumours, albumin-bound paclitaxel caused these macrophages to switch from their immunosuppressive state into an immune system-enhancing state, encouraging other immune cells to identify cancer cells and destroy them.
“Our study reveals a previously unappreciated role for Abraxane in tumour immunology,” said corresponding author Dafna Bar-Sagi, chief scientific officer at NYU Langone. “In doing so, it suggests ways to improve the drug and argues for its inclusion in new kinds of combination treatments.”
The new role for Abraxane suggests the drug could be a useful addition to new types of combination therapies that target the immune system in order to treat cancer. Binding albumin to other drugs may also offer a new mode of delivery for both old and new drugs, ensuring they remain in macrophages longer and have a greater therapeutic effect.