There are two FDA-approved nanoparticle cancer drugs, Doxil and Abraxane. Nanoparticles are incredibly tiny molecular packages for drug delivery. Nanoparticle cancer treatments differ from traditional chemotherapy in that drugs inside nanoparticles can be delivered more gently and more accurately to the cancer cell to lessen collateral damage (side effects) to normal cells. Beyond these two FDA-approved treatments, there are a dozen clinical trials for other nanoparticle cancer treatments that may be FDA approved in the future, in addition to animal studies, which may proceed to clinical trials.
Doxil
Doxil is approved to treat three diseases if traditional chemotherapy is not working: recurrent ovarian cancer, AIDS-related Kaposi's sarcoma and multiple myeloma. Doxil is a reformulation of doxorubicin, a traditional chemotherapy drug. Doxorubicin is repackaged into fat bubbles called lysosomes, which are then surrounded by a rubber coating (methoxypolyethylene glycol). This new packaging as a nanoparticle allows the drug to avoid destruction by the immune system and last longer in the body, making it more effective. These Doxil nanoparticles are given by IV infusion in a doctor's office, usually once per month.
Abraxane
Abraxane is approved to treat metastatic breast cancer. Paclitaxel, the active agent in Abraxane, is packaged as a nanoparticle in a protein- (albumin) coated shell. The traditional formulation of this drug requires the use of solvents, which by themselves produce serious side effects. By packaging the drug in an albumin-coated nanoparticle, the use of solvents and their side effects are avoided. Paclitaxel works by preventing cancer cells from multiplying.
Future Treatments
There are a dozen clinical trials described on the NIH website (www.nano.cancer.gov) that hold promise for progressing to new FDA-approved nanoparticle cancer treatments and cancer detection methods in the future.
One clinical trial is studying the use of nanoparticles to safely package adenovirus particles to stimulate the immune system. Another trial studies the effectiveness of using nanoparticle-enclosed RNAs to disrupt the production of a specific enzyme the cancer cells need to grow. A third clinical trial is using nanoparticles to help cancer drugs pass the blood-brain barrier easily to make treatment of glioblastoma, a type of brain tumor, more effective.
Researchers at the Massachusetts Institute of Technology reported in the July 2009 issue of MIT News that nanoparticles can deliver genetic instructions to ovarian cancer cells to produce a toxin to kill the cancer cells. This study is at the animal research stage but is expected to progress to clinical trials in a year or two. Other research studies in animals also show promise for moving into clinical trials and suggest that nanoparticle cancer treatments may replace traditional chemotherapy in the future.
