In updating my Nanotechnology in Medicine page recently, I noticed that several efforts to use nanotechnology in medicine have moved from the realm of research papers to the pre-clinical or clinical testing stage. For example, CytImmune has published the preliminary results of a phase 1 clinical trial of a targeted chemotherapy treatment method. They use gold nanoparticles attached to a molecule of a tumor-killing agent called tumor necrosis factor alpha (TNF) as well as a molecule of Thiol-derivatized polyethylene glycol (PEG-THIOL), which hides the TNF bearing nanoparticle from the immune system. The PEG-THIOL allows the nanoparticle to flow through the blood stream without being attacked. The combination of a gold nanoparticle, TNF and PEG-THIOL is named Aurmine.
The nanoparticle carrying the TNF tends to accumulate in cancer tumors but does not appear to accumulate in other regions of the body, which limits the toxic effects of TNF on healthy cells. CytImmune uses a combination of two techniques to target the TNF-carrying nanoparticle to cancer tumors. First, the nanoparticle is designed to be too big to exit most healthy blood vessels, however some blood vessels located at the site of tumors are leaky, allowing the nanoparticle to exit the blood vessel at the tumor site. The second technique involves the TNF molecules binding to the tumor.
The fact that they had to get all these details right, determine the right size, a way to hide the nanoparticle from the immune system as well as choosing a targeting molecule to bind to the cancer turmor, gives you some idea as to why it has taken a while to go from research concept to clinical testing.
TNF has been shown to be most effective when administered with other chemotherapy drugs.Therefore, now that the phase 1 trial involving 16 patients is over, CytImmune is planning a phase 2 trial with Aurmine combined with other chemotherapy drugs. They are also performing pre-clinical testing of another combination in which TNF, PEG-THIOL and a chemotherapy drug called paclitaxel is bound to the surface of the nanoparticle. Three other treatments are under development using nanoparticles combined with TNF and other chemotherapy drugs. It will take a while to bring these treatments through all the phases required for qualification with the FDA, however it is exciting that they have progressed from the realm of research papers to trials that will lead to targeted treatment for patients.
Other companies have developed various treatments using nanotechnology in preclinical or clinical testing. If you want to know more about some of the nanotechnology-based techniques that may soon be used with actual patients, visit Targeted X-Ray Therapy for Cancer Tumors or Targeted Heat Therapy for Cancer Tumors.