FDA Approves Cornell Dots for Human Trials
The FDA (U.S. Food and Drug Administration) has approved the first clinical trial in humans of Cornell dots, brightly glowing nanoparticles that can light up cancer cells in PET-optical imaging. The technology aims to safely show surgeons extent of tumors in human organs.
C dots harmlessly fluoresce brightly enough to be seen through the skin of a mouse.
Earlier, the FDA determined that Cornell dots (or C dots) are an “investigational new drug.”
C dots are an ultra small, cancer-targeted, multimodal silica nanoparticle less than 8 nanometers in diameter that enclose several dye molecules. The silica shell, essentially glass, is chemically inert and small enough to pass through the body and out in the urine. Coating the dots with polyethylene glycol, a process called PEGylation, further protects them from being recognized by the body as foreign substances, giving them more time to find targeted tumors.
The outside of the shell can also be coated with organic molecules that will attach to such desired targets as tumor surfaces or even locations within tumors. The cluster of dye molecules in a single dot fluoresces under near-infrared light much more brightly than single dye molecules, and the fluorescence will identify malignant cells, showing a surgeon exactly what needs to be cut out and helping ensure that all malignant cells are found.
MSKCC researchers also found C dots can show the extent of a tumor's blood vessels, cell death, treatment response and invasive or metastatic spread to lymph nodes and distant organs.
Leading to the FDA approvals, the C dots were optimized for efficient renal clearance, allowing the body to pass them through the kidneys. The team also was able to perform real-time imaging of lymphatic drainage patterns and particle clearance rates, as well as sensitively detect nodal metastases.
For the clinical trials, the dots will be coated with polyethylene glycol (PEG) so the body will not recognize them as foreign substances, according to Michelle S. Bradbury, M.D., of the Memorial Sloan-Kettering Cancer Center and an assistant professor of radiology at Weill Cornell Medical College.
"This is the first FDA IND approved inorganic particle platform of its class and properties that can be used for multiple clinical indications, two of which are explored: cancer targeting for diagnostics and future therapeutic diagnostics, as well as cancer disease staging and tumor burden assessment via lymph node mapping," Dr. Bradbury said in a statement.
To make the C dots stick to tumor cells, organic molecules that bind to tumor surfaces (or even within tumors) can be attached to the PEG shell, she added.
MSKCC, Cornell and HST researchers are forming a new commercial entity to transition the research into commercial products that will benefit cancer patient care. Cornell dots were developed in 2005 by Hooisweng Ow, as a graduate student working with Ulrich Wiesner, Cornell associate professor of materials science and engineering.
A paper describing the C dots will appear in the July 2011 edition of the Journal of Clinical Investigation. Authors of the paper include Ow, Bradbury, Wiesner, Miriam Benezra and Oula Penate-Medina, who are researchers at MSKCC.