Short drug circulation times and difficulty localizing therapy to tumor sites are but two of the challenges associated with existing cancer treatments. More troubling are the issues of drug toxicity and tumor resistance. Toxicity can cause major complications, such as low white-blood-cell counts or heart failure, that necessitate cessation of treatment. The tissue damage inflicted by some therapies can even be fatal. And evolution of drug resistance by tumors accounts for the vast majority of cases in which treatment fails. Given these and other issues associated with treatment safety and efficacy, scientists are applying tremendous effort toward the utilization of nanomedicine in the fight against cancer.
Nanotechnology-based therapeutics have exhibited clear benefits when compared with unmodified drugs, including improved half-lives, retention, and targeting efficiency, and fewer patient side effects. Researchers have already made progress with chemotherapeutic nanomedicines in the clinic. Several compounds that are in various stages of trials or already approved by the U.S. Food and Drug Administration (FDA). For example, Calando Pharmaceuticals has demonstrated the first evidence of nanoparticle-delivered clinical RNA interference (RNAi) (Nature, 464:1067-70, 2010). BIND Biosciences has shown that nanoparticles combining a chemotherapeutic drug with prostate-specific membrane antigen (PSMA) can reduce lung and tonsillar lesions with greater efficacy compared with the drug alone, and at substantially lower doses (Sci Transl Med, doi:10.1126/scitranslmed.3003651, 2012). Furthermore, Celgene’s Abraxane, an albumin-functionalized paclitaxel formulation, was initially approved by the FDA for sale as a breast cancer therapy, but also recently received approval for the treatment of lung and pancreatic cancers…
