Challenges and opportunities in the delivery of cancer therapeutics.

The idea that cancer is not one but many diseases has completely changed the oncology landscape and promoted the development of personalized cancer therapy. Based on a better understanding of the mechanisms of cancer cell proliferation and tumor growth, novel therapies have emerged to address unmet medical needs and effectively treat pre-identified, responsive patients. These novel therapies require specific drug-delivery strategies that depend on the type and location of cancer, as well as the type of drugs administered, that is, a small molecule, a peptide, a therapeutic protein or a monoclonal antibody. Systemic cancer drugs are administered through three major routes that show different challenges with regard to delivery: these are oral administration, intravenous infusion and subcutaneous injection. This review presents and discusses the challenges and opportunities of the drug-delivery systems for each of these administration routes. It will be shown that, for the good of the patients, every time a drug-delivery system is used to administer anticancer drugs, the patients get a major benefit from that specific system: either improved efficacy, a better tolerability and toxicity profile, or even a combination of both effects.