Personalized Anticancer Chemotherapy
Cancer is a highly individualized disease
The American Cancer Society estimates that close to 1.5 million people are diagnosed with cancer annually in the U.S. and more than 550,000 die as a result of the disease. The estimated costs of cancer care reached $89 billion in 2007 and are growing, driven by increases in early detection and an aging population.
Anticancer drugs are approved by FDA on the basis of the clinical trial results from a population of cancer patients. If a favorable response from a drug regimen is observed in 20-30% of the patient cohort then this drug is likely to be approved by the FDA for marketing. These results from the population cannot be directly identifiable to individual patients in trial. Thus, an individual patient may have 20-30% chance of belonging to the responsive group or 70-80% chance of belonging to the non responsive group for this cancer.
Cancer is a highly individualized disease. Since every tumor has distinct characteristics, targeted therapeutic drug treatment is the preferred approach. Effective treatment relies on selecting a specific drug (or drug combination) that targets a patient’s unique tumor(s). Unfortunately, there are significant side effects, as well as costs that can exceed $30,000 per year for one patient.
The need for multiple target identification is critical. It is no longer sufficient to merely identify a person who may or may not have cancer. Now, the challenge is to develop individualized treatment regimens that will effectively treat that patient’s disease.
Targeted Treatment for Individual Cancer Therapy
An example of successful treatment based on diagnostic results is estrogen therapy on breast cancer. Estrogen receptor positive patients are responsive to hormonal/antiestrogen drugs. Thus, estrogen receptor has been shown to be a reliable “drug response indicator” for the hormonal treatment of breast cancer patients.
Another example of targeted treatment is the coupling of the HER-2/neu diagnostic test and Herceptin, a therapeutic monoclonal antibody that binds to the HER-2/neu protein. The HER-2/neu diagnostic test identifies patients with the sub-type of metastatic breast cancer that is most likely to respond to Herceptin therapy.
Herceptin has been cleared by the FDA to be used only for patients who test positive for HER-2/neu expression. Treatment can induce unwanted side effects, including cardiac toxicity and respiratory problems and costs more than $30,000 per year for each patient. The chemotherapy regimen is ineffective in 60%-70% of patients receiving Herceptin.
Currently, there is no standard procedure for optimal chemotherapy treatment selection.