PROGRESS IN THE DRUG THERAPY OF CANCER
By: Dr. James Ellis, Medical Oncologist
Friday July 15, 2011
Treatment of cancer beyond the local modalities of surgery and radiation therapy is referred to as systemic therapy. This is the form of therapy most important in reducing mortality since it is the growth and spread of cancer away from its origin that is most likely to cause death. Systemic therapy includes hormonal, biologic, targeted and chemotherapeutic agents. I would like to discuss the ongoing development of two chemotherapy drugs and how they are being used today as an example of drug development progress. This is only one front in the war on cancer, but chemotherapy is currently the most commonly used and important systemic therapy.
The drugs I want to discuss are Alimta and Cabazitaxel. Both are members of new generations of a drug group which has been used for years. Alimta is an antifolate, the first of which used in clinical oncology was Methotrexate. Cabazitaxel is a member of the taxane group of which there are now four members. The first drug used from this group was Taxol. Once oncology researchers identify an effective drug, the mechanism of action of the drug and its class is determined. Research efforts then shift to finding related agents with improved efficacy and less toxicity.
Methotrexate was one of the first chemotherapy drugs identified and has been used to treat Leukemia, Lymphoma, Breast Cancer and some other solid tumors. It now has a small role in clinical oncology. Researchers identified a compound that acted as an anti-folate at multiple sites on the target enzyme. It was originally named mutli-targeted anti-folate or MTAF. MTAF was shown to have activity in Mesothelioma and Non-Small Cell Lung Cancer. The Cancer Center of Thibodaux Regional was a participant in the clinical trial that led to the FDA approval of MTAF in Mesothelioma. The drug was then given the name Alimta. It is now part of the treatment of choice for advanced Mesothelioma. We commonly use Alimta in the management of Lung Cancer.
The taxanes (Taxol, Taxotere and Abraxene) came into use in the 1990’s and are among the most commonly used chemotherapeutic agents in multiple cancers. The drug group has been heavily studied and multiple agents have been developed. Cabazitaxel was developed and studied in advanced refractory Prostate Cancer. It showed good activity and tolerance in clinical trials and was recently approved. One of my patients who had failed Taxotere, Mitoxantrone and several other drugs was told by his M.D. Anderson Oncologist to come home and enter hospice. Though elderly and fragile, I offered the patient a therapeutic trial of Cabazitaxel and he agreed. He has now had 6 cycles with excellent tolerance and a dramatic response based on his PSA level. Though not a cure, this new agent is helping this patient live longer and with more quality of life with his disease.
These two drugs are effective agents developed based on knowledge of the mechanism of older drugs. This new generation of drugs is made possible by pharmacologic and clinical research. The Cancer Center of Thibodaux Regional has participated in some of this research and is ready to utilize these leading edge drugs as soon as they are commercially available. In this way we continue to deliver the finest cancer care possible to our patients.