On The Heels Of Chemo-Approved Cancer Drugs
There are multiple chemotherapy-based drugs available to treat the deadliest forms of cancer. They are administered in various manners - injection, oral, etc. - with varying degrees of success and side effects, some of which are so severe that they are life threatening, ahead of the cancer itself. All are designed to extend the valuable months of life left after a diagnosis. Many have questioned and wrestled with the severeside effects that reduce the quality of life along the way and the search for more effective drugs with fewer side effects and longer life extension is highly competitive. Research is also progressing on non-chemo-based remedies that attempt the same or better life extension but with significantly fewer side effects. Cancer treatments and the costs as we know them would change dramatically if these companies and their drugs were to succeed.
Brain cancer is diagnosed in approximately 200,000 patients per year with approximately 40,000 considered primary brain cancer. The remainder is the result of metastasis from other distant primary cancers such as breast, lung and colon. Approximately 60% of brain cancers are diagnosed as astrocytoma of which there are four forms, grade I through IV. Glioblastoma multiforme (GBM) is the most aggressive and lethal form of astrocytoma and is classified as grade IV. Brain tumors are the leading cause of solid tumor cancer death in children under the age of 20. Glioblastoma multiforme represents about 50% of the astrocytoma, and is the most lethal form of brain cancer for which there are currently few treatment options that significantly influence disease outcome. In the United States, the incidence of GBM is about 10,000 -12,000 new cases per year, prevalence is approximately 25,000 at any one time, and there is no gender or age bias. Worldwide, the incidence rate and prevalence are approximately double that number. Survival at one year is about 28%, at two years 8% and at five years 3%.
Chemotherapy-based Treatments
Cancer cells no longer have the normal checks and balances in place that control and limit cell division. The process of cell division, whether normal or cancerous cells, is through the cell cycle: resting phase; active growing phases; and then mitosis (division). Chemotherapy is based on its ability to kill cancer cells via halting out of control cell division. The chemo damages the RNA or DNA that tells the cell how to copy itself in division. If the cells are unable to divide, they die. Chemotherapy drugs that affect cells only when they are dividing are called cell-cycle specific. Chemotherapy drugs that affect cells when they are at rest are called cell-cycle non-specific. The scheduling for a patient as to when chemotherapy is administered is set based on the type of cells, rate at which they divide and the time at which a given drug is likely to be effective. This is why chemotherapy is typically given in cycles.
Chemotherapy is most effective at killing cells that are rapidly dividing. The problem is that chemotherapy does not know the difference between the cancerous cells and the normal cells so it damages or kills them all. Normal cells grow back, but in the meantime, side effects occur. The "normal" cells most commonly affected by chemotherapy are the blood cells, the cells in the mouth, stomach and bowel, and the hair follicles, resulting often in low blood counts, mouth sores, nausea, diarrhea and hair loss.
A look at some of the existing chemo-approved cancer drugs in the (GBM) brain tumor area are Temodar, developed by Schering-Plough, [now part of Merck (MRK)], Erbitux made by ImClone Systems, [a wholly-owned subsidiary of Eli Lilly and Company (LLY)], and Avastin by Genentech, a member of the Roche Group (RHHBY.PK)
There are also a host of firms working on cancer treatments that do not involve chemotherapy. One such drug currently in clinical trials is DCVax, developed by Northwest Biotherapeutics, Inc. (NWBO.OB), a development stage biotech that develops and commercializes immunotherapy products that generate and enhance immune system responses to treat cancer.
Temodar ®, whose generic name is Temozolomide is an anti-cancer ("antineoplastic" or "cytotoxic") chemotherapy drug, classified as an "alkylating agent" Temodar is prescribed for treatment of anaplastic astrocytoma and glioblastoma multiforme brain tumors. Administered orally via capsule form and varied in dosage by prescription, side effects include (occurring in greater than 30% of patients) nausea and vomiting, constipation, headache, and fatigue.
side effects occurring in about 10-29% of patients include low blood counts, increasing risk for infection, anemia and/or bleeding. Some delayed effects include swelling (edema), dizziness and balance problems, weakness of one side of body (hemiparesis), seizures, or excessive sleepiness. A slight risk of developing a blood cancer such as leukemia after taking Temodar is also apparent. Temodar reportedly costs between fifty and sixty thousand per year.
ERBITUX® (cetuximab), is designed for certain types of regionally advanced head and neck cancers, and often is combined with radiation therapy. It is also indicated for use alone to treat patients with a certain type of head and neck cancer whose tumor has returned in the same location, or spread to other parts of the body and progressed. Severe allergic reactions and symptoms can include trouble with breathing (including tightening of the airways, wheezing, or hoarseness), low blood pressure, shock, loss of consciousness, and/or heart attack. Lung disease and skin problems are also noted.
Avastin, given as an infusion is a tumor-starving (or anti-angiogenic) therapy. The drug is designed to block a protein called vascular endothelial growth factor, or VEGF. Normal cells produce VEGF, but some cancer cells overproduce VEGF. Blocking VEGF may prevent the growth of new blood vessels that feed tumors. Side effects include high blood pressure or severe high blood pressure that may lead to stroke, difficulty breathing, decreased oxygen in red blood cells, serious allergic reaction, chest pain, headache, tremors, and excessive sweating. Avastin reportedly costs sixty to eighty thousand dollars a year.
A polar opposite approach towards the same problem
Some scientists believe that the more we learn about cancer, the better it is understood to be a personalized disease, in need of personalized treatment. Potentially huge patient-to-patient variability exists, and even within an individual patient, the cancer mutates and evolves over the course of the disease quite significantly.
DCVax, as developed by Northwest Biotherapeutics, has performed in clinical trials consistently across patients as well as across diverse cancers. It is not a chemotherapy-based drug. More than eighty percent, of the patients that have taken DCVax have substantially exceeded standard of care in terms of time to progression, and survival time.
The product mobilizes the entire immune system, T cells, B cells, natural killer cells, macrophages and neutrophils, therefore reportedly providing multiple types of weapons to kill cancer cells off, as opposed to a specific target area in which all cells are killed. The treatment uses the biomarkers from the patient's own tumor, also a distinguishing factor of use versus other immune therapies.
Often cancer drugs stop working due to the sophisticated nature of the cancer cells and their ability to stop expressing themselves. Targeting the entire set of biomarkers works around that issue. Most key is the delivery system for DCVax, which is administered locally in a doctor's offices, via standard syringe. The projected cost of DCVax is in the range of thirty-seven thousand dollars a year for a three year treatment regimen.
Other biopharmaceutical firms have immunotherapy therapies in the works at various degrees of clinical trial testing as well. With fewer patient side effects, possibly longer life expectancy, reduced costs, and simplified delivery systems, the field looks promising for patients, the health care system, and investors alike.
By John Eastman
Disclosure: I have no positions in any stocks mentioned, and no plans to initiate any positions within the next 72 hours.
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