New Treatment for Lung Cancer: A Hint of Good News?
Those of you who are familiar with the malignancy known as NSCLC, or non-small cell lung cancer, are well aware that patients with advanced stage disease or metastases have a dismal prognosis. Most studies with combination chemotherapy produce a median survival of 9-10 months and a one-year survival of 30-44%. The percentage of patients alive two years after diagnosis is 11-19%, depending upon the size of the study and other malleable variables.
Once a patient's disease is refractory to chemotherapy, that is, once the lung cancer begins to grow after a combination of two drugs have been given, "second-line" chemotherapy is often recommended. The agent used for second-line treatment is either docetaxel or pemetrexed, which both produce a similar response rate of only 9%. The median survival time with either drug, however, is 8 months and the one year survival is 30%, compared with 4.5 months and 11% for supportive care, respectively. Because of these statistics they are FDA-approved and in wide usage.
The results of second-line therapy, while appearing meager to the lay reader, are embraced by oncologists like a parent reuniting with a lost child. This should give an idea as to how awful the outcomes were prior to the release of these "modern" chemotherapy drugs, when largely ineffective agents were used. We therefore with gusto recommend chemotherapy to our lung cancer patients, automatically exposing them to all of its various annoying, humiliating and sometimes deadly side-effects - all for a few more months of life.
This is the background I took with me to New York last week, where I attended a lecture describing a pilot study for the second-line therapy of NSCLC. In this trial patients were treated with the esoterically named agents erlotinib and bevacizumab, given simultaneously. The results were eye-opening for me, as this new combination produced a 20% response rate, a median survival of 12.6 months, and a one year survival of 52%. Why are these data provocative to a medical oncologist? They appear to be an improvement, but what's all the hubbub over these agents with the tongue-twister names?
The answer is: erlotinib and bevacizumab are not chemotherapy drugs!
They represent a new class of anti-cancer treatment called targeted therapy. This type of agent blocks a specific molecular target found on the cancer cell, which then inhibits cellular growth and division (mitosis) and promotes programmed cellular suicide (apotosis), among other functions.
Targeted therapy compounds such as erlotinib and bevacizumab also have the advantage of not causing the distresssing toxicities of chemotherapy so familiar to us all: they do not cause hair loss, vomiting, anemia, or fatigue. Their side-effects for the most part are mild, and include rash and diarrhea (trust me folks, this is mild stuff).
So keep an eye out for more encouraging news about targeted therapy agents. I predict that their role in the treatment of cancer will expand tremendously over the next several years, and that their value will increase as they are used earlier in the course of a patient's disease. Let's hope I'm right!