WEDNESDAY, July 13, 2005 (HealthDay News) -- For those diagnosed with late-stage lung cancer, treatment options are few.
That's one of the reasons why the FDA "fast-tracked" the approval of the targeted lung cancer therapy erlotinib, which is sold under the brand name Tarceva. The agency approved the drug after a clinical trial conducted by the National Cancer Institute of Canada found that people with late-stage lung cancer who responded to the drug could expect to live an average of at least two more months. Some people on the drug lived an additional two years or more, the study found.
"There is now a treatment option available after other treatments have failed. It's tolerable, and it doesn't have a negative impact on quality of life," said study co-author Dr. Frances Shepherd, a professor of medicine at Princess Margaret Hospital and the University of Toronto.
Results of the study appear in the July 14 issue of the New England Journal of Medicine.
Each year, 172,000 Americans are diagnosed with lung cancer, according to the American Lung Association. More than 160,000 die from the disease every year, which makes lung cancer the leading cancer killer, causing more deaths than breast, prostate and colon cancer combined.
Erlotinib works by inhibiting the epidermal growth factor receptor (EGFR) in tumor cells. EGFR is often found in non-small lung cancer cells, and is believed to help fuel the cancer's growth.
The current study looked at 731 people with stage III or stage IV cancer at the start of the study, although Shepherd said that by the time the analysis was done, all were stage IV. That means the cancer is very advanced, and has spread beyond the lungs. All had been unsuccessfully treated with two different chemotherapy regimens.
Four hundred and eighty-eight of the patients received 150 milligrams of erlotinib daily, while 243 were given a placebo. Five percent in the erlotinib group stopped the drug due to side effects.
The overall response rate was 8.9 percent for those treated with erlotinib and less than 1 percent for those in the placebo group. Response, in terms of cancer research, means that the tumor shrinks.
Overall survival was 6.7 months for those on erlotinib, compared to 4.7 months for those on a placebo.
"Survival was prolonged two months on average. For the one-third in the treatment group that lived more than a year, it was another year of good life. Fifteen percent in the treatment group lived longer than two years, compared to none in the placebo group," said Shepherd.
In terms of response, patients with adenocarcinoma, women, Asians and lifetime nonsmokers had better response rates to erlotinib. Also, those who had more than 10 percent of tumor cells expressing EGFR had better than average response rates to the drug. But, in terms of survival, only lifetime nonsmokers had a significant benefit over other groups, the study found.
"Patients who never smoked derived greater benefit from the treatment. They did 60 percent better [in survival] than patients treated with placebo," said Shepherd.
Erlotinib was very well tolerated, according to Shepherd, and didn't adversely affect quality of life, as some chemotherapy regimens can.
Dr. James Doroshow, director of the division of cancer treatment and diagnosis at the National Cancer Institute, wrote an accompanying editorial in the same issue of the journal. "If I were a patient with non-small cell lung cancer, I would be heartened by the fact that even in the third-line setting, we have a treatment that benefits patients," he said.
Shepherd and her colleagues also tested tumor samples from 325 of the patients included in the clinical trial of erlotinib. Some were analyzed for the EGFR mutation and some where analyzed for the number of EGFR genes.
The researchers found that while the presence of EGFR mutations could increase the response to erlotinib, it didn't appear to affect survival rates. Both Shepherd and Doroshow said more study is needed to see which molecular markers truly show who will benefit from this therapy.
Also in this issue of the journal, Taiwanese researchers reported finding an additional mutation that may contribute to the development of resistance to Iressa (gefitinib), another drug in the same class of medications as erlotinib.
Iressa was initially touted as a promising therapy for late-stage lung cancer, but was later found to only benefit people with specific genetic mutations, and even those people eventually stopped responding because they developed resistance to the drug.
In June, the FDA announced that the sale of Iressa would be limited to those already benefiting from it, because additional trials had shown no significant survival benefits.
More information
To learn more about lung cancer treatment options, visit the National Cancer Institute.
