Lung cancer drug that powerfully shrinks tumors most effective treatment in a generation

Main Category: Cancer / Oncology
Article Date: 30 Apr 2004 - 0:00 PDT

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A new lung cancer drug, called Iressa, powerfully shrinks tumors and is being viewed by experts as the most effective breakthrough in lung cancer treatment for over a generation. Lung cancer is the most deadly cancer there is, say many experts.

Iressa was approved in May last year. It was approved as a last resort for lung cancer patients. Clinical trials had revealed sporadic results. Some patients, however, had significant benefits and survived lung cancer for at least one year longer than had been expected.

Scientists at Massacheusetts General Hospital have found a way of detecting the type of patient who will respond best to this drug, they have applied for a patent for their detection method. Soon, patients with lung cancer will be able to know which drug best suits them and start their medication as soon as their lung cancer is diagnosed, instead of going through the chemotherapy first.

Those who are found not to be the type of patient to benefit from the drug would not have to undergo the very expensive treatment.

Iressa is produced by Astra Zeneca.

Only about 13% of lung cancer patients will be suitable for this drug. However, those 13% will experience fantastic benefits if they can take it right at the beginning of treatment. Many lung cancer patients die within months of a diagnosis.

Dr. Bruce E. Johnson, author of one of the studies carried out on detecting the right type of patient said "A small but substantial subset of patients will respond to taking one pill a day. We think that's pretty dramatic. We're talking about more than 10,000 patients a year in the US."

This is one more step in the direction of matching the patient to his/her drug.

Drs Matthew Meyerson and William Sellars, who are researching into just this, matching patients with cancer drugs, said "I think its the new paradigm in cancer treatment, and it's the first example of it in a major human cancer."

Another drug, Tarceva, seems to be able to make another subset of lung cancer patients live longer, says a team of scientists who work at Genentech, California.

The initial Iressa trials confused doctors somewhat. They found that about 85% of patients experienced no benefit at all, in fact some died earlier than expected. However, a sizeable minority, about 14% experienced rapid shrinkage of their tumours.

Scientists began to investigate why some people responded well and others did not. They eventually found the telltale DNA sign (genetic marker that tells you if someone is a good match). You can read about their research in the New England Journal of Medicine and the online edition of Science.

Dr. Daniel Haber, Director of the Massachusetts General Cancer Center, said "It turns out that the mutations we found make the cancer cells more sensitive to the drug, almost 10 times as sensitive."

About Iressa From Astra Zeneca Web Site
http://www.astrazeneca.com/productbrowse/5_84.aspx

Iressa (gefitinib, ZD1839) is the first in a new class of anti-cancer drugs known as epidermal growth factor receptor tyrosine kinase (EGFR-TK) inhibitors to gain market approval. Currently available in a number of countries including the US, Japan, Canada and Australia, regulatory reviews are ongoing in several other countries, including the European Union.

NSCLC is the most common form of lung cancer, which kills more people each year than breast cancer and prostate cancer combined. Administered as a once-daily oral tablet, Iressa acts within the cell to target and block signalling pathways that are implicated in the growth and survival of cancer cells.

Approvals were based on data from pivotal phase II trials, IDEAL 1 and 2, which showed Iressa to be an effective treatment for many patients with previously treated NSCLC. More than 40% of patients saw tumour shrinkage or stabilized disease, often associated with symptom relief, with the median time to symptom improvement being 8-10 days. Approximately 30% of patients with a very poor prognosis were alive 1 year after treatment. Due to the targeted mode of action, side effects with Iressa (e.g.skin rash and diarrhoea) are generally mild and reversible [1] [2].

Iressa targets signalling pathways that appear to play a major role in the growth of many solid tumours and therefore may have therapeutic potential in a broad range of common cancers. Ongoing investigation of this potential includes trials in head and neck, colorectal and breast cancer and additional trials in NSCLC.

[1] Fukuoka, M et al. J Clin Oncol 2003; 21:2237-2246

[2] Kris M et al. A phase II trial of ZD1839 (' Iressa ') in advanced non-small cell lung cancer (NSCLC) patients who had failed platinum- and docetaxel-based regimens (IDEAL 2). 38th Annual Meeting of the American Society of Clinical Oncology (ASCO), Orlando, US, May 2002. Abstract number 1166.