An extremely promising experimental drug, called crizotinib for lung cancer patients with a specific gene has shrunk tumors in 90% of patients in a clinical study within two months, researchers from Pfizer. Inc. said. With expectations of just a 10% response rate to this new medication – which would have been good news anyway – a 90% rate surprised everybody.

The 80 patients involved in the trial had advanced lung cancer, in a number of cases the cancer had already spread to the brain. Most of them had already tried 3 other medications.

Study leader, Dr. Yung-Jue Bang, Seoul National University College of Medicine in South Korea, said that responses to crizotinib have so far lasted up to 15 months – it has been fast-tracked into late-stage testing.

Crizotinib targets a gene that promotes the growth of the tumor, i.e. it targets that genetic defect in the cancer cell. Approximately 1 in every 20 patients with lung cancer has this gene (a specific re-arrangement of the ALK gene) – mainly younger patients who do not and have not smoked. Approximately, 10,000 people with this gene are diagnosed with lung cancer in the USA each year.

Cancer is a class of diseases characterized by out-of-control cell growth, and lung cancer occurs when this uncontrolled cell growth begins in one or both lungs. Rather than developing into healthy, normal lung tissue, these abnormal cells continue dividing and form lumps or masses of tissue called tumors. Tumors interfere with the main function of the lung, which is to provide the bloodstream with oxygen to be carried to the entire body. If a tumor stays in one spot and demonstrates limited growth, it is generally considered to be benign.

More dangerous, or malignant, tumors form when the cancer cells migrate to other parts of the body through the blood or lymph system. When a tumor successfully spreads to other parts of the body and grows, invading and destroying other healthy tissues, it is said to have metastasized. This process itself is called metastasis, and the result is a more serious condition that is very difficult to treat.

Lung cancer is called “primary” if the cancer originates in the lungs and “secondary” if it originates elsewhere in the body but has metastasized to the lungs. These two types are considered different cancers from diagnostic and treatment perspectives.

In 2007, about 15% of all cancer diagnoses and 29% of all cancer deaths were due to lung cancer. It is the number one cause of death from cancer every year and the second most diagnosed after breast and prostate cancers (for women and men, respectively). Lung cancer is usually found in older persons because it develops over a long period of time.

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Pfizer’s crizotinib study results were presented at the ASCO (American Society of Clinical Oncology) annual meeting today.

Written by Christian Nordqvist