Creator of the erectile dysfunction drug Viagra and cholesterol fighter Lipitor, Pfizer has been able to get good results for its lung cancer drug.

The early stage study results have found that the cancer drug crizotinib was able to shrink tumors of non-small-cell lung cancer patients whose tumors carried a specific genetic mutation, EML4-ALK, fusing together two genes, according to a report in New England Journal of Medicine.

According to Center for Disease Control and Prevention, lung cancer has the most number of casualties than any other type of cancer. In 2006, lung cancer death were more than breast cancer, prostate cancer and colon cancer combined. While, approximately 200,000 people were diagnosed with lung cancer, nearly 160,000 died from lung cancer in 2006.

During the crizotinib trial, 82 patients had the gene mutation. The tumors of 46 patients shrank by more than 30 percent after taking the oral drug. One patient's tumor even disappeared totally. As much as 57% of patients had either a complete or partial response to the treatment. The drug even stopped tumor growth in 27 of the patients. The study authors also estimated that the disease wouldn't worsen for six months in 72 per cent of patients.

Dr. Eunice Kwak, from Harvard Medical School and lead author of the study said the results are especially gratifying as most patients had already received two or more therapies by the time they entered the trial.

However, the study also found that it was only the patients with the specific gene abnormality responded to the drug. The number of such patients is also very low. Kwak added that there is a need for more studies in this regard. As, mutation is also found in other cancers such as sarcoma, childhood brain tumors and some lymphomas, breast and colon cancers, the company hopes crizotinib could treat rest of the cancers as well.