The knock on Pfizer's ($PFE) crizotinib is that it only targets a tiny percentage of lung cancer patients, but the important thing is that the drug appears to have an impact for that tiny percentage.
Pfizer seems to be on schedule to complete a submission in the first half of this year for FDA approval of the drug for patients whose non-small cell lung cancer expressed the anaplastic lymphoma kinase (ALK) gene, which is found in 3-5 percent of patients with the disease. While potential sales of this drug aren't expected to reach blockbuster levels, Pfizer has signaled through its emphasis on targeted drug development and investments in rare diseases treatments that it's happy to be in niche markets with important new drugs.
Last year Pfizer provided details from an early-state clinical data showing that 46 of 82 patients with NSCLC who took the drug had a partial response to the drug and one patient had a complete response. The company also reported last year that patients on averaged lived for 9.2 months without their cancer getting worse. A key in these studies was making sure that patients who took the drug had cancer with ALK mutations. When present, the mutations drive tumor growth and survival.