The U.S. Food and Drug Administration approved a Pfizer Inc. drug that shrinks tumors in lung-cancer patients with a rare genetic abnormality, the latest molecularly targeted therapy to win a rapid approval from the agency.

Crizotinib treats a deadly form of lung cancer that often affects the people least expected to develop the disease: young nonsmokers. Patients with this cancer would be identified by a genetic test made by Abbott Laboratories that was also approved Friday, and then take the pills twice a day.