ROCKVILLE, MarylandThe FDA has granted expanded approval to Enzon's Oncaspar (pegaspargase) as part of multidrug chemotherapy for treating children and adults with newly diagnosed acute lymphoblastic leukemia (ALL). The agency acted on the basis of results from a randomized, 118-patient pediatric study that showed Oncaspar was equivalent in safety and efficacy to Elspar (L-asparaginase, Merck), which has been the standard treatment for ALL.
Use of Oncaspar reduces the number of injections required during a 20-week course of treatment to 3, compared to the 21 injections needed for Elspar. Oncaspar was initially approved in February 1994 for the treatment of ALL patients unable to tolerate L-asparaginase because of allergic reactions.
To support the new indication, Enzon submitted results from two trials involving patients who had standard-risk ALL. FDA based its approval on Study 1, conducted by the Children's Cancer Group (CCG). Study 2, an ongoing, multifactoral design study also conducted by CCG, provided interim safety data from 2,770 pediatric patients with a median age of 4 years.
Study 1 was an active-control, open-label trial in which researchers randomized 118 patients (age 1.1 to 9.9 years) to receive Oncaspar or native E coli L-asparaginase. "In the trial, researchers demonstrated that Oncaspar could be safely and effectively substituted for Elspar as part of the multidrug cancer regimen," FDA said. Due to the risk of anaphylaxis and other serious allergic reactions, the drug's labeling warns physicians to observe patients for 1 hour after administering Oncaspar "in a setting with resuscitation equipment and other agents necessary to treat anaphylaxis."