The FDA grants priority review status to products that are considered to be potentially significant therapeutic advancements over existing approved therapies in the treatment, diagnosis or prevention of a disease.
Based on the designation of priority review, the FDA has up to six months from the submission date, or by late February 2006, to take action on the Rituxan submission. The companies submitted the application in August 2005.
The application was based primarily on 24-week results of a multi-center, randomized, double-blind, placebo-controlled phase III study.
In the trial, patients who received a single course of two infusions of Rituxan with a stable dose of methotrexate displayed a statistically significant improvement in symptoms, compared to those who received placebo and methotrexate.
According to the companies, the most common side effects in the Rituxan arm of the trial included headache, upper respiratory tract infection and nasopharyngitis. The rate of serious adverse events reported was comparable across treatment arms.