Janssen Contests Lilly's Risperdal/Zyprexa Study

Janssen-Cilag told the Marketletter at the 6th World Congress ofBiological Psychiatry in Nice, France, that it is strongly contesting Eli Lilly's comparative study of Janssen's Risperdal (risperidone) and Lilly's Zyprexa (olanzapine). It is questioning the validity of the study design and the "clinical relevance of its conclusions, given the inappropriate dosing of Risperdal used."

The double-blind, head-to-head study reported that Zyprexa was found to be more effective in several clinical outcomes, including extrapyramidal side effects, negative symptoms and incidence of relapse (Marketletter June 23). However, Janssen stresses that the dose of Risperdal used in the trial was too high: "an average dose of olanzapine was compared to an overdose of risperdal," said Martin Brecher, director of medical development, central nervous system, at Janssen.

A company statement added that "the 7.2mg/day mean modal dose of Risperdal...as well as the 8.3mg/day mean maximal dose...is substantially higher than the 4.7mg/day average dose used in US clinical practice, and considerably higher than the worldwide average daily maintenance dose for Risperdal of 4mg-6mg." Janssen urges that "Lilly provide full disclosure of the methods used, and access to the full data set to this study."