TYSABRI PROBLEMS The Problems Associated with Natalizumab[TYSABRI], Coupled with the Withdrawal of the COX-2 Inhibitors in Late 2004, Have Created Increased Scrutiny in the Regulatory Process :
"More a4 integrin antagonists are under development for the treatment of asthma than for any other therapeutic area, but progress on these compounds has been slow. The safety concerns associated with long-term use and physicians' generally conservative prescribing attitude for this indication make the future of VLA-4 antagonists in this therapeutic market questionable.
The problems associated with natalizumab, coupled with the withdrawal of the COX-2 inhibitors in late 2004, have created increased scrutiny in the regulatory process. In the short term, the FDA will likely begin demanding more-rigorous clinical trials of emerging agents. Other potential changes include increased transparency of clinical trial data and increasing FDA control over labeling and direct-to-consumer advertising."