July 25, 2008

Nabi: Pharmaceutical Giants Should Cough Up for Smoking Vaccine

Positive interim results, assessing the antibody response and safety of a 400mcg, six-dose immunization schedule of Nabi Biopharmaceuticals' NicVAX, provide a new indication of the vaccine's potential to treat nicotine addiction and prevent smoking relapse. These results make the product a more attractive licensing proposition as Nabi gears up to initiate pivotal Phase III trials.

The open-label Phase II study in 35 patients evaluated whether a new dosing schedule would improve anti-nicotine antibody stimulation. The new schedule, which included an additional injection at three months, resulted in more than 80% of subjects achieving the target antibody level at 14 weeks, compared to 50% of subjects in the Phase IIb proof of concept study. In addition, the revised schedule was well tolerated, with an adverse event profile comparable to previous NicVAX clinical studies.

The current nicotine dependence market consists of a wide range of over-the-counter products, yet only two prescription drugs are approved for this indication. Despite the availability of these treatments, nicotine dependence remains a chronically relapsing condition with only a minority of patients achieving permanent abstinence in an initial attempt to quit.

In February 2006, the FDA granted Fast Track status to NicVAX for use as a therapeutic for smoking cessation, thereby affirming that the FDA views nicotine dependence as a significant unmet need. NicVAX consists of 3'-aminomethylnicotine bound to Pseudomonas aeruginosa exoprotein A, an exotoxin that has been made non-toxic by an amino acid deletion. The vaccine is designed to stimulate the production of antibodies which prevent nicotine from crossing the blood-brain barrier and entering the brain.

Nabi has previously stated that it intends to seek a commercialization partner and/or obtain external funding for the development of NicVAX. With Phase III trials planned to start by the end of 2008, these latest results should attract greater interest from large pharmaceutical companies looking to enter the lucrative nicotine dependence market.

With the launch now predicted for 2011, Datamonitor anticipates NicVAX to be the first vaccine to enter the nicotine dependence market. Its novel mechanism of action is expected to generate strong interest among physicians and, assuming a licensing deal, Datamonitor forecasts the drug to achieve sales of almost $700m by 2012 across the seven major markets. However, from 2012 onwards, Novartis's NIC-002 therapeutic vaccine is expected to offer stiff competition, restricting further sales growth.