Nabi Pharmacetuicals’ stock bombed, dropping more than 66% yesterday on the release of Phase III trial data suggesting that its lead candidate, an immunotherapy-based smoking cessation drug called NicVAX (Nicotine Conjugate Vaccine), was ineffective. The reported study, which is the first of two Phase III trials, involved over 1,000 patients, and was designed to evaluate whether NicVAX improved smokers’ ability to abstain for 16 weeks, over the 12-month trial period.
The results showed that therapy with NicVAX resulted in an approximately 11% smoking cessation rate, which was similar to that among placebo patients. Nabi admits it was “surprised and deeply disappointed” with the findings. “We are in the process of assessing the reasons for these unexpected data, as we await the results of the second Phase III trial,” remarks Raafat Fahim, president and CEO.
“Data from this second trial may provide clues that could help explain the disappointing results from the first trial.” In the meantime, the Nabi board is investigating potential alternative options for the firm’s future, while its management works to conserve cash.
NicVAX is designed to stimulate the immune system to produce antibodies that bind to nicotine in the bloodstream and prevent it from crossing the blood-brain barrier and entering the brain. The Phase III development program has been supported by a $10 million grant from NIDA awarded in 2009.
The second 1,000-patient Phase III NicVAX study, which was fully enrolled in November 2010, is due to report results during early 2012. A Phase IIb trial of NicVAX was completed in 2007 and found that the treatment significantly improved the number of subjects who managed to quit smoking for eight consecutive weeks. The final 12-month data confirmed the highly significant trends seen at six months and nine months for both smoking cessation and long-term smoking abstinence.
In March Nabi inked an exclusive, worldwide option and license agreement with GlaxoSmithKline for the development and commercialization of NicVAX. Under terms of the deal Nabi received $40 million up front and was eligible for potentially $460 million in option fees and regulatory, development, and sales milestones for NicVAX and follow-on nicotine vaccines.