After Giving up Nabi Starts Again with Nicotine Vaccine

November 05, 2009 After giving up Nabi starts again with nicotine vaccine

Lisa Urquhart

It has been a big news week for Nabi Biopharmaceuticals, on Wednesday the Florida-based group announced that it would finally be moving its smoking vaccine and lead drug, NicVAX, into phase III trials and yesterday it confirmed the close of its deal with GlaxoSmithKline, that will see it receive $21.5m of a possible $46m, for selling the rights to is pentavalent S. aureus vaccine PentaStaph.

But while the deal for PentaStaph has been executed fairly swiftly since being unveiled in August, the group has not been quite so speedy in moving on its clinical programmes and some investors maybe forgiven for feeling a small amount of déjà vu. Way back in June 2008, the group saw its shares rise sharply after it announced that it was moving NicVAX into phase III.

Going it alone

What may have caused the 15-month delay on its promises is the fact that at earlier in 2008 it put itself up for sale and may have been more focused on this process rather than clinical development. There had been hopes that that Glaxo or Pfizer, who both have big smoking cessation products, might step in and snap up the whole group (Nabi's progress with smoking vaccine should lead to deal, July 24, 2008).

A statement on Wednesday that the group would press on with phase III trials on its own, while advancing partnering discussions, implies that Nabi might also have previously been waiting for a partner to come on board and help fund the trials that it now has the cash to at least start.

Confidence in Nabi’s ability to make good on its promises this time round should be instilled by recent cash injections. Aside from the Glaxo deal, in September it announced that the National Institute on Drug Abuse had awarded it $10m to work on the nicotine vaccine, which will raise Nabi’s cash pile to about $140m. That sum is close the group's market capitalisation of $170m.

Long term benefit

NicVAX works by stimulating the immune system to produce antibodies that bind to nicotine, this antibody nicotine combination is too large to cross the blood-brain barrier. So with the nicotine blocked from reaching the receptors in the brain the addictive pleasure sensation experienced by smokers is negated.

The group also believes that because the immune system can be stimulated to produce long-lasting antibodies this should prevent lapses among previous smokers. With an estimated 90% of people using existing smoking cessation products relapsing in the first year, if the drug can prevent this it would represent a significant breakthrough.

Little competition

In the very limited race to develop an effective anti-smoking vaccine, by going into phase III trials Nabi’s product will be the most advanced out of the three remaining nicotine vaccines in development.

Nicotine Vaccines in Development

Product Company Phase

NicVAX Nabi Biopharmaceuticals Phase III

NIC002 Cytos Biotechnology/Novartis Phase II

TA-NIC Celtic Pharma Phase II

But it is debatable if the other two candidates are really in the race. There has been almost total silence over Celtic Pharma’s product since 2007, even though the group is keeping some sort of flame flickering by stating it is on the look out for a partner. Given Nabi’s lack of success in this field to date it might not be wise to hold your breath on this.

As for the other contender, there are questions over whether Cytos Pharmaceuticals' partner, Novartis, will continue the development of NIC002 after it failed to show any benefits in phase II trials. Novartis had already repeated phase II trials in an effort to improve the immune response of the drug and many believe that as this measure has failed the Swiss group will hand back rights to the vaccine (Cytos has much to prove after second pipeline setback October 16, 2009).

The lack of competition extends to the market for prescription drugs, with Glaxo’s Zyban and Pfizer’s Chantix the only significant products. But the biggest seller, Chantix, has seen its sales fall off dramatically following warnings about the psychiatric side effects of the drug. In October 2008 consensus for 2012 sales was $1.19bn, now it is $835m (Chantix warnings strengthened but lack of competition will mitigate damage, July 3, 2009).

Big opportunity

Given the paucity of available treatments and the side effects, if Nabi does manage to show strong results in the phase III trials and is safe, not only is approval almost likely to be a dead cert, but commercial success would be guaranteed.

However a look at the history of nicotine vaccines, where NicVAX is the only one to have made it this far, and the general difficulties in coming up with a successful product in this tricky area mean Nabi is looking at very long odds.