In a development which has resulted in Nabi shares recording a 26% rise, the Rockville based company has signed a $540 Million licensing deal with GlaxoSmithKline over Nabi's experimental nicotine de-addiction vaccine which prevents smoking relapse as well, as has been confirmed by both the parties involved.

Under the agreement, Nabi will receive $40 Million upfront from Glaxo, and an additional $500 Million as and when certain financial and sales targets are met. The deal will entitle the British drug-maker with an option to exclusively in-license the vaccine in question, called NicVAX, and other follow-on nicotine addiction drugs.

The vaccine's development received a $10 Million grant from the National Institute on Drug Abuse in October. It works by stimulating the body's immune system to produce antibodies, which then bind nicotine.

Nabi will be involved in first two of the late stage trails, after successful completion of which Glaxo will take over the vaccine's further development. The deal is expected to close by next year's first quarter.

"It's the biggest deal we've ever had", shared Raafat Fahim, Nabi's President and Chief Executive.