Ablynx has received a boost on news AbbVie has snapped up rights to its experimental rheumatoid arthritis drug.

The Belgian drugmaker's shares rose as much as 25% yesterday as investors welcomed news of the deal, under which the group could gain as much as $840 million.

US-based AbbVie - which was born out of drug giant Abbott Laboratories earlier this year - will shell out $175 million upfront for global rights to develop ALX-0061 in RA and lupus.

But terms of the deal mean that milestones could bring an extra $665 million to Ablynx, which also stands to receive "double-digit" royalties on commercialisation.

ALX-0061 - which targets the interleukin 6 pathway via its IL-6 receptor - successfully completed a Phase IIa study earlier this year, reporting strong efficacy and safety data in patients with moderately to severely active RA on a stable background of methotrexate, the firms noted.

Ablynx will complete Phase II clinical development in both RA and systemic lupus erythematosus (SLE), after which, as long as pre-defined success criteria are met, AbbVie will exercise its right to in-license the drug and take on subsequent Phase III clinical development and commercialisation. 

The Ghent-based group also retains an option for co-promotion rights in Belgium, the Netherlands and Luxembourg.