* Will make initial $300 mln payment to buy compound
* Further $200 mln after start of a phase III study
* Up to $534 mln to be paid if milestones met
* Will pay royalties of up to 12 pct on future net sales (Adds comment from head of Novartis Pharmaceuticals, detail)
ZURICH, Aug 21 (Reuters) - Novartis has agreed tobuy all remaining rights to Ofatumumab from Britain'sGlaxoSmithKline for up to $1 billion, boosting the Swissdrugmaker's stable of multiple sclerosis (MS) treatments.
Basel-based Novartis had previously acquired the rights toOfatumumab for oncology indications, but it is currently beingdeveloped for relapsing remitting multiple sclerosis and otherauto-immune conditions.
"Novartis is pleased to further reinforce our commitment toneuroscience and to add an exciting new treatment to our strongMS portfolio," David Epstein, head of Novartis Pharmaceuticals,said in a statement.
Novartis will pay GSK $300 million up front to buy thecompound and a further $200 million is payable after the startof a phase III study in MS by Novartis.
Payments of up to $534 million will be made if pre-agreedmilestones are met.
Novartis will also pay royalties of up to 12 percent to GSKon any future net sales of Ofatumumab in auto-immune conditions.
(Reporting by Joshua Franklin; Editing by Gopakumar Warrier andDavid Goodman)