Swiss drugmaker Novartis said on Friday it had agreed to buy all remaining rights to Ofatumumab, which is being developed for relapsing remitting multiple sclerosis and other autoimmune indications, from Britain's GlaxoSmithKline. Basel-based Novartis will make an initial upfront payment of $300 million to GSK for the acquisition of the compound and a further $200 million payable following the start of a phase III study in MS by Novartis.