ZURICH Novartis said on Tuesday it would accelerate its bid to win approval for its experimental multiple sclerosis (MS) drug BAF312 and said it was now targeting patients at an earlier stage of the neurological disease.

With BAF312, Basel-based Novartis aims to join its rival Roche in developing a lucrative new drug to treat MS.

Novartis plans to file BAF312 for approval with the U.S. Food and Drug Administration in the first half of 2018 for patients with relapsing/remitting MS (RRMS), a form of the disease where patients suffer clearly defined attacks.

The drugmaker previously said it would seek regulatory approval in 2019 for the drug to treat secondary progressive MS (SPMS) in patients whose RRMS enters a new phase of progressive worsening of function, irrespective of relapses.

Novartis said this change approach was appropriate because SPMS was a continuation of RRMS, in a disease area that defies strict diagnostic categories.

Vas Narasimhan, the firm’s chief drug developer, said he would seek to convince the FDA to take into account characteristics of SPMS patients involved in the Novartis trial when the regulator decides how and to whom to prescribe BAF312.

“The best path forward is to pursue RRMS and try to clearly describe the unique population (we) studied in the indication statement and in the clinical trials section,” Narasimhan told analysts on a call.

Last month, Roche secured FDA approval for its Ocrevus drug to be used against both RRMS and primary progressive MS (PPMS) in which patients’ neurological function deteriorates steadily.

(Reporting by John Miller; Editing by Edmund Blair)