The FDA approved Sanofi’s oral-only MS medication Aubagio (teriflunomide) Wednesday. The approval adds another oral to the mix of patient options, which includes interferons along with injectables including Copaxone and Biogen Idec‘s Tysabri and Novartis’ Gilenya pill.

The company told MM&M it is set to launch the drug in the US over the next few weeks and it will cost about $45,000 per year. The pricing puts the drug on the lower range of its tiers — Sanofi noted that the $45,000 figure is 6.5% cheaper than Copaxone, 8% less than Avonex and 28% less than Gilenya. Phase III trials indicated Sanofi’s drug reduced the relapse late by about 30% compared with patients who were taking the placebo. Common side effects include abnormal liver tests, nausea and hair loss.

Ben Weintraub, director of research at the health analytics firm InThought, told MM&M that the approval is good for MS patients, but it’s unlikely to provide a major shift in treatment patterns. A key reason: Biogen Idec’s experimental oral treatment BG-12, which the company expects to have in US markets by 2013. Weintraub said BG-12’s front-end advantages include trust in its efficacy and safety profile. He said he expects BG-12 will take off. He said the unapproved contender lacks hurdles, like Gilenya, which requires an observed six-hour waiting period after the first dose, or Tysabri, which has been linked to a potentially fatal brain disease.

Instead, Weintraub said doctors will be more likely to move patients to BG-12 with a degree of ease, saying, for example, “OK, you’re failing at interferon and Copaxone, you’re going to use BG-12,” as opposed to working through other treatments like Aubagio or Tysabri first.

The analyst also said Aubagio faces the standard physician test of seeing how an approved drug plays out in the real world, as opposed to a clinical trial’s limited, controlled conditions. Weintraub said this means doctors will initially prescribe Aubagio to their sickest patients and use those results before considering it as a first-line option. He said this is pretty standard and he expected the same scenario to play out for Pfizer’s approval-pending RA drug, Tofacitinib.

“It will be a drug for a certain population of people that don’t want to take interferons, that don’t need something as strong as Gilenya or Tysabri,” he said.