Aubagio (teriflunomide) is an oral disease-modifying therapy approved for relapsing forms of multiple sclerosis that works by slowing the proliferation of overactive immune cells involved in MS attacks. Taken as a single daily tablet, it occupies a specific niche in the MS treatment landscape: a convenient, moderately effective option with a well-characterized safety profile that makes it a common first-line choice for many people newly diagnosed with relapsing-remitting MS. The drug has been studied extensively since its approval, and the picture that emerges is one of modest but meaningful relapse reduction, good tolerability for most people, and a handful of safety concerns that require ongoing monitoring.
How Aubagio Works
Teriflunomide targets a mitochondrial enzyme called dihydroorotate dehydrogenase, which plays a central role in the production of new pyrimidines, one of the building blocks cells need to replicate their DNA. By selectively and reversibly blocking this enzyme, the drug reduces the rapid multiplication of activated T and B lymphocytes, the immune cells that drive the inflammatory attacks on myelin in MS. Crucially, this effect is cytostatic rather than cytotoxic: it slows immune cell proliferation without killing the cells outright.1PubMed Central. Teriflunomide and its mechanism of action in multiple sclerosis Resting immune cells and slowly dividing cells rely on a separate salvage pathway to get their pyrimidines, so they are largely spared. This selectivity is part of why Aubagio does not suppress the immune system as broadly as some other MS drugs.
What the Clinical Trials Showed
The drug’s approval rested primarily on two large placebo-controlled trials, TEMSO and TOWER, along with a head-to-head trial called TENERE that compared it against interferon beta-1a. In the TEMSO trial, which enrolled over a thousand people with relapsing-remitting MS, the higher 14 mg dose reduced the annualized relapse rate by about 36% compared to placebo and cut the risk of sustained disability progression over 12 weeks by roughly 32%.2Multiple Sclerosis Association of America. Aubagio® (Oral Teriflunomide) Receives FDA Approval The lower 7 mg dose also reduced relapses, though by a smaller margin of about 22%. Only the 14 mg dose is used in clinical practice today.
Across both pivotal trials and the TENERE study, teriflunomide improved not just clinical relapse rates but also MRI measures of disease activity, including the number of new brain lesions.3PubMed. Teriflunomide: A Review in Relapsing-Remitting Multiple Sclerosis In the TENERE trial, teriflunomide performed comparably to interferon beta-1a, which had been a mainstay injectable therapy for years. This finding helped position Aubagio as a reasonable oral alternative for people who wanted to avoid self-injection.
How Aubagio Stacks Up Against Other Oral Options
Teriflunomide is one of several oral disease-modifying therapies available for relapsing MS. The others in common use include fingolimod (Gilenya), dimethyl fumarate (Tecfidera), and newer entries like diroximel fumarate and cladribine. When researchers have compared the oral agents side by side, a general pattern emerges: fingolimod tends to have the edge in reducing relapses and brain volume loss, but it also comes with more safety baggage, including risks of cardiac rhythm problems during the first dose, increased susceptibility to infections, and elevated liver enzymes. Dimethyl fumarate is effective but frequently causes flushing and gastrointestinal upset that drives some people off the drug. Teriflunomide’s side effects, by contrast, are described as well characterized and manageable.4PubMed Central. Comparison of efficacy and safety of oral agents for the treatment of relapsing-remitting multiple sclerosis
In practice, this means Aubagio tends to be positioned as a solid first-line oral therapy for people with less aggressive disease. People with highly active MS or frequent breakthrough relapses are more likely to be directed toward higher-efficacy agents like fingolimod, natalizumab, or ocrelizumab. But for someone newly diagnosed with mild to moderate relapsing MS who values convenience and tolerability, teriflunomide fills an important role.
Staying on Treatment
One underappreciated measure of a drug’s real-world value is how long people actually keep taking it. A large retrospective study of over 16,000 patients newly starting oral MS therapies found that teriflunomide and fingolimod had the highest persistence rates after 12 months, at about 60% and 66% respectively. Dimethyl fumarate and diroximel fumarate lagged behind at 44% and 49%.5PubMed Central. Persistence, Adherence, and Switching to Higher-Cost Therapy in Patients with Multiple Sclerosis Initiating Oral Disease-Modifying Therapies: A Retrospective Real-World Study Adherence followed a similar pattern. Among those who did switch away from teriflunomide, the most common destination was ocrelizumab, a higher-efficacy infusion therapy, and the average time to that switch was about 342 days, longer than for any of the other oral agents. These numbers suggest that while Aubagio’s efficacy is moderate, many people find it tolerable enough to stick with for a meaningful stretch.
Patient-reported outcomes tell a similar story. In a Greek real-world study of people treated with teriflunomide for two years, psychological well-being scores improved significantly, and patients reported meaningful gains in satisfaction with the drug’s effectiveness and convenience.6PubMed Central. Real-World Assessment of Quality of Life in Patients with Relapsing Remitting Multiple Sclerosis Treated with Teriflunomide for Two Years: Patient-Reported Outcomes from the AURELIO Study in Greece A separate French study found that fatigue, one of the most disabling symptoms in MS, remained stable over two years on teriflunomide, with no worsening in depression or overall quality of life.7PubMed. Fatigue in teriflunomide-treated patients with relapsing remitting multiple sclerosis in the real-world Teri-FAST study More recently, a study evaluating brand-generic teriflunomide over 18 months reported significant improvements in treatment satisfaction scores.8PubMed. The patient-reported outcomes for the new brand-generic teriflunomide in relapsing-remitting multiple sclerosis None of these outcomes are dramatic, but in a disease where people may take a drug for years, feeling reasonably good on it counts for a lot.
Side Effects Worth Knowing About
The most commonly reported side effects of Aubagio include hair thinning, diarrhea, nausea, and elevated liver enzymes. The hair thinning tends to appear in the first few months of treatment and is usually temporary; most people see it resolve even while continuing the drug. Gastrointestinal symptoms are generally mild and tend to ease over time as well.
Two side effects deserve more attention because they require active monitoring.
Liver Function
Teriflunomide can elevate liver enzymes, and in rare cases this progresses to serious liver injury. The prescribing information calls for liver function tests before starting the drug and periodically during treatment, usually monthly for the first six months and then as clinically indicated. A case report documented a patient who developed significant liver injury during treatment, reinforcing that monitoring liver markers like transaminases, bilirubin, and alkaline phosphatase should not be treated as optional.9PubMed Central. Hepatotoxicity associated with the use of teriflunomide in a patient with multiple sclerosis If your liver enzyme levels climb significantly, your neurologist will likely stop the drug and initiate an accelerated elimination procedure.
Peripheral Neuropathy
A lesser-known but clinically meaningful concern is peripheral neuropathy, including small fiber neuropathy that causes burning or tingling pain in the hands and feet. The product labeling reports neuropathy rates of about 1.4% at the 7 mg dose and 1.9% at the 14 mg dose.10PubMed Central. Painful Small Fiber Neuropathy Associated With Teriflunomide: A Case Series and Literature Review Related to Teriflunomide and Leflunomide A study comparing nerve conduction in teriflunomide-treated patients versus untreated controls found measurably slower nerve conduction velocities and lower signal amplitudes in the peroneal nerves of the treatment group. The encouraging finding was that all neuropathic symptoms reversed after switching to a different MS therapy.11PubMed Central. Neuropathy in multiple sclerosis patients treated with teriflunomide If you develop new numbness, tingling, or burning in your extremities while on Aubagio, it is worth raising with your neurologist rather than assuming it is just your MS.
Pregnancy, Fertility, and the Accelerated Washout
Teriflunomide is classified as a drug that should not be used during pregnancy due to evidence of harm in animal studies. This is one of the most practically important aspects of the drug for people of childbearing potential: teriflunomide has an extremely long half-life and can linger in the body for months after the last dose if nothing is done to clear it. Without intervention, it can take up to two years for blood levels to drop below a threshold considered safe.
To address this, there is a well-established accelerated elimination procedure. It involves taking cholestyramine (8 grams three times daily) or activated charcoal (50 grams twice daily) for 11 days. Both work by trapping the drug in the gut and preventing it from being reabsorbed into the bloodstream. In a study of healthy volunteers, this procedure reduced plasma teriflunomide levels by about 96% over the 11-day period.12PubMed Central. Effectiveness and Tolerability of Colesevelam HCl for Accelerated Elimination of Teriflunomide in Healthy Participants This washout is used not only for planned pregnancies but also whenever a rapid reduction in blood levels is medically needed, such as when switching to another MS therapy or addressing a serious side effect.
Real-world pregnancy data offer some reassurance, though they should be interpreted cautiously. A Danish study tracked 112 pregnancies with teriflunomide exposure, split between maternal and paternal exposure. Among 91 births with any teriflunomide exposure, adverse events including preterm births and congenital malformations occurred in about 13% of cases, a rate that was virtually identical to the 13% rate in a matched control group with no drug exposure. The statistical comparison showed no significant difference in risk.13ScienceDirect (Multiple Sclerosis and Related Disorders). Pregnancy outcomes following maternal or paternal exposure to teriflunomide in the Danish MS population Still, this was a relatively small sample, and current guidelines continue to recommend avoiding pregnancy during treatment and completing the washout procedure with confirmed low blood levels before conceiving.
Vaccinations While on Aubagio
Because Aubagio modulates the immune system, a reasonable question is whether it blunts the response to vaccines. This became especially pressing during the COVID-19 pandemic, when people on various MS therapies wondered whether their vaccinations would “take.” The available evidence for teriflunomide is fairly encouraging. Studies suggest it has minimal influence on the response to seasonal influenza vaccination.14PubMed Central. Vaccine Response in Patients With Multiple Sclerosis Receiving Teriflunomide This contrasts with some other MS therapies, particularly anti-CD20 drugs like ocrelizumab and rituximab, which substantially reduce antibody responses to vaccines. For people on teriflunomide, standard inactivated vaccines are generally considered safe and effective. Live vaccines, however, are a different story and are typically avoided during treatment because of the theoretical risk that even the drug’s moderate immune suppression could allow a live vaccine strain to cause infection.
Aubagio in Children and Adolescents
Pediatric MS is uncommon but tends to be more inflammatory than adult-onset disease, with higher relapse rates and greater MRI lesion burden early on. Teriflunomide was tested in children and adolescents in the TERIKIDS trial and its open-label extension. In children who received teriflunomide from the start, the estimated risk of clinical relapse was reduced by about 38% compared to those who started on placebo before switching over, and MRI lesion counts dropped substantially: new or enlarging lesions were reduced by roughly half.15PubMed Central. Teriflunomide in pediatric patients with relapsing multiple sclerosis: Open-label extension of TERIKIDS These results were broadly consistent with what had been seen in adults. Safety was acceptable for most participants, though two children in the treatment group developed pancreatitis, a serious event that was not commonly seen in adult trials. Discontinuation rates due to safety concerns were lower among children who had been on teriflunomide from the outset (4%) compared with those who switched from placebo (about 14%), suggesting that those who tolerated the drug early on tended to continue doing well.
Cost Considerations
The economics of MS treatment are notoriously complex. Most disease-modifying therapies carry high list prices, and the availability of generic teriflunomide has changed the financial landscape somewhat. A cost-effectiveness analysis modeled teriflunomide against ofatumumab (Kesimpta), a newer self-injected anti-CD20 therapy, over ten years. Total direct costs were lower for teriflunomide (about $121,000 versus $151,000 for ofatumumab), but ofatumumab generated more quality-adjusted life years, about 0.64 more over the decade.16Dove Medical Press. Cost-Effectiveness Analysis of Ofatumumab versus Teriflunomide for Relapsing-Remitting Multiple Sclerosis: A 10-Year Markov Model These models are sensitive to local drug pricing, discount arrangements, and the willingness-to-pay threshold a given health system uses, so the conclusion will differ by country. In practice, the availability of generic teriflunomide makes it one of the more affordable oral options, which can matter for people facing high out-of-pocket costs or for health systems managing large MS populations.
Tracking Treatment Response With Blood Biomarkers
One of the broader challenges in MS care is knowing whether a given drug is actually working before the next relapse or MRI proves otherwise. Serum neurofilament light chain, a protein released into the blood when nerve fibers are damaged, has emerged as a promising marker that could fill this gap. Reliable detection in blood samples, rather than spinal fluid, has become possible with newer assay technologies, and studies have linked serum neurofilament levels to inflammatory activity, disease progression, and treatment response.17PubMed Central. Serum neurofilament light in MS: The first true blood-based biomarker? While this marker is not yet standard in routine clinical practice and is not specific to any one therapy, it represents the direction the field is heading: toward real-time, blood-based monitoring that could eventually help neurologists decide sooner whether to escalate treatment or stay the course on a drug like teriflunomide.
An Unexpected Angle on Viral Infections
Because teriflunomide blocks the same pyrimidine synthesis pathway that viruses hijack to replicate their own DNA, researchers have investigated whether the drug has antiviral properties beyond its intended immune-modulating role. Lab studies have shown that teriflunomide inhibits Epstein-Barr virus (EBV) replication in cell culture, both by blocking the early steps of the virus reactivating from its dormant state and by preventing the replication of viral DNA during active infection.18PubMed Central. Leflunomide/teriflunomide inhibit Epstein-Barr virus (EBV)- induced lymphoproliferative disease and lytic viral replication This is particularly intriguing given the growing body of evidence linking EBV infection to the development of MS itself. Whether teriflunomide’s anti-EBV activity contributes to its clinical benefit in MS patients, or whether this is merely a laboratory curiosity, remains an open question. No clinical trial has been designed to test this directly. But it is a line of research that adds an interesting dimension to a drug that might be doing more than simply putting the brakes on overactive immune cells.