A clinical-stage biopharmaceutical company, Immunic, with a pipeline of selective oral immunology therapies aimed at treating chronic inflammatory and autoimmune diseases, announced positive top-line data from the Phase II EMPhASIS trial of IMU-838 (vidofludimus calcium) in patients with relapsing-remitting multiple sclerosis (RRMS).

IMU-838 is a dihydroorotate dehydrogenase (DHODH) inhibitor. DHODH is a key enzyme involved in pyrimidine biosynthesis and the drug acts by inhibiting DHODH, which leads to a series of pharmacological effects such as induction of apoptosis in activated lymphocytes through P53 accumulation and cell cycle arrest, inhibition of STAT3 signalling in inflamed colonic tissue, and reduction in the number of Th17 and Th1 cells and related cytokines.

In the randomised, double-blind, placebo-controlled, multicentre Phase II trial, EMPhASIS, IMU-838 achieved all primary and key secondary endpoints. In the primary endpoint, IMU-838 demonstrating a statistically significant reduction in the cumulative number of combined unique active (CUA) magnetic resonance imaging (MRI) lesions up to Week 24 in patients receiving 45mg of IMU-838 once daily, by 62% (p=0.0002), as compared to placebo. In its secondary endpoint, IMU-838 showed a statistically significant reduction in the cumulative number of CUA MRI lesions for the 30mg once-daily dose, by 70% (p<0.0001), as compared to placebo.

RRMS patients who are ineligible for treatments with monoclonal antibodies (mAbs) might benefit from treatment with IMU-838 if it proves to be safer than Aubagio (teriflunomide) in the planned Phase III trial by the company. IMU-838 is a DHODH inhibitor with the same mechanism of action (MOA) of Aubagio, which, while it is seeing modest success in the treatment of MS, is currently not being used as first-line therapy due to its modest efficacy and safety concerns.

However, it is unlikely that any patients who are already stable on existing mAb treatment would want to switch to what might be perceived as a less efficacious medicine, as DHODH inhibitors are used later in the treatment algorithm for MS. Even though the Phase II trial showed positive data in terms of efficacy and safety, it is unclear how much safer IMU-838 will be over Aubagio as the EMPhASIS trial was not a head-to-head study, and it could be explored more in another clinical trial.

IMU-838 has a convenient oral route of administration and the positive clinical trial results from the Phase II might give this drug a slight market potential in RRMS; however, Aubagio has shown already its modest efficacy and safety concerns that limited its market share.

The current MS market is becoming increasingly competitive, including a large number of drugs that offer good safety profiles but moderate efficacy. Many of the players with recently introduced or late-stage pipeline candidates are focusing on addressing unmet needs in the MS market.