The enrollment of the phase 2 CALLIPER clinical trial testing the safety, efficacy, and tolerability of the experimental multiple sclerosis (MS) treatment vidofludimus calcium has been completed, according to a press release from Immunic Incorporated, the developers of the treatment.

The trial enrolled 467 patients with primary progressive MS (PPMS) or active or nonactive secondary progressive MS (SPMS), who will randomly receive either 45 mg of vidofludimus calcium or a placebo.

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It is running in parallel with Immunic’s phase 3 ENSURE trials that are testing the experimental treatment in patients with relapsing forms of the disease.

“Enrollment of the final PMS patient, according to plan, is another important milestone in the clinical development of our lead asset in MS,” said Daniel Vitt, PhD, the chief executive officer and president of Immunic in the press release. 

CALLIPER is an international, randomized, double-blind, placebo-controlled trial. Its primary endpoint is the change in the annualized rate of percent brain volume for up to 120 weeks. Key secondary endpoints are the annualized rate of change in whole brain atrophy and time to 24-week confirmed disability progression based on the expanded disability status scale.

An interim analysis comprising unblinded biomarker data is expected in the fall of 2023. This will include data from around half of the enrolled patients who will have completed a follow-up period of at least 24 weeks. A top-line data readout of all enrolled patients is expected in April 2025. The estimated completion date of the trial is July 28, 2024.

Vidofludimus calcium is an investigational small molecule drug being developed as a next-generation treatment option for patients with MS as well as other chronic inflammatory and autoimmune diseases. 

It is thought to work by activating a neuroprotective transcription factor called nuclear receptor related 1. It also inhibits the dihydroorotate dehydrogenase (DHODH) enzyme, which plays a key role in the overactive immune cell metabolism as well as the metabolism of virus-infected cells.  The treatment has already been tested in over 1,400 people and has been shown to have a positive pharmacokinetic, safety and tolerability profile.


Immunic completes enrollment of its phase 2 CALLIPER trial of vidofludimus calcium in progressive multiple sclerosis. News release. Immunic Inc; August 17, 2023. 

Study to evaluate efficacy, safety, and tolerability of IMU-838 in patients with progressive multiple sclerosis (CALLIPER). US National Library of Medicine. Updated February 1, 2023. Accessed August 25, 2023.