Immunic’s lead oral small molecule has failed to hit the primary endpoint of a phase 2 trial in patients with progressive multiple sclerosis (PMS), but the New York biotech is pointing to other measures from the study as reason to continue developing the asset.
Vidofludimus calcium, called IMU-838 by Immunic, showed only a “modest benefit” of 5% over placebo at improving the yearly rate of percent brain volume change in patients with PMS after the approximately two-year treatment period, Immunic said in an April 30 press release.
This measure of brain volume change is the primary endpoint of the still-ongoing phase 2 Calliper trial, which has enrolled 467 patients with PMS. The treatment period followed patients for about 120 weeks, while an open-label extension will continue for up to eight years.
The company did not disclose the statistical significance of the result, but a spokesperson confirmed that the trial missed its primary goal.
During an April 30 webinar about the top-line results, Immunic CEO Daniel Vitt, Ph.D., dismissed the primary endpoint, saying the measure had fallen behind current scientific advancements.
"Nobody should care at all about whole brain volume change anymore," Vitt said. "This is a little bit of a leftover of our design of a study we did five years ago."
Though IMU-838 had a marginal effect on reducing whole brain volume loss, patients receiving the drug candidate did see a 20% reduction in loss of the thalamus, Immunic said.
"Change in thalamic volume is considered a more sensitive MRI atrophy marker," Immunic said in the release. "Thalamic atrophy is prevalent in PMS and data has shown strong associations with clinical disability progression."
Daily oral 45-mg doses of IMU-838 also reduced the risk of a patient experiencing an event that worsened their disability for at least 24 weeks by 20% compared to placebo, as measured by the Expanded Disability Status Scale (EDSS) score, Immunic reported. This figure jumped to 30% when focusing on the subset of patients with primary progressive multiple sclerosis (PPMS), whose disease did not start with the more common relapsing MS (RMS).
The time to 24-week confirmed disability worsening based on EDSS is a secondary endpoint of the trial. Immunic did not disclose detailed data in its communications about the top-line results. Results for another secondary endpoint, an MRI measure of change in brain parenchymal fraction, have also not been disclosed yet.
"We ourselves have not seen all data from all endpoints yet and we will continue to receive them over the next weeks and months to come," Vitt said in the webinar.
The frequency of adverse events in the group of patients receiving treatment was similar to the rate in the placebo group, according to the company's release.
“We are particularly thrilled to see such a clinically meaningful effect in the PPMS population,” Vitt said in the release, noting “the relative risk of 24-week confirmed disability worsening events” would be the primary endpoint of a potential future phase 3 study.
“We look forward to discussing these results with healthcare authorities to determine appropriate next steps for vidofludimus calcium in PMS,” Vitt added.
Analysts from William Blair wrote April 30 that "with usual cross-trial comparison caveats, in our view, vidofludimus calcium demonstrated a competitive risk/benefit profile" compared to Genentech's Ocrevus (ocrelizumab), Novartis' Mayzent (siponimod) and Sanofi's experimental tolebrutinib.
"The FDA appears to be focused on confirmed disability worsening endpoints where vidofludimus compares well in the PPMS population," the analysts wrote.
Immunic's stock price dropped sharply after the data reveal, from $1.41 per share in the evening of April 29 to 99 cents per share by 2 p.m. EDT on April 30.
William Blair analysts attributed this stock drop to concerns about Immunic's ability to fund a phase 3 trial for IMU-838; the company reported $35.7 million in cash and cash equivalents as of March 31, which is expected to fund the company through the third quarter of this year.
"We acknowledge the financing overhang is material and Immunic will likely need a partner and/or additional capital to fund future phase III studies," the analysts wrote.
Most patients with MS have relapsing MS, where symptoms like numbness, fatigue, vision changes and brain fog periodically flare up. In progressive MS, these symptoms instead gradually worsen over time; flare-ups may still happen but are less common.
Relapsing MS can develop into progressive MS over time, called secondary progressive MS, but about 10% of MS patients are diagnosed with primary progressive MS without first having any relapsing symptoms.
IMU-838 is also currently in a pair of phase 3 trials in RMS, after previously hitting the primary endpoint of reducing brain lesions in a phase 2 trial. The phase 3 trials are analyzing the time to first symptom relapse as the primary endpoint.
Immunic’s phase 3 RMS program recently underwent an interim futility analysis, the company said in October 2024, with the independent data monitoring committee determining that no changes to the trial protocol were needed.
In addition to MS, Immunic is also testing IMU-838 in a phase 2 ulcerative colitis trial. The company has two other drug candidates in development, one clinical-stage asset for celiac disease and other gastrointestinal disorders and another preclinical gastrointestinal asset.
This is, however, a more narrow focus for the biotech, which in 2023 revealed that it was deprioritizing development in psoriasis and castration-resistant prostate cancer and throwing its remaining resources to multiple sclerosis and celiac disease.