Mirum Pharmaceuticals Announces Enrollment Completion in the Phase 2b VISTAS Study
- Topline data announcement expected second quarter of 2026
“Completing enrollment in VISTAS is a major milestone for the PSC community and for Mirum,” said Joanne Quan, M.D., Chief Medical Officer. “This progress reflects the dedication of patients, investigators, and our team working together toward the shared goal of addressing the daily challenges of PSC, including persistent itch and fatigue. We believe the data generated from VISTAS will be an important step toward bringing meaningful medicines to patients who currently have no approved therapies.”
Ricky Safer, CEO and Founder of PSC Partners Seeking a Cure, a patient-led advocacy organization dedicated to supporting those affected by PSC, added “PSC Partners is thrilled to see Mirum reach this important milestone with the VISTAS study. Completing enrollment marks a significant step forward in advancing a possible treatment for itch in PSC, bringing tremendous hope to our community. We are grateful to Mirum for their commitment and to all the patients and families who made this kind of progress possible. Together, we are moving closer to new possibilities and a brighter future for those impacted by PSC.”
Volixibat is also being evaluated in the Phase 2b VANTAGE study for primary biliary cholangitis (PBC), which is expected to complete enrollment in 2026 and announce topline results in the first half of 2027.
About the VISTAS Phase 2b Study
The VISTAS study (NCT04663308) is a global, randomized, double-blind, placebo-controlled Phase 2b trial evaluating the efficacy and safety of volixibat in patients with primary sclerosing cholangitis and cholestatic pruritus over a 28-week period. The primary endpoint is a reduction in pruritus as measured by the Adult ItchRO, a pruritus numerical rating scale ranging from 0 (no itch) to 10 (worst possible itch). Secondary endpoints include assessments of fatigue, serum bile acids, and safety.
About Primary Sclerosing Cholangitis (PSC)
Primary sclerosing cholangitis (PSC) is a rare, chronic, progressive liver disease in which the bile ducts inside and outside the liver become inflamed, scarred, and narrowed over time. This bile duct damage leads to bile accumulation, liver injury, and eventually liver failure. Patients with PSC experience a heavy symptom burden, with pruritus (severe itching), fatigue, and abdominal pain that may be debilitating and life-altering. Beyond symptom burden, PSC is associated with increased risk of bile duct cancer and need for liver transplantation. There are currently no approved therapies for PSC, leaving patients with limited treatment options focused on symptom management and supportive care.
About Volixibat
Volixibat is an oral, minimally absorbed agent designed to selectively inhibit the ileal bile acid transporter (IBAT). Volixibat may offer a novel approach to the treatment of adult cholestatic diseases by blocking the recycling of bile acids, through inhibition of IBAT, thereby reducing bile acids systemically and in the liver. Volixibat is currently being evaluated in Phase 2b studies for primary sclerosing cholangitis (PSC) (VISTAS study), and primary biliary cholangitis (PBC) (VANTAGE study). In 2024, Mirum announced positive interim results from the Phase 2b VANTAGE study showing statistically significant improvement in pruritus as well as meaningful reductions in serum bile acids and improvements in fatigue for patients treated with volixibat. No new safety signals were observed, and the most common adverse event was diarrhea with all cases mild to moderate. The Phase 2 VISTAS study met its pre-specified efficacy and safety thresholds at the blinded interim analysis for dose selection conducted in 2024. Volixibat has been granted breakthrough therapy designation for the treatment of cholestatic pruritus in patients with PBC.
About Mirum Pharmaceuticals, Inc.
Mirum Pharmaceuticals, Inc. is a biopharmaceutical company dedicated to transforming the treatment of rare diseases affecting children and adults. Mirum has three approved medications: LIVMARLI® (maralixibat) oral solution/LIVMARLI® (maralixibat) tablets, CHOLBAM® (cholic acid) capsules, and CTEXLI™ (chenodiol) tablets.
LIVMARLI, an IBAT inhibitor, is approved for the treatment of two rare liver diseases affecting children and adults. It is approved for the treatment of cholestatic pruritus in patients with Alagille syndrome in the
CTEXLI is FDA-approved for the treatment of cerebrotendinous xanthomatosis (CTX) in adults.
Mirum's late-stage pipeline includes two investigational treatments for several rare diseases.
Volixibat, an IBAT inhibitor, is being evaluated in two potentially registrational studies including the Phase 2b VISTAS study for primary sclerosing cholangitis (PSC) and Phase 2b VANTAGE study for primary biliary cholangitis. Volixibat has been granted Breakthrough Therapy Designation for the treatment of cholestatic pruritus in patients with PBC. Mirum is also planning for a Phase 2 study evaluating MRM-3379, a PDE4D inhibitor for the treatment of Fragile X syndrome, a rare genetic neurocognitive disorder.
To learn more about Mirum, visit mirumpharma.com and follow Mirum on Facebook, LinkedIn, Instagram and X.
Forward-Looking Statements
Statements contained in this press release regarding matters that are not historical facts are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Such forward-looking statements include statements regarding, among other things, the results and progress of our ongoing and planned studies for our product candidates, the timing and results of topline data for our ongoing studies and the regulatory approval path for our product candidates in any indication or any specific territory. Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Words such as “expected,” “will,” “could,” “would,” “guidance,” “potential,” “continue” and similar expressions are intended to identify forward-looking statements. These forward-looking statements are based upon Mirum’s current expectations and involve assumptions that may never materialize or may prove to be incorrect. Actual results could differ materially from those anticipated in such forward-looking statements as a result of various risks and uncertainties, which include, without limitation, risks and uncertainties associated with Mirum’s business in general, the impact of geopolitical and macroeconomic events, and the other risks described in Mirum’s Annual Report for the year ended December 31, 2024, filed with the Securities and Exchange Commission on February 26, 2025, and subsequent filings with the Securities and Exchange Commission, which are available at www.sec.gov. All forward-looking statements contained in this press release speak only as of the date on which they were made and are based on management’s assumptions and estimates as of such date. Mirum undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made, except as required by law.
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Investor Contact:
Andrew McKibben
ir@mirumpharma.com
Media Contact:
Bryan Blatstein
Spectrum Science Communications
BBlatstein@spectrumscience.com
Source: Mirum Pharmaceuticals, Inc.
