Core Insights - Mirum Pharmaceuticals has initiated the phase II BLOOM study for MRM-3379, a PDE4D inhibitor aimed at treating Fragile X syndrome (FXS), with the first patient enrolled [1][6] - The study will focus on safety, tolerability, and potential clinical benefits, with top-line data expected in 2027 [2][6] - FXS affects approximately 50,000 males in the U.S. and Europe, and currently, there are no approved therapies for this condition [2] Company Developments - MRM-3379 has shown promise in improving cognitive and behavioral symptoms associated with FXS in preclinical studies, indicating a potential novel treatment approach [3] - Mirum's lead product, Livmarli, is approved for treating cholestatic pruritus in patients with Alagille syndrome and progressive familial intrahepatic cholestasis, generating significant revenue [7][8] - Livmarli's net product sales reached $253.6 million in the first nine months of 2025, reflecting a 70% year-over-year increase [8] Pipeline Progress - Mirum is advancing other products, including Cholbam capsules and Ctexli tablets, which are also approved for rare diseases, contributing to revenue growth [9] - The lead pipeline candidate, volixibat, is undergoing evaluation in two phase IIb studies for primary biliary cholangitis and primary sclerosing cholangitis, with top-line data expected in 2026 [9][10] Market Performance - Year-to-date, Mirum's shares have increased by 69.3%, outperforming the industry average rise of 20.3% [4]