In this episode of The Top Line, Fierce Biotech host Chris Hayden sits down with Ajay Narasimha, senior vice president of corporate strategy and business development at Mirum Pharmaceuticals, to discuss how the company is building a focused, high-impact rare disease portfolio. The conversation explores Mirum’s approach to growth—combining targeted M&A, capital-efficient development, and patient-centric decision-making—to expand its late-stage rare disease pipeline. That strategy is reflected in Mirum’s recent acquisition of Bluejay Therapeutics, which Narasimha discusses, and how it aligns with the company’s long-term strategy.
Narasimha explains why Bluejay’s lead asset, brelovitug, represents a compelling investigational opportunity in hepatitis delta virus (HDV)—the most severe form of viral hepatitis, with no FDA-approved treatments and a significant unmet medical need. Backed by Phase 2 data and an ongoing Phase 3 program, brelovitug fits squarely within Mirum’s focus on high-impact, underappreciated assets within rare disease.
The episode also highlights Mirum’s multiple near-term clinical catalysts, with four potential registrational readouts expected over the next 18 months. Narasimha outlines how Mirum’s established development, regulatory, and commercial infrastructure enables efficient integration and future launches across its growing rare disease portfolio.
For biotech professionals, this discussion provides insight into mid-cap biotech M&A strategy, pipeline building without internal R&D, and how patient-centric dealmaking can drive both growth and impact in rare disease.
Please see the following USPI, US ISI, EU SmPC and Canadian Product Monograph for complete LIVMARLI product information:
US Important Safety Information
US Prescribing Information
EU SmPC
Canadian Product Monograph
Learn more about the latest research for Mirum’s investigational therapies: MRM-3379, volixibat in PSC and PBC, and brelovitug. LIVMARLI is also currently being evaluated in the Phase 3 EXPAND study in additional settings of cholestatic pruritus.
References
1. What is hepatitis delta? » Hepatitis B Foundation. Accessed January 14, 2026. https://www.hepb.org/research-and-programs/hepdeltaconnect/what-is-hepatitis-delta/
2. Agarwal K, Jucov A, Dobryanska M, et al. Brelovitug (BJT-778) monotherapy achieved 100% virologic response in patients with chronic hepatitis D: on treatment week 48 phase 2 study results. Presented at: AASLD 2025; November 7-11, 2025; Washington, D.C.
3. Sagnelli C, Sagnelli E, Russo A, Pisaturo M, Occhiello L, Coppola N. HBV/HDV co-infection: epidemiological and clinical changes, recent knowledge and future challenges. Life (Basel). 2021;11(2):169. doi:10.3390/life11020169
4. Negro F, Lok AS. Hepatitis D: a review. JAMA. 2023;330(24):2376-2387. doi:10.1001/jama.2023.23242
5. Hunter J, Rivero-Arias O, Angelov A, Kim E, Fotheringham I, Leal J. Epidemiology of fragile X syndrome: A systematic review and meta‐analysis. doi:10.1002/ajmg.a.36511
