Enanta Pharmaceuticals FY Conference Summary Company Overview - Enanta Pharmaceuticals is a virology and immunology company with a history in hepatitis C, having developed the drug Glecaprevir, part of Mavyret, which has cured over a million patients with chronic hepatitis C [2][3] - The company has expanded its focus to respiratory virology, particularly targeting respiratory syncytial virus (RSV) and has also branched into immunology with new programs [2][3] Key Programs and Developments Respiratory Syncytial Virus (RSV) - RSV has a significant unmet medical need, with no safe and effective treatments available despite its long history [3] - In the 2024-25 RSV season, there were approximately 6.5 million outpatient visits, hundreds of thousands of hospitalizations, and tens of thousands of deaths in the U.S. [4] - Vaccination rates for RSV are low, with only about 20% of the eligible population vaccinated [5] - Enanta's lead asset, Ziresovir, has shown promising results in two Phase 2 studies, particularly in high-risk populations, including adults over 65 and those with comorbidities [6][9] - Ziresovir reduced the time to complete resolution of symptoms by about one week compared to placebo and lowered hospitalization rates from 5% to 1% [9] - The company is preparing for a Phase 3 study of Ziresovir and is in discussions with the FDA regarding the study design [24] Immunology Programs - Enanta has initiated several immunology programs, including: - **EDP-978**: A KIT inhibitor aimed at mast cell-driven diseases, with an IND filing expected in Q1 2026 [13][25] - **EDP-3903**: A STAT6 inhibitor designed to provide an oral alternative to Dupixent, with an IND filing planned for the second half of 2026 [15][25] - **X2 Program**: Targeting mast cell activation, with a development candidate expected in the second half of 2026 [20][25] Competitive Landscape and Strategic Considerations - Enanta is exploring business development opportunities in the RSV field and is considering partnerships for commercialization [25][27] - The company aims to maintain its leadership position in the RSV treatment space, especially as competitors have faced setbacks [27][28] - The potential for combination therapies using EDP-323 and Ziresovir is being evaluated for severely immune-compromised patients [30] Additional Insights - The company emphasizes the importance of maintaining drug concentrations above the effective threshold to ensure efficacy, particularly in the context of viral infections [32] - Enanta's approach to drug development focuses on small molecule inhibitors, which offer predictable dosing and pharmacokinetic properties [19][38] - The X2 program has potential applications beyond mast cell-driven diseases, including conditions like migraines due to its expression on peripheral neurons [37][38] Conclusion - Enanta Pharmaceuticals is positioned to address significant unmet needs in both virology and immunology, with promising data from ongoing studies and a strategic focus on maintaining leadership in the RSV treatment landscape [25][27]

Core Viewpoint - Enanta Pharmaceuticals has announced a proposed public offering of common stock amounting to $50 million, with an additional option for underwriters to purchase up to $7.5 million more [1][2]. Offering Details - The public offering is being conducted under a shelf registration statement filed with the SEC, which became effective on February 8, 2024 [3]. - J.P. Morgan, Jefferies, and Evercore ISI are acting as joint book-running managers for the offering [2]. Company Background - Enanta Pharmaceuticals is a clinical-stage biotechnology company focused on developing small molecule drugs for virology and immunology [5]. - The company’s clinical programs are currently targeting respiratory syncytial virus (RSV) and developing treatments for inflammatory diseases [5]. - Enanta's notable product, glecaprevir, is part of a leading treatment regimen for hepatitis C and is marketed by AbbVie [6].

Financial Status - Enanta Pharmaceuticals reported a strong balance sheet with $193.4 million in cash as of March 31, 2025[6] - The company is leveraging ongoing royalties to support its robust pipeline[6] Respiratory Syncytial Virus (RSV) - Zelicapavir (EDP-938) - Zelicapavir is the only N-inhibitor in clinical development for RSV[17] - A Phase 2 pediatric study showed a viral load decline of 1.18 log at Day 5 in a prespecified subset of patients[25] - A Phase 2 pediatric study showed a viral load decline of 1.4 log at the end of treatment in Part 2[30] - EDP-323, an RSV L-protein inhibitor, demonstrated an 85-87% reduction in viral load AUC in a human challenge model[42] Immunology - KIT Inhibitor (EPS-1421) - EPS-1421 inhibits KIT with nanomolar potency in both binding and cellular assays[63] - EPS-1421 exhibits greater than 500-fold selectivity for KIT over other KIT family members[68] - In mice, EPS-1421 inhibits SCF-mediated histamine release with an EC50 (free drug) of 0.25nM[65] Immunology - STAT6 Inhibitor - Prototype STAT6 inhibitors exhibit nanomolar inhibition in biochemical and cellular assays[84] - Prototype STAT6 inhibitor demonstrates good selectivity, with greater than 1000x biochemical selectivity for STAT6 over other STATs[88] - Prototype STAT6 oral inhibitor results in complete inhibition of pSTAT6 in a mouse model[93]

Virology - Respiratory Syncytial Virus (RSV) - Zelicapavir (EDP-938) is the only N-inhibitor in clinical development for RSV, with Phase 2 pediatric study complete and Phase 2 high-risk adult study ongoing[17, 6] - In a Phase 2 pediatric study, zelicapavir showed a viral load decline of 0.88 log at Day 3 and 1.18 log at Day 5 in the prespecified mITT-3 population[25] - EDP-323, an RSV L-protein inhibitor, demonstrated 85-87% reduction in viral load AUC in a human challenge model[42] - A Phase 2 high-risk adult study is designed to show a clinically meaningful reduction in symptom duration of at least ~1 day with Zelicapavir[37] Immunology - The company is developing a KIT inhibitor for mast cell driven diseases like Chronic Spontaneous Urticaria (CSU) and a STAT6 inhibitor for type 2 immune diseases like atopic dermatitis[6] - EPS-1421, a KIT inhibitor development candidate, inhibits KIT with nanomolar potency and demonstrates sub-nanomolar activity in vivo[63] - Prototype STAT6 inhibitors inhibit STAT6 with nanomolar potency and are highly selective for STAT6 versus other STATs[79] - Prototype STAT6 oral inhibitor results in complete inhibition of pSTAT6 in a mouse model[89] Financial Status - The company had $193.4 million in cash as of March 31, 2025[6] Business Development - The company plans to pursue partnerships for zelicapavir and/or EDP-323[102]