Atea Pharmaceuticals, Inc. Q1 FY2026 earnings call

HCV Global Phase III Program Progress

• Patient enrollment for the North American C-Beyond trial was completed in Q4 2025 with over 880 patients, representative of North American HCV genotypes and demographics, top-line data expected mid-2026
• The ex-North America C-Forward trial has completed 95% enrollment of cirrhotic and non-cirrhotic patients; enrollment is only open for less prevalent genotypes 4, 5, and 6 to support a broad regulatory label; enrollment is on track to complete mid-2026, with top-line data expected around year-end 2026
• This is the first active-controlled global Phase III HCV program, comparing the company's regimen against current standard-of-care Ipclusa (Fosbovir / Velpatasvir), with a combined total expected enrollment of over 1,760 patients across 240 clinical sites globally
• Preliminary clinical data confirms the company's regimen has a differentiated potential best-in-class profile: high efficacy, shorter treatment duration, low drug-drug interaction risk, convenient once-daily dosing, and no food effect; new data confirms no meaningful interactions with proton pump inhibitors (used by ~35% of HCV patients) and statins

HCV Commercial Preparation

• The U.S. HCV market is ~$1.3 billion in annual net sales, half of the $2.6 billion global market; an estimated 4 million people in the U.S. live with HCV, with 160,000 new chronic infections annually, and only 85,000 patients treated each year, so most countries are not on track to hit WHO 2030 elimination goals
• Independent IQVIA market research with 153 high-prescribing U.S. physicians found that prescribers would likely prescribe the company's regimen to ~50% of their HCV patients, regardless of cirrhosis status
• Atea plans a capital-efficient launch: the HCV prescriber base is highly concentrated (7,800 physicians write 80% of all DAA prescriptions), so a specialty sales force of ~75 can reach most of the market; commercial launch supply production is already underway, with low cost of goods relative to expected net pricing
• Payer research indicates a favorable outlook for broad formulary inclusion across Medicaid, Medicare, and commercial segments, subject to regulatory approval

HEV Pipeline Expansion

• Atea expanded its antiviral pipeline in late 2025 to target chronic hepatitis E infection in immunocompromised patients, a population with no approved therapies; untreated chronic HEV progresses to cirrhosis in 3-5 years, much faster than HBV/HCV
• Preclinical data for lead candidate AT587 shows it is a potent first-in-class direct acting antiviral against HEV genotype 3 (the most prevalent form in developed countries), with low drug-drug interaction potential and a clean preclinical safety profile
• CTA-enabling toxicology and safety pharmacology studies for AT587 are completed; a first-in-human Phase I study in healthy volunteers is expected to initiate mid-2026, with a proof-of-concept trial expected to start around year-end 2026
• The annual U.S./European HEV market opportunity is estimated at $750 million to $1 billion

Atea Pharmaceuticals is a clinical-stage biopharmaceutical company focused on antiviral development, and does not report commercial product revenue in Q1 2026. As of March 31, 2026, the company held $256 million in total cash, cash equivalents, and marketable securities. R&D expenses increased year-over-year in Q1 2026, driven by higher external spending for the HCV Phase III program and HEV preclinical development, offset by lower internal stock-based compensation and payroll expenses. General and administrative expenses decreased quarter-over-quarter, primarily due to lower salaries, stock-based compensation, and professional fees. 100% of the company's operating spending is allocated to two development pipeline segments: the lead HCV combination regimen (benifosbovir / bruzosvir) accounts for the substantial majority of 2026 spending, and the HEV candidate AT587 accounts for the remaining balance.

• Two major Phase III catalyst events are on track for 2026: top-line C-Beyond data in mid-2026, and top-line C-Forward data around year-end 2026
• With $256 million in cash as of March 31, 2026, the company projects its cash runway extends through 2027, sufficient to complete the HCV Phase III program and advance the AT587 HEV program through key milestones
• Substantially all 2026 operating spending will be focused on advancing the HCV Phase III program, preparing regulatory filings, and completing pre-launch commercial and manufacturing activities
• AT587 first-in-human study initiation is planned for mid-2026, with proof-of-concept study initiation planned for end-2026

• All forward-looking statements related to trial readout timelines, clinical efficacy, regulatory approval, and commercial launch are subject to inherent risks and uncertainties, which are detailed in the company's recent SEC filings; actual results may differ materially from current expectations
• Clinical trial success in Phase II does not guarantee that Phase III trials will replicate efficacy and safety results, though management notes Phase II data typically translates well to Phase III for infectious disease programs
• Commercial adoption after approval depends on successful payer contracting, formulary inclusion, and market acceptance, which cannot be guaranteed prior to trial readout and regulatory approval
• There is no guarantee that the company's regimen will meet the non-inferiority endpoint required for regulatory approval, or that it will be able to support a superiority claim over current standard-of-care therapies

Q: What data will be included in the C-Beyond and C-Forward top-line announcements, and how will commercial launch adoption be impacted by contracting and test-and-treat program requirements? / A: The top-line press releases will include the primary efficacy endpoint (SVR24) for both the modified intent-to-treat and per-protocol populations, as well as key secondary efficacy endpoints. Launch preparation activities, including payer targeting and formulary timeline analysis across Medicaid, Medicare, and commercial segments, are already underway, and full commercial execution will begin immediately after Phase III data readout. Management will evaluate market penetration timelines as launch planning progresses post-data.

Q: Given market research is based on Phase II results, what Phase III outcomes could impact prescriber and payer response? / A: Management expects Phase III results to match the positive trends seen in Phase II, including high efficacy, low drug-drug interaction risk, and no food effect, as Phase II data typically translates well to Phase III for infectious disease. Payers and prescribers are particularly interested in this program because it is the first head-to-head active-controlled Phase III trial for HCV in recent years, which will provide unique comparative data that supports favorable coverage and adoption.

Q: Is the trial powered to support a superiority claim for your HCV regimen over current standard of care, and what are the planned treatment durations for AT587? / A: The trial is powered for the primary non-inferiority endpoint with a 5% margin, which is the key regulatory requirement. A combined analysis of both Phase III trials is pre-planned and agreed with the FDA, which will provide additional power to evaluate potential superiority. For AT587, the multiple ascending dose portion of the Phase I first-in-human study will test 7 days of treatment. The planned end-of-year proof-of-concept trial will use an initial 12-week treatment duration, with preclinical chronic toxicology studies ongoing to support a potential 24-week duration if needed, which is well-tolerated by this immunocompromised patient population.