- Late-Breaking Livdelzi (Seladelpar) Data Expand the Evidence Base in PBC, while Interim Data Show Durable, Consistent Results Across Key Markers -

- Bulevirtide Data Strengthen Evidence of Efficacy and Safety Across Broad HDV Populations -

- New Findings Highlight Progress Toward HCV Elimination and Improved HDV Risk Insight -

Gilead Sciences, Inc. (NASDAQ:GILD) will present findings from 29 abstracts, including late-breaking presentations at the European Association for the Study of the Liver (EASL) Congress, May 27-30, 2026, Barcelona. These presentations advance understanding of primary biliary cholangitis (PBC) and viral hepatitis.

In PBC, Gilead will present randomized and long-term study data for Livdelzi® (seladelpar), known as Lyvdelzi^® in the European Union.

Analyses from the Phase 3 RESPONSE trial (NCT04620733) will evaluate efficacy and safety in participants with risk factors for disease progress, including elevated liver stiffness and metabolic syndrome.
Interim data from the Phase 3 ASSURE study (NCT03301506) will assess the relationship between biochemical response and liver stiffness trends over 36 months, including outcomes in individuals with alkaline phosphatase (ALP) levels between 1 to 1.67x the upper limit of normal (ULN).

Together these data provide a multidimensional view of Livdelzi's efficacy, safety and durability across a broad PBC population. Livdelzi is a first‑in‑class delpar (selective PPAR‑delta agonist) indicated for the treatment of PBC to be used in combination with ursodeoxycholic acid (UDCA) for those with an inadequate response to UDCA, or as monotherapy for patients unable to tolerate UDCA.

"Primary biliary cholangitis is a chronic, progressive disease where reducing disease activity is critical to improving long‑term outcomes. Minimizing impact on quality of life is also key for people living with PBC," said Swati Tole, MD, MS, Senior Vice President, Clinical Development, Inflammation at Gilead Sciences. "At EASL, we are sharing data that further define Livdelzi's potential to address both disease activity and symptoms such as pruritus."

Advancements in Hepatitis Delta Virus

Presentations will also focus on hepatitis delta virus (HDV), a severe co‑infection in people with chronic hepatitis B. The program will include several analyses evaluating investigational bulevirtide, a first‑in‑class entry inhibitor, in diverse HDV patient populations, reflecting continued efforts to better understand HDV disease management and treatment approaches.

"People living with HDV face a severe disease with limited treatment options. These analyses highlight the breadth of ongoing research and Gilead's continued leadership in advancing the understanding of HDV, including efforts to evaluate Hepcludex across diverse patient populations," said Jared Baeten, MD, PhD, Senior Vice President, Clinical Development, Virology at Gilead Sciences. "We remain committed to continuously building on emerging evidence to help improve how this disease is managed over time, and we encourage clinicians to engage with evolving data to help inform care for people living with HDV."

Analyses from Phase 2 and Phase 3 studies, including MYR301 (NCT03852719) and MYR204 (NCT03852433) will evaluate clinical, virologic, and biochemical outcomes, as well as safety and tolerability, through 96 weeks across HDV subgroups.

An additional study uses a machine‑learning model to identify risk factors for progression to advanced liver disease in adults with HDV infection in the United States.

Advancing Equitable Care for Hepatitis B and C

Additional presentations highlight progress across viral hepatitis, including HBV cure research, long‑term disease management, and HCV elimination efforts.

In hepatitis B, Gilead will present data from its cure research program, including studies of GS‑2829 and GS‑6779, evaluating HBeAg loss and immune biomarkers.
In hepatitis C, presentations highlight real‑world elimination efforts and patient‑centered outcomes.

Key Abstracts at EASL 2026:

ID	Abstract Title
*PBC*
Clinical Data
LBP-037	Seladelpar leads to decreases in serum proteins associated with PBC disease severity: proteomic analysis from the pivotal RESPONSE trial
SAT-316	Efficacy and safety of seladelpar in patients with primary biliary cholangitis and alkaline phosphatase levels between 1 and 1.67 × upper limit of normal: interim results from the open-label ASSURE study
THU-270	Biochemical response is associated with liver stiffness stability in patients with primary biliary cholangitis treated with seladelpar for up to 36 months: interim results from the open-label ASSURE study
SAT-363	Efficacy and safety of seladelpar in patients with primary biliary cholangitis and risk factors for progression including younger age at diagnosis or higher liver stiffness in the pivotal RESPONSE study
SAT-362	Efficacy and safety of seladelpar vs placebo in patients with primary biliary cholangitis and metabolic syndrome in the pivotal phase 3 RESPONSE study
RWE
SAT-306	Demographic and clinical characteristics of United States real-world patients with primary biliary cholangitis and alkaline phosphatase between 1 and 1.67 vs >1.67 × upper limit of normal despite ursodeoxycholic acid treatment
HEOR
SAT-387	Meaningful within-patient change on the 5-D itch scale in patients with primary biliary cholangitis experiencing pruritus
*HDV*
Clinical Data
FRI-587	Bulevirtide monotherapy is safe and well tolerated in chronic hepatitis delta: An integrated safety analysis of bulevirtide clinical trials at week 96
WED-593	Integrated efficacy analysis of bulevirtide 10 mg from studies MYR204 and MYR301 at weeks 48 and 96 across subgroups
WED-576	Safety of bulevirtide 10 mg is consistent across demographic and clinical subgroups: Results from an integrated analysis
RWE
FRI-031	Predictors of advanced liver disease events among individuals with hepatitis delta virus infection in a large United States administrative claims dataset: a machine learning analysis
HEOR
FRI-605	Impact of bulevirtide treatment on patient-reported outcomes among patients with hepatitis delta in Europe
*HCV*
RWE
WED-047	Progress towards hepatitis C virus elimination in English prisons - 7-year outcomes on a multi-stakeholder project
*HBV*
Clinical Data
FRI-624	Factors associated with lack of alanine aminotransferase normalization in patients with chronic hepatitis B virus after 8 years of tenofovir-based treatment
RWE
FRI-030	Synergistic effect of diabetes and hypertension on the risk of liver disease progression in hepatitis B virus infection
*HBV Cure*
Clinical Data
WED-580	Baseline and on-treatment characteristics of HBeAg-positive patients and correlates of HBeAg loss following GS-2829 and GS-6779 therapeutic vaccination in virally suppressed patients with chronic hepatitis B
WED-578	Transcriptomic profiling reveals distinct immune signatures in chronic hepatitis B and identifies blood transcriptional modules associated with hepatitis B e antigen loss

For more information, including a complete list of abstract titles being presented at the meeting, please visit the EASL website.

Please see below for the U.S. Indications and Important Safety Information for Livdelzi.

Marketing Authorizations for Bulevirtide

In July 2023, the European Commission granted full Marketing Authorization (MA) for Hepcludex (bulevirtide) 2 mg for the treatment of adults with chronic hepatitis delta virus (HDV) infection and compensated liver disease (conditional approval was received in July 2020). Hepcludex 2 mg also has full marketing authorization in the United Kingdom, Switzerland, Australia, Canada, United Arab Emirates, Israel and Kuwait.

Bulevirtide is not approved in the United States. In the U.S. and other regions where it is not authorized, bulevirtide 2 mg is an investigational product, and its safety and efficacy have not been established or approved by the U.S. Food and Drug Administration (FDA) or other health authorities.

Bulevirtide 10 mg, GS-2328 and GS-6779 are investigational and not approved anywhere globally. The safety and efficacy of these programs have not been established.

U.S. Indication for Livdelzi

Livdelzi is indicated for the treatment of primary biliary cholangitis (PBC) in combination with ursodeoxycholic acid (UDCA) in adults who have had an inadequate response to UDCA, or as monotherapy in patients unable to tolerate UDCA. The FDA approved this indication under accelerated approval based on a reduction of alkaline phosphatase (ALP). Improvement in survival or prevention of liver decompensation events have not been demonstrated. Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trial(s).

Limitations of Use for Livdelzi:

Use of Livdelzi is not recommended in patients who have or develop decompensated cirrhosis (e.g., ascites, variceal bleeding, hepatic encephalopathy).

U.S. Important Safety Information for LIVDELZI

Warnings and Precautions

Fractures: Fractures occurred in 4% of LIVDELZI-treated patients compared to no placebo-treated patients. Consider the risk of fracture in the care of patients treated with LIVDELZI and monitor bone health according to current standards of care.
Liver Test Abnormalities: LIVDELZI has been associated with dose-related increases in serum transaminase (AST and ALT) levels > 3 x ULN in patients receiving 50 mg and 200 mg once daily (5x and 20x higher than the recommended dosage of 10 mg once daily). Perform baseline clinical and laboratory testing when starting LIVDELZI and monitor thereafter according to routine patient management. Interrupt treatment if the liver tests (ALT, AST, total bilirubin, and/or ALP) worsen, or if the patient develops signs and symptoms of clinical hepatitis (eg, jaundice, right upper quadrant pain, eosinophilia). Consider permanent discontinuation if liver tests worsen after restarting LIVDELZI.
Biliary Obstruction: Avoid use of LIVDELZI in patients with complete biliary obstruction. If biliary obstruction is suspected, interrupt LIVDELZI and treat as clinically indicated.

Adverse Reactions

The most common adverse reactions (≥5%) with LIVDELZI were headache (8%), abdominal pain (7%), nausea (6%), abdominal distension (6%), and dizziness (5%).

Drug Interactions

OAT3 Inhibitors and Strong CYP2C9 Inhibitors: Avoid coadministration with LIVDELZI due to increased LIVDELZI exposure.
Rifampin: Monitor biochemical response (e.g., ALP and bilirubin) when patients initiate rifampin during LIVDELZI treatment. Coadministration may result in delayed or suboptimal biochemical response of LIVDELZI.
Dual Moderate CYP2C9 and Moderate-to-Strong CYP3A4 Inhibitors and BCRP Inhibitors (eg, cyclosporine): Monitor closely for adverse effects. Concomitant administration with LIVDELZI may increase LIVDELZI exposure.
CYP2C9 Poor Metabolizers Using Moderate-to-Strong CYP3A4 Inhibitors: Monitor more frequently for adverse reactions as concomitant use of a moderate-to-strong CYP3A4 inhibitor in patients who are CYP2C9 poor metabolizers may increase LIVDELZI exposure and risk of LIVDELZI adverse reactions.
Bile Acid Sequestrants: Administer LIVDELZI at least 4 hours before or 4 hours after taking a bile acid sequestrant, or at as great an interval as possible.

Pregnancy and Lactation

Pregnancy: There are insufficient data from human pregnancies exposed to LIVDELZI to allow an assessment of a drug-associated risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes. Report pregnancies to Gilead Sciences, Inc., at 1-800-445-3235.
Lactation: There are no data on the presence of LIVDELZI in human milk, the effects on the breastfed infant, or the effects on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for LIVDELZI and any potential adverse effects on the breastfed infant from LIVDELZI.

About Gilead Sciences in Liver Disease

For decades, Gilead has pioneered the way forward to improve the lives of people living with liver disease around the world. We have helped to transform hepatitis C from a chronic condition into one that can be cured for millions of people. For people living with hepatitis B or D, our focus on advancing our medicines drives hope that today's research will turn into tomorrow's cures. Beyond viral hepatitis, we're working to deliver advanced treatments for people living with PBC. But our commitment doesn't stop there. Through our ground-breaking science and collaborative partnerships, we strive to create healthier futures for everyone living with liver disease. We are committed to a future without liver disease.

About Gilead Sciences

Gilead Sciences, Inc. is a biopharmaceutical company that has pursued and achieved breakthroughs in medicine for more than three decades, with the goal of creating a healthier world for all people. The company is committed to advancing innovative medicines to prevent and treat life-threatening diseases, including HIV, viral hepatitis, COVID-19, cancer and inflammation. Gilead operates in more than 35 countries worldwide, with headquarters in Foster City, California.

Forward-Looking Statements

This press release includes forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 that are subject to risks, uncertainties and other factors, including Gilead's ability to initiate, progress or complete clinical trials or studies within currently anticipated timelines or at all, and the possibility of unfavorable results from ongoing or additional clinical trials or studies, including those involving bulevirtide, Livdelzi, GS-2829 and GS-6779 (such as RESPONSE, ASSURE, MYR301 and MYR204); uncertainties relating to regulatory applications and related filing and approval timelines, including additional pending and potential applications for programs and/or indications currently under evaluation, and the risk that any such approvals, if granted, may be subject to significant limitations on use or subject to withdrawal or other adverse actions by the applicable regulatory authority; the possibility that Gilead may make a strategic decision to discontinue development of these programs and, as a result, these programs may never be successfully commercialized for the indications currently under evaluation; and any assumptions underlying any of the foregoing. These and other risks, uncertainties and factors are described in detail in Gilead's Quarterly Report on Form 10-Q for the quarter ended March 31, 2026, as filed with the U.S. Securities and Exchange Commission. These risks, uncertainties and other factors could cause actual results to differ materially from those referred to in the forward-looking statements. All statements other than statements of historical fact are statements that could be deemed forward-looking statements. The reader is cautioned that any such forward-looking statements are not guarantees of future performance and involve risks and uncertainties and is cautioned not to place undue reliance on these forward-looking statements. All forward-looking statements are based on information currently available to Gilead, and Gilead assumes no obligation and disclaims any intent to update any such forward-looking statements.

Hepcludex, Livdelzi, Lyvdelzi, Gilead and the Gilead logo are registered trademarks of Gilead Sciences, Inc., or its related companies.

U.S. full Prescribing Information for Livdelzi is available at www.gilead.com.

For more information about Gilead, please visit the company's website at www.gilead.com, follow Gilead on X/Twitter (@Gilead Sciences) and LinkedIn (@Gilead-Sciences).

View source version on businesswire.com: https://www.businesswire.com/news/home/20260512412079/en/

Priscilla White, Media

public_affairs@gilead.com

Jacquie Ross, Investors

investor_relations@gilead.com

Gilead to Present New Data Advancing Care in PBC and Viral Hepatitis at EASL 2026