Phase 2 SWIFT Study of Emvistegrast, a Potential Differentiated Once-daily Oral Treatment, Meets Primary Endpoint in Ulcerative Colitis

FOSTER CITY, Calif. October 19, 2026 - Gilead Sciences, Inc. today announced positive results from the Phase 2 SWIFT dose-ranging study evaluating its investigational, once-daily oral α4β7 integrin inhibitor, emvistegrast (GS-1427), in adults with moderately to severely active ulcerative colitis (UC). The 12-week placebo-controlled induction phase data was presented as a late-breaking abstract at the United European Gastroenterology Week (UEGW) 2026 meeting in Barcelona, Spain.

Key Highlights

• Emvistegrast is an investigational once-daily oral therapy designed to selectively inhibit the α4β7 pathway, a clinically validated target in inflammatory bowel disease.
• Emvistegrast 200 mg met the primary endpoint and demonstrated significant differences across multiple secondary measures of disease activity based on nominal p-values, with a generally well-tolerated safety profile.
• The findings support the continued development of emvistegrast as a potential new treatment option for people living with UC, where significant unmet need remains despite available therapies.

"The SWIFT results suggest that selectively targeting the α4β7 pathway through an oral therapy may offer a promising new treatment option for people living with UC," said Professor Silvio Danese, Professor of Gastroenterology at Vita-Salute San Raffaele University and President Elect UEG. "The improvements observed across multiple efficacy endpoints, together with a generally well-tolerated safety profile, support further investigation of emvistegrast in ulcerative colitis."

Ulcerative colitis is a chronic, relapsing inflammatory bowel disease that can substantially affect quality of life and long-term health outcomes. Despite the availability of multiple advanced therapies, many people living with UC do not achieve sustained disease control, underscoring the need for additional treatment approaches.

At Week 12, the primary endpoint of clinical response was achieved by 66% (33/59) of participants receiving emvistegrast 200 mg compared with 37% (22/60) of participants receiving placebo (nominal p<0.001). Clinical remission was achieved by 31% (18/59) and 8% (5/60) of participants receiving emvistegrast 200 mg or placebo, respectively (nominal p<0.05). Three-quarters (78%) of participants were naive to advanced therapies (AT) or did not fail any AT for UC, while 22% had previously failed 1 or 2 ATs. The SWIFT study remains ongoing, with additional maintenance-phase data and analyses planned.

"While treatment options for ulcerative colitis have expanded in recent years, many people continue to cycle through therapies without achieving lasting disease control. The SWIFT results demonstrated promising improvements across efficacy endpoints alongside a generally well-tolerated safety profile reinforcing our confidence in emvistegrast as a potentially differentiated, investigational therapy for people living with UC," said Swati Tole, Senior Vice President, Clinical Development, Inflammation, Gilead Sciences. "We plan to initiate a Phase 3 monotherapy study in 2027 and see emvistegrast as a potential backbone for future combination approaches. The depth of our pipeline provides optionality to evaluate complementary mechanisms as we work to bring forward new treatment options for people living with inflammatory diseases who continue to face significant unmet needs."

Key Findings from the SWIFT Study

• Primary Endpoint: At Week 12, clinical response (based on modified Mayo clinical score) was achieved by 66% (39/59) of participants receiving emvistegrast 200 mg compared with 37% (22/60) of participants receiving placebo (nominal P<0.001).
• Secondary Endpoints: At Week 12, clinical remission was achieved in 31% (18/59) and 8% (5/60) of participants receiving emvistegrast 200 mg and placebo, respectively (nominal P <0.05). Histological Endoscopic Mucosal Improvement (HEMI) was achieved by 25% (15/59) of emvistegrast 200 mg participants versus 10% (6/60) for placebo (nominal P <0.05).
• Mucosal healing was achieved by 24% (14/59) of emvistegrast 200 mg participants versus 10% (6/60) of placebo participants (nominal P <0.05). A total of 39% (23/59) of 200 mg emvistegrast participants versus 12% (7/60) of placebo participants had endoscopic improvement (nominal P <0.001).
• Tolerability: Emvistegrast was generally well tolerated. Adverse events (AEs) occurred in 86/238 participants (emvistegrast: 64/178 [36%]; placebo: 22/60 [37%]) and were largely Grade ≤2. Serious AEs occurred in 4/178 (2%) of participants receiving emvistegrast (200 mg; 75 mg or 25 mg) and no participants receiving placebo; all were deemed unrelated to study drug. Overall, 3/238 (1%) patients discontinued the study due to AEs.

"Emvistegrast is an example of the science being advanced by our research teams at Gilead," said Wenjun Ouyang, Senior Vice President, Inflammation Research. "Discovered and developed internally, it reflects the deep medicinal chemistry and immunology expertise of our scientists and our ability to translate insights in disease biology into potential new medicines. The SWIFT results reinforce our commitment to building a differentiated inflammation pipeline rooted in scientific innovation."

Emvistegrast is an investigational compound and has not been approved anywhere globally. Its safety and efficacy have not been established.

Advancing Gilead's Commitment to Inflammation

Gilead is committed to advancing innovative treatments with the potential to transform care for people living with chronic inflammatory conditions.

The company is building a disciplined, differentiated inflammation portfolio focused on significant unmet needs across immune-mediated diseases. By combining immunology expertise, precision oral medicines and a deep internal pipeline spanning complementary scientific approaches, Gilead has the optionality to advance both monotherapies and future combinations that address underlying drivers of disease and improve outcomes that matter most to patients.

Our areas of focus include inflammatory bowel disease, type 2 inflammatory diseases, lupus and B cell-mediated autoimmune diseases.

About Emvistegrast

Emvistegrast (GS-1427) is an investigational oral α4β7 integrin inhibitor being developed for inflammatory bowel disease (IBD). The α4β7 pathway is a clinically validated target in IBD, and emvistegrast is part of Gilead's broader effort to advance differentiated therapies for inflammatory diseases. Emvistegrast is not approved anywhere globally, and its safety and efficacy have not been established.

About the SWIFT Study

SWIFT is a Phase 2 randomized, placebo-controlled study evaluating the efficacy, safety and tolerability of emvistegrast in adults with moderately to severely active ulcerative colitis. The study was designed to assess the potential of emvistegrast to improve disease activity and clinically meaningful outcomes for people living with ulcerative colitis, while further characterizing its safety profile.

SWIFT Study Design

• Phase 2, randomised, double-blind, placebo-controlled, multicentre, dose-ranging study evaluating the efficacy and safety of emvistegrast in adults aged 18-75 years with moderately to severely active ulcerative colitis (UC; determined by endoscopy at screening with a total modified Mayo Clinic Score [mMCS] of 5-9 points, including a centrally-read endoscopic subscore of ≥2) who had inadequate response, loss of response, or intolerance to ≥1 UC treatment and <3 advanced therapy (AT) mechanisms of action for UC.
• Participants were randomised 1:1:1:1 to receive once-daily oral emvistegrast (200 mg, 75 mg, or 25 mg) or placebo. The study comprised 3 sequential phases: a 12-week placebo-controlled induction phase (Part A); a blinded, placebo re-randomised maintenance phase through Week 52 (Part B); and a continued blinded treatment extension through Week 116 (Part C). Primary endpoint was the proportion of participants achieving clinical response at Week 12. Key secondary endpoints included safety and clinical remission, histologic endoscopic mucosal improvement (HEMI), mucosal healing, and endoscopic improvement.

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 and additional clinical trials or studies, including those involving emvistegrast (such as SWIFT); uncertainties relating to regulatory applications and related filing and approval timelines, including potential applications for programs and/or indications currently under evaluation, and the risk that any regulatory 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 June 30, 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.

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