European Commission Approves Trodelvy® as a First-Line Treatment for Metastatic Triple-Negative Breast Cancer Patients Not Candidates for PD-(l)1 Inhibitors

–Trodelvy is the First Antibody-Drug Conjugate (ADC) and First New Treatment Option in 20 Years in Europe for Certain Patients with First-Line Metastatic Triple-Negative Breast Cancer –

– Authorization Based on ASCENT-03 Study in Which Trodelvy Demonstrated Highly Statistically Significant and Clinically Meaningful Progression-Free Survival (PFS) Versus Chemotherapy in PD-(L)1 Inhibitor Ineligible Patients –

Gilead Sciences, Inc. (NASDAQ:GILD) today announced that the European Commission (EC) has granted marketing authorization for Trodelvy^® (sacituzumab govitecan-hziy) as monotherapy for the treatment of adult patients with unresectable or metastatic triple-negative breast cancer (TNBC) who have not received prior systemic therapy for metastatic disease and are not candidates for PD-1 or PD-L1 inhibitor therapy. Trodelvy is the first antibody-drug conjugate (ADC) to be approved in first-line metastatic TNBC in the European Union’s 27 member states, as well as Norway, Iceland and Liechtenstein.

"This approval brings a profound sense of hope to a community that has long been waiting for progress," said Dr. Javier Cortes, Head of the International Breast Cancer Center, Madrid and Barcelona, Spain. "For women diagnosed with metastatic TNBC, particularly those who are younger, every second counts, and having an effective treatment option that can delay the progression of their disease is invaluable. This is the kind of meaningful advance our community needs."

For many living with metastatic TNBC, the most aggressive form of breast cancer, first-line therapy may be their only line of treatment, creating an urgent need for effective treatment options to be used as early as possible.

"This approval represents a significant step forward in how we treat people with first-line metastatic TNBC in Europe," said Mika Kakefuda Derynck, MD, Senior Vice President, Clinical Development, Oncology at Gilead Sciences. "We have long recognized the challenges that patients and clinicians face with this aggressive cancer, and we believe this approval will provide a much-needed new option for people with metastatic TNBC."

The EC’s marketing authorization is based on data from the Phase 3 ASCENT-03 study which demonstrated a highly statistically significant and clinically meaningful progression-free survival for Trodelvy compared to standard of care chemotherapy as a first-line treatment. In ASCENT-03, Trodelvy demonstrated a 38% reduced risk of disease progression or death in patients who are not candidates for PD-1/PD-L1 inhibitors. The ASCENT-03 study utilized a patient-centered crossover design, which allowed patients in the chemotherapy arm to receive Trodelvy after their disease progressed. The EC’s approval, based on the strength of the PFS data, confirms the study's objective to demonstrate using Trodelvy earlier provides a clinical benefit over chemotherapy for metastatic TNBC patients.

Continued Global Regulatory Filings for Trodelvy in First-Line Metastatic TNBC

Gilead has submitted a supplemental filing to the European Medicines Agency for Trodelvy in combination with Keytruda^® (pembrolizumab) for patients with PD-L1 positive unresectable locally advanced or metastatic TNBC, based on data from the Phase 3 ASCENT-04 study. This application is currently under review. If approved, Trodelvy has the potential to be a backbone treatment in 1L metastatic TNBC, across PD-L1 status in Europe. In the U.S., Gilead has also submitted supplemental filings to the Food and Drug Administration (FDA) for Trodelvy for the first-line treatment of adult patients with unresectable locally advanced or metastatic TNBC as a single agent for patients who are not candidates for PD-(L)1 inhibitor-based therapy, or in combination with Keytruda or Keytruda Qlex in patients whose tumors express PD-L1 (CPS ≥10) as determined by an FDA-authorized test.

KEYTRUDA^® and KEYTRUDA QLEX™ are trademarks of Merck Sharp & Dohme LLC., a subsidiary of Merck & Co., Inc., Rahway, NJ, USA

About Triple-Negative Breast Cancer In Patients Who Are Not Candidates for PD-1/PD-L1 Inhibitors

TNBC is the most aggressive type of breast cancer and has historically been difficult to treat, accounting for approximately 15% of all breast cancers. TNBC disproportionally impacts younger, premenopausal, and Black and Hispanic women. TNBC cells do not have estrogen and progesterone receptors and have limited HER2 expression. Due to the nature of TNBC, treatment options are extremely limited compared with other breast cancer types. TNBC has a higher chance of recurrence and metastases than other breast cancer types. The average time to metastatic recurrence for TNBC is approximately 2.6 years compared with 5 years for other breast cancers, and the relative five-year survival rate is much lower. Among women with metastatic TNBC, the five-year survival rate is 12%, compared with 28% for those with other types of mBC.

About Trodelvy

Trodelvy (sacituzumab govitecan-hziy) is a Trop-2-directed antibody-drug conjugate. Trop-2 is a cell surface antigen highly expressed in multiple tumor types, including in more than 90% of breast and lung cancers. Trodelvy is intentionally designed with a proprietary hydrolyzable linker attached to SN-38, a topoisomerase I inhibitor payload. This unique combination delivers potent activity to both Trop-2 expressing cells and the tumor microenvironment through a bystander effect.

Outside of Europe, Gilead has submitted supplemental applications to the U.S. Food and Drug Administration (FDA) for approval of Trodelvy based on the ASCENT-03 and ASCENT-04 studies.

Healthcare professionals have substantial clinical experience with Trodelvy, with more than 75,000 breast cancer patients treated since 2020. In addition to its first-line indication approval, Trodelvy is currently approved in more than 60 countries for patients with second-line or later mTNBC and in over 50 countries for certain patients with pre-treated HR+/HER2- metastatic breast cancer. It is the only ADC with four positive Phase 3 trials in HER2-negative metastatic breast cancer and the only Trop-2-directed ADC to demonstrate a meaningful overall survival benefit in two distinct types of metastatic breast cancer.

Trodelvy is currently being evaluated in multiple ongoing Phase 3 trials across different tumor types, including in small cell lung cancer and gynecologic cancers, where previous proof-of-concept studies have demonstrated clinical activity.

U.S. Indications for Trodelvy

TRODELVY^® (sacituzumab govitecan-hziy) is a Trop-2-directed antibody and topoisomerase inhibitor conjugate indicated for the treatment of adult patients with:

• Unresectable locally advanced or metastatic triple-negative breast cancer (mTNBC) who have received two or more prior systemic therapies, at least one of them for metastatic disease.

• Unresectable locally advanced or metastatic hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative (IHC 0, IHC 1+ or IHC 2+/ISH–) breast cancer who have received endocrine-based therapy and at least two additional systemic therapies in the metastatic setting.

U.S. Important safety information FOR TRODELVY

BOXED WARNING: NEUTROPENIA AND DIARRHEA

• TRODELVY can cause severe, life-threatening, or fatal neutropenia. Withhold TRODELVY for absolute neutrophil count below 1500/mm³ or neutropenic fever. Monitor blood cell counts periodically during treatment. Primary prophylaxis with G-CSF is recommended for all patients at increased risk of febrile neutropenia. Initiate anti-infective treatment in patients with febrile neutropenia without delay.

• TRODELVY can cause severe diarrhea. Monitor patients with diarrhea and give fluid and electrolytes as needed. At the onset of diarrhea, evaluate for infectious causes and, if negative, promptly initiate loperamide. If severe diarrhea occurs, withhold TRODELVY until resolved to ≤ Grade 1 and reduce subsequent doses.

CONTRAINDICATIONS

• Severe hypersensitivity reaction to TRODELVY.

WARNINGS AND PRECAUTIONS

Neutropenia: Severe, life-threatening, or fatal neutropenia can occur as early as the first cycle of treatment and may require dose modification. Neutropenia occurred in 64% of patients treated with TRODELVY. Grade 3-4 neutropenia occurred in 49% of patients. Febrile neutropenia occurred in 6%. Neutropenic colitis occurred in 1.4%. Primary prophylaxis with G-CSF is recommended starting in the first cycle of treatment in all patients at increased risk of febrile neutropenia, including older patients, patients with previous neutropenia, poor performance status, organ dysfunction, or multiple comorbidities. Monitor absolute neutrophil count (ANC) during treatment. Withhold TRODELVY for ANC below 1500/mm³ on Day 1 of any cycle or below 1000/mm³ on Day 8 of any cycle. Withhold TRODELVY for neutropenic fever. Treat neutropenia with G-CSF and administer prophylaxis in subsequent cycles as clinically indicated or indicated in Table 2 of USPI.

Diarrhea: Diarrhea occurred in 64% of all patients treated with TRODELVY. Grade 3-4 diarrhea occurred in 11% of patients. One patient had intestinal perforation following diarrhea. Diarrhea that led to dehydration and subsequent acute kidney injury occurred in 0.7% of all patients. Withhold TRODELVY for Grade 3-4 diarrhea and resume when resolved to ≤ Grade 1. At onset, evaluate for infectious causes and if negative, promptly initiate loperamide, 4 mg initially followed by 2 mg with every episode of diarrhea for a maximum of 16 mg daily. Discontinue loperamide 12 hours after diarrhea resolves. Additional supportive measures (e.g., fluid and electrolyte substitution) may also be employed as clinically indicated. Patients who exhibit an excessive cholinergic response to treatment can receive appropriate premedication (e.g., atropine) for subsequent treatments.

Hypersensitivity and Infusion-Related Reactions: TRODELVY can cause serious hypersensitivity reactions including life-threatening anaphylactic reactions. Severe signs and symptoms included cardiac arrest, hypotension, wheezing, angioedema, swelling, pneumonitis, and skin reactions. Hypersensitivity reactions within 24 hours of dosing occurred in 35% of patients. Grade 3-4 hypersensitivity occurred in 2% of patients. The incidence of hypersensitivity reactions leading to permanent discontinuation of TRODELVY was 0.2%. The incidence of anaphylactic reactions was 0.2%. Pre-infusion medication is recommended. Have medications and emergency equipment to treat such reactions available for immediate use. Observe patients closely for hypersensitivity and infusion-related reactions during each infusion and for at least 30 minutes after completion of each infusion. Permanently discontinue TRODELVY for Grade 4 infusion-related reactions.

Nausea and Vomiting: TRODELVY is emetogenic and can cause severe nausea and vomiting. Nausea occurred in 64% of all patients treated with TRODELVY and Grade 3-4 nausea occurred in 3% of these patients. Vomiting occurred in 35% of patients and Grade 3-4 vomiting occurred in 2% of these patients. Premedicate with a two or three drug combination regimen (e.g., dexamethasone with either a 5-HT3 receptor antagonist or an NK₁ receptor antagonist as well as other drugs as indicated) for prevention of chemotherapy-induced nausea and vomiting (CINV). Withhold TRODELVY doses for Grade 3 nausea or Grade 3-4 vomiting and resume with additional supportive measures when resolved to Grade ≤ 1. Additional antiemetics and other supportive measures may also be employed as clinically indicated. All patients should be given take-home medications with clear instructions for prevention and treatment of nausea and vomiting.

Increased Risk of Adverse Reactions in Patients with Reduced UGT1A1 Activity: Patients homozygous for the uridine diphosphate-glucuronosyl transferase 1A1 (UGT1A1)*28 allele are at increased risk for neutropenia, febrile neutropenia, and anemia and may be at increased risk for other adverse reactions with TRODELVY. The incidence of Grade 3-4 neutropenia was 58% in patients homozygous for the UGT1A1*28, 49% in patients heterozygous for the UGT1A1*28 allele, and 43% in patients homozygous for the wild-type allele. The incidence of Grade 3-4 anemia was 21% in patients homozygous for the UGT1A1*28 allele, 10% in patients heterozygous for the UGT1A1*28 allele, and 9% in patients homozygous for the wild-type allele. Closely monitor patients with known reduced UGT1A1 activity for adverse reactions. Withhold or permanently discontinue TRODELVY based on clinical assessment of the onset, duration and severity of the observed adverse reactions in patients with evidence of acute early-onset or unusually severe adverse reactions, which may indicate reduced UGT1A1 function.

Embryo-Fetal Toxicity: Based on its mechanism of action, TRODELVY can cause teratogenicity and/or embryo-fetal lethality when administered to a pregnant woman. TRODELVY contains a genotoxic component, SN-38, and targets rapidly dividing cells. Advise pregnant women and females of reproductive potential of the potential risk to a fetus. Advise females of reproductive potential to use effective contraception during treatment with TRODELVY and for 6 months after the last dose. Advise male patients with female partners of reproductive potential to use effective contraception during treatment with TRODELVY and for 3 months after the last dose.

ADVERSE REACTIONS

In the pooled safety population, the most common (≥ 25%) adverse reactions including laboratory abnormalities were decreased leukocyte count (84%), decreased neutrophil count (75%), decreased hemoglobin (69%), diarrhea (64%), nausea (64%), decreased lymphocyte count (63%), fatigue (51%), alopecia (45%), constipation (37%), increased glucose (37%), decreased albumin (35%), vomiting (35%), decreased appetite (30%), decreased creatinine clearance (28%), increased alkaline phosphatase (28%), decreased magnesium (27%), decreased potassium (26%), and decreased sodium (26%).

In the ASCENT study (locally advanced or metastatic triple-negative breast cancer), the most common adverse reactions (incidence ≥25%) were fatigue, diarrhea, nausea, alopecia, constipation, vomiting, abdominal pain, and decreased appetite. The most frequent serious adverse reactions (SAR) (>1%) were neutropenia (7%), diarrhea (4%), and pneumonia (3%). SAR were reported in 27% of patients, and 5% discontinued therapy due to adverse reactions. The most common Grade 3-4 lab abnormalities (incidence ≥25%) in the ASCENT study were reduced neutrophils, leukocytes, and lymphocytes.

In the TROPiCS-02 study (locally advanced or metastatic HR-positive, HER2-negative breast cancer), the most common adverse reactions (incidence ≥25%) were diarrhea, fatigue, nausea, alopecia, and constipation. The most frequent serious adverse reactions (SAR) (>1%) were diarrhea (5%), febrile neutropenia (4%), neutropenia (3%), abdominal pain, colitis, neutropenic colitis, pneumonia, and vomiting (each 2%). SAR were reported in 28% of patients, and 6% discontinued therapy due to adverse reactions. The most common Grade 3-4 lab abnormalities (incidence ≥25%) in the TROPiCS-02 study were reduced neutrophils and leukocytes.

DRUG INTERACTIONS

UGT1A1 Inhibitors: Concomitant administration of TRODELVY with inhibitors of UGT1A1 may increase the incidence of adverse reactions due to potential increase in systemic exposure to SN-38. Avoid administering UGT1A1 inhibitors with TRODELVY.

UGT1A1 Inducers: Exposure to SN-38 may be reduced in patients concomitantly receiving UGT1A1 enzyme inducers. Avoid administering UGT1A1 inducers with TRODELVY.

Please see full Prescribing Information, including BOXED WARNING.

About Gilead and Kite Oncology

Gilead and Kite Oncology are working to transform how cancer is treated. We are innovating with next-generation therapies, combinations and technologies to deliver improved outcomes for people with cancer. We are purposefully building our oncology portfolio and pipeline to address the greatest gaps in care. From antibody-drug conjugate technologies and small molecules to cell therapy-based approaches, we are creating new possibilities for people with cancer.

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. In 2025, Gilead announced a planned $32 billion investment to further strengthen its U.S. footprint to power the next era of discovery, job creation and public health preparedness – while continuing to invest globally to ensure patients everywhere benefit from its scientific innovation. Gilead operates in more than 35 countries worldwide, with headquarters in Foster City, Calif.

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 Trodelvy; uncertainties relating to regulatory applications and related filing and approval timelines, including such as the pending applications for Trodelvy in 1L mTNBC and 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 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.

Trodelvy, Gilead and the Gilead logo are trademarks of Gilead Sciences, Inc., or its related companies.

U.S. Prescribing Information for Trodelvy, including BOXED WARNING, 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).

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Priscilla White, Media

Public_affairs@gilead.com

Jacquie Ross, Investors

investor_relations@gilead.com