Gilead Sciences (GILD) 8-K Regulation FD Disclosure

Exhibit 99.1

Byoung Chul Cho, Yonsei Cancer Center, Republic of Korea 1 DRAFT Sacituzumab Govitecan + Pembrolizumab in 1L Metastatic Non-Small Cell Lung Cancer: Preliminary Results of the EVOKE-02 Study Byoung Chul Cho,1 Manuel Cobo Dols,2 Roxana Reyes Cabanillas,3 David Vicente,4 Jose Fuentes Pradera,5 Salvatore Grisanti,6 Afshin Eli Gabayan,7 Ki Hyeong Lee,8 Eun Kyung Cho,9 Sabeen Mekan,10 Farnoush Safavi,10 Nelumka Fernando,10 Michael J. Chisamore,11 Martin Reck12 1Division of Medical Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Republic of Korea; 2Regional and Virgen de la Victoria University Hospitals, IBIMA, Malaga, Spain; 3Hospital Clinic de Barcelona, Barcelona, Spain; 4Hospital Universitario Virgen Macarena, Seville, Spain; 5Hospital Universitario Virgen de Valme, Seville, Spain; 6Azienda Ospedaliera Spedali Civili di Brescia, Brescia, Italy; 7Beverly Hills Cancer Center, Beverly Hills, CA, USA; 8Chungbuk National University Hospital, Chungbuk, Republic of Korea; 9Gachon University Gil Medical Center, Incheon, Republic of Korea; 10Gilead Sciences, Inc., Foster City, CA, USA; 11Merck & Co., Inc., Rahway, NJ, USA; 12Airway Research Center North, German Center for Lung Research (DZL), LungenClinic, Grosshansdorf, Germany Draft as of August 16, 2023

Byoung Chul Cho, Yonsei Cancer Center, Republic of Korea 2 DRAFT Introduction • PD-(L)1 inhibitor-based regimens have been established as the standard-of-care 1L treatment for mNSCLC,1,2 and novel combination therapies are needed to further improve outcomes • Sacituzumab govitecan is a Trop-2–directed ADC approved in the United States for the treatment of 2L+ mTNBC and pretreated HR+/HER2– mBC, and received accelerated approval for 2L mUC3 • Sacituzumab govitecan has previously demonstrated clinical activity and manageable safety in heavily pretreated patients with mNSCLC4 • EVOKE-02 (NCT05186974) is an ongoing, multicohort phase 2 study of sacituzumab govitecan + pembrolizumab ± platinum agent in patients with untreated 1L mNSCLC • Here, we report preliminary results of patients treated with sacituzumab govitecan + pembrolizumab in Cohorts A and B from the EVOKE-02 study 1L, first-line; 2L, second-line; 2L+, second-line and beyond; ADC, antibody-drug conjugate; HER2–, human epidermal growth factor receptor 2-negative; HR+, hormonal receptor-positive; mBC, metastatic breast cancer; mNSCLC, metastatic non-small cell lung cancer; mTNBC, metastatic triple-negative breast cancer; mUC, metastatic urothelial cancer; PD-(L)1, programmed death (ligand) 1. 1. Hendriks LE, et al. Ann Oncol. 2023;34:358-376. 2. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Non-Small Cell Lung Cancer V.3.2023. © National Comprehensive Cancer Network, Inc. 2023. All rights reserved. Accessed June 15, 2023. 3. TRODELVY® (sacituzumab govitecan-hziy) [prescribing information]. Foster City, CA: Gilead Sciences, Inc.; February 2023. 4. Heist RS, et al. J Clin Oncol. 2017;35:2790-2797.

Byoung Chul Cho, Yonsei Cancer Center, Republic of Korea 3 DRAFT aDose de-escalation safety run-in period to determine the RP2D of SG for Cohorts C and D. bCarboplatin dosed as area under the concentration versus time curve 5. cPer RECIST v1.1. ECOG PS, Eastern Cooperative Oncology Group performance status; D, day; DLT, dose-limiting toxicity; DCR, disease control rate; DOR, duration of response; IV, intravenous; NSCLC, non-small cell lung cancer; Nsq, nonsquamous; ORR, objective response rate; OS, overall survival; PD-L1, programmed death ligand 1; PD, progressive disease; Pembro, pembrolizumab; PFS, progression-free survival; RECIST v1.1, Response Evaluation Criteria in Solid Tumors version 1.1; RP2D, recommended phase 2 dose; SG, sacituzumab govitecan; Sq, squamous; TPS, tumor proportion score. EVOKE-02: An Open-Label, Multicohort Phase 2 Study • At data cutoff (16 June 2023), median (range) follow-up for Cohorts A and B was 5.0 (1.7-12.0) and 5.8 (1.0-12.2) months, respectively • The preliminary efficacy data reported in this presentation are results by investigator assessment Key eligibility criteria • Stage IV NSCLC • Measurable disease per RECIST v1.1 • No known actionable genomic alterations • ECOG PS 0-1 • No prior systemic treatment for metastatic NSCLC N ≈ 176-224 Cohort A PD-L1 TPS ≥ 50% Nsq or Sq n ≈ 30 Cohort B PD-L1 TPS < 50% Nsq or Sq n ≈ 60 Cohort C Any PD-L1 TPS Nsq only n ≈ 40 Cohort D Any PD-L1 TPS Sq only n ≈ 40 Carboplatin Safety Run-ina Any PD-L1 TPS Nsq or Sq n ≈ 6-18 21-day cycles: SG 10 mg/kg IV on D1 and D8 (until PD or unacceptable toxicity) + Pembro 200 mg IV on D1 (up to 35 cycles) 21-day cycles: SG RP2D IV on D1 and D8 (until PD or unacceptable toxicity) + Pembro 200 mg IV on D1 (up to 35 cycles) + Carboplatinb IV on D1 (up to 4 cycles) End points Primary • ORRc • DLTs in safety run-in Secondary • DCR, DOR, and PFSc • OS • Safety

Byoung Chul Cho, Yonsei Cancer Center, Republic of Korea 4 DRAFT aDisease stage at diagnosis: Stage I-III (Cohort A, n = 5; Cohort B, n = 5). bThe PD-L1 IHC 22C3 pharmDx assay was required for PD-L1 testing. Local and central tumor tissue testing were allowed. ECOG PS, Eastern Cooperative Oncology Group performance status; PD-L1, programmed death ligand 1; Pembro, pembrolizumab; SG, sacituzumab govitecan; TPS, tumor proportion score. Patient Baseline Characteristics, Exposure, and Disposition Characteristic Cohort A (PD-L1 TPS ≥ 50%) SG + Pembro n = 30 Cohort B (PD-L1 TPS < 50%) SG + Pembro n = 33 Median age (range), years 67 (47-77) 68 (47-80) Male, % 80 79 Race, % Asian 20 15 Black 7 3 White 73 82 ECOG PS 1, % 80 76 Histology, % Nonsquamous 60 61 Squamous 40 39 Stage IV disease at diagnosis,a % 80 85 PD-L1 TPS,b % ≥ 50% 100 0 1-49% 0 48 < 1% 0 52 Patient exposure and disposition Cohort A (PD-L1 TPS ≥ 50%) SG + Pembro n = 30 Cohort B (PD-L1 TPS < 50%) SG + Pembro n = 33 Median duration of treatment (range), months SG 4.1 (0-11.2+) 4.1 (0-11.9+) Pembro 3.6 (0-11.2+) 3.8 (0-11.7+) Median number of cycles received (range), cycles SG 6 (1-17+) 6 (1-17+) Pembro 6 (1-17+) 6 (1-17+) Continuing treatment with SG, % 63 39 Continuing treatment with Pembro, % 63 42 Discontinued all study treatment, % 37 58 • Across both cohorts, the most common reason for discontinuation of sacituzumab govitecan was progressive disease

Byoung Chul Cho, Yonsei Cancer Center, Republic of Korea 5 DRAFT Only patients enrolled ≥ 13 weeks prior to the data cutoff date (16 June 2023) were included in the efficacy analysis. aPatients without tumor assessment (Cohort A, n = 1; Cohort B, n = 5). bORR was defined as BOR of CR + PR. c DCR was defined as BOR of CR + PR + SD ≥ 6 weeks. dEvaluated in patients with a confirmed complete or partial response. eBased on Kaplan-Meier estimates. BOR, best overall response; CI, confidence interval; CR, complete response; DCR, disease control rate; DOR, duration of response; INV, investigator assessment; NR, not reached; ORR, objective response rate; PD, progressive disease; PD-L1, programmed death ligand 1; Pembro, pembrolizumab; PR, partial response; SD, stable disease; SG, sacituzumab govitecan; TPS, tumor proportion score. Efficacy by Investigator Assessment Efficacy by INVa Cohort A (PD-L1 TPS ≥ 50%) SG + Pembro n = 29 Cohort B (PD-L1 TPS < 50%) SG + Pembro n = 32 Total SG + Pembro n = 61 ORR,b n (%) 20 (69) 14 (44) 34 (56) PR, n (%) – confirmed and unconfirmed 20 (69) 14 (44) 34 (56) Confirmed PR, n (%) 18 (62) 12 (38) 30 (49) SD, n (%) 5 (17) 11 (34) 16 (26) PD, n (%) 3 (10) 2 (6) 5 (8) DCRc (95% CI), % 86 (68-96) 78 (60-91) 82 (70-91) Median DORd,e (95% CI), months NR (5.6-NR) NR (3.5-NR) NR (7.9-NR) DOR rate at 6 monthsd,e (95% CI), % 88 (39-98) 88 (39-98) 87 (58-97) ORRb (95% CI), % 69 (49-85) 44 (26-62) 56 (42-69)

Byoung Chul Cho, Yonsei Cancer Center, Republic of Korea 6 DRAFT Only patients enrolled ≥ 13 weeks prior to the data cutoff date (16 June 2023) were included in the efficacy analysis. PD-L1, programmed death ligand 1; TPS, tumor proportion score. Waterfall Plot for Change in Target Lesions Total Best overall response Partial response (n = 30) Stable disease (n = 20) Progressive disease (n = 4) Cohort A (PD-L1 TPS ≥ 50%) Cohort B (PD-L1 TPS < 50%) 100 80 60 40 20 0 -20 -40 -60 -80 -100 Best percent change from baseline Participant

Byoung Chul Cho, Yonsei Cancer Center, Republic of Korea 7 DRAFT Only patients enrolled ≥ 13 weeks prior to the data cutoff date (16 June 2023) were included in the efficacy analysis. PD-L1, programmed death ligand 1; Pembro, pembrolizumab; SG, sacituzumab govitecan; TPS, tumor proportion score. Depth and Duration of Response Cohort A (PD-L1 TPS ≥ 50%) SG + Pembro Cohort B (PD-L1 TPS < 50%) SG + Pembro 100 Percent change from baseline – target lesions Weeks 90 80 70 60 50 40 30 20 10 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 0 6 12 18 24 30 36 42 48 54 Best overall response Partial response (n = 18) Stable disease (n = 7) Progressive disease (n = 3) Last assessment before data cutoff 100 Percent change from baseline – target lesions Weeks 90 80 70 60 50 40 30 20 10 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 0 6 12 18 24 30 36 42 48 54 Best overall response Partial response (n = 12) Stable disease (n = 13) Progressive disease (n = 1) Last assessment before data cutoff

Byoung Chul Cho, Yonsei Cancer Center, Republic of Korea 8 DRAFT All patients who received ≥ 1 dose of study treatment were included in the safety analysis. Pembro, pembrolizumab; SG, sacituzumab govitecan; TEAE, treatment-emergent adverse event. Safety Summary Safety-evaluable patients, n (%) Total SG + Pembro n = 63 Any-grade TEAEs 63 (100) Related to study treatment 57 (90) Grade ≥ 3 TEAEs 44 (70) Related to study treatment 24 (38) Serious TEAEs 34 (54) Related to study treatment 9 (14) TEAEs leading to treatment discontinuation 11 (18) TEAEs leading to discontinuation of SG 9 (14) TEAEs leading to discontinuation of Pembro 8 (13) TEAEs leading to SG dose reductions 11 (18) TEAEs leading to deatha 4 (6) Related to study treatment 1 (2) aTEAEs leading to death included: malignant lung neoplasm (n = 1), respiratory tract infection (n = 1), sepsis (n = 1), and sudden death (n = 1). The 1 case of sepsis leading to death was deemed related to study treatment.

Byoung Chul Cho, Yonsei Cancer Center, Republic of Korea 9 DRAFT All patients who received ≥ 1 dose of study treatment were included in the safety analysis. aGrade 3 pneumonitis was the highest grade observed to date (n = 2). Pembro, pembrolizumab; TEAE, treatment-emergent adverse event. • Immune-mediated TEAEs were consistent with the known safety profile of Pembro 5 5 2 2 3 2 2 2 0 10 20 30 40 50 60 Pneumonitis Hyperthyroidism Colitis Nephritis Maculopapular rash Hypothyroidism Percent of patients (%) Immune-mediated TEAEs Grade 1-2 Grade ≥ 3 a 51 42 38 37 30 9 20 24 22 17 19 18 3 6 2 18 5 5 2 0 10 20 30 40 50 60 Diarrhea Anemia Asthenia Alopecia Nausea Neutropenia Respiratory tract infection Constipation Decreased appetite Dyspnea Fatigue Mucosal inflammation Percent of patients (%) Any-grade TEAEs reported in ≥ 15% of patients Grade 1-2 Grade ≥ 3 • The most common any-grade TEAEs were diarrhea (54%), anemia (48%), and asthenia (38%)

Byoung Chul Cho, Yonsei Cancer Center, Republic of Korea 10 DRAFT 1L, first-line; DCR, disease control rate; DOR, duration of response; mNSCLC, metastatic non-small cell lung cancer; ORR, objective response rate; PD-L1, programmed death ligand 1; Pembro, pembrolizumab; SG, sacituzumab govitecan; TEAE, treatment-emergent adverse event; TPS, tumor proportion score. Conclusions • SG + Pembro demonstrated encouraging antitumor activity in patients with 1L mNSCLC across PD-L1 subgroups ‒ ORR was 69% and DCR was 86% in Cohort A ‒ ORR was 44% and DCR was 78% in Cohort B ‒ Median DOR was not reached, and DOR rate at 6 months was 88% in both cohorts • The safety profile of SG + Pembro was manageable and consistent with the known safety of each agent ‒ The most common any-grade TEAEs were diarrhea, anemia, and asthenia ‒ TEAEs leading to treatment discontinuation were low (18%) • These preliminary results warrant further investigation of SG + Pembro for the 1L treatment of mNSCLC ‒ The ongoing, open-label, global, randomized, phase 3 EVOKE-03 study (NCT05609968) is evaluating SG + Pembro versus Pembro monotherapy in patients with untreated 1L mNSCLC with PD-L1 TPS ≥ 50%

Byoung Chul Cho, Yonsei Cancer Center, Republic of Korea 11 DRAFT Acknowledgments • We would like to thank the patients, their caregivers, and families for their participation and commitment to clinical research • Thank you to the clinical trial investigators and their team members, without whom this work would not have been possible • This study was sponsored by Gilead Sciences, Inc. • This study is in collaboration with Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA • Medical writing and editorial support was provided by Andrew Scott, PharmD, of Parexel and funded by Gilead Sciences, Inc.