Gilead Sciences (GIS) Risk Analysis

We are required to demonstrate the safety and efficacy of product candidates that we develop for each intended use through extensive preclinical studies and clinical trials. The results from these studies do not always accurately predict results in later, large-scale clinical trials. Even successfully completed large-scale clinical trials may not result in marketable products. We face numerous risks and uncertainties with our clinical trials that could result in delays or prevent completion of the development and approval of our product candidates, including challenges in clinical trial protocol design, our ability to enroll patients in clinical trials, the possibility of unfavorable or inadequate trial results to support further development of our product candidates, including failure to meet a trial's primary endpoint, safety issues arising from our clinical trials, and the need to modify or delay our clinical trials or to perform additional trials. For example, in June 2026, we and Merck announced the discontinuation of the Phase 3 EVOKE-03 study evaluating sacituzumab govitecan-hziy in combination with pembrolizumab in certain patients with previously untreated metastatic non-small cell lung cancer, which resulted in us recording an impairment charge during the three months ended June 30, 2026 (for more information, see Note 7. Intangible Assets of the Notes to the Condensed Consolidated Financial Statements included in Part I, Item 1 of this Quarterly Report on Form 10-Q). As a result, we may be unable to successfully complete our clinical trials on our anticipated timelines, or at all. Based on trial results, it is possible that FDA and other regulatory authorities do not approve our product candidates, or that any market approvals include significant limitations on the products' use. Additionally, products and indications approved under accelerated approval pathways may be subject to withdrawal where confirmatory studies are unsuccessful. In addition, clinical trials involving our commercial products can raise new safety issues for our existing products, which could adversely impact our business. Further, we have in the past and we may in the future make a strategic decision to discontinue development of our product candidates, including but not limited to situations where we believe commercialization will be difficult relative to other opportunities in our pipeline. Therefore, our product candidates may never be successfully commercialized, and we may be unable to recoup the significant R&D, clinical trial, acquisition-related and other expenses incurred. We expect to spend significant time and resources on our clinical trial activities without any assurance that we will recoup our investments or that our efforts will be commercially successful. There are also risks associated with the use of third parties in our clinical trial activities. We extensively outsource our clinical trial activities and usually perform only a small portion of the start-up activities in-house. We rely on third-party contract research organizations ("CROs") to perform most of our clinical studies, including document preparation, site identification, screening and preparation, pre-study visits, training, program management, patient enrollment, ongoing monitoring, site management and bioanalysis. Many important aspects of the services performed for us by the CROs are not within our direct control. If there is any dispute or disruption in our relationships with our CROs, including as a result of legislative or regulatory actions (such as the BIOSECURE Act in the U.S.), our clinical trials and regulatory submissions may be delayed and our costs may increase. Moreover, in our regulatory submissions, we rely on the quality and validity of the clinical work performed by our CROs and investigators at the clinical trial sites. If any of their processes, methodologies or results were determined to be invalid, inadequate or in violation of Good Clinical Practices and related regulations, our own clinical data and results and related regulatory approvals may be adversely affected.