Principal Scientist, GI/Liver Biomarkers & Translational Research

Role Overview

Gilead Sciences is seeking a highly accomplished and scientifically rigorous Principal Scientist to lead biomarker and translational strategy and execution for complex clinical-stage programs across inflammatory bowel disease (IBD) and liver disease. This is a hands-on scientific leadership role for an individual who combines deep disease biology with demonstrated clinical biomarker development experience and a strong record of scientific productivity. The Principal Scientist will serve as cross-functional biomarker lead for assigned programs, translating mechanism and human biology into fit-for-purpose biomarker plans from early clinical development through Phase II/III. This is a site based role at our global headquarters in Foster City, CA.

Key Responsibilities

• Lead end-to-end biomarker strategy for assigned GI/IBD and liver programs, including target engagement, pharmacodynamic, mechanism-of-action, disease activity, safety, predictive and treatment-response biomarkers.
• Translate program hypotheses into decision-focused clinical biomarker plans, sampling strategies, assay requirements, analysis plans and interpretation frameworks.
• Provide hands-on scientific leadership for blood, stool, intestinal and liver tissue, endoscopic, histologic, imaging and multi-omic biomarker approaches.
• Lead assay selection, characterization, qualification or validation, outsourcing, technology transfer and CRO/vendor oversight; proactively resolve scientific, quality and operational issues.
• Partner with Clinical Development, Clinical Pharmacology, Biostatistics, Bioinformatics, Pathology, Research, Clinical Operations and Regulatory to embed biomarker objectives into protocols and development plans.
• Lead integrated interpretation of clinical, pathology, imaging, transcriptomic, proteomic, cellular, spatial and other high-dimensional datasets; generate testable hypotheses and actionable development recommendations.
• Drive forward and reverse translational analyses, including responder/non-responder studies and investigation of mechanisms of response, resistance, relapse and patient heterogeneity.
• Author or provide biomarker content for protocols, investigator brochures, analysis plans, clinical study reports, briefing documents, regulatory submissions, publications and presentations.
• Communicate complex findings clearly to program teams and governance forums; manage risks and trade-offs and influence decisions with limited guidance.
• Mentor colleagues, establish high scientific and executional standards, and contribute to reusable biomarker tools, datasets and best practices across the portfolio.

Basic Qualifications

• PhD, MD, MD/PhD, PharmD or equivalent advanced degree in immunology, gastroenterology, hepatology, inflammation biology, translational medicine, pharmacology or a related discipline.
• Typically 8+ years of relevant postdoctoral, biotechnology, pharmaceutical, clinical development or human translational research experience, including meaningful experience in clinical-stage drug development.
• Demonstrated success independently leading biomarker strategy and execution for one or more complex clinical programs, with examples of biomarker evidence informing dose, proof-of-concept, patient population, go/no-go or development decisions.
• Strong scientific depth in human immunology and immune-mediated inflammatory disease, with direct GI/IBD and/or liver disease experience.
• Proven scientific productivity and creativity, evidenced by a sustained record of impactful peer-reviewed publications, patents, clinical or translational datasets, invited presentations, externally recognized collaborations or comparable achievements.
• Hands-on experience with assay development or externalization, clinical sample operations, biomarker data analysis and interpretation, and work in regulated development environments.
• Ability to lead cross-functional workstreams, manage external partners, deliver high-quality work on time and communicate effectively with scientific and clinical stakeholders.

Preferred Qualifications

• Direct experience in Crohn's disease and/or ulcerative colitis, including endoscopic, histologic, intestinal tissue, blood and stool assessments.
• Experience in liver inflammation, fibrosis, noninvasive biomarkers, imaging and/or liver histopathology.
• Experience supporting Phase I through Phase III studies and contributing to health authority interactions or regulatory documents.
• Experience with single-cell or spatial profiling, transcriptomics, proteomics, cytometry, digital pathology, genetics, microbiome analysis or integrated multi-omic approaches.
• Working knowledge of companion diagnostic or in vitro diagnostic considerations.

Leadership Profile

A rigorous, creative and execution-oriented scientist who remains close to the data, independently leads complex program work, challenges assumptions constructively, develops others and consistently converts scientific insight into meaningful translational and development impact.