Principal Associate Scientist, Bioanalytical Science

Xaira; South San Francisco (CA); On-site; USD 110,000 - 138,000; Full time

Job summary

Xaira Therapeutics is seeking a Principal Associate Scientist to join the Bioanalytical Sciences team. The role focuses on developing and executing ligand binding assays to support PK, PD, and target engagement studies across discovery and translational programs.

The ideal candidate has extensive hands-on experience with ELISA and MSD/ECL, flow cytometry-based assays, and PK/PD analysis in NHP/rodent models. Join a fast-paced, collaborative biotech startup in CA."

Qualifications

• 7+ years of relevant industry experience in bioanalytical sciences.
• Hands-on experience with ligand binding assay platforms (ELISA, MSD/ECL).
• Experience executing flow cytometry-based assays for receptor occupancy or target engagement.
• Experience supporting PK/PD analysis across NHP/rodent species in discovery or translational research.
• Ability to independently execute experiments and troubleshoot technical issues.
• Strong data summarization and presentation skills.
• Excellent attention to detail and rigorous record-keeping.
• Ability to collaborate effectively in a fast-paced team.

Responsibilities

• Develop, optimize, and execute ligand binding assays (ELISA, MSD/ECL) and flow cytometry methods for PK/PD studies in biologic programs.
• Support assay development, qualification, and validation for non-GLP, IND-enabled GLP, and clinical studies.
• Contribute to DMPK and bioanalytical studies to generate PK/PD data for candidate selection.
• Support bioanalytical method development and validation across discovery to clinical programs.
• Process and analyze samples from NHP and rodent matrices.
• Generate and document experimental data to support team decisions.
• Prepare data summaries and presentations for internal program groups and CROs.
• Maintain accurate lab records and ensure reproducibility.
• Collaborate with cross-functional teams on ongoing research programs.

Skills

Ligand binding assays

ELISA

MSD/ECL

Flow cytometry

PK/PD analysis

Data analysis

Laboratory troubleshooting

Documentation

Education

B.S./M.S. in Biochemistry/Immunology/Analytical Chemistry

Job description

Principal Associate Scientist, Bioanalytical Science

About Xaira Therapeutics

Xaira is an innovative biotech startup focused on leveraging AI to transform drug discovery and development. The company is leading the development of generative AI models to design protein and antibody therapeutics, enabling the creation of medicines against historically hard-to-drug molecular targets. It is also developing foundation models for biology and disease to enable better target elucidation and patient stratification. Collectively, these technologies aim to continually enable the identification of novel therapies and to improve success in drug development. Xaira is headquartered in the San Francisco Bay Area, Seattle, and London.

About the Role Xaira Therapeutics is seeking a Principal Associate Scientist to join our Bioanalytical Sciences team. This is a hands-on, lab-based role focused on developing and executing ligand binding assays to support pharmacokinetic, pharmacodynamic, and target engagement studies across discovery and translational programs.

This position is ideal for someone with strong experience in bioanalytical assay development and execution who enjoys bench work and contributing to data generation in a fast-paced, collaborative environment. You will work closely with scientists across biology and pharmacology to generate high-quality data that supports ongoing discovery efforts.

What You’ll Do

• Develop, optimize, and execute ligand binding assays (ELISA, MSD/ECL) and flow cytometry-based methods to support PK, PD, receptor occupancy, and target engagement studies for biologic programs
• Support assay development, optimization, qualification, and validation activities for both non-GLP, IND-enabling GLP, and clinical studies
• Contribute to the design and execution of DMPK and bioanalytical studies, generating PK/PD and exposure data to support candidate selection
• Support bioanalytical method development, qualification, and validation for discovery, translational, and clinical programs
• Process and analyze samples across NHP and rodent matrices, including serum, plasma, and tissue
• Generate, analyze, and clearly document experimental data to support team decision-making
• Prepare presentations and data summaries to communicate experimental findings with internal program groups and external CROs.
• Maintain accurate lab records and ensure reproducibility of experimental workflows
• Collaborate with cross-functional teams to support ongoing research programs

What We’re Looking For

• B.S. or M.S. in Biochemistry, Immunology, Analytical Chemistry, or a related field with 7+ years of relevant industry experience
• Strong hands-on experience with ligand binding assay platforms (ELISA, MSD/ECL)
• Proven experience executing flow cytometry-based assays, ideally for receptor occupancy or target engagement
• Experience supporting PK/PD sample analysis across NHP and/or rodent species in a discovery or translational research setting
• Ability to independently execute experiments and troubleshoot technical issues
• Past experience with summarizing data and presenting to internal or external groups.
• Strong attention to detail, organization, and record keeping
• Ability to work effectively in a fast-paced, team-oriented environment

Compensation

Annual

We offer a competitive compensation and benefits package, seeking to provide an open, flexible, and friendly work environment to empower employees and provide them with a platform to develop their long-term careers. A Summary of Benefits is available for all applicants. We offer a competitive package that includes base salary, bonus, and equity. The base pay range for this position is expected to be $110,000 to $138,000 annually; however, the base pay offered may vary depending on the market, job-related knowledge, skills and capabilities, and experience.

Xaira Therapeutics an equal-opportunity employer. We believe that our strength is in our differences. Our goal to build a diverse and inclusive team began on day one, and it will never end.