Senior Scientist, Bioanalytical, Pharmacokinetics, and Immunology Assays

Location: South San Francisco, CA – Onsite

Position Summary:

We are seeking a Senior Scientist with strong expertise in pharmacokinetic (PK) assay development and hands-on experience with protein and biomarker assays. The ideal candidate will bring proven skills across immunoassay platforms, as well as familiarity with immune cell surface marker analysis. This role offers the opportunity to directly impact the advancement of our therapeutic pipeline by connecting preclinical studies to mechanism of action and translational outcomes.

Key Responsibilities include but are not limited to:

• Design, develop, and execute assays to support PK/PD package of preclinical programs
• Develop and optimize bioanalytical assays to quantify therapeutic proteins and biomarkers (e.g., ELISA, MSD)
• Apply immunological techniques (e.g., flow cytometry, multiplex cytokine profiling) to characterize surface markers and immune cell states
• Interpret and present data to cross-functional teams, contributing to dose-response and exposure–response modeling
• Collaborate closely with discovery biology, in vivo pharmacology, and computational groups to advance pipeline candidates
• Provide subject matter expertise in assay design, validation, and troubleshooting
• Mentor junior scientists and contribute to team growth and best practices
• Maintain detailed records in compliance with industry standards; support preparation of data packages for internal reviews and external partners

Required Qualifications:

• PhD in Immunology, Pharmacology, Biochemistry, or a related discipline with 3 years of postdoctoral or industry experience; OR MS with 7 years of biotech/pharma experience
• Demonstrated expertise in bioanalytical assay development for therapeutic proteins
• Strong technical proficiency in across immunoassay platforms and immune profiling techniques (e.g., ELISA, MSD, and flow cytometry)
• Familiarity with immune cell surface marker analysis and characterization
• Strong data analysis skills with the ability to communicate findings clearly across disciplines
• Proven ability to work effectively in collaborative, fast-paced environments
• Experience with regulatory assay validation (GLP/GCLP) desirable but not required

Compensation: $130,000 - $160,000, plus Discretionary Bonus.

TRexBio is a clinical stage biotechnology company leveraging cutting edge computational biology tools, a focus on human tissue, and expertise in immunobiology to develop revolutionary therapeutics for inflammatory diseases. Our powerful ‘deep biology’ discovery engine maps human tissue Treg behavior to disease processes, allowing us to identify and characterize novel targets for therapeutic intervention. Leveraging this platform, we are building a broad portfolio of novel therapies that modulate the immune system to restore human tissue immune homeostasis.

Our Culture:

At TRexBio, you will have the opportunity to work with amazingly smart humans who strive to make the world a better place. In addition to our team-centric culture, we believe that your individual creativity will help us to be our best. Our staff happy hours, organized by our Culture Club, bring us all together in creative and social activities. Our colleagues admire and respect one another. We celebrate our wins, update company news and acknowledge each other’s achievement weekly and monthly at all company meetings that celebrate our work and our people.

TRexBio is proud to be an AA/EEO employer and all qualified candidates will receive consideration without regard to characteristics protected by applicable local, state, or federal law, such as race, color, sex, age, religion, national origin, physical or mental disability, pregnancy, marital status, veteran or military status, genetic information, or sexual orientation.