Senior Scientist I, Bioassay

Exelixis•Alameda, CA

About The Position

The Senior Scientist I, Analytical Development, Biologics CMC supports CMC analytical development for biologic therapeutics by establishing and advancing phase-appropriate cell-based bioassay, potency, functional, and binding assay capabilities. This hands-on position independently develops, optimizes, qualifies, transfers, and manages fit-for-purpose assays that reflect product mechanism of action and relevant critical quality attributes across ADCs, monoclonal antibodies, bispecifics, multispecifics, Fc-fusion proteins, VHH-Fc constructs, and other novel biologic modalities. The role supports scientifically rigorous, regulatory-relevant, cost-effective, and timely potency assay strategies through laboratory execution, technical ownership, and collaboration with internal teams and external partners. The position may provide technical guidance, training, and work direction to junior scientists, research associates, consultants, CDMOs, CTLs, and other external partners; it has no direct people-management responsibility. Work takes place primarily in laboratories and office settings, with potential exposure to biological materials, chemical reagents, hazardous materials, and extreme cold. The company describes its office as a modern, collaborative space and provides equipment including dual monitors and ergonomic chairs.

Requirements

Ph.D. in a listed life sciences discipline or related discipline with relevant industry experience; or a Master’s degree in a listed discipline with 5 or more years of relevant industry experience; or a Bachelor’s degree in a listed discipline with 7 or more years of relevant industry experience; or an equivalent combination of education and experience.
Hands-on experience developing complex cell-based bioassays or functional assays from concept through optimization, qualification, troubleshooting, documentation, and method transfer.
Advanced knowledge of cell-based bioassay and potency assay development for biologic therapeutics, including mammalian cell culture, flow cytometry, receptor-expression analysis, functional assay design, and binding/kinetic methods such as SPR or BLI.
Strong understanding of potency as a critical quality attribute and ability to translate product mechanism of action into scientifically justified assay strategies, biological readouts, cell models, controls, and acceptance criteria.
Ability to develop assays with limited precedent, troubleshoot complex assay performance issues, interpret cell-based assay, flow cytometry, and binding data, and make practical CMC development recommendations.
Working knowledge of phase-appropriate method development, qualification, comparability, method transfer, and lifecycle management for biologics.
Technical writing skills for assay protocols, SOPs, development reports, qualification or transfer documents, comparability assessments, regulatory-supporting summaries, and investigation reports.
Effective communication, collaboration, presentation, data interpretation, organization, prioritization, and problem-solving skills in a fast-paced, cross-functional CMC environment.
Strong ownership, scientific curiosity, attention to detail, laboratory discipline, and commitment to high-quality technical execution.

Nice To Haves

Experience with mammalian cell culture, assay-ready cells, transient transfection or engineered cell models, flow cytometry, plate-based assays, and functional potency readouts.
Working knowledge of biologics CMC, analytical control strategy, phase-appropriate method development, and CDMO/CTL interactions.

Responsibilities

Develop complex cell-based bioassays and potency assays from concept through optimization, qualification, and method transfer for biologic therapeutics.
Perform mammalian cell culture, transient transfection, engineered cell model development, receptor-expression confirmation, and assay-ready cell support.
Develop and troubleshoot functional bioassays, including reporter-gene, cytotoxicity, proliferation/inhibition, receptor blockade, ADCC/CDC, and immune-cell engagement assays.
Use flow cytometry, ELISA or plate-based binding assays, SPR/BLI, and other orthogonal methods to support assay development, comparability, and structure-function understanding.
Evaluate assay performance, robustness, system suitability, relative potency, parallelism, and critical assay parameters to support phase-appropriate method qualification and transfer.
Author and review assay procedures, development reports, qualification or transfer documents, technical summaries, and CMC-relevant regulatory supporting materials.
Collaborate with Discovery, Translational Sciences, Process Development, Quality, Regulatory, CDMOs, CTLs, and external partners to align assay strategy with program needs.
Contribute to internal bioassay capabilities, including cell culture workflows, flow cytometry practices, plate-reader methods, data analysis tools, and critical reagent management.
Provide technical guidance, training, and work direction to junior scientists, research associates, consultants, CDMOs, CTLs, and other external partners.

Benefits

401k plan with generous company contributions
Group medical coverage
Dental coverage
Vision coverage
Life insurance
Disability insurance
Flexible spending accounts
Eligibility for a discretionary annual bonus program, or a sales-based incentive plan for field sales staff
Opportunity to purchase company stock
Long-term incentives
15 accrued vacation days in the first year
17 paid holidays, including a company-wide winter shutdown in December
Up to 10 sick days throughout the calendar year