Senior Associate Scientist

At RayzeBio, every day is an opportunity to ignite meaningful change. As a wholly-owned subsidiary of Bristol Myers Squibb, RayzeBio blends the nimble, pioneering spirit of an emergent biotech with the global expertise and resources of a leading innovator in oncology. Our mission is to develop transformative radiopharmaceutical therapies that offer new hope for patients living with cancer. Here, you’ll join a multidisciplinary team where your ideas are valued, your expertise is amplified, and collaboration is at the heart of everything we do. From day one, expect to make an immediate impact—on our science, on our teams, and most importantly, on patients. Learn more about RayzeBio: https://careers.bms.com/rayzebio/

Senior Associate Scientist

Background

RayzeBio is a dynamic biotechnology company headquartered in San Diego, CA. Launched in late 2020 and recently acquired by Bristol Myers Squibb (BMS) as a wholly owned subsidiary, RayzeBio focuses on improving survival for people with cancer by harnessing the power of targeted radioisotopes. The company operates as a standalone entity within BMS, maintaining its biotech culture while leveraging best-in-class oncology capabilities. RayzeBio is developing innovative drugs targeting solid tumors, with its lead asset, RYZ101, in Phase 3 testing for gastroenteropancreatic neuroendocrine tumors (GEP-NETs) and earlier-stage testing for small cell lung cancer (SCLC). The company is led by a successful, experienced entrepreneurial team and aims to be the global leader in radiopharmaceuticals.

Job Description

The Senior Associate Scientist will independently execute and support preclinical research activities, with a primary focus on mammalian cell culture, cell expansion, and in vivo study execution. This role requires strong hands‑on expertise in cell culture workflows and in vivo research, including preparation of high‑quality cell suspensions for animal studies and direct participation in in vivo procedures.

The successful candidate will be responsible for delivering reproducible, high‑quality cell preparations, supporting in vivo studies through hands‑on animal work, monitoring study outcomes, and generating and interpreting experimental data. This position requires strong organizational skills, the ability to manage concurrent workflows and timelines, and the capability to independently troubleshoot experimental challenges in a fast‑paced research environment.

Key Responsibilities

• Independently conduct mammalian cell culture and expansion for adherent and suspension cell lines to support preclinical in vivo research.
• Prepare and manage cell culture media, buffers, and formulation components in accordance with established procedures.
• Prepare high‑quality cell suspensions for in vivo applications, including cell counting, viability assessment, formulation, and handling to maintain cell integrity.
• Maintain consistent quality, viability, and optimal health across multiple cell cultures.
• Build and manage cell expansion and preparation timelines to ensure alignment with in vivo study schedules.
• Perform and document routine quality control prior to inoculation, including viability, morphology assessment, pathogen screening, and verification against defined acceptance criteria.
• Execute in vivo animal procedures, including cell inoculation and compound administration (IV, IP, SC, PO), tumor measurements, and general animal handling.
• Monitor tumor growth, body weight, and clinical signs, and document study progress according to protocol requirements.
• Perform necropsy and tissue collection in accordance with approved study protocols.
• Collect, analyze, and interpret experimental data, ensuring accurate documentation and data integrity.
• Proactively troubleshoot issues related to cell culture performance and in vivo study execution, escalating risks as appropriate.
• Contribute to a safe and compliant laboratory environment and adhere to established animal welfare, biosafety, and radiation safety procedures.
• This role may require work outside of standard business hours, including early mornings, weekends, or holidays, to support critical in vivo studies and project timelines.

Education and Experience

• BS or MS in Biology, Cell Biology, Biomedical Sciences, or related field.
• BS with 4-5+ years or MS with 2-3+ years of relevant experience.

• Experience with cell characterization techniques (e.g., flow cytometry) is considered an asset.
• Prior experience handling radioactive materials is preferred.

Skills

• Advanced proficiency in mammalian cell culture and aseptic technique.
• Demonstrated proficiency in animal handling and in vivo techniques, with the ability to execute studies in compliance with animal welfare and IACUC‑regulated requirements.
• Ability to independently manage cell culture and in vivo workflows to support study execution and timelines.
• Experience in applying quality control and acceptance criteria to cell preparations used for in vivo studies.
• Strong attention to detail and commitment to reproducibility, data integrity, and accurate documentation.
• Proven troubleshooting skills related to cell culture quality, study readiness, and in vivo execution.
• Excellent organizational, communication, and documentation skills.
• Ability to work independently while collaborating effectively within cross‑functional research teams.
• Experience analyzing and interpreting experimental data using Excel, GraphPad Prism, or similar tools.
• Uses AI tools to enhance individual productivity and quality of work

Physical Demands & Work Environment

• Regularly required to sit, reach with hands and arms, and communicate effectively.
• Must occasionally lift and/or move up to 30–50 pounds.
• Specific vision abilities required: close vision and distance vision.
• Laboratory and vivarium environment with radioactive and biohazard materials; protective clothing, gloves, and safety glasses are mandatory at all times.
• Noise level is typically moderate.

If you come across a role that intrigues you but doesn’t perfectly line up with your resume, we encourage you to apply anyway. You could be one step away from work that will transform your life and career.

The starting compensation range(s) for this role are listed above for a full-time employee (FTE) basis. Additional incentive cash and stock opportunities (based on eligibility) may be available. The starting pay rate takes into account characteristics of the job, such as required skills, where the job is performed, the employee’s work schedule, job-related knowledge, and experience. Final, individual compensation will be decided based on demonstrated experience. 
Eligibility for specific benefits listed on our careers site may vary based on the job and location. For more on benefits, please visit https://careers.bms.com/life-at-bms/.
 

Benefit offerings are subject to the terms and conditions of the applicable plans in effect at the time and may require enrollment. Our benefits include:

• Health Coverage: Medical, pharmacy, dental, and vision care.

• Wellbeing Support: Programs such as BMS Well-Being Account, BMS Living Life Better, and Employee Assistance Programs (EAP).

• Financial Well-being and Protection: 401(k) plan, short- and long-term disability, life insurance, accident insurance, supplemental health insurance, business travel protection, personal liability protection, identity theft benefit, legal support, and survivor support.

​Work-life benefits include:

Paid Time Off

• US Exempt Employees: flexible time off (unlimited, with manager approval, 11 paid national holidays (not applicable to employees in Phoenix, AZ, Puerto Rico or Rayzebio employees)

• Phoenix, AZ, Puerto Rico and Rayzebio Exempt, Non-Exempt, Hourly Employees: 160 hours annual paid vacation for new hires with manager approval, 11 national holidays, and 3 optional holidays

Based on eligibility*, additional time off for employees may include unlimited paid sick time, up to 2 paid volunteer days per year, summer hours flexibility, leaves of absence for medical, personal, parental, caregiver, bereavement, and military needs and an annual Global Shutdown between Christmas and New Years Day.

All global employees full and part-time who are actively employed at and paid directly by BMS at the end of the calendar year are eligible to take advantage of the Global Shutdown.

*Eligibility Disclosure: The summer hours program is for United States (U.S.) office-based employees due to the unique nature of their work. Summer hours are generally not available for field sales and manufacturing operations and may also be limited for the capability centers. Employees in remote-by-design or lab-based roles may be eligible for summer hours, depending on the nature of their work, and should discuss eligibility with their manager. Employees covered under a collective bargaining agreement should consult that document to determine if they are eligible. Contractors, leased workers and other service providers are not eligible to participate in the program.

RayzeBio and Bristol Myers Squibb

RayzeBio was acquired by Bristol Myers Squibb (BMS) in 2024 and is a wholly-owned subsidiary of BMS; however, RayzeBio will continue to operate as a standalone organization.

Supporting People with Disabilities

BMS and RayzeBio are dedicated to ensuring that people with disabilities can excel through a transparent recruitment process, reasonable workplace accommodations/adjustments and ongoing support in their roles. Applicants can request a reasonable workplace accommodation/adjustment prior to accepting a job offer. If you require reasonable accommodations/adjustments in completing this application, or in any part of the recruitment process, direct your inquiries to [email protected]. Visit careers.bms.com/eeo-accessibility to access our complete Equal Employment Opportunity statement.

Candidate Rights

BMS and RayzeBio will consider for employment qualified applicants with arrest and conviction records, pursuant to applicable laws in your area.

If you live in or expect to work from Los Angeles County if hired for this position, please visit this page for important additional information: https://careers.bms.com/california-residents/

Data Protection

We will never request payments, financial information, or social security numbers during our application or recruitment process. Learn more about protecting yourself at https://careers.bms.com/fraud-protection/

Any data processed in connection with role applications will be treated in accordance with applicable data privacy policies and regulations.

If you believe that the job posting is missing information required by local law or incorrect in any way, please contact BMS at [email protected]. Please provide the Job Title and Requisition number so we can review. Communications related to your application should not be sent to this email and you will not receive a response.