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 p