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Principal Researcher, Downstream Process Development - Biologics

Eisai
United States, Pennsylvania, Exton
210 Welsh Pool Road (Show on map)
Aug 04, 2026

At Eisai, satisfying unmet medical needs and increasing the benefits healthcare provides to patients, their families, and caregivers is Eisai's human health care (hhc) mission. We're a growing pharmaceutical company that is breaking through in neurology and oncology, with a strong emphasis on research and development. Our history includes the development of many innovative medicines, notably the discovery of the world's most widely-used treatment for Alzheimer's disease. As we continue to expand, we are seeking highly-motivated individuals who want to work in a fast-paced environment and make a difference. If this is your profile, we want to hear from you.

Job Summary

The Principal Researcher of Downstream Development will be responsible for executing laboratory scale experiments for all aspects of protein purification including chromatography, filtration and membrane separations (TFF, UFDF, microfiltration, viral filtration, and depth filtration), investigating and evaluating novel technologies to improve current purification processes, participating in internal/external technology transfers, performing standard analytical methods to characterize biologics and reagents including UV/Vis spectroscopy, HPLC, electrophoresis and ELISA, participate in design, planning and execution of viral clearance studies and planning and execution of process validation experiments in support of late stage products. The individual will also be responsible for maintaining PD equipment and laboratories to ensure efficient, safe and effective operations of the laboratory. The individual might also participate in project sub teams and provide cross-functional support for other departments at the discretion of management.

Essential Functions

  • Under minimal supervision, design and performs laboratory Experiments for early and late-stage biologic drug products, support viral clearance studies, support authoring of regulatory documents, maintain critical data in laboratory notebooks, and maintain PD equipment and laboratories to ensure efficient and effective operations of the laboratory

  • Under minimal supervision perform scale up and tech transfer of purification processes for internal GMP production and to external partners and CMOs.

  • Writing, preparation and review of technical reports, presentations and protocols.

  • Perform characterization assays such as concentration measurements, HPLC SEC, capillary electrophoresis, and ELISA to support purification process development and reagent preparation activities.

  • Order supplies, manage samples, discard expired reagents and perform housekeeping and other laboratory maintenance tasks to assure laboratories are continuously maintained in a safe, orderly and efficient condition.

  • Interact cross-functionally with Upstream Process Development, Operations, Facilities, R&D, Quality Assurance, Quality Control, Validation, QC Biochemistry, and other internal and external functions to support successful product development.

Requirements

  • Education: BS or MS in biological sciences, chemistry, biochemistry or equivalent job experience/degree is strongly preferred.

  • Minimum 5 years' experience with protein purification techniques for biopharmaceuticals

  • Must have CMC protein purification development experience with standard bioprocess unit operations such as chromatography separations (resin/membrane: affinity, CEX, AEX, HIC, MM) and filtration operations (depth filtration, virus filtration, sterile filtration, TFF)Must have extensive experience with AKTA chromatographic instruments and Unicorn method writing (for systems such as AKTA Avant and AKTApilot)

  • Must have excellent attention to detail and ability to keep detailed written records

  • Able to author clear and concise technical reports and presentations

  • Demonstrated ability to independently design, execute, and interpret experimental data to further process/product knowledge

  • Experience in Design of Experiments (DoE) and multivariate analysis preferred

  • Experience with high throughput screening techniques, including Tecan, preferred

  • Knowledge or experience with scale-up, technology transfer, process validation, viral clearance studies, and GMP manufacturing desirable.

  • Experience with analytical techniques such as HPLC, electrophoresis and ELISA desirable.

  • Strong written and oral communication skills and good interpersonal skills.

  • Team player who can excel in fast-paced entrepreneurial environment.

  • Physical requirements: handling of laboratory equipment, chemicals and biological materials.

Eisai Salary Transparency Language:

The annual base salary range for the Principal Researcher, Downstream Process Development - Biologics is from :$80,200-$105,200 Under current guidelines, this position is eligible to participate in : Eisai Inc. Annual Incentive Plan.

Final pay determinations will depend on various factors including but not limited to experience level, education, knowledge, and skills.

Employees are eligible to participate in Company employee benefit programs. For additional information on Company employee benefits programs, visit https://careers.eisai.com/us/en/compensation-and-benefits.

Certain other benefits may be available for this position, please discuss any questions with your recruiter.

Eisai is an equal opportunity employer and as such, is committed in policy and in practice to recruit, hire, train, and promote in all job qualifications without regard to race, color, religion, gender, age, national origin, citizenship status, marital status, sexual orientation, gender identity, disability or veteran status. Similarly, considering the need for reasonable accommodations, Eisai prohibits discrimination against persons because of disability, including disabled veterans.

Eisai Inc. participates in E-Verify. E-Verify is an Internet based system operated by the Department of Homeland Security in partnership with the Social Security Administration that allows participating employers to electronically verify the employment eligibility of all new hires in the United States. Please click on the following link for more information:

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