Eisai Inc. Posted August 3, 2026

Principal Researcher, Downstream Process Development - Biologics

Pennsylvania, United States Full time
Manufacturing & CMC Principal

Eisai Inc. is the source of truth for this posting and owns the application process. We surface normalized context and market comparison you won't find on the original listing.

About this opportunity

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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Job details

Seniority
Principal
Function
Manufacturing & CMC
Therapeutic area
Not listed
Location
Pennsylvania, United States
Employment type
Full time

How this role compares

Computed from every other active Manufacturing & CMC role in our database, not just this employer's listings.

We currently track 480 comparable Principal Manufacturing & CMC roles across 62 biopharma companies.

480Comparable roles tracked
443Currently active
62Companies hiring similar roles
26Countries represented

Salary context

218 of 480 peers report a salary range (USD, annualized)

Peers share this role's job function and a matching or adjacent seniority level -- not necessarily the same therapeutic area or country.

This roleSubject Not listed on this posting
Lowest disclosed · Senior Scientist II – CMC Developmental Sciences · AbbVie $0/hr – $0/hr (≈ $0–$0/yr)
Highest disclosed · Director, Global Automation Engineering · AbbVie $182,000/yr – $346,000/yr
Peer group range $0 – $264,000 (median $150,600)

Where these roles are based

Top locations among the 480 comparable roles

United States334
India44
Ireland15
Netherlands12
Switzerland8
Singapore8

+ 20 more countries

Seniority mix

480 of 480 peers have a known seniority level

Senior309
Principal97
Director74

Therapeutic area mix

2 of 480 peers have a known therapeutic area; the rest are genuinely unlabeled, not hidden

Oncology1
Respiratory1

Similar opportunities

The closest matches from our peer group, ranked by how similar they are, not how well you'd qualify for them -- treat this as market context, not a guaranteed shortlist; a weak match is labeled as one below.

60%similar
Lilly Indianapolis, Indiana, United States of America Principal
Same function Same seniority Same country
60%similar
Lilly Louisville, Colorado, United States of America Principal
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60%similar
Lilly Watertown, Massachusetts, United States of America Principal
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60%similar
Lilly Indianapolis, Indiana, United States of America Principal
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60%similar
Lilly Indianapolis, Indiana, United States of America Principal
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60%similar
Lilly Indianapolis, Indiana, United States of America Principal
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Notify me about similar jobs

Get an email when we spot other openings like this one – same job function, comparable seniority, roles you'd actually want to see.

How we calculate "similar"

No black box, no LLM guesswork: a deterministic score built from four normalized attributes. Here's this role's own peer group at different match levels, so you can see the mechanism, not just the result.

Every comparison starts from the same 100-point budget: 25 for working in the same function, 40 for the same therapeutic area, 20 for the same or adjacent seniority, 15 for the same country. A dimension we can't confirm on both sides contributes nothing, never a guess, never a free pass.

60%
Senior/Principal Scientist, Bioprocess Purification Development
Lilly · Indianapolis, Indiana, United States of America · Principal
Function Therapeutic area Seniority Country
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Unmatched or unknown dimensions score exactly the same: 0 points, never a partial guess. A role we know almost nothing about beyond its function bottoms out at 25%; it never inflates to 100% just because there's little to compare against. Seniority uses a defined ladder (Associate → Manager → Associate Director → Senior → Principal → Director → Senior Director → Executive/VP) so "Director" and "Senior Director" count as adjacent, but "Director" and "Executive/VP" do not.