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Lead/Principal Scientist CMC Potency & Assay

Ambrx, Inc.
La Jolla, CA
$143,000- $171,000
Start date
Dec 1, 2023

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Science/R&D, Biotechnology, CMC
Required Education
Masters Degree/MBA
Position Type
Full time
Biotech Beach

Job Details

What We Do:

Ambrx Biopharma, Inc. is a clinical-stage biologics company focused on discovering and developing a novel class of specific and selective engineered precision biologics, using our proprietary platform technology that allows site-specific incorporation of synthetic amino acids (SAAs) into proteins within living cells. Our product candidates are designed to overcome the inherent limitations of conventional conjugation approaches that use non-site-specific conjugation, in order to optimize for safety and efficacy benefits across multiple therapeutic classes in broad therapeutic areas.


How will you contribute to our mission:
Ambrx is seeking a highly motivated, senior bioassay scientist to be a key member of the Translational Sciences (TS) team. The successful candidate will be primarily responsible for developing ELISA and cell-based assays for use as CMC potency assays, qualifying/validating potency assays at GMP CROs, and working with the broader CMC team to meet project deliverables.  

  • Develop plate-based and cell-based potency methods for use in GMP testing and set stage-appropriate systems suitability and acceptance criteria.
  • Manage CRO/CMOs to transfer and qualify/validate potency methods within aggressive timelines, ensure GMP batch release and stability samples are tested within specified time frames, maintain critical reagents, and quickly resolve any deviations or investigations.
  • Track potency methods performance and identify key parameters for improvement; trend intermediate, drug substance, and drug product stability data; and estimate shelf-life or re-evaluation periods.
  • Work with CMC team members to draft/review study protocols, change control documents, and specifications.  Help set strategy for reference standard life cycle management and comparability studies.
  • Attend weekly evening meetings (approx. 1 hour) with international CMO/CRO.
  • Author development reports, memos, and relevant CMC sections for regulatory submissions.
  • Interview GMP CROs, negotiate quotes, and perform on-site audits of CROs to evaluate technical capabilities.
  • Represent bioassay function and effectively communicate progress or issues at CMC sub-team meetings.
  • Perform non-GMP potency assays to support programs, as needed.
  • Supervise junior scientists on the TS team.

What you will need for consideration:

  • PhD with 7-10+ years experience (or MS with 12-15+ years experience) in the CMC potency assay field
  • Hands-on experience developing and optimizing CMC potency assays for method qualification or method validation at GMP CROs
  • Demonstrated capability to quickly troubleshoot issues and identify solutions.
  • Familiarity with PLA 3.0 software to perform equivalence testing.
  • Previous experience using JMP for Design of Experiments to identify and optimize critical assay parameters, estimating shelf-life, determining method capability, and running statistical analyses.
  • Successful track record of qualifying and validating CMC potency assays at GMP CROs and actively managing CROs to meet timelines and stay within budget.
  • Deep knowledge of relevant ICH and USP chapters and industry best practices.
  • Prior experience working with ADCs, bispecific molecules, and/or PEGylated proteins.
  • Written CMC sections of regulatory filings (IND, annual reports, CMC amendments, etc.)
  • Previous supervisory experience.
  • Ability to work collaboratively in a goal-oriented, fast-paced, matrixed team environment. 
  • Attention-to-detail, organizational skills, and strong written and oral communication skills are required. 
  • Flexibility to contribute to other functional areas is desirable.

Pay Scale:

The pay scale for this position is: $143,000- $171,000  commensurate with experience. We believe this to be possible compensation for this role at the time of this posting, and we may modify this pay scale in the future.

As an equal opportunity employer, Ambrx is committed to a diverse workforce. Ambrx will consider all qualified applicants without regard to race, color, religion, national origin, gender, age, sexual orientation, physical or mental disability, genetic information or characteristic, gender identity and expression, veteran status, or other non-job related characteristics or other prohibited grounds specified in applicable federal, state and local laws.


Ambrx®, Inc. is a biopharmaceutical company with a mission to deliver breakthrough protein therapeutics using an expanded genetic code. Unlike conventional conjugation techniques that create a mixture of suboptimal molecules, Ambrx technology combines site specific conjugation with proprietary linkers, payloads and pharmacokinetic extenders to create a single molecular species that is optimized for safety, efficacy and biophysical properties. We call this process Protein Medicinal Chemistry™.

Protein Medicinal Chemistry™ can optimize any protein or antibody to create potentially best-in-class therapeutics such as long-acting proteins, bi-specifics and antibody drug conjugates. The Ambrx advantage allows us to safely and effectively target cytotoxic agents or recruit effector function to tumor cells (oncology) or modulate biological pathways implicated in disease areas such as autoimmune, metabolic and cardiovascular.

At Ambrx, we are dedicated to assembling and developing an exceptional team and a novel technology to create the next generation of protein-based medicines.

Company info
10975 North Torrey Pines Road
La Jolla
United States

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