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Sr. Scientist, Potency Assays

4D Molecular Therapeutics

4D Molecular Therapeutics

Emeryville, CA, USA
Posted on Wednesday, July 19, 2023

At 4D Molecular Therapeutics, Inc. (“4DMT”), we boldly innovate to unlock the full potential of genetic medicines for countless patients. We are committed to breaking boundaries and daring to cure as we develop new and foundational products and product components through our growing technology platforms.

4DMT is a clinical-stage biotherapeutics company harnessing the power of directed evolution for targeted genetic medicines. We seek to unlock the full potential of gene therapy using our platform, Therapeutic Vector Evolution (TVE), which combines the power of directed evolution with our approximately one billion synthetic AAV capsid-derived sequences to invent evolved vectors for use in our products. We believe key features of our targeted and evolved vectors will help us create targeted product candidates with improved therapeutic profiles. These profiles will allow us to treat a broad range of large market diseases, unlike most current genetic medicines that generally focus on rare or small market diseases.

We have built a deep portfolio of AVV-based gene therapy product candidates, with five product candidates in clinical trials: 4D-150 for the treatment of wet age-related macular degeneration (wet AMD) and diabetic macular edema (DME), 4D-710 for the treatment of cystic fibrosis lung disease, 4D-310 for the treatment of Fabry disease cardiomyopathy, 4D-125 for the treatment of X-linked retinitis pigmentosa (XLRP), and 4D-110 for the treatment of choroideremia. In addition, we have two product candidates in preclinical studies: 4D-175 for geographic atrophy (GA) and 4D-725 for alpha-1 antitrypsin deficiency.

To-date, we have demonstrated clinical proof-of-concept for three evolved vectors in three therapeutic areas and routes of administration with five products and patient populations. We believe this validates the power of our directed evolution platform for discovering superior vectors compared to wildtype viral vectors. We have built a robust and efficient product engine with 6 open Investigational New Drug Applications (INDs) in the U.S., 1 IND in Taiwan, and 1 Clinical Trial Approval (CTA) in Australia. We believe we are positioned to create, develop, manufacture and, if approved, effectively commercialize targeted genetic medicines that could transform the lives of patients suffering from debilitating diseases.

In addition to TVE, our technology includes a robust AAV manufacturing platform and onsite manufacturing facility that allows us to rapidly produce and test research grade material and scale up to GMP clinical material. This internal capability and close collaboration between our R&D and Manufacturing teams has greatly accelerated the pace of discovery at 4DMT.

Company Differentiators:

• Fully integrated clinical-phase company with internal manufacturing
• Demonstrated ability to move rapidly from idea to IND
• Five candidate products in the clinic and two declared pre-clinical programs
• Robust technology and IP foundation, including our TVE and manufacturing platforms
• Initial product safety and efficacy data substantiates the value of our platforms
• Opportunities to expand to other indications and modalities within genetic medicine


The position of Sr Scientist, Potency Assays, will join our cell-based assay group, overseeing the development, optimization and qualification of cell-based assays and execute experiments for the lot release, characterization, stability and formulation assessment of AAV-based gene therapy drug substance and drug products. The successful candidate must have hands-on experience with mammalian cell culture, virus transduction and phase-appropriate method development, optimization, qualification and tech transfer of cell-based potency assays for complex biologics. He/She will be responsible for driving assay design, planning, execution and data analysis/presentation of complex projects under QC settings. This is a CMC and not R&D position.


  • Work with the Cell-based assay team on the optimization, qualification/validation, and execution of phase-appropriate potency assays/lot release assays and broad spectrum of cell-based characterization assays (including immunoassays, nucleic acid-based assays, enzymatic assays, imaging-based assays, among others).
  • Scientific leader who can independently design, execute, and guide effective experiments with clear goals in a very fast paced environment. Interprets and tracks data and effectively communicates information or risk mitigation strategies that drive critical decisions in CMC department.
  • Authors technical reports, SOPs and relevant sections of regulatory filings and responses.
  • Supervises and provides technical expertise to Research Associates and/or junior Scientists in assay qualification, troubleshooting, as well as routine testing efforts
  • Serves as a scientific liaison for outsourced assay development, technology transfer and data management in a CRO or CMO/CDMO environment.
  • Expected to be informed on matters of state-of-the-art or innovative technologies that advance AAV characterization and integrate within the department.



  • PhD or MA in a relevant area of specialization (biological sciences, cell biology, molecular biology, virology), or equivalent in years of biotech experience


  • 7+ years of industry within the Biotech or similar industry, within QC or Analytical Development groups
  • Demonstrated experience with potency assay development and qualification (under ICH/FDA guidelines) for biologics or gene therapy products is required.
    • Must have thorough understanding of cell biology required for development of robust cell-based assays.
  • Thorough understanding of developing phase-appropriate potency assays and data analysis.
  • Sound scientific understanding of Quality by Design (QbD) and Design of Experiments (DoE) principles, knowledge of basic statistics and experience of QC-compliance practices and documentation is highly desired.
  • Knowledge of relative potency calculation using parallel line, slope ratio, 4PL analyses etc. and experience of softwares such as JMP, SoftMax Pro will be a plus.
  • Demonstrated track record of developing different spectrum of bioassays by utilizing appropriate methodologies (i.e cell imaging systems, flow cytometry, qPCR, ddPCR etc)
  • Experience in writing SOPs, developmental and technical reports, contributions to regulatory submission documents to support CMC efforts.


  • Strong verbal and written communication skills and effective interpersonal, technical discretion and troubleshooting skills are essential.
  • Must be a team player, strong critical thinker, exhibit a willingness to meet project timelines and multitask effectively in a dynamic fast-paced environment under challenging timelines
  • Demonstrated history of working independently and leading teams while managing multiple projects
  • Strong attention to detail supported by excellent time management and organizational skills

Bay Area Range - $150,000.00 - $186,000.00

Please note, the base salary compensation range and actual salary offered to the final candidate depends on various factors: candidate’s geographical location, relevant work experience, skills, and years of experience.

4DMT provides equal employment opportunities to all employees and applicants for employment without regard to race, color, religion, gender, sexual orientation, national origin, age, disability, genetic information, marital status, status as a covered veteran, and any other category protected under applicable federal, state, provincial and local laws.
Equal Opportunity Employer/Protected Veterans/Individuals with Disabilities