Principal​/Senior Scientist, PK​/PD Assays

Principal/Senior Scientist, PK/PD Assays

South San Francisco

New Limit is a biotechnology company working to radically extend human healthspan. We're developing medicines to treat age-related diseases by reprogramming the epigenome, a new therapeutic mechanism to restore regenerative potential in aged and diseased cells. We leverage functional genomics, pooled perturbation screening, and machine learning models to unravel the biology of epigenetic aging and disease using experiments of unprecedented scale.

New Limit is seeking a Scientist or Senior Scientist with deep expertise in molecular biology, pharmacokinetics and translational biomarker assay development. In this role, you will lead the design, development, and qualification of pharmacokinetic (PK) and pharmacodynamic (PD) assays that characterize the biodistribution and biological activity of our mRNA-LNP medicines in preclinical and IND enabling studies. You will serve as a technical leader within our bioanalytical function, shaping biomarker assay strategy and partnering cross-functionally to advance our therapeutic programs toward IND-enabling milestones.

• Own the end-to-end design, development, and qualification of PK and PD biomarker assays across various platforms to support preclinical and IND-enabling studies
• Discover and validate pharmacodynamic biomarkers to support the clinical development of drugs across multiple programs
• Drive data analysis, interpretation, and reporting for bioanalytical studies to support program decision-making with audit-ready data packages
• Contribute to sample processing workflows including tissue harvesting, primary cell culture, and complex matrix handling
• Mentor research associates, establish SOPs, and build institutional knowledge within the bioanalytical function

• PhD in molecular biology, biochemistry, cell biology, or a related field or equivalent industry experience (5+ years)
• 3+ years of hands-on experience in various quantitative bioanalytical assay platforms (e.g., RT-qPCR, ddPCR, ELISA, MSD, Olink, SOMAscan, NGS-based methods) in complex biological matrices (serum, plasma, tissue homogenates)
• Strong working knowledge of bioanalytical method qualification/validation principles for PK/PD biomarker measurements, including familiarity with ICH M10 guidelines and fit-for-purpose frameworks
• History of delivering results for bioanalytical projects -- you've discovered a PD biomarker or built an assay and solved all the problems along the way
• Experience with primary cell culture and tissue-derived sample workflows

• Track record of bioanalytical method transfer and CRO management for outsourced projects
• Familiarity with preclinical drug development timelines and regulatory submissions (IND, TGA, CTD format)
• Experience with mRNA-LNP biodistribution or nucleic acid–based PK assays
• Experience developing products in emerging therapeutic modalities (gene therapy, nucleic acid therapies, cell therapy)

New Limit provides generous benefits so our team can remain focused on our mission:

• Comprehensive Health, Dental, and Vision insurance
• 401(k) plan with company match
• Paid parental leave
• Industry-leading PTO: 20 days per year plus holidays
• On-site meals and snacks

Salary Range: $155,000 to $200,000. Compensation for the role will depend on a number of factors, including a candidate's qualifications, skills, competencies, and experience. New Limit offers a competitive benefits package, which includes a 401k, healthcare coverage, and 20 days of PTO.