Principal Scientist, Biologics Process Development

Overview

Profoundly Improve People’s lives by Revolutionizing the Delivery of RNA Therapeutics
Avidity Biosciences is committed to delivering a new class of RNA therapeutics using Antibody Oligonucleotide Conjugates (AOCs). We are focused on advancing therapies for diseases previously unreachable with existing RNA approaches. Our culture is integrated, collaborative, agile, and patient-focused. For more information about our AOC platform and pipeline, visit  and engage with us on Linked In and X.

We are seeking a highly motivated and experienced downstream process development leader to support late-stage biologics programs through licensure and lifecycle management. This role will serve as the technical lead for downstream process development activities across clinical and commercial programs and will be accountable for process design, optimization, characterization, validation readiness, and regulatory authorship. This is a primarily hands-on role (approximately 70% technical execution / 30% strategic leadership) supporting monoclonal antibodies, antibody-related variants, and antibody-oligonucleotide conjugates.

The successful candidate will operate as a key CMC contributor for BLA-stage programs and will play a central role in regulatory filings and health authority interactions. This position is structured as a flexible-level hire at either the Principal Scientist or Associate Director level, depending on experience.

Technical Leadership & Execution

• Serve as the technical lead for downstream process development from late clinical stage through commercialization.
• Design, optimize, and characterize purification processes including Protein A capture, polishing chromatography, viral clearance, filtration, and UF/DF.
• Lead process characterization studies to identify and justify critical process parameters (CPPs), support control strategy development, and enable process performance qualification (PPQ).
• Drive process robustness, scalability, and lifecycle management strategies consistent with commercial manufacturing requirements.
• Troubleshoot purification performance issues across development, scale-up, and commercial manufacturing.
• Provide technical oversight for scale-up and technology transfer activities to manufacturing sites.
• Review and approve development protocols, reports, and technical documentation.
• Interpret process development data to support regulatory filings and internal decision-making.

Regulatory & CMC

• Author and own downstream process development sections of regulatory submissions (e.g., IND, BLA Module
  3), including process description, control strategy, and process characterization summaries.
• Support responses to regulatory questions and participate in health authority interactions as subject matter expert.
• Ensure process development documentation supports comparability, validation, and commercial readiness.
• Contribute to control strategy development and regulatory justification of CPPs and IPCs.

Cross-Functional Collaboration

• Partner closely with Upstream Development, Analytical Development, Manufacturing, Quality, Regulatory, and Supply Chain.
• Contribute to integrated CMC strategy and program risk assessments.
• Support internal and external manufacturing campaigns through data review and real-time problem solving.
• Provide mentorship and technical guidance to junior scientists.
• Strategic Contribution (30%)
• Contribute to downstream platform evolution and technical innovation.
• Support long-term process optimization and lifecycle management planning.
• Help build internal technical capabilities aligned with commercial strategy.
• May assume people leadership responsibilities as the organization grows.

Education

• Ph.D. in Chemical Engineering, Biochemical Engineering, Bioengineering, or related field with 5+ years of relevant experience OR
• M.S. with 8+ years of experience OR
• B.S. with 12+ years of experience

Level will be commensurate with experience and demonstrated leadership.

Required Experience

• Extensive experience in downstream process development for monoclonal antibodies or related biologics, including chromatography-based purification and…