Role Summary  The Senior Scientist supports development, optimization, and scale-up of AAV manufacturing processes using Sf9/baculovirus and HEK-based systems. This role contributes to early and late-stage CMC activities including process characterization, technology transfer, control strategy development, and regulatory documentation. The level of responsibility, technical leadership, and cross-functional ownership will be commensurate with experience.  PRIMARY RESPONSIBILITIES Design, execute, and lead process development and optimization studies for AAV manufacturing using Sf9 cells/baculovirus and HEK platforms. Perform hands-on laboratory work to execute process development and optimization experiments, generate critical process data, and support technical troubleshooting. Support and, as appropriate, define study designs to drive process optimization, scalability, robustness, and technology transfer for clinical and late-stage programs. Collaborate with and provide technical leadership across upstream, downstream, analytical, manufacturing, and quality teams to evaluate process performance and product quality. Support or own late-stage CMC deliverables, including process characterization, risk assessments, control strategy development, technology transfer, and validation readiness. Author, review, and provide technical input for study protocols, technical reports, and regulatory documentation. Support or lead troubleshooting, investigations, mentoring of junior staff, and continuous process improvement initiatives.  REQUIRED SKILLS AND QUALIFICATIONS Master’s degree in biochemical engineering, bioprocess engineering, molecular biology, cell biology, or relevant life sciences or engineering discipline with a minimum of 6 years of relevant experience, or PhD with at least 3 years of relevant experience. Hands-on experience with upstream AAV production using Sf9 cells/baculovirus and HEK platforms required. Understanding of virus/viral vector properties and experience with development of upstream and downstream processes for viral vectors or gene therapy products are highly desirable. Working knowledge of downstream processing and analytical testing preferred. Experience supporting process optimization, characterization, and late-stage CMC activities preferred. Demonstrated leadership in process development, cross-functional collaboration, and late-stage CMC readiness is expected. Experience authoring and reviewing regulatory documentation preferred.  About LEXEO   Lexeo Therapeutics is a clinical-stage genetic medicine company headquartered in New York City, pioneering cardiac genetic medicine candidates to treat the root causes of inherited cardiovascular diseases. Our lead program, LX2006, targets cardiomyopathy associated with Friedreich’s Ataxia and anchors a broader pipeline addressing genetically defined conditions such as hypertrophic and arrhythmogenic cardiomyopathies. Backed by a strong financial foundation, Lexeo is positioned to translate groundbreaking science into durable clinical impact.    Our work culture is a hybrid model with 2 days in the New York City office and 3 days working from home.    LEXEO Therapeutics is an EEO employer committed to an exciting, diverse, and enriching work environment.