Senior Director, Pharmacology and Toxicology

Flagship Pioneering•Cambridge, MA

15d•$213,000 - $280,500

About The Position

We are seeking a highly experienced nonclinical toxicologist with deep expertise in lipid nanoparticles (LNPs) and nucleic acid therapeutics. The successful candidate will be responsible for leading and executing nonclinical safety strategies across discovery and development programs, and work in a dynamic and fast-paced entrepreneurial environment as part of a highly collaborative team. Serve as the nonclinical safety lead for lipid nanoparticle (LNP) and nucleic acid–based therapeutic programs from discovery through IND-enabling and early clinical development Design, execute, interpret, and report non-GLP and GLP toxicology and safety pharmacology studies, including but not limited to repeat-dose toxicity, local tolerance, immunotoxicity, cytokine release, complement activation, histopathology, and biodistribution Oversee, design and direct toxicology, bioanalytical, and biodistribution studies at CROs; conduct site visits for NHP studies and ensuring timely completion of end points and study reports Act as the primary nonclinical safety representative on cross-functional teams, providing clear scientific judgment to guide program decisions balancing speed, scientific rigor, and regulatory expectations in a startup environment Anticipate, assess, and mitigate modality- and platform-specific safety risks related to LNP delivery of nucleic acid cargoes Partner with internal and external study leads to ensure studies are executed with high quality, appropriate timelines, and regulatory compliance Review and approve study protocols, amendments, and final reports; ensure submission-ready documentation. Lead authorship of nonclinical sections for regulatory documents Integrate nonclinical safety data with PK/PD, biodistribution, and translational findings to support dose selection and clinical starting dose rationale Represent the company in interactions with regulatory agencies including FDA and EMA Clearly communicate safety risks, uncertainties, and mitigation strategies to project teams and senior leadership Prepare and deliver concise written and verbal summaries to support go/no-go and investment decisions Mentor and manage junior pharmacology and bioanalytical scientists and establish platform level safety principles and best practices for non-viral nucleic acid therapeutics Operate effectively in a fast-paced, resource-constrained, and highly collaborative startup environment

Requirements

Ph.D. in pharmacology, toxicology, DVM or a related field with at least 10 years of industry experience
Deep expertise in non-viral delivery platforms including LNPs, nucleic acid therapeutics, with strong knowledge of immunogenicity and biodistribution
Direct experience supporting FDA regulatory submissions and agency meetings
Strong written and verbal communication skills with the ability to influence cross-functionally
Proven track record of project management and mentorship skills

Responsibilities

Serve as the nonclinical safety lead for lipid nanoparticle (LNP) and nucleic acid–based therapeutic programs from discovery through IND-enabling and early clinical development
Design, execute, interpret, and report non-GLP and GLP toxicology and safety pharmacology studies, including but not limited to repeat-dose toxicity, local tolerance, immunotoxicity, cytokine release, complement activation, histopathology, and biodistribution
Oversee, design and direct toxicology, bioanalytical, and biodistribution studies at CROs; conduct site visits for NHP studies and ensuring timely completion of end points and study reports
Act as the primary nonclinical safety representative on cross-functional teams, providing clear scientific judgment to guide program decisions balancing speed, scientific rigor, and regulatory expectations in a startup environment
Anticipate, assess, and mitigate modality- and platform-specific safety risks related to LNP delivery of nucleic acid cargoes
Partner with internal and external study leads to ensure studies are executed with high quality, appropriate timelines, and regulatory compliance
Review and approve study protocols, amendments, and final reports; ensure submission-ready documentation. Lead authorship of nonclinical sections for regulatory documents
Integrate nonclinical safety data with PK/PD, biodistribution, and translational findings to support dose selection and clinical starting dose rationale
Represent the company in interactions with regulatory agencies including FDA and EMA
Clearly communicate safety risks, uncertainties, and mitigation strategies to project teams and senior leadership
Prepare and deliver concise written and verbal summaries to support go/no-go and investment decisions
Mentor and manage junior pharmacology and bioanalytical scientists and establish platform level safety principles and best practices for non-viral nucleic acid therapeutics
Operate effectively in a fast-paced, resource-constrained, and highly collaborative startup environment