Senior Director, Pharmacology and Toxicology

Company Summary: FL87, Inc. is a privately held, early-stage biotechnology company developing a novel approach to gene therapy that can address currently untreatable diseases. FL87, Inc was founded by Flagship Pioneering, an innovation enterprise that conceives, creates, resources, and grows first-in-category life sciences companies. Flagship Pioneering has created over 100 groundbreaking companies over the past twenty years, all of which are pioneering novel and proprietary biological, industrial, and engineering approaches to solve major needs in human health and sustainability. These companies include Moderna (MRNA), Syros Pharmaceuticals (SYRS), Seres Therapeutics (NASDAQ:MCRB), Generate Biomedicines, Tessera Tx, Evelo Biosciences (EVLO), and Indigo Agriculture. Position Summary: 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 Qualifications: 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 We are an equal opportunity employer . All qualified applicants will be considered for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, protected veteran status, or any other char ... (truncated, view full listing at source)