Director, Medical Writing

About Us … Obsidian Therapeutics is pioneering engineered cell and gene therapies to deliver transformative outcomes for patients. Obsidian’s programs apply our cytoDRiVE® technology in Cell and Gene therapy products to control expression of proteins for enhanced therapeutic efficacy and safety. Obsidian’s lead program is currently in clinical development for the treatment of patients with metastatic melanoma and non-small cell lung cancer. We’re proud of our diverse talented team and committed to cultivating an environment of inclusion where each person feels a strong sense of belonging and is supported to continuously learn and contribute their best work. Our Research team is based in the heart of Cambridge, MA, and Technical Operations team is based in our purpose built facility in Bedford, MA. Obsidianites enjoy a highly collaborative culture, competitive salary and benefits, and potential for ownership through stock options. Our Opportunity... We’re looking for a highly motivated Director, Medical Writing with BLA/NDA experience to lead the strategic planning, development, and execution of regulatory and clinical documents supporting the advancement of Obsidian’s clinical development programs. This individual will serve as the company's medical writing leader and subject matter expert, responsible for ensuring the delivery of high-quality, scientifically rigorous, regulatory-compliant documents that effectively communicate the clinical evidence supporting the product. The role combines strategic leadership with hands-on execution and will partner closely with Clinical Science, Regulatory Affairs, Biometrics, Clinical Operations, Clinical Safety, CMC, and external vendors. This is a unique opportunity to establish a phase-appropriate medical writing capability within a clinical-stage biotechnology company preparing for its first product submission. Y ou will be a vital part of a highly collaborative team working to unlock the promise of precision cell therapy for patients, starting with our lead program amsoki-cel (OBX-115), a novel engineered tumor-infiltrating lymphocyte (TIL) cell therapy that uses our proprietary cytoDRiVE® platform. This is a unique opportunity to be a valuable contributor in a well-funded clinical company with field-leading advisors, best-in-class partners, and an experienced team. This is a remote role ; travel to support job duties may be occasionally required. You Will... Core responsibilities • Develop and execute the company's medical writing strategy in support of clinical development, regulatory submissions, and launch readiness. • Partner with Regulatory Affairs to ensure strategic alignment, submission readiness, consistency of messaging, and compliance with applicable regulatory guidance. • Translate complex clinical, statistical, safety, translational, and manufacturing information into clear, scientifically accurate narratives. • Lead the authoring, review, and finalization of major regulatory documents, including: BLA submission documents, Module 2 clinical summaries, Clinical Study Protocols, Investigator Brochures, • Clinical Study Reports (CSRs), Statistical Analysis Plan summaries, Integrated Summaries of Safety (ISS), Integrated Summaries of Efficacy (ISE), responses to health authority questions. • Collaborate with Clinical Development and Biometrics to construct compelling evidence packages. • Serve as the primary medical writing representative on cross-functional program and submission teams; drive alignment on scientific messaging, timelines, and review processes. • Establish document planning, governance, standards, templates, and quality systems. • Ensure consistency across protocols, SAPs, CSRs, safety documents, and regulatory summaries. • Contribute to inspec