Director, Nonclinical Development - Toxicology

Company Overview
Rhythm is a global, commercial-stage biopharmaceutical company committed to transforming the lives of patients living with rare neuroendocrine diseases. We develop medicines for previously untreatable or undertreated diseases. We recognize the courage it takes for patients and their caregivers to begin their journey of advocacy to find the answers they need. Their courage inspires us to challenge convention, ask bold questions and seek answers for them. Every day, we strive for excellence through our willingness to adapt, learn, and our tenacity to overcome barriers, together.

Opportunity Overview
We are seeking an experienced Director of Nonclinical Development, Toxicology to provide strategic scientific leadership and hands ‑ on execution of nonclinical safety strategies across our pipeline. This individual will serve as the toxicology subject matter expert and will be accountable for driving integrated, cross ‑ functional nonclinical development strategies and workstreams — leading the design, interpretation, and regulatory positioning of safety assessment programs supporting small molecule and peptide therapeutics from IND ‑ enabling studies through late ‑ stage development and registration.

The Director will lead nonclinical safety strategy across multiple active programs, ensuring that toxicology packages appropriately support clinical development, regulatory submissions, and benefit ‑ risk assessment. Success in this role requires strong scientific judgment, experience navigating complex development challenges, the ability to operate comfortably in a fast ‑ paced environment, and the confidence to contribute an independent scientific perspective in a collaborative and constructive manner. This individual will be an independent self ‑ starter who thrives in a highly collaborative cross ‑ functional team environment.

This is a highly visible role that requires an exceptional scientific communicator. The Director will be expected to distill complex scientific and technical information into clear, actionable messages and to communicate strategic priorities, data interpretation, and risk cross ‑ functionally and to senior leadership with clarity and confidence. This is an individual contributor role with significant cross ‑ functional leadership scope; the Director will lead through influence across program teams rather than through direct reports. This role will contribute to portfolio-level decision making, development prioritization, and governance discussions by providing expert assessment of nonclinical safety risks, mitigation strategies, and overall development readiness across the pipeline.

Responsibilities and Duties
- Own and drive integrated nonclinical safety strategies supporting programs from IND ‑ enabling studies through Phase 2/3 development, NDA submission, and life ‑ cycle management.
- Serve as the Toxicology representative and strategic Nonclinical Development partner on cross ‑ functional program teams, providing scientific leadership in development strategy, risk assessment, and candidate progression decisions.
- Accountable for the planning, prioritization, and delivery of cross ‑ functional Nonclinical Development workstreams, including timelines, budgets, and interdependencies with Clinical, Regulatory, CMC, and other functions.
- Design, oversee, and interpret GLP and non ‑ GLP toxicology studies, including general toxicology, safety pharmacology, genetic toxicology, reproductive and developmental toxicology, juvenile toxicology (as applicable), and carcinogenicity strategy and assessment.
- Design and oversee investigative and mechanistic toxicology studies to characterize safety findings, evaluate biological relevance, and inform development decisions.
- Lead mechanism ‑ based safety assessment and integrate toxicology findings with pharmacology, clinical, biomarker, and translational data to inform development decisions.
- Provide scientific interpretation of toxicology findings within the broader context of mechanism of action, clinical relevance, benefit-risk assessment, and global regulatory expectations.
- Evaluate nonclinical data packages, identify gaps and potential safety risks, and develop mitigation strategies aligned with ICH guidelines, GLP regulations, and evolving global regulatory expectations.
- Provide scientific oversight of external CROs, including protocol development, study conduct, data interpretation, final report review, timelines, and budget management.
- Partner closely with Clinical Development and Clinical Pharmacology to define safety margins, support clinical monitoring strategies, and lead ongoing safety risk management across the portfolio.
- Author, review, and substantially contribute to nonclinical sections of regulatory documents, including INDs, Investigator’s Brochures, DSURs, briefing packages, NDAs, and other marketing applications.
- Represent the toxicology and nonclinical functions in interactions with global health authorities (e.g., FDA, EMA, PMDA), including preparation for agency meetings and responses to regulatory questions.
- Lead regulatory toxicology strategy, including development, positioning, and defense of nonclinical safety assessments supporting global regulatory submissions and agency interactions.
- Communicate complex safety findings and strategic recommendations clearly and persuasively to development teams, governance committees, senior leadership, and other partners.
- Operate effectively in a dynamic, growing environment, demonstrating flexibility and agility, and contribute to the continuous improvement of nonclinical development standards, processes, and ways of working across the organization.

Qualifications and Skills
Required
- PhD, DVM, or equivalent advanced degree in Toxicology, Pharmacology, Veterinary Sciences, or a related scientific discipline.
- 10+ years of industry experience in nonclinical development within pharmaceutical or biotechnology organizations, with significant toxicology leadership responsibility.
- Small molecule drug development experience is required with a proven track record advancing candidates from discovery through IND-enabling and clinical stage development.
- Deep expertise in toxicology, nonclinical safety assessment, safety pharmacology, and translational safety interpretation, supported by strong working knowledge of DMPK principles and exposure-response relationships.
- Demonstrated ability to set and drive nonclinical strategy and to lead cross ‑ functional workstreams through influence, with clear accountability for delivery.
- Proven experience delivering nonclinical safety packages supporting IND ‑ enabling and clinical ‑ stage development programs.
- Extensive experience designing and managing outsourced toxicology studies and working effectively with CRO partners.
- Strong understanding of ICH guidance, GLP regulations, and global nonclinical regulatory requirements.
- Demonstrated authorship or major contribution to key regulatory documents, including INDs and Investigator’s Brochures, and participation in health authority interactions.
- Exceptional written and verbal communication skills, with a demonstrated ability to synthesize complex data and communicate scientific and strategic concepts clearly to cross ‑ functional teams and senior leadership.

Preferred
- Experience supporting nonclinical development for Phase 2/3 clinical programs and beyond, including NDA submissions and post ‑ approval life ‑ cycle activities.
- Experience with peptide therapeutics, conjugated peptides, or novel modalities in addition to small molecules.
- Experience with pediatric/juvenile animal toxicology models and rare disease therapeutic programs
- Exposure to global regulatory submissions or interactions (e.g., EMA, PMDA).
- Prior experience working in an early ‑ stage or startup biotech environment.

This role is based out of our corporate office in Boston, Massachusetts. Rhythm operates in a hybrid-work model. Candidates applying must be willing and able to be in the Boston office in coordination with their department and business needs. This role may involve some travel.

The expected salary range for this position is $182,000 - $275,000. Actual pay will be determined based on experience, level, qualifications, geographic location, and other job-related factors permitted by law. A discretionary annual bonus may be available based on individual and company performance. This role may be eligible for benefits and other compensation such as restricted stock units.

More about Rhythm We are a dynamic and growing global team spanning more than a dozen countries. At Rhythm we are dedicated to transforming the lives of patients living with rare neuroendocrine diseases by rapidly advancing care and precision medicines that address the root cause. Our team is passionate about expanding access to reach more patients and developing novel therapies for other rare neuroendocrine diseases, including congenital hyperinsulinism.

At Rhythm our core values are:
- We are committed to advancing scientific understanding to improve patients’ lives
- We are inspired to tackle tough challenges and have the courage to ask bold questions
- We are eager to learn and adapt
- We believe collaboration and ownership are foundational for our success
- We value the unique contribution each individual brings to furthering our mission

Inherent in our core values is the commitment to act ethically and with integrity in all we do.

Rhythm is an equal employment opportunity employer and does not discriminate against any applicant because of race, creed, color, age, national origin, ancestry, religion, gender, sexual orientation, disability, genetic information, veteran status, military status, application for military service, or any other class protected by state or federal law.

Headquartered in Boston, Rhythm is proud to have been named one of the Top Places to Work (https://www.bostonglobe.com/magazine/top-places-work/2025/) in Massachusetts.