Assistant Director​/Associate Director, Toxicology

Job Category
:
Development - Ionis

Requisition Number
: IONIS
004030

• Posted :
  September 2, 2026
• Full-Time

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Headquartered in Carlsbad, California, and with offices in Boston, Massachusetts, and Dublin, Ireland, Ionis has been at work for more than three decades discovering medical breakthroughs that have redefined life for people with serious diseases. We’re pioneers in RNA-targeted medicines, and our platform continues to revolutionize drug discovery and transform lives for patients with unmet needs. With multiple marketed medicines and a leading pipeline in neurology, cardiology and select areas of high patient needs, we continue to drive innovation in RNA therapies in addition to advancing new approaches in gene editing to provide greater value to patients and are well positioned financially to deliver on our strategic goals.

At Ionis, we pride ourselves on cultivating a challenging, motivating and rewarding environment that fosters innovation and scientific excellence. We know that our success is a direct result of the exceptional talents and dedication of our employees.

With an unprecedented opportunity to change the course of human health, we look to add diverse individuals, skill sets and perspectives to our exceptional team. We continue to invest time, money and energy into making our onsite, hybrid and remote work environments a place where solid and lasting relationships are built and where our culture and employees can thrive.

We’re building on our rich history, and we believe our greatest achievements are ahead of us. If you’re passionate about the opportunity to have meaningful impact on patients in need, we invite you to apply and join us. Experience and contribute to our unique culture while you develop and expand your career!

ASSISTANT DIRECTOR/ ASSOCIATE DIRECTOR, TOXICOLOGY

SUMMARY:

Ionis is seeking a talented and highly motivated Toxicologist to join the Preclinical Development Department and provide scientific leadership in the nonclinical safety assessment of drug candidates. The department is composed of highly collaborative scientists and offers a supportive environment that fosters professional growth and continuous learning. The expectation will be for this person to work on site in Carlsbad, CA.

RESPONSIBILITIES:

• Serve as the nonclinical safety representative on cross-functional project teams, providing strategic toxicology input to support candidate selection, risk assessment, and program advancement
• Design, oversee, and interpret non-GLP and GLP nonclinical pharmacology and toxicology studies
• Manage outsourced toxicology studies at CROs, including study design, protocol and report review, issue resolution, and timeline management
• Drive integrated nonclinical safety assessments by synthesizing pharmacology, toxicology, clinical pathology, and TK/PK data
• Develop nonclinical toxicology and regulatory strategies for assigned programs
• Author and review nonclinical sections of regulatory documents, including Investigator's Brochures, INDs, NDAs, DSURs, and related submissions, and represent Ionis in interactions with regulatory authorities
• Assess mechanisms of toxicity to determine human relevance and development impact
• Communicate key nonclinical safety findings, risk assessments, and development implications to project teams and governance committees
• Represent Ionis externally through scientific meetings, industry consortia, working groups, and professional societies
• Contribute to scientific publications in high-impact, peer-reviewed journals

REQUIREMENTS:

• Master’s or Doctoral degree in Toxicology or a related life sciences discipline
• At least 6 years (Master’s degree) or 3 years (Ph.D.) of experience in nonclinical safety within the pharmaceutical…