Senior MSL - West

Definium Therapeutics; San Diego (CA); On-site; USD 226,000 - 255,000; Full time

Benefits offered by this job

Health benefits

401(k) match

Flexible time off

Parental leave

Job summary

Definium Therapeutics is seeking a Senior Medical Science Liaison (MSL) to serve as a field-based scientific and clinical expert for our psychiatry portfolio. You will build strong relationships with KOLs, healthcare providers, and policy influencers while communicating scientific data and clinical insights to align research with real-world practice needs.

The ideal candidate will have a deep understanding of psychiatric disorders, a passion for science-driven conversations, and the ability to

Qualifications

• Advanced scientific degree required (PharmD, PhD, MD, or equivalent).
• Minimum of 5+ years of MSL or related medical affairs experience, psychiatry/CNS experience required.
• Experience engaging with policy, government affairs, or advocacy stakeholders in healthcare preferred.
• Deep understanding of psychiatric disease states and U.S. healthcare landscape.
• Strong presentation, communication, and interpersonal skills.
• Willingness to travel up to 60%.

Responsibilities

• Identify and maintain trusted relationships with KOLs, clinical investigators, and stakeholders in academic and clinical psychiatry.
• Serve as the primary medical resource in the field, delivering accurate scientific information about programs.
• Support scientific education at national/regional psychiatry conferences and advisory boards.
• Gather and communicate field insights to inform strategy and decision-making.
• Provide clinical and scientific input to cross-functional teams (R&D, Clinical Development, Commercial).
• Respond to unsolicited medical information requests from healthcare professionals.
• Monitor and report on competitor landscape.
• Support trial site identification and enrollment initiatives.
• Support IIT and Phase IV trial activities as needed.
• Ensure interactions comply with company policies and regulatory guidelines.

Skills

MSL experience

Excellent communication

Presentation skills

Cross-functional collaboration

Scientific writing

Travel up to 60%

Education

PharmD/PhD/MD or equivalent

Tools

CRM systems

Job description

Definium Therapeutics is a late-stage clinical biopharmaceutical company and our mission is to forge a new era of psychiatry by applying scientific rigor to psychedelics, with the goal of developing accessible treatments that unlock healing at scale.

Our lead product candidate, lysergide tartrate (our proprietary orally disintegrating tablet form of lysergide (LSD) D-tartrate), represents a highly differentiated, potential best-in-class opportunity for patients suffering from generalized anxiety, major depressive disorder, and posttraumatic stress disorder.

Our early stage pipeline includes DT402, the R-enantiomer of MDMA and is under development to target the core symptoms of autism spectrum disorder (ASD), specifically addressing social communication challenges.

Guided by the recognition that patients deserve more than better, Definium is relentlessly advancing a new generation of therapeutics intended to address the underlying causes of psychiatric and neurological disorders. By turning evidence into impact, Definium aims to change the trajectory of today's mental health care crisis and enable a healthier future.

Headquartered in New York, Definium Therapeutics trades on Nasdaq under the symbol DFTX.

Together we are moving psychiatry forward—beyond better, into a boundless future. Join us!

The Senior Medical Science Liaison (MSL) will serve as a field-based scientific and clinical expert for our psychiatry portfolio, building and maintaining strong relationships with Key Opinion Leaders (KOLs), healthcare providers, policy influencers, and other stakeholders. This role will focus on engaging the medical community to communicate scientific data, provide clinical insights, and ensure that our research and development efforts align with real-world practice needs. Additionally, this role will also help shape internal resources, training, and capabilities for the broader Field Medical Function The ideal candidate will have a deep understanding of psychiatric disorders, a passion for science-driven conversations, and the ability to operate effectively in a small, fast-growing biotech environment.

Responsibilities

Medical Affairs & Scientific Engagement

• Identify, develop and maintain trusted relationships with KOLs, clinical investigators, and key stakeholders across academic and clinical psychiatry
• Serve as the primary medical resource in the field, delivering accurate and balanced scientific information about our programs to facilitate high-quality scientific exchange
• Support scientific education at national and regional psychiatry conferences, advisory boards, and educational events
• Gather and communicate field insights to internal stakeholders to inform strategy and decision-making
• Provide clinical and scientific input to cross‑functional teams, including R&D, Clinical Development, and Commercial
• Respond to unsolicited requests for medical information from healthcare professionals
• Monitor and report on competitor landscape
• Support clinical teams as needed with clinical trial site identification enrollment initiatives
• Support investigator-initiated trial (IIT) and Phase IV trial activities as needed
• Ensure all interactions are conducted in accordance with company policies, regulatory guidelines, and compliance requirements

Government Affairs, Advocacy and HEOR

• Serve as point person as needed with Government Affairs and HEOR to provide scientific and clinical expertise in policy discussions, public comment submissions, and stakeholder briefings
• Support Government Affairs and Patient Advocacy in identifying and maintaining relationships with relevant government agencies, policymakers, and advocacy groups in mental health and psychiatry
• Oversee creation of specific slide decks and training materials for state and federal government policymakers
• Collaborate with internal teams to develop educational materials for HEOR and advocacy organizations
• As requested, represent the company at government affairs forums, mental health advocacy events, and policy-related conferences

Medical Affairs Infrastructure & Capability Building

• Partner with leadership to develop core training programs for future MSL onboarding, disease state fluency, and scientific platform mastery
• Contribute to the design of field materials, medical decks, and engagement resources (e.g., CRM design)
• Assist in establishing best practices for field insights capture, CRM documentation, and KOL engagement

Qualifications

• Advanced scientific degree (PharmD, PhD, MD, or equivalent) strongly preferred
• Minimum of 5+ years of MSL or related medical affairs experience; psychiatry/CNS experience required
• Record of successfully supporting pre-launch through launch staged companies with an entrepreneurial mindset
• Experience engaging with policy, government affairs, or advocacy stakeholders in the healthcare sector strongly preferred
• Deep understanding of psychiatric disease states, treatment paradigms, and the U.S. healthcare landscape
• Strong presentation, communication, and interpersonal skills
• Ability to interpret and present complex scientific data in a clear and concise manner
• Familiarity with CRM systems, insight tools, and compliant field operations
• Comfortable working in a high-growth, fast-paced biotech environment with cross‑functional collaboration
• Willingness to travel up to 60% as needed

The starting base pay range for this position is $225,560.00 - $255,000.00. Compensation will be determined based on several factors including, but not limited to, skill set, years of experience, and the employee's geographic location.

Employees in this role may be entitled to additional compensation, including bonus and equity. Benefits information is listed on our Jobs Page. The Company provides competitive benefits to employees including:

• 100% paid health benefits including Medical, Dental and Vision for you and your dependents
• 401(k) program with company match and vesting after the turn of the first month after your start date
• Flexible time off
• Generous parental leave and some fun fringe perks!

The starting base pay range for this position is $225,560.00 - $255,000.00. Compensation will be determined based on several factors including, but not limited to, skill set, years of experience, and the employee's geographic location.

Employees in this role may be entitled to additional compensation, including bonus and equity. Benefits information is listed on our Jobs Page. The Company provides competitive benefits to employees including:

• 100% paid health benefits including Medical, Dental and Vision for you and your dependents
• 401(k) program with company match and vesting after the turn of the first month after your start date
• Flexible time off
• Generous parental leave and some fun fringe perks!