Atrium is a biopharmaceutical company pioneering delivery of RNA therapeutics to the heart to transform the standard of care for people living with cardiomyopathies. Our proprietary technology leverages the targeted RNA delivery platform initially designed at Avidity, which combines the tissue selectivity of mAbs and other targeted delivery ligands with the precision of oligonucleotides. This unique combination is designed to allow selective targeting of the underlying genetic drivers of disease that were previously undruggable. Through targeted, non-viral delivery of siRNA to cardiac tissues, our approach has the potential to overcome key limitations of nonspecific viral and nanoparticle-based delivery systems, including challenges related to tissue specificity, immunogenicity, and redosing. Position Overview: Atrium is seeking a pragmatic, business-oriented attorney to serve as our Head of Legal. This role will partner closely with the leadership team and across functions to support day-to-day operations, enable strategic decision-making, and manage legal risk across the organization. We are looking for someone who is intellectually curious, highly collaborative, and comfortable operating in a hands-on environment. You must be diligent and proactive, show excellent business judgment and strategic thinking, along with the ability to work independently and collaboratively in a collegial, fast-paced team environment. This position requires an attorney to be responsible for a broad array of matters, including partnering with internal and external stakeholders to ensure the Company’s compliance with U.S. securities laws, prepare and coordinate Board of Directors and committee matters, and providing timely and efficient legal advice across the Company. Experience in the biopharmaceutical industry is necessary. The ideal candidate thrives in a resource-conscious environment, enjoys building from the ground up, and is excited to develop scalable legal processes while staying closely connected to the business. This role reports to the Chief Financial Officer. Responsibilities: Business Partnership & Legal Guidance - Serve as a trusted advisor to leadership and cross-functional teams (Finance, Clinical, Regulatory, Operations, HR) - Provide practical, risk-balanced legal advice to support business decisions and company priorities - Translate complex legal issues into clear, actionable guidance - Apply commercially realistic judgment to balance legal risk, compliance, and operational goals Corporate, Securities & Governance - Support public company obligations, including drafting/reviewing SEC filings (periodic reports, current reports, proxy statements, Section 16 filings) in coordination with internal teams and external counsel - Advise on securities law matters, including fundraising activities - Lead preparation and coordination of Board of Directors and committee materials - Manage annual proxy statement process and stockholder meeting logistics - Provide guidance on disclosure matters (investor presentations, press releases, and internal/external communications) - Support corporate governance, including development of policies and employee training - Coordinate equity and stock administration matters in partnership with Finance and HR Contracts & Transactions - Own and scale the Company’s contracting function, including templates, workflows, and processes - Draft, review, and negotiate a broad range of agreements (e.g., CRO, vendor, licensing, collaboration, consulting) - Partner with Finance and Procurement to streamline contract intake, tracking, and execution - Provide legal support across company transactions and operational initiatives Risk Management & Compliance - Identify, assess, and proactively mitigate legal and operational risks - Develop, implement, and maintain company policies and compliance programs - Stay current on applicable laws, regulations, and industry developments; update policies accordingly - Provide risk mitigation counseling across all areas of the business External Counsel Management - Serve as the primary interface with outside counsel across corporate, securities, IP, employment, and regulatory matters - Determine when to handle matters internally versus engage external expertise - Manage scope, quality, timelines, and cost of external legal support Operational Enablement - Build and refine legal processes appropriate for a growing biotech company - Enable efficient execution of business priorities through practical, solutions-oriented support - Collaborate cross-functionally to support corporate activities and strategic initiatives - Contribute to a low-ego, highly collaborative culture Education & Experience Requirements: - Juris Doctor (JD) from an accredited law school; active bar membership - Licensed attorney with 10+ years of experience in a leading law firm and/or in-house biotechnology/pharmaceutical industry - Experience supporting a public or late-stage private life sciences company is a plus - Strong generalist mindset with the ability to operate across multiple legal domains - Demonstrated ability to provide practical, business-oriented legal advice - Experience managing outside counsel effectively - Ability to work independently in a lean, fast-paced environment and manage multiple priorities - Demonstrated leadership qualities including experience coordinating with cross-functional teams, as well as providing sound business and legal judgment, and strategic and analytical thinking - Experience working with all levels of management and key business stakeholders with a demonstrated ability to effectively communicate legal risks to executive leadership and senior management - Excellent organizational skills and able to work with a team to meet critical deadlines; flexible and capable of managing multiple projects simultaneously What we Provide: - The base salary range for this role is $327,000-$362,000. The final compensation will be commensurate with such factors as relevant experience, skillset, internal equity and market factors. - Atrium offers competitive compensation and benefits which include stock options, as well as a 401(k) with an employer match. In addition, the comprehensive wellness program includes coverage for medical, dental, vision, and LTD, and unlimited of time off including spring, summer & winter breaks - A commitment to learning and development which includes a variety of programming internally developed by and for Atrium employees, opportunities for job-specific training offered by industry, and an education reimbursement program. $327,000 - $362,000 a year

• Draft, review, and negotiate a narrow range of time sensitive franchise amendments and assist with a wide range of commercial contracts, including supply agreements, service contracts, and confidentiality agreements • Oversee and manage legal projects from inception to completion, ensuring timely delivery and adherence to project goals • Coordinate with internal and external stakeholders to facilitate smooth project execution • Prepare, draft, and review legal documents, contracts, and agreements with precision and attention to detail resulting on properly executed agreements • Ensure all drafted documents are compliant with legal standards and company policies

Solo Estate Planning Attorney? Grow Your Practice Without Chasing Clients Are you a solo or small-firm estate planning attorney who’s tired of wearing every hat—marketer, intake coordinator, office manager, and lawyer? If you’d rather spend your time advising clients instead of worrying about where the next one will come from, this could be a great fit. We’re looking for experienced estate planning attorneys to join our Network Attorney program, where we handle client acquisition and back-office support so you can focus on delivering high-quality legal work. Why Attorneys Love This Model - Consistent new clients each week introduced to your practice - No-cost client acquisition – we handle the marketing and outreach - Full back-office support (intake, scheduling, document support) from marketing through delivery - Control over your schedule – plug this into your practice at the level you choose - 100% virtual/telephonic consultations possible for maximum flexibility - Direct weekly payments – no invoicing or collections hassle What You’ll Do - Provide estate planning consultations to pre-qualified clients - Draft and review estate planning documents consistent with our program standards - Conduct virtual or in-office signings as appropriate in your jurisdiction - Maintain professional communication and timely turnaround on client matters What We’re Looking For - Licensed attorney in good standing, focused on estate planning - Solo or small firm practitioner looking to grow or stabilize their client flow - Experience with wills, trusts, POAs, and related planning documents - Strong client communication skills and commitment to quality work - Ability to integrate our systems and processes into your existing workflow This May Not Be a Fit If - You are not currently practicing estate planning - You are unable to take on additional client matters - You prefer to manage your own marketing and intake exclusively Ready to Explore the Opportunity? If partnering for steady, qualified estate planning clients and full support from marketing to delivery aligns with your goals, we’d like to hear from you.

• Handle a broad range of commercial and transactional matters, serving as an escalation point for issue resolution and improving contract templates and playbooks. • Work cross-functionally to support Omnidian’s initiatives on a wide variety of commercial transactions related to the business operations. • Provide legal and strategic guidance to assess and mitigate legal risk by building a deep understanding of the business and collaborate with internal clients to support their goals. • Review, draft, and negotiate a wide range of commercial and transactional contracts, including customer contracts, business development arrangements, and vendor agreements such as master service agreements, vendor service agreements and other purchase agreements. • Support compliance, data privacy, and intellectual property strategy as the company scales and expands into new markets.