Lassen Therapeutics is a technology company.
Lassen Therapeutics is developing novel, best-in-class biotherapeutics to improve the lives of patients suffering from serious diseases.
Lassen Therapeutics has raised $85.0M across 1 funding round.
Lassen Therapeutics has raised $85.0M in total across 1 funding round.
Lassen Therapeutics has raised $85.0M in total across 1 funding round.
Lassen Therapeutics's investors include Alta Partners, Astellas Venture Management, Frazier Healthcare Partners, Insight Partners, Longwood Fund, Carol Gallagher, Osage University Partners.
# Lassen Therapeutics: A Clinical-Stage Biopharmaceutical Company, Not a Technology Company
Lassen Therapeutics is not a technology company—it is a clinical-stage biopharmaceutical company developing antibody-based therapeutics for fibrotic and inflammatory diseases.[1][3] The company specializes in discovering and developing novel antibody drugs rather than building software, platforms, or technology infrastructure.
What Lassen Builds: Lassen develops antibody biotherapeutics targeting interleukin-11 (IL-11), a cytokine central to fibrosis and tumor microenvironment biology.[1][3] The company's lead candidate, LASN01, is a fully human clinical-stage antibody that blocks IL-11 signaling to prevent IL-11-driven fibrotic diseases.[3]
Who It Serves: Lassen targets patients suffering from serious diseases including idiopathic pulmonary fibrosis, thyroid eye disease, heart failure, and oncology-related conditions.[3][4]
Problem It Solves: IL-11 is a key mediator of fibrosis and inflammatory disease progression. By suppressing IL-11 signaling, Lassen's therapeutics aim to address diseases with significant unmet medical needs where current treatment options are limited.[1][4]
Growth Momentum: The company closed an oversubscribed $85 million Series B financing in December 2023 and has advanced LASN01 into Phase 2 clinical trials for thyroid eye disease, with the first patient dosed in the Phase 1 trial.[3] If successful, LASN01 could become the standard of care in thyroid eye disease markets worth several billion dollars each.[4]
Founding & Leadership: Lassen was founded in 2018 and is headquartered in San Diego, California.[6] The company was co-founded by Mark Barrett (Chief Executive Officer) and David King, Ph.D. (Chief Scientific Officer), both industry veterans with deep expertise in antibody drug discovery and development.[1]
Creation & Backing: Lassen was formed as part of Frazier Healthcare Partners' company creation efforts.[1] Frazier's Life Sciences team has started or seeded more than twenty companies since 2005, identifying and licensing assets into focused new companies with exceptional management teams.[1]
Track Record: The Lassen leadership team has collectively brought more than twenty antibody therapeutics into the clinic, with several already on the market in oncology and inflammation.[1] This extensive experience positions the company to rapidly develop its pipeline of novel antibodies.
Lassen operates within the antibody therapeutics sector, which has become one of the most successful modalities in drug development. The company is riding the wave of increased understanding of IL-11's role in fibrotic and inflammatory diseases—a mechanism that has gained significant scientific validation in recent years.[1][4]
The timing is favorable: fibrotic diseases represent a massive unmet medical need with limited effective treatments. Thyroid eye disease alone represents a multi-billion-dollar market opportunity.[4] Additionally, the company benefits from Frazier Healthcare Partners' extensive network of pharmaceutical companies and academic institutions, providing access to partnerships, manufacturing expertise, and potential commercialization pathways.[1]
Lassen's success could influence the broader biotech ecosystem by validating IL-11 as a therapeutic target and demonstrating the continued viability of antibody-based approaches for fibrotic and inflammatory indications—potentially spurring additional investment in this therapeutic area.
Lassen is positioned at a critical inflection point. With Phase 2 trials underway for thyroid eye disease and a well-capitalized balance sheet from its Series B, the company's near-term focus will be generating clinical efficacy and safety data that could support regulatory approval and establish LASN01 as a new standard of care.
The broader trajectory depends on clinical trial outcomes and the company's ability to expand LASN01 into additional fibrotic indications (pulmonary fibrosis, heart failure) while advancing its pipeline of novel IL-11-targeting antibodies. Success in thyroid eye disease could unlock significant commercial value and attract additional partnerships or acquisition interest from larger pharmaceutical companies seeking validated antibody platforms in high-value therapeutic areas.
Lassen Therapeutics has raised $85.0M across 1 funding round. Most recently, it raised $85.0M Series B in December 2023.
| Date | Round | Lead Investors | Other Investors |
|---|---|---|---|
| Dec 1, 2023 | $85.0M Series B | Alta Partners, Astellas Venture Management, Frazier Healthcare Partners, Insight Partners, Longwood Fund, Carol Gallagher, Osage University Partners |