Esker Therapeutics Launches to Transform the Treatment of Autoimmune Diseases

– $70 Million Series A Financing from Foresite Capital to Advance Pipeline, Including a Highly Selective, Clinical-stage TYK2 Inhibitor and Early-stage Discovery Programs –

SAN FRANCISCO – Esker Therapeutics, a Foresite Labs-incubated precision medicine company that is reimagining the discovery, development and treatment of autoimmune disorders, launched today with a $70 million Series A financing from Foresite Capital. Esker plans to address the limitations of currently available treatments for autoimmune diseases by developing precision therapies that target the patient populations most likely to benefit from them.

“Autoimmune diseases are the third most common cause of chronic illness. In the U.S. alone, they impact 25 million people and cost more than $100 billion annually,” said June Lee, M.D., founder, president and chief executive officer of Esker Therapeutics. “While a number of targeted therapies have emerged in recent decades, response rates to treatments are low, and there remains a significant need for treatments that are specific to certain patient populations and that can be tolerated over long periods of time. Our goal at Esker is to rewrite the autoimmune treatment playbook by developing the right medicine for each patient.”

To advance its programs, Esker is leveraging a precision analytics platform, powered by Foresite Labs. This platform comprises high-quality curated genetic, clinical and health records data, a systems immunology toolkit for prospective data collection and tools for building patient registries. Combined with a team of experts specialized in precision medicine and immunology, this platform is informing which targets, pathways, indications and patient subsets to pursue.

“Our knowledge of the central molecular players in autoimmune diseases has been greatly enhanced through insights from human genetics and systems immunology,” said Vik Bajaj, Ph.D., co-founder and CEO of Foresite Labs and managing director at Foresite Capital. “This platform is already being applied to advance Esker’s lead program, ESK-001, in psoriasis, and we believe its utility across autoimmune disease is far larger. We are proud to support Dr. June Lee in launching this transformative company.”

Esker’s pipeline is led by ESK-001, a highly selective TYK2 inhibitor with greater selectivity for TYK2 over JAK1 compared to current therapies in development. It is initially being developed for the treatment of psoriasis and is currently being evaluated in a Phase 1 clinical trial in healthy volunteers.

TYK2 is a gene that encodes a member of the tyrosine kinase and, more specifically, the well-known Janus kinases (JAKs) protein families. It is a central node in the signaling pathways of cytokines known to be key mediators of inflammation and autoimmune diseases. This highly validated target has the potential to effectively treat multiple autoimmune indications beyond psoriasis. In preclinical studies, ESK-001 demonstrated potent and highly selective TYK2 inhibition, allowing for dosing at high levels, while avoiding unwanted side effects often seen with JAKs.

Beyond ESK-001, Esker’s pipeline includes additional discovery-stage assets focused on the causal drivers of multiple autoimmune disease indications.

Founders and Leadership

Esker’s founding management team and board of directors brings together leaders in the fields of precision medicine and immunology, with demonstrated track records of success and decades of experience within the biotechnology industry, including

  • June Lee, M.D., founder, president and CEO
  • Mark Bradley, chief development officer
  • David Zhang, Ph.D., senior vice president, chief information officer
  • Jim Tananbaum, M.D., board member at Esker; founder and CEO, Foresite Capital; and co-founder, Foresite Labs
  • Vik Bajaj, Ph.D., board observer at Esker; co-founder and CEO, Foresite Labs; and managing director, Foresite Capital
  • Michael Rome, Ph.D., board member at Esker; and managing director, Foresite Capital

“Foresite Capital is committed to empowering visionary entrepreneurs, like June and the Esker team, to create meaningful life sciences companies with the potential to address some of the biggest challenges in healthcare today,” said Dr. Tananbaum.

About Esker Therapeutics

Esker is a precision medicines company looking to eliminate the “all comer” approach that is seen with today’s treatments for people with autoimmune disease. Even with innovation of the last decade, many patients continue to cycle through the approved therapies while continuing to look for the right therapy to alleviate the impact of their disease without life-impacting side effects. Esker leverages a precision analytics platform, powered by Foresite Labs, coupled with a team of experts with deep experience in precision medicine drug development and immunology, in order to create medicines that change the lives of people with autoimmune disease. For more information, please visit

About Foresite Labs

Foresite Labs supports the next generation of healthcare entrepreneurs who will create innovative companies that transform the way that we discover and develop new medicines, and the way that we deliver care to patients in need. Foresite Labs systematically uses the tools of data science to create companies in healthcare that connect true changes in patient outcomes to all of the activities that are needed to develop, design and deploy therapeutics. For more information about Foresite Labs, please visit

Dan Budwick, 1AB