Esker Therapeutics launches with $70M and a focused approach for autoimmune diseases beyond JAKs

There’s a new autoimmune disease player in town: Esker Therapeutics has raised $70 million to work on a new, focused way that can go beyond some of the limitations of JAK1 drugs.

That series A cash comes from Foresite Capital, and, while it has some earlier programs, the main focus for now is on TYK2 inhibitor ESK-001, initially for psoriasis.

TYK2 is a gene that encodes a member of the tyrosine kinase and 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.

In preclinical studies, Esker says its asset showed “potent and highly selective TYK2 inhibition,” while “avoiding unwanted side effects often seen with JAKs.”

This put its in the same space as Bristol Myers Squibb and its TYK2 deucravacitinib, which recently outperformed Amgen’s Otezla in a phase 3 clinical trial of patients with moderate to severe plaque psoriasis and is much closer to a possible approval.

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While looking into psoriasis first, with a phase 1 now ongoing, it will hope to move beyond that into more autoimmune targets, and it hopes bring in the sort of blockbuster sales seen with older meds that have gone after the same indications, like AbbVie’s Humira.

“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 CEO 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.”

There is also a “precision analytics platform” powered by Foresite Labs that comes with the biotech. 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,” according to the biotech.

“Our knowledge of the central molecular players in autoimmune diseases has been greatly enhanced through insights from human genetics and systems immunology,” added 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.”