Kesmalea Therapeutics Appoints Industry Veteran Tim Clackson to Board of Directors

Dr. Clackson is former CEO of IDRx, acquired by GSK in 2025 for up to $1.15 billion

Kesmalea’s SELFTAC^® platform is designed to solve the ‘size problem’ of large, bifunctional protein degraders by transforming them into small molecules

SELFTAC^® drug candidates are oral and CNS penetrant, combining powerful protein degradation with a rational small molecule design process

Kesmalea Therapeutics, a biopharmaceutical company developing a pipeline of novel therapeutics founded on the ability to transform large heterobifunctional protein degraders into small molecules, today announced the appointment of senior life sciences executive Dr. Tim Clackson to its Board of Directors. Dr. Clackson brings to Kesmalea more than three decades of experience building oncology companies, including leading the R&D behind three approved drugs. He most recently served as Chief Executive Officer of Boston-based IDRx, Inc., a precision oncology therapy developer which was acquired by GSK in 2025 for up to $1.15 billion.

“Kesmalea’s science represents a highly innovative, modular and scalable solution to unlock the full potential of targeted protein degradation,” said Dr. Clackson. “I look forward to working with their impressive team and the Board to help bring SELFTAC technology to the clinic and maximize its value.”

“Targeted protein degradation holds enormous promise for medicine, but its most prominent drug class, PROTACs, faces innate issues caused by molecular size and structure. As we work to solve these challenges with our unique approach, we're assembling a world-class team to bring our mission to life," said Clive Dix, Chairman of the Kesmalea Board. "We're delighted to welcome Tim to the Board - his impressive track record of discovering and developing high impact targeted therapies for a range of cancer types will be invaluable as we translate our drug discovery research into revolutionary new medicines.”

As IDRx CEO, Dr. Clackson led a team developing a best-in-class targeted therapy for gastrointestinal stroma tumor (GIST), through clinical proof-of-concept, a Series B financing and the acquisition by GSK. Prior to IDRx, Dr. Clackson was President and CEO of Theseus Pharmaceuticals, a clinical stage biotechnology company focused on development of targeted oncology therapies, where he led the Company through its initial public offering and early clinical development for its lead product candidate for GIST and other targeted therapies in its pipeline. Prior to Theseus, he served as President at Xilio Therapeutics, a privately held oncology company developing tumor-selective immunotherapies, where he led the development of the company’s technology and product strategy.

From 1994 to 2018, Dr. Clackson was with ARIAD Pharmaceuticals, serving as President of R&D and Chief Scientific Officer from 2010. He played a key role in the company’s evolution from early research to a global commercial oncology company, and its subsequent acquisition by Takeda for $5.2 billion. Dr. Clackson led the multi-disciplinary R&D team that internally discovered and developed five clinical-stage product candidates, including ICLUSIG^® (ponatinib), approved for patients with treatment-resistant Ph+ leukemias; ALUNBRIG^® (brigatinib), approved for ALK+ non-small cell lung cancer (NSCLC); and EXKIVITY™, approved for Exon20 insertion+ NSCLC.

Dr. Clackson received his B.A. in Biochemistry from the University of Oxford, his Ph.D. in Biology from the University of Cambridge, and completed a postdoctoral fellowship at Genentech. He serves as a Director on the Board of Elevation Oncology and previously served as a Director on the Boards of Forma Therapeutics (acquired by Novo Nordisk), Spring Bank Pharmaceuticals, and the Massachusetts Biotechnology Council (MassBio).

About Kesmalea Therapeutics

Kesmalea is developing a pipeline of novel therapeutics founded on the ability to transform large protein degraders into small molecules. This is achieved through SELFTAC^®, a platform designed to combine the power of protein degradation with small molecule advantages such as oral bioavailability and central nervous system (CNS) penetration, among others. Kesmalea’s current research spans targets in oncology and diseases of the CNS, with broader applicability. The company is built on foundational scientific work by founder & CSO Harry Finch, Ph.D., a noted medicinal chemist and entrepreneur. Kesmalea has offices and labs in London, UK. Kesmalea's £25m Series A was led by Syncona Ltd alongside Oxford Science Enterprises. For more information, please visit: www.kesmalea.com.

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“Kesmalea’s science represents a highly innovative, modular and scalable solution to unlock the full potential of targeted protein degradation,” said Dr. Clackson.