Outsmarting cancer resistance. That’s in our DNA.

Theseus is developing best-in-class kinase inhibitors
to shape the future of targeted oncology.

down

Outsmarting cancer resistance. That’s in
our DNA.

Theseus is developing best-in-class
kinase inhibitors to shape the
future of targeted oncology.

down

About

Our oncology therapies are specifically designed to overcome treatment-resistant cancer mutations.

Theseus Pharmaceuticals is passionately committed to outsmarting cancer resistance. Cancer is constantly mutating, allowing it to evade initially effective oncology treatments. Theseus believes we can predict how cancer will change, enabling new therapies to stay ahead of future mutations and overcome the challenge of treatment resistance. Led by a team of pioneers in the discovery and development of tyrosine kinase inhibitors (TKIs), we are developing best-in-class, pan-variant kinase inhibitors, to shape the future of targeted oncology.

As tumor mutations arise during treatment, current-generation TKIs become ineffective. With predictive assays and a pan-variant strategy, Theseus can anticipate why treatments fail. Empowered by this knowledge, we aim to design TKIs that target known mutations, and prevent the emergence of new ones.

Identifying novel, transformative treatments for cancer is a staggering responsibility. With over a century of collective experience developing therapies to outsmart cancer resistance, our team makes thoughtful decisions informed by science. We embrace our mission to design safe, effective treatments that provide durable responses for people living with cancer.

Science

Theseus takes a pan-variant approach to targeting oncogenes with kinase inhibitors structured to retain their effectiveness even as the cancer mutates.

See our scientific presentations

Existing tyrosine kinase inhibitors (TKIs) are limited by constantly mutating cancers, and data demonstrate their inability to compensate for a broad array of driver oncogene variants. At Theseus, we believe truly transformative, targeted therapeutics must inhibit all clinically relevant variants. We are focused on conquering cancer resistance by predicting how a cancer will mutate, before it happens, to improve potential treatment outcomes.

Outsmarting cancer resistance is not new to the Theseus team. We target cancer mutations by taking a rigorous, structure-based approach to the design of new compounds for a variety of oncology targets. We combine deep biology and medicinal chemistry expertise with molecular modeling approaches to optimize the development of compounds that can prevent the formation of new mutations.

Our previous work discovering, developing, and launching cancer treatments serves as a springboard for the research and development of our advanced TKIs.

Pipeline

Best-in-class pan-variant TKIs to fight cancer.

We are developing a pipeline of TKIs that can anticipate and adapt to cancer mutations across a variety of targets.

Program

Indication Stage

Early
Discovery

Lead
Optimization

IND-Enabling

Phase 1

GIST

GIST IND-Enabling

THE-630 is a next-generation, pan-variant KIT inhibitor designed for patients with gastrointestinal stromal tumors (GIST) whose cancer has developed resistance to earlier lines of kinase inhibitor therapy.

NSCLC

NSCLC Lead Optimization

We are developing a next-generation, selective EGFR inhibitor to overcome C797S-mediated resistance to first- or later-line osimertinib treatment for patients with non-small cell lung cancer.

Undisclosed

Undisclosed Early Discovery

Next-generation inhibitor against a genetically validated driver oncogene.

Team

Theseus is led by targeted-oncology pioneers with a proven track record in kinase inhibition.

Together, our leadership team has discovered and developed two FDA-approved oncology therapies and a third in late-stage clinical development. These treatments provide cancer patients with clinically meaningful efficacy improvements over prior standard-of-care.

Theseus is led by targeted-oncology pioneers with a proven track record.

Management Board of Directors Investors

Tim Clackson, Ph.D.

President and Chief Executive Officer

Tim Clackson, Ph.D., is President and Chief Executive Officer of Theseus Pharmaceuticals. Tim most recently served as President and Chief Technology Officer 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, Tim was with ARIAD Pharmaceuticals, where he was President of Research & Development and Chief Scientific Officer. 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. He 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 mobocertinib, currently under FDA priority review for Exon20 insertion+ NSCLC. Prior to ARIAD, Tim was a postdoctoral research fellow at Genentech. He received his Ph.D. in Biology from the University of Cambridge, and his B.A. in Biochemistry from the University of Oxford. Tim serves as a director on the boards of Forma Therapeutics, Elevation Oncology and the Massachusetts Biotechnology Council (MassBio).

William Shakespeare, Ph.D.

Co-Founder, President of Research & Development

William Shakespeare, Ph.D., is Co-Founder and President of Research and Development at Theseus Pharmaceuticals. Bill is a renowned leader in chemistry and drug discovery, previously serving as the Vice President, Drug Discovery at ARIAD Pharmaceuticals. During his tenure of over two decades at ARIAD, he led multi-disciplinary teams in the discovery of two FDA-approved oncology drugs, ponatinib and brigatinib, and one additional compound, mobocertinib, with Breakthrough Therapy designation. Bill conducted his postdoctoral studies at the University of Pennsylvania; he is the author or co-author of more than 70 publications in peer-reviewed journals and is a co-inventor on more than 40 patents and patent applications. He received his Ph.D. in Chemistry from the University of New Hampshire and his B.S. in Chemistry from Gettysburg College.

David Dalgarno, D.Phil.

Co-Founder, Chief Technical Officer

David Dalgarno, D.Phil., is Co-Founder and Chief Technical Officer at Theseus Pharmaceuticals. An accomplished leader in drug design, structural chemistry and biophysics, David was with ARIAD Pharmaceuticals for two and a half decades, spanning the company’s history. His leadership roles included serving as Vice President of ARIAD’s Research Technologies Discovery Group, co-inventing ponatinib, brigatinib and mobocertinib and providing key scientific expertise for the discovery and development of rimiducid and ridaforolimus. Prior to ARIAD, David was a scientist at Schering-Plough Corporation. Dr. Dalgarno conducted postdoctoral research at Yale University. He earned his D.Phil. and B.A., both in Chemistry, from the University of Oxford.

Victor Rivera, Ph.D.

Co-Founder, Chief Scientific Officer

Victor Rivera, Ph.D., is Co-Founder and Chief Scientific Officer at Theseus Pharmaceuticals. Vic is an accomplished drug discovery and translational research leader. In over two decades at ARIAD Pharmaceuticals, beginning as a postdoctoral scientist and most recently as Vice President, Preclinical and Translational Research, he co-led the discovery and led the translational research for the company’s mobocertinib, brigatinib, ponatinib, ridaforolimus, and rimiducid programs. He has authored or co-authored over 75 peer-reviewed publications. Vic earned his Ph.D. in Microbiology and Molecular Genetics from Harvard Medical School and his A.B. in Molecular Biology from Princeton University.

Wei-Sheng Huang, Ph.D.

Co-Founder, Vice President, Chemistry

Wei-Sheng Huang, Ph.D., is Co-Founder and Vice President of Chemistry at Theseus Pharmaceuticals. As Director, Discovery Chemistry at ARIAD Pharmaceuticals, where he served for 14 years, Wei-Sheng led the medicinal chemistry team that was the engine behind the discovery of ponatinib, brigatinib and mobocertinib. Previously, as Senior Scientist at UCB Pharma, he focused on discovering sigma receptor agonists and opioid receptor-like-1 antagonists. Wei-Sheng conducted postdoctoral research at University of Virginia and Massachusetts Institute of Technology; he has co-authored over 60 publications in peer-reviewed journals; and is co-inventor of over 30 granted patents or patent applications. Wei-Sheng received his Ph.D. from Shanghai Institute of Organic Chemistry, Chinese Academy of Science and his B.S. from Huazhong University of Science and Technology.

David Kerstein, M.D.

Chief Medical Officer

David Kerstein, M.D. is Chief Medical Officer at Theseus Pharmaceuticals. David is a physician and an experienced oncology clinical research and development leader. Prior to joining Theseus, David served as Chief Medical Officer and Senior Vice President at Anchiano Therapeutics, a clinical-stage oncology company. He previously served as Senior Medical Director of Oncology Clinical Research at Takeda Pharmaceuticals, where he was the lung cancer clinical portfolio strategy lead and global clinical lead for brigatinib. Prior, David was Senior Medical Director of Clinical Research at ARIAD Pharmaceuticals, where he led the clinical development program, and New Drug Application and Marketing Authorization submissions for brigatinib. Previously, at Boston Biomedical, he was Director of Clinical Development and Regulatory Affairs. David received his M.D. from Tufts University School of Medicine and his B.S. in Biology from Tufts University.

Iain Dukes, D.Phil.

Co-Founder and Executive Chairman of Theseus, Venture Partner, OrbiMed Advisors

Iain D. Dukes, D.Phil., is a Venture Partner with OrbiMed Healthcare Fund Management. Iain also serves on the Board of Lion Biotechnologies. Most recently Iain was a Senior Vice President, Business Development & Licensing Merck where he oversaw all licensing deals for Merck Research Laboratories, including external research, out-licensing, regional deals and academic alliances. Iain has more than 20 years of experience in pharmaceutical research, drug discovery, scientific and technology licensing, start-up company leadership, as well as consulting for numerous biotech and venture capital organizations. Before joining Merck, he served as Vice President of External Research and Development at Amgen. He has also held positions as President and CEO of Essentialis Therapeutics and as Vice President, Scientific and Technology Licensing at GlaxoSmithKline. Iain received his D.Phil. from the University of Oxford where he also received a B.A. in Jurisprudence.

Tim Clackson, Ph.D.

President and Chief Executive Officer

Carl Gordon, Ph.D., CFA

General Partner, OrbiMed Advisors

Carl L. Gordon, Ph.D., CFA, is a founding Partner and Co-Head of Global Private Equity at OrbiMed Healthcare Fund Management. For the last six years (2014 to 2019) Forbes® Magazine named Dr. Gordon one of the top 100 venture capitalists in the world when it placed him on the "Forbes Midas List.” He received a Ph.D. in Molecular Biology from the Massachusetts Institute of Technology and a B.A. from Harvard College, and was a Fellow at The Rockefeller University from 1993 to 1995.

Michael Rome, Ph.D.

Managing Director, Foresite Capital

Dr. Michael Rome is Managing Director at Foresite Capital, where he co-leads the therapeutics investing practice. Michael is a board director at Kinnate Biopharma, Pharvaris, and Remix Therapeutics, with board observer roles (past and present) at Turning Point Therapeutics, Maze Therapeutics, PACT Pharma, and Nurix Therapeutics. Michael served as Vice President for Foresite Development Corporation (FSDC) and has led investments in several public companies across the portfolio. Prior to Foresite Capital, he was an analyst at DAFNA Capital Management, covering and formulating investment ideas for small/mid-cap biotech companies. Michael previously worked in early-stage drug development for an academic start-up out of the California NanoSystems Institute at UCLA. He received his Ph.D. in Biochemistry from Caltech as an NSF graduate research fellow, and his B.S. in Molecular, Cell and Developmental Biology from UCLA. He has more than 12 years of experience as a research scientist and has authored numerous publications in biomedical research journals.