Ep209: Mathai Mammen on Developing Drugs Against Undruggable Targets

Episode Summary

Executive Summary: Matai Mamon traces a career from immigrant roots and scientific training to leadership at Theravance, Merck, J&J, and now Parabilis, where he is betting on alpha-helical peptides to drug historically undruggable intracellular targets. He explains how Parabilis’ lead drug, zolocatatide, is showing early promise against beta-catenin-driven diseases, especially desmoid tumors, and how the company is using AI, data, and a platform approach to expand into multiple indications and targets.

Main Topics: Personal origin story and values (Priority: 5/5): Mamon describes growing up in Halifax after being born in India, the sacrifices of his parents, and how personal tragedy shaped his mission-driven approach to biotech and patient impact. Scientific training and invention of multivalency-based drug design (Priority: 5/5): He recounts his Harvard MD-PhD work with George Whitesides on multivalency, entropy, and electrostatics in molecular interactions, which later inspired his first company, Theravance. Theravance and the apprenticeship model of company building (Priority: 4/5): Mamon reflects on Theravance as a formative training ground where he learned research, development, hiring, and how to build a productive biotech culture from the ground up. Merck and Johnson & Johnson leadership lessons (Priority: 4/5): He discusses running major R&D organizations, changing portfolios, betting on bold programs, and using a strict filter for whether a project truly matters to patients. Parabilis platform: alpha-helical peptides for undruggable targets (Priority: 5/5): Mamon explains Parabilis’ approach to stabilizing peptides as alpha helices and expanding chemical diversity with synthetic amino acids to reach flat intracellular protein surfaces that small molecules and biologics cannot. Zolocatatide and beta-catenin/TCF clinical strategy (Priority: 5/5): He details the lead program’s clinical data in desmoid tumors, why colorectal cancer was not the right first commercial setting, and the strategy to move into better-fit indications and eventually basket-style studies. AI, data science, and future pipeline expansion (Priority: 4/5): He describes using machine learning, pre/post biopsies, PDX models, and automation to improve discovery, patient selection, and development, while also building new programs beyond oncology.

Key Arguments: Biotech should focus on work that truly changes patients’ lives; Mamon repeatedly emphasizes choosing projects that would matter if they disappeared tomorrow. His Harvard work on multivalency showed that repeated binding elements can create powerful biological effects, which became the conceptual basis for Theravance and later informed his leadership style. Hiring for curiosity, hunger, humility, and mission alignment is central to building durable biotech organizations. Large pharma is not homogeneous: Merck values rigor and analytics, while J&J is more risk-tolerant and biotech-like in its willingness to try new things. Parabilis’ platform is differentiated because it uses hundreds of peptide-stabilizing chemistries and thousands of synthetic amino acids, enabling far greater design space than older stapled-peptide approaches. Beta-catenin was a high-risk target choice, but early safety, tolerability, and signal in desmoid tumors validate the platform and justify broader development. The company is aiming first for discrete indications with unmet need, then for broader basket trials based on genetic signatures. AI is useful not as branding, but as a practical layer in discovery and development: predicting peptide behavior, selecting patients, and improving trial design.

Data Points: Birthplace: Dhar, India - Mamon was born in India before moving to Canada as a child. Move to Canada: Age 3 - His family relocated to Halifax, Nova Scotia when he was three. Theravance founding year: 1997 - He and colleagues pitched the multivalency-based company concept to venture investors. Theravance tenure: About 14-15 years - He spent roughly 15 years at Theravance across research, development, and executive roles. Theravance people who became biotech CEOs: 16 - Mamon says 16 people from the first 200 employees later became biotech CEOs. Theravance candidates nominated for clinical development: 30 - He cites 30 candidates advanced during the company’s run. Theravance proof-of-concepts: 9 - He says the company achieved nine proof-of-concept readouts. Medicines on market from Theravance: 5 - He notes five medicines from Theravance are on the market today. Mamon daughters who died: 2 - Mia and Lainey both died at age six, shaping his outlook on medicine and life. J&J tenure: 5.5 years - He spent about five and a half years running R&D at Johnson & Johnson. J&J deals completed: 21 - He says he executed 21 deals while there. J&J deals still performing well: 18 - He states 18 of those deals are still doing well. Products/pipeline assets approved at J&J under his watch: 9 approved, 6 more later approved - He attributes nine approvals to his time there, plus six more advanced under his watch and approved after he left. Parabolis / FOG financing: $770 million IPO - The company went public in 2026, raising a record amount for a venture-backed biotech IPO. IPO distinction: Largest IPO ever for a venture-backed biotech company - Describes the scale of Parabolis’ public offering. Synthetic amino acids used: Over 3,000 - Parabolis’ platform uses thousands of synthetic amino acids beyond the natural 20. Desmoid tumor ORR: 74% - Early clinical response rate reported for zolocatatide in desmoid tumors. Desmoid tumor patients: 38 - The early desmoid dataset discussed included 38 patients. Disease prevalence / beta-catenin relevance: ~10% of all cancers - Beta-catenin is implicated in an estimated 10% of cancers. Typical desmoid patient treatment duration in practice: Up to 3 years on therapy - He notes patients have remained on drug for up to three years in the trial experience.

Pivotal Quotes: "the test for me is: would someone actually care that you're not working on that project?" — Matai Mamon: Explaining his post-2014 philosophy for prioritizing only projects with meaningful patient impact. "we use alpha helical peptides as drugs" — Matai Mamon: Summarizing Parabilis’ core platform approach to reaching intracellular proteins with flat surfaces. "what we do in our industry is so profound" — Matai Mamon: Describing how making medicines can affect not only patients but families and communities, especially after his personal losses.

Implications: The interview highlights a platform bet on alpha-helical peptides as a credible route to once-undruggable targets, with early human data de-risking the approach. If Parabilis expands beyond desmoid tumors, it could reshape oncology drug design and validate AI-enabled peptide discovery at scale.