Parabilis, with CEO Mathai Mammen, Pursues New Class of Medicines to Treat Cancer
Parabilis Medicines CEO Mathai Mammen co-founded Theravance and was a senior manager at Johnson & Johnson
June 13, 2026
Parabilis Medicines, a US clinical-stage biopharmaceutical company, listed on the Nasdaq Stock Exchange this week. “(W)e have advanced a new class of medicines, Helicons, designed to reach targets long considered undruggable and move closer to our goal of creating extraordinary medicines for patients with serious diseases.” Mathai Mammen, Chairman and Chief Executive of the company, based in Cambridge, Massachusetts, posted on LinkedIn.
In March 2026, Parabilis’s zolucatetide was approved as an orphan drug to treat desmoid tumors, by the US Food and Drug Administration. An orphan drug status is granted to drugs that treat rare diseases affecting fewer than 200,000 people in the US. Mammen said in a statement that the drug, “could help redefine the standard of care for patients with desmoid tumors and other tumors driven by the same elusive biology.”
Parabilis is developing medicines, based on its helicon peptide platforms, to treat both rare and common cancers. Helicons are a type of peptides capable of modulating proteins in a cell, a task which conventional medicines could not accomplish. Peptides are short chains of molecules called amino acids, which make up a protein.
Many peptides are naturally found in humans, acting as important messengers, telling cells when to produce hormones, repair damaged tissues, reduce inflammation, and more, according to a post on a Columbia University medical site. One well-known peptide is insulin, which is produced by the pancreas to regulate blood sugar.
Previously, from 2017 to 2023, Mammen was the global head of research and development at Janssen Pharmaceutical Companies, the drug division of Johnson & Johnson. Based in New Brunswick, New Jersey, Johnson & Johnson has a market value of $574 billion. It develops drugs to treat a variety of medical issues: cardiovascular and metabolism, immunology, infectious diseases and vaccines, neuroscience, oncology, and pulmonary hypertension.
Mammen oversaw an annual research and development budget of $4.5 billion. He led his team to global approvals for nine medicines. He also led Johnson & Johnson’s effort to develop a COVID-19 vaccine. In 2020, the company got $1 billion in funding from the US Department of Health to rapidly pursue the development, manufacture and distribution of its potential vaccine. But, after the vaccine was in use, in rate cases it triggered blood clots and other harmful side-effects. In 2023, the vaccine’s emergency use authorization expired and it was no longer available in the US, according to the US Centers For Disease Control.
Earlier, 2016-2017, Mammen was a Senior Vice President at Merck, overseeing therapeutic areas including immunology, oncology, immuno-oncology, cardiovascular, metabolic, and renal diseases.
In 1997, Mammen co-founded and ran the research and development team at Theravance, a San Francisco Bay Area company, which was based on his earlier research at Harvard University. Over the next 17 years, his team of 200 scientists created five approved products as well as a pipeline containing many additional drug candidates. In 2014, Theravance separated into two publicly traded companies: lnnoviva, which has a royalty income and invests in medical companies, with a market value of $1.7 billion, and, Theravance Biopharma, focused in the area of pulmonary disease, with a market value of $845 million.
(Photo: Mathai Mammen, CEO, Parabilis)
Mammen serves on the board of Sandoz and other corporations and is an advisor to investment firms General Atlantic and Foresite Capital. He has more than 150 peer-reviewed publications and patents. He earned his MD from Harvard Medical School/Massachusetts Institute of Technology and his PhD in Chemistry from Harvard University. He received his BSc in Chemistry and Biochemistry from Dalhousie University in Halifax, Nova Scotia, Canada.
His mother Molly Mammen was a technician scientist in a cancer lab at Dalhousie University. “I witnessed both overt and subtle discrimination, bias and powerful perseverance and courage, and success in everything that my mother took on professionally and personally,” Mathai Mammen states in a LinkedIn post. His parents migrated to Canada, from Kerala, India, when he was a toddler.
One of Mammen’s heroes is his aunt Aleyamma Chetty, his mother’s older sister. Chetty graduated from the Christian Medical College, Vellore, India. After training at the Children’s Hospital, Boston, she returned to practice and teach at CMC Vellore, including as head of the pathology department.
In a 2020 LinkedIn post, Mammen writes about the loss of his daughters Mia and Madelaine (Laine), both at age six - Mia from a still-unknown chronic illness in 2010 and Laine from appendicitis in 2014. He has a son Mathew.
In his post, Mammen says, “it’s crucial to acknowledge the blessings we’ve received with heartfelt gratitude. In honoring this philosophy, and as a life-long tribute to Mia and Laine, I’ve devoted my life to creating truly meaningful medicines by working with and enabling brilliant teams.”
In 2023, Mammen took over as the CEO of Parabilis from the company’s co-founder Gregory Verdine. The research which led to the development of helicons - and founding of Parabilis - was conducted, since the late 1990s, by Verdine and members of his laboratory in the Department of Chemistry and Chemical Biology at Harvard University. A serial entrepreneur, Verdine, 66, is a professor emeritus at Harvard and a venture partner at Andreessen Horowitz, a Menlo Park, California venture capital firm with more than $90 billion in assets.
One of the companies partnering with Parabilis is Regeneron Pharmaceuticals, which invested $125 million in Parabilis. The plan is to combine “the intracellular access and binding capabilities of our Helicons against challenging targets with antibodies from Regeneron,” Mammen said in a statement. If certain commercial and other targets are met, Parabilis could receive up to $2.2 billion in royalty and other payments from Regeneron - which has a market value of $64 billion.
In 2025, Mathai earned $1.3 million in salary and other income at Parabilis. He owns stock in the company worth roughly $85 million.
In a post on LinkedIn, Mammen states that Parabilis “was founded on the belief that some of the most important targets in human disease were not beyond the reach of medicine – they simply required a different approach.”
By Ignatius Chithelen. He is the publisher of Global Indian Times and author of Six Degrees of Education and Passage from India to America. A Chartered Financial Analyst, he is manager of Banyan Tree Capital, New York. Neither he nor Banyan has any financial or other interests in any of the companies mentioned in this story.