Parabilis Medicines is taking an early lead in the 2026 biotech fundraising race, closing a $305 million series F round that will fuel a pivotal push for its potential first-in-class cancer drug.
The funds come from a smorgasbord of existing investors including venBio Partners, Cormorant Asset Management and Arch Venture Partners, alongside newcomers Frazier Life and Soleus Capital. RA Capital Management, Fidelity Management & Research and Janus Henderson Investors led the round.
The Massachusetts biotech, formerly known as FogPharma, will harness the cash to advance FOG-001, recently renamed zolucatetide, toward a pivotal phase 3 trial in desmoid tumors, the company’s CEO Mathai Mammen, M.D., Ph.D., told Fierce Biotech in an interview.
Desmoid tumors are rare noncancerous growths that form in connective tissue. Zolucatetide snagged a fast-track designation from the FDA for the indication in November. The biotech then plans to pursue further oncology indications one by one and potentially conduct a basket study, Mammen said, highlighting the data zolucatetide has generated thus far in rare cancers like ameloblastoma as well as common ones like hepatocellular carcinoma.
Parabilis had an easier time raising its series F than it did with past funds, Mammen said, because now the biotech has the data to back up its lead candidate. The company recently shared early readouts in several cancer types.
After 10 years of trying to convince investors to buy in, “people understand that we're working on real drugs,” Mammen said. “The proof is in the pudding.”
If fundraising in the past was difficult, the results often didn’t show it—Parabilis pulled in $145 million in 2024, $178 million in 2022 and $107 million back in 2021. Mammen took the reins in March 2023, just as the company was prepping for zolucatetide’s clinical debut. The biotech was chosen as a Fierce 15 honoree later that year.
Zolucatetide targets beta-catenin, an intracellular protein that is implicated in a large swath of cancer types and has long been a Holy Grail for the industry. Scientists have tried to create drugs attacking beta-catenin since its discovery in the early 1990s, Mammen explained, including himself during past stints at Big Pharmas.
“I tried really hard at Merck—we threw the book at it,” Mammen said. “J&J—same. I think every major oncology company has done the same.”
Mammen, who started his career as founder of Theravance, chose to join Parabilis after leading Johnson & Johnson’s R&D organization because the biotech is “working on something real that can open the door to targets that we have all found, in the pharmaceutical industry, very frustrating,” he said.
The company’s Helicon peptides, including zolucatetide, are engineered into a corkscrew shape that can more easily enter cells and access previously hard-to-reach targets hidden inside.
While the company’s focus for now is oncology, Mammen believes the sky is the limit for Parabilis’ technology.
“If you look at the entire universe of intracellular proteins, 80% of them would be considered undruggable,” he said. “I think we could hit the vast majority of those.”
While zolucatetide will take up a lot of oxygen in 2026, Parabilis will also use funds to support the rest of its pipeline, all preclinical, as well as to build out its platform capabilities.
An ERG degrader is expected to enter the clinic this year, according to Mammen, while an androgen receptor degrader is also in development. The experienced CEO’s goal is to position Parabilis for growth into a “big, important company.”
“I want to be a company that does research, development, manufactures and commercializes product,” he said. Starting zolucatetide in smaller patient populations, which are easier to commercialize in, is part of this strategy. Money from pharma partnerships, several of which he said are in the works now, will also help fund Mammen’s dream.
“I'd like to think I have established a culture that's built for this kind of innovation,” the Parabilis chief said. “As we progress through different stages of development and eventually commercialization, I see plenty of opportunity to upend the status quo along the way.”