A biotech you probably haven't heard of just broke Moderna's eight-year IPO record with a $670 million Nasdaq debut. Parabilis Medicines targets "undruggable" cancers, and Wall Street is betting billions that it can deliver.
A Name You Didn't Know Just Made History
In December 2018, Moderna pulled off the unthinkable: a $604 million IPO for a company that had never sold a single product. It was the largest venture-backed biotech debut ever, and the record stood for nearly eight years.
That record is now dead.
Parabilis Medicines, a Cambridge-based cancer biotech most people hadn't heard of a year ago, just raised $670 million in its Nasdaq debut under the ticker PBLS. The offering priced at $20 per share, above the top of its original range. And the company wasn't done there: Regeneron bought another $75 million in stock through a private placement at $18 per share, bringing the total haul north of $745 million.
If underwriters exercise their full over-allotment option (about 5 million additional shares), gross proceeds could reach roughly $770 million. For a company that started in a rented lab with secondhand equipment, that's not a bad week.
From "Friends of Greg" to $3 Billion
The origin story reads like a Hollywood pitch. Harvard chemist Gregory Verdine founded the company in 2015 as FogPharma. The name wasn't a weather reference; FOG stood for "Friends of Greg," a nod to the wealthy personal contacts who bankrolled the early days instead of traditional venture capitalists.
Verdine's big idea was a class of molecules called Helicon peptides, designed to sneak inside cells and block protein interactions that traditional drugs can't reach. Think of it like this: most drugs work by sticking to the outside of a cell, like putting a lock on a door. Helicons are more like a burglar who picks the lock, gets inside, and disarms the security system from within.
The company rebranded to Parabilis Medicines in 2024 and brought in Mathai Mammen, a former head of global R&D at Johnson & Johnson, as CEO. That hire signaled a shift from scrappy lab startup to IPO-ready machine. Between its $145 million Series E in 2024 and a massive $305 million Series F in January 2026, Parabilis had raised before ever touching the public markets.
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more than $800 million in private funding
Its investor roster tells the story. RA Capital, Fidelity, Janus Henderson, GV (formerly Google Ventures), T. Rowe Price, and Deerfield Management all backed the company at various stages. When that many heavyweights pile in, Wall Street takes notice.
The Drug Behind the Dollars
Parabilis isn't selling a vague platform promise. Its lead drug, zolucatetide (FOG-001), is the first and only direct inhibitor of the interaction between two proteins, β-catenin and TCF, that drive cancer growth when they team up unchecked. This signaling pathway (called Wnt/β-catenin, for the curious) is hyperactive in colorectal cancer, liver cancer, and a handful of rare tumors.
The early clinical data is striking. In a Phase 1/2 study of patients with desmoid tumors (rare connective-tissue growths), all 10 evaluable patients showed tumor reductions. Not most. Not a majority. All of them. The company plans to launch a Phase 3 trial in desmoid tumors in the first half of 2027.
Beyond zolucatetide, Parabilis has a preclinical pipeline targeting prostate cancer through novel approaches to degrading proteins like ERG and the androgen receptor. An ERG degrader is expected to enter the clinic later this year. And then there's the Regeneron collaboration: a deal worth up to $2.3 billion in milestones to develop "antibody-Helicon conjugates," essentially combining Regeneron's antibody expertise with Parabilis' cell-penetrating peptides.
That partnership isn't just money. It's a stamp of credibility from one of the most respected drug companies on the planet.
Wall Street's Verdict: Hot Open, Quick Cool
The market's initial reaction was enthusiastic, bordering on giddy. PBLS opened at $33.35 on its first day of trading, a 67% pop above the $20 offer price. It closed at $31.60, still up 58%. IPO investors who got shares at the offering price were having a very good day.
But biotech giveth and biotech taketh away. Shares pulled back 4% on Thursday, then dropped another 10% on Friday to close at $27.26. That kind of volatility is par for the course with splashy biotech debuts; early buyers lock in profits, momentum traders chase the wave, and the stock eventually settles into a range that reflects actual conviction rather than first-day adrenaline.
IPOX Research's Lukas Muehlbauer told Reuters that the upsizing signaled a "much healthier" biotech IPO pipeline, while noting that Parabilis "distinguishes itself" through its Regeneron partnership. PitchBook's Ben Zercher offered useful context too, contrasting Parabilis with Kailera Therapeutics (which raised $625 million in April 2026). While Kailera rapidly stockpiled private capital and sprinted to market, Parabilis took a "longer and far less linear road" to its debut.
What This Means for the 2026 IPO Wave
Parabilis is among the latest in a growing wave of biotech and pharma IPOs in 2026. That's a dramatic turnaround from 2025, which saw decade-low issuance.
But the comeback isn't indiscriminate. Every company that's successfully gone public this year shares a common trait: de-risked, late-stage clinical programs with real data. No preclinical companies have gone public in the U.S. since 2024. Investors aren't writing blank checks for science projects anymore; they want proof that the drug works before they'll fund the journey to approval.
The pattern is clear. Larger deals, fewer companies, higher quality bars. Nasdaq executives projected about a dozen biotech IPOs in Q3 2026 alone, and analysts at Baker McKenzie have described investors as "cautious, investing in more de-risked assets rather than early-stage, flavor-of-the-day companies."
There's also a feedback loop with M&A activity. Big pharma has been on a shopping spree, closing multiple deals above $5 billion. That gives IPO investors confidence because they see a realistic exit: if the drug works, someone will buy the company. That M&A backstop makes it easier to stomach the risk of buying into a clinical-stage biotech at a multi-billion-dollar valuation.
The Bottom Line
Parabilis Medicines just proved that investors will write enormous checks for the right biotech story in 2026. A first-in-class drug with a 100% response rate in early trials, a $2.3 billion pharma partnership, a seasoned CEO, and a platform that promises to crack "undruggable" targets: that's a combination Wall Street couldn't resist.
The company's IPO valuation was approximately $2.3 billion at the $20 offering price, with shares soaring to around $3.7 billion in market cap after the first-day pop. Whether it grows from here depends on Phase 3 results, pipeline execution, and whether Helicon peptides can deliver on a decade of promise. The record-breaking IPO bought Parabilis a war chest and a spotlight. Now it has to prove the science is worth the hype.
Moderna's old record lasted almost eight years. It'll be interesting to see how long this one stands.
Clinical & Regulatory
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