In what’s shaping up to be a historic year for biotech initial public offerings, Parabilis Medicines (Nasdaq: PBLS) made its mark on Wall Street this past week by pricing the largest-ever IPO by a drug developer. This upsized offering raised an eye-popping $770.5 million in gross proceeds.
No sooner did Parabilis begin trading public shares on Wednesday, a day after offering 33.5 million shares of its common stock at $20 per share, than its stock price leaped 58% from the IPO price, closing its first full trading day at $31.60. Those shares slid 4% on profit taking Thursday, closing at $30.31, then fell another 10% Friday to finish the week at $27.26.
A day earlier, Parabilis announced the closing of its IPO, including a full exercise by underwriters of their 30-day option to buy an additional 5.025 million shares at the IPO price, less underwriting discounts and commissions. That added another $100.5 million to the initial $670 million in gross proceeds, which translates to another $93.5 million in net proceeds. When added to the $618.2 million net that Parabilis garnered from the original IPO, the company’s haul from the offering rises to a no-less-eye-popping $711.7 million, according to Parabilis’ IPO final prospectus.
Parabilis priced its IPO above its initial price range of $17–19 a share. The company initially planned to offer 25 million shares, then raised that offer to 33.3 million before adding 200,000 more shares to finalize its offering.
Parabilis’ IPO surpasses the $625 million IPO carried out in April by Kailera Therapeutics (Nasdaq: KLRA), which topped the previous record-high among U.S. biotechs, the $604 million offering of Moderna (Nasdaq: MRNA) in December 2018, two years before the messenger RNA (mRNA) vaccine developer won FDA emergency authorization for its COVID-19 vaccine.
Based in Cambridge, MA, Parabilis is a developer of drugs and antibody-drug conjugates (ADCs) targeting historically undruggable protein targets and based on stabilized helical peptides or Helicons. Parabilis says it has generated proprietary datasets, comprising millions of data points for hundreds of thousands of Helicons across dozens of drug-like properties, following a decade of Helicon drug discovery.
“Unlike Kailera, which formed in 2024 and quickly stockpiled private capital before going public, Parabilis took a longer and far less linear road,” commented Ben Zercher, senior biotech & pharma analyst with PitchBook.
Parabilis was founded in 2015 as FogPharma to commercialize technology developed in and in-licensed from the lab of Harvard University researcher and serial entrepreneur Gregory Verdine, PhD, who served as the company’s co-founder and CEO from 2015–2023.
Six venture rounds
While the company closed six venture rounds, Zercher noted, its valuation had fluctuated in the face of the post-pandemic period that saw private biotechs struggle, as well as leadership turnover and the rebrand through which FogPharma became Parabilis in 2024.
The rebranded company built momentum last year, according to Zercher, on the strength of its lead candidate zolucatetide (formerly FOG-001), a stabilized peptide built using the company’s Helicon platform. Zolucatetide is the first and only direct inhibitor of the elusive β-catenin:TCF interaction, according to the company.
Parabilis stated in its final prospectus that it plans to spend approximately $150 million in IPO proceeds toward continuing ongoing clinical development of zolucatetide in desmoid tumors, including continuation of dose expansion and the launch of a Phase III registrational trial to topline data.
Approximately $120 million is set to be spent on continuing the ongoing clinical development of zolucatetide across several additional indications, including dose escalation and expansion in familial adenomatous polyposis (FAP); hepatocellular carcinoma, the most common type of primary liver cancer; and other rare tumors, with the aim of collecting data to support a registrational trial.
Parabilis plans to use the largest share of its IPO proceeds, approximately $190 million, toward advancing its pipeline of additional programs—including its ETS-related gene (ERG) protein degrader, an allosteric androgen receptor in its active state (ARON), and beta-catenin degraders—to Phase I clinical data.
“Our current pipeline is focused on various cancers and tumor types; however, we believe Helicons could also have broad applicability against targets in many diseases with substantial unmet need outside oncology, and we plan to evaluate other therapeutic areas in the future,” Parabilis stated in the final prospectus.
The remainder of the proceeds would be used, Parabilis said, toward continued evolution of the Helicon platform for discovering and developing drug candidates, as well as toward general corporate purposes that include additional development efforts, working capital, and operating expenses.
Zolucatetide received the FDA’s Fast Track designation last year, followed in March by the agency’s Orphan Drug designation. In January, Parabilis closed on a $305.2 million Series F crossover financing round by selling 49,518,175 shares at $6.1644 per share to various investors, garnering $304.5 million in net proceeds. Parabilis finished the first quarter with $329.039 million in cash and cash equivalents as of March 31.
Fifteenth biopharma IPO so far in 2026
Parabilis is the 15th and latest biotech or pharmaceutical company to carry out an IPO this year, raising a combined $12.11 billion in proceeds, according to PitchBook data. Biotech and pharma accounted for 15 IPOs in all of 2025, raising a combined $10.49 billion—an improvement in dollars over 2024’s $8.83 billion, which was raised in 33 IPOs.
Seven of this year’s IPO companies have seen their shares rise since their initial offerings, led by the 466% share price increase of Veradermics (NYSE: MANE), a developer of treatments for dermatology and aesthetic conditions that closed Friday at $96.24 a share.
“With the biotech window reopened, the volume of IPOs reflects a backlog of quality companies that kept building through the biotech funding downturn rather than a wave of hype,” Zercher added. “Where the pandemic-era class sold preclinical optionality, Parabilis and the 2026 cohort are being priced on de-risked clinical programs with clear regulatory paths.”
In addition to its IPO, Parabilis said, it has also closed on selling 4,166,666 shares at $18 per share—90% of the IPO price per share—through a concurrent private placement to Regeneron Pharmaceuticals that has raised approximately $75 million in proceeds.
Parabilis’ initial IPO filing, dated May 19, came just a day after Parabilis inked an up-to-$2.3 billion-plus strategic research collaboration with Regeneron to discover and develop an initial five candidates encompassing “antibody-Helicon conjugates,” a new form of ADCs aimed at challenging and historically undruggable targets by combining the cell permeability of small molecules with the binding capabilities of larger biologics, in order to reach targets long considered undruggable.
Financial runway into H2 2029
Regeneron agreed to pay Parabilis $50 million upfront toward launching the collaboration. That upfront payment, plus proceeds from the IPO and the company’s existing cash and cash equivalents, “will be sufficient to fund our operations into the second half of 2029,” Parabilis stated in its IPO final prospectus.
According to that final prospectus, Parabilis ended the first quarter with a $45.316 million net loss, up 18% from its $38.326 million net loss of Q1 2025, as well as a net loss of $145.889 million for last year, up nearly 24% from its $117.914 million net loss for 2024. The company has no reported revenue.
Parabilis’ accumulated deficit rose 8% during Q1, to $586.82 million from $541.504 million at the end of 2025.
To fund its operations, Parabilis reported, it has raised a total of $876.8 million as of March 31. That total consisted of $811.8 million from sales of its convertible preferred stock, $15 million in borrowings under a term loan, and a $50 million Simple Agreement for Future Equity (SAFE).
Leerink Partners, BofA Securities, Evercore ISI, and Guggenheim Securities are acting as active book-running managers for Parabilis’ IPO, while LifeSci Capital is acting as a passive book-running manager.
Leaders and laggards
Propanc Biopharma (Nasdaq: PPCB) shares soared 80% from $1.35 to $2.43 Thursday after the Australian developer of therapies for pancreatic, ovarian, and colorectal cancers said it approved a share repurchase program authorizing the company to repurchase up to $5 million of its common stock. “The management team believes we are entering a transformative stage for the company,” CEO James Nathanielsz stated, citing recent progress by Propanc’s lead asset PRP, a first-in-class therapy designed to treat and prevent metastatic cancer from solid tumors, toward entering the clinic with a pivotal Phase Ib, first-in-human study in 30–40 advanced cancer patients. He also cited the company’s efforts to publish key scientific data, file patentable discoveries, and form partnerships with contract research organizations (CROs), contract development and manufacturing organizations (CDMOs), and suppliers: “The foundation is clearly there, and as a result, we believe we are undervalued significantly.”
Tango Therapeutics (Nasdaq: TNGX) shares rocketed 53% from $20.22 to $30.93 June 8 after the developer of precision oncology treatments based on synthetic lethality announced positive initial data from its ongoing Phase I/II trial (NCT06922591) assessing its next-generation, MTA-cooperative PRMT5 inhibitor candidate vopimetostat (TNG456) in combination with Revolution Medicines’ (Nasdaq: RVMD) RAS(ON) inhibitors daraxonrasib (RMC-6236) and zoldonrasib (RMC-9805) in patients with MTAP-deleted and RAS-mutant metastatic pancreatic ductal adenocarcinoma (PDAC). Tango reported that 92% of patients with PDAC in the trial’s vopimetostat plus daraxonrasib arm achieved an objective response, while patients with second and third line PDAC treated with the combination showed a six-month progression-free survival (PFS) rate of 90% (median PFS not yet reached), suggesting durability of clinical benefit. Tango said it plans to finalize the design of a Phase III randomized-controlled trial of the combination approach in front-line pancreatic cancer and disclose vopimetostat lung cancer monotherapy data in the second half of 2026.
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