A strong crossover raise can suggest that a company has “reached a level of maturity” and could go public soon, according to Sofinnova Investments’ Jim Healy.
Crossover fundraisings this year could top 2025 in terms of both deal count and value, with PitchBook projecting $4.22 billion across 28 raises. But so far, 2025’s biggest individual rounds still top this year’s.
2025 had three of the top six highest value crossovers in biotech history, accounting for 3% of the year’s $3.83 billion total. These included Kailera Therapeutics, whose $600 million raise a year ago this month holds the number one spot. The obesity specialist followed that up with a $625 million IPO in April 2026.
“Crossover financings are the gateway to public markets,” Jim Healy, the managing partner at Sofinnova Investments, told BioSpace in an email interview. “A large crossover round can therefore indicate that a company has reached a level of maturity and institutional interest that extends beyond traditional venture investors.”
Crossovers, typically the last fundraising round before a biotech goes public, give private companies access to an expanded investor base and additional capital, acting as a “late-stage bridge to an IPO,” said Ben Zercher, senior biotech and pharma analyst at PitchBook.
That doesn’t mean that public investors don’t sometimes throw their support behind earlier-stage companies, Healy and Zercher both noted. Indeed, some of the biggest funding efforts with crossover participation involved drugmakers with no assets to their name.
These include Eikon Therapeutics, which bagged nearly $520 million in a series B in early 2022, and computation-centric insitro, which attracted a $400 million C. Both raises happened before the companies had assembled their pipelines.
Of course, earlier participation means greater risk for these public-markets investors, Healy explained. “They may be underwriting the quality of the science, management team, platform, pipeline and potential market opportunity well before the company reaches traditional public-market milestones.”
Alongside Kailera, Eikon and insitro, BioSpace here looks at biopharma’s biggest crossover rounds of all time, as collected by PitchBook.
Kailera Therapeutics
Date: Oct. 14, 2025
Deal size: $600 million
Funding stage: Series B
Just months before its record-breaking $625 million IPO in April 2026, Kailera Therapeutics closed a hefty $600 million series B that counted among its participants certain public investors.
The money was meant to advance KAI-9531, a dual GLP-1/GIP receptor agonist, into global Phase 3 development for weight loss, the company said at the time. The asset, also known as ribupatide, was originally developed by China’s Jiangsu Hengrui. Kailera acquired exclusive rights to the asset outside the Greater China region in October 2024, concurrent with the Boston biotech’s $400 million series A.
Kailera has earmarked some $625 million to support the Phase 3 testing of ribupatide and around $150 million to develop a pill form of the drug. Enrollment into the Phase 3 KaiNETIC program, which includes three studies, is ongoing, with data expected in 2028, the company said in its Q2 report in August.
Kailera has set aside about $50 million for the daily GLP-1 pill KAI-7535, also from Hengrui. In July, topline Phase 3 data from a study conducted in China demonstrated 9.5% and 10.9% mean weight reduction at 44 weeks for the 120-mg and 180-mg doses, respectively, as compared with 2.5% in placebo. In a July 7 note, analysts at William Blair said they were “particularly alarmed” by the high rates of nausea and vomiting in patients treated with KAI-7535 versus placebo.
Kailera’s stock dipped in the days following the readout and has continued a steady downward trend that started as soon as it hit the public markets. All told, shares are down 54% since the IPO.
The company has launched a global Phase 2 trial for KAI-7535, with topline data expected next year, according to the Q2 report.
Eikon Therapeutics
Date: Jan. 6, 2022
Deal size: $517.8 million
Funding stage: Series B
Eikon Therapeutics is a prime example of how a company can drum up substantial crossover support even before unveiling a pipeline. In early 2022, the California biotech brought in $517.8 million in a series B round.
At the core of Eikon’s pitch is its proprietary platform, which uses advanced imaging, high-performance computing and robotics to characterize how proteins interact inside cells. The series B proceeds went towards this platform as well as several discovery programs, though the biotech at the time didn’t identify specific disease targets or areas of priority.
In June 2023, the startup acquired a portfolio of drug candidates, including TLR7/8 immune modulators from Seven and Eight Biotherapeutics, PARP1-selective blockers from Impact Therapeutics and a host of preclinical assets from Cleave Therapeutics. Two of these—the TLR7/8 asset EIK1001 and the PARP1 candidate EIK1003—are now the biotech’s most mature molecules, with both undergoing Phase 2 studies.
Laronde
Date: Aug. 30, 2021
Deal size: $440 million
Funding stage: Series B
Like Eikon, Laronde attracted early crossover interest and drew in public investors for its $440 million series B in August 2021—the biotech’s first external financing effort.
At the time, the company earmarked the money to advance its endless RNA platform, which allows prolonged and continuous expression of proteins to address various pathologies. The series B proceeds were also meant to help the Flagship Pioneering–founded company develop a pipeline of therapies across a wide variety of indications, though the biotech didn’t specify priority targets.
Investors’ early bet on Laronde didn’t pan out, however, at least not by way of an IPO. In October 2023—amid the fallout of a STAT News investigation about data integrity problems underpinning the biotech’s massive series B—Laronde merged with Flagship’s Senda Biosciences to form Sail Biomedicines. The merger’s financial details were not disclosed.
Laronde’s series B involved Flagship, as well as other investors like T. Rowe Price Associates, Invus and accounts managed by BlackRock. Sail continues to operate privately under Flagship.
Tubulis
Date: Oct. 30, 2025
Deal size: €344 million ($401 million)
Funding stage: Series C
In October 2025, Tubulis’ series C round topped $400 million, thanks in part to the participation of a number of public backers.
Crossover buzz for Tubulis at the time was driven by the biotech’s next-generation antibody-drug conjugate TUB-040, designed to target a protein found on the surface of cells that helps maintain phosphate concentrations. This target, called NaPi2b, is highly expressed in a variety of tumors.
Days before closing the series C round, Tubulis presented Phase 1/2a data for TUB-040, touting a 59% overall response rate in heavily pretreated patients with platinum-resistant ovarian cancer. The capital raised was earmarked for the expansion of TUB-040’s development program, including exploring earlier lines of treatment and other solid tumor indications. Aside from ovarian cancer, TUB-040 is also in Phase 1/2 testing for non-small cell lung cancer.
Tubulis gave investors a pretty happy ending when Gilead in April acquired the company for $3.15 billion upfront plus up to $1.85 billion in milestones.
Insitro
Date: March 15, 2021
Deal size: $400 million
Funding stage: Series C
Insitro, the other company that generated crossover interest in the absence of a pipeline, roped in a number of public backers for its $400 million series C in March 2021.
At the time, insitro’s main appeal was driven by its machine learning platform, designed to overcome key bottlenecks in drug development, the biotech said. In particular, the biotech used its computation-heavy approach to discover potential therapeutic targets and segment patient populations for better clinical strategies.
Insitro mostly dedicated the series C proceeds to expanding this platform and opening up access to enabling datasets and complementary technologies. The company also planned to set aside some of the money for potentially in-licensed assets.
Indeed, since the series C, insitro has added wholly owned investigational therapies to its pipeline—largely enabled by an alliance with Eli Lilly. The companies in October 2024 entered into a trio of agreements: Two deals gave the biotech access to a delivery technology for liver-directed siRNA therapies, while the third focused on an unspecified metabolic disease. No financial details were disclosed.
Insitro’s pipeline also includes an ALS program in collaboration with Bristol Myers Squibb, obesity assets enabled by Lilly and a wholly in-house project for dry age-related macular degeneration.
Insitro remains a private company.
Eikon Therapeutics
Date: Feb. 26, 2025
Deal size: $350.7 million
Funding stage: Series D
Eikon makes a second appearance on this list with a funding round more than three years after its 2021 series B raise that attracted crossover interest. In February 2025, the biotech corralled another $350.7 million in a series D raise, once again pulling in public investors.
Crossover buzz was more typical for this round, with Eikon being much nearer to an IPO; just under a year later, the company went public with a raise that topped $380 million.
Eikon earmarked the series D proceeds for EIK1001 and EIK1003, though the biotech at the time also pointed to EIK1004, another PARP1 inhibitor that can penetrate the central nervous system and is being tested for brain cancers.
These assets were at the heart of Eikon’s IPO as well, according to a securities filing at the time. Around $100 million went to EIK1001, pushing the asset through the Phase 2 portion of its Phase 2/3 program in melanoma, as well as supporting the molecule’s advancement in non-small cell lung cancer (NSCLC). EIK1001’s melanoma program is underway, while a registrational Phase 2/3 study in NSCLC kicked off in July.
EIK1003 received some $60 million to carry it through Phase 1/2 development, while EIK1004 got $40 million to help complete the Phase 1 portion of a Phase 1/2 trial. These programs are ongoing.
