Lilly’s Ajax Deal Required Hart-Scott-Rodino Antitrust Clearance

Eli Lilly’s $2.3 billion acquisition of Ajax Therapeutics was subject to U.S. antitrust review under the Hart-Scott-Rodino (HSR) Antitrust Improvements Act, adding a regulatory step to Lilly’s effort to acquire Ajax and its investigational Type II JAK2 inhibitor AJ1-11095.

The HSR requirement was a standard but important closing condition for the transaction. Lilly announced the acquisition in April 2026, and the deal was subsequently completed in June after the required regulatory conditions were satisfied.

What the Ajax Deal Involved

Lilly agreed to acquire Ajax Therapeutics for up to $2.3 billion, with the consideration structured around an upfront payment and additional payments tied to clinical and regulatory milestones.

At the center of the transaction was AJ1-11095, an investigational once-daily oral Type II JAK2 inhibitor being developed for myelofibrosis and polycythemia vera.

The asset was particularly attractive to Lilly because it uses a different binding mechanism from currently approved JAK2 inhibitors. While existing JAK2 inhibitors primarily target the Type I conformation, AJ1-11095 is designed to selectively target the Type II conformation.

The acquisition therefore represented both a pipeline expansion and a strategic bet on a differentiated approach to treating myeloproliferative neoplasms.

Why Hart-Scott-Rodino Review Was Required

The Hart-Scott-Rodino Antitrust Improvements Act of 1976 requires parties to certain sufficiently large mergers and acquisitions to notify U.S. antitrust authorities before completing the transaction.

The purpose is to give the Federal Trade Commission (FTC) and the Department of Justice (DOJ) an opportunity to review transactions that could potentially raise competition concerns.

For Lilly and Ajax, HSR clearance was listed among the customary conditions required before the acquisition could close. The announcement therefore did not mean that the transaction would immediately transfer ownership of Ajax to Lilly. The companies first had to satisfy applicable regulatory and other closing requirements.

HSR Clearance Does Not Mean the Deal Was Considered Anticompetitive

An important distinction is that an HSR filing should not automatically be interpreted as evidence that regulators viewed the transaction as problematic.

HSR is fundamentally a premerger notification and review process. Qualifying transactions are reported so regulators can determine whether further antitrust scrutiny is warranted.

This is particularly relevant in pharmaceutical M&A, where companies regularly acquire biotechnology businesses, drug candidates and technology platforms.

The presence of an HSR condition therefore reflects the regulatory framework surrounding a transaction rather than a finding that the acquisition itself threatens competition.

Lilly's Acquisition Was Ultimately Completed

The regulatory process did not prevent Lilly from completing the Ajax transaction.

Lilly completed the acquisition on June 8, 2026, according to transaction records.

The Federal Register subsequently included the Eli Lilly and Company–Ajax Therapeutics transaction among matters for which early termination of the HSR waiting period was granted. The notice explains that the HSR Act requires advance notification and a designated waiting period before certain acquisitions can be consummated.

The completed transaction transferred Ajax into Lilly's portfolio and allowed Lilly to advance AJ1-11095 as part of its expanding hematology pipeline.

Why the Regulatory Step Matters for Lilly's M&A Strategy

The Ajax transaction occurred during an unusually active period of business development for Lilly.

Lilly's second-quarter 2026 regulatory filing records Ajax as one of several major acquisitions made during the year. The company recognized $909 million of acquired in-process research and development associated with Ajax in its accounting for the transaction.

Other major 2026 deals included acquisitions involving Orna Therapeutics and Kelonia Therapeutics, giving Lilly exposure to in-vivo CAR-T technologies alongside its growing hematology and oncology portfolio.

The regulatory review of Ajax therefore sits within a much broader acquisition strategy in which Lilly is deploying significant capital to obtain external innovation.

The Deal's Competitive Significance Is More About Pipeline Innovation

From an antitrust perspective, Ajax was different from an acquisition involving two major companies competing across large commercial markets.

Ajax was a biotechnology company centered on an investigational drug program. Its lead candidate, AJ1-11095, was still in Phase 1 when Lilly announced the transaction.

Lilly's acquisition was therefore primarily about obtaining a promising early-stage therapeutic platform rather than consolidating a large established pharmaceutical market.

That distinction can be important in understanding why the transaction could move through the HSR process while still involving substantial regulatory notification requirements.

AJ1-11095 Remains the Strategic Prize

Although the HSR process was necessary for the transaction to close, the underlying reason Lilly pursued Ajax was scientific and commercial.

AJ1-11095 is being developed as a first-in-class Type II JAK2 inhibitor for patients with myelofibrosis and potentially polycythemia vera.

The drug's different mechanism could become particularly valuable in patients who have previously received Type I JAK2 inhibitors and subsequently experienced inadequate response or loss of response.

Lilly's June 2026 filing identifies AJ1-11095 as a Phase 1 asset for myelofibrosis and polycythemia vera and records the Ajax acquisition as completed in June.

Early Clinical Data Strengthen the Rationale

The timing of the acquisition also coincided with the release of the first clinical data for AJ1-11095.

At the 2026 European Hematology Association meeting, Ajax presented results from the Phase 1 AJX-101 study. Lilly had announced ahead of the meeting that Ajax would present the first clinical data for the investigational Type II JAK2 inhibitor in patients with myelofibrosis previously treated with a Type I JAK2 inhibitor.

These early results provide an important scientific backdrop to the acquisition.

The HSR process determined whether the transaction could proceed from a U.S. antitrust standpoint; the clinical program will ultimately determine whether Lilly's investment produces a successful medicine.

A Growing Regulatory Layer Around Pharma M&A

The Ajax transaction illustrates how modern pharmaceutical acquisitions involve several different types of scrutiny.

A deal can simultaneously require:

• Antitrust review under laws such as the HSR Act

• Corporate and securities compliance

• Regulatory approvals where applicable

• Contractual closing conditions

• Scientific and clinical due diligence

• Financial and accounting assessment

For large pharmaceutical companies pursuing multiple acquisitions, managing these requirements becomes an important part of business-development execution.

The HSR process is therefore not simply a legal formality. It forms part of the timeline between announcing an acquisition and actually gaining control of the acquired company.

What the Ajax Clearance Means for Lilly

With the acquisition completed, the key issue has shifted away from transaction clearance and toward clinical execution.

Lilly now has control of AJ1-11095 and can determine how aggressively to advance the program through subsequent clinical development.

Schrödinger, which co-founded Ajax and held an equity stake, reported that it received approximately $57.2 million in connection with the completed acquisition, including payment for its Ajax equity stake and a collaboration milestone. Schrödinger also remains eligible for additional payments tied to future clinical and regulatory milestones.

This milestone-based structure means that the ultimate economic value of the transaction will depend partly on how AJ1-11095 performs during development.

Conclusion

Lilly's acquisition of Ajax Therapeutics demonstrates how even targeted biotechnology deals must navigate the U.S. premerger regulatory framework.

The $2.3 billion transaction was subject to Hart-Scott-Rodino clearance, and the parties could not complete the acquisition until the applicable regulatory conditions were satisfied. The transaction ultimately closed on June 8, 2026, following the required review process.

For Lilly, however, the completion of the HSR process was only the beginning.

The company's real objective is to determine whether AJ1-11095 can establish a meaningful new treatment option through Type II JAK2 inhibition. With early clinical data now available and the asset inside Lilly's pipeline, attention has shifted from whether the acquisition could close to whether the $2.3 billion investment can produce a differentiated medicine for blood-cancer patients.