Anaptys Files Motion to Dismiss Tesaro’s Claim of Anticipatory Breach of Contract in Ongoing Litigation Against Tesaro, a GSK subsidiary

Rhea-AI Summary

{"summary":"","positive":[],"negative":[],"faq":[]}

News Market Reaction – ANAB

+1.99%

1 alert

+1.99% News Effect

On the day this news was published, ANAB gained 1.99%, reflecting a mild positive market reaction.

Data tracked by StockTitan Argus on the day of publication.

Key Figures

Trial dates: July 14–17, 2026 Motion unsealed date: Jan 8, 2026 Tesaro lawsuit date: Nov 20, 2025 +2 more

5 metrics

Trial dates July 14–17, 2026 Scheduled trial window for Anaptys vs. Tesaro/GSK dispute

Motion unsealed date Jan 8, 2026 Date the Motion to Dismiss was unsealed

Tesaro lawsuit date Nov 20, 2025 Date Tesaro initiated lawsuit against Anaptys

Motion to Dismiss filing Dec 30, 2025 Date Anaptys filed Motion to Dismiss Tesaro claim

Anti-SLAPP hearing timing By early March Expected hearing timing under Delaware’s anti-SLAPP law

Market Reality Check

Price: $55.11 Vol: Volume 416,102 vs 20-day ...

normal vol

$55.11 Last Close

Volume Volume 416,102 vs 20-day average 507,971, indicating below-average activity ahead of the trial. normal

Technical Shares at $43.80, trading above the $27.88 200-day moving average.

Peers on Argus

ANAB fell 3.12% while close biotech peers showed mixed moves (e.g., KROS +0.27%,...

ANAB fell 3.12% while close biotech peers showed mixed moves (e.g., KROS +0.27%, IMTX -4.90%), and no peers appeared in the momentum scanner, indicating a stock-specific move tied to its litigation narrative.

Historical Context

5 past events · Latest: 2026-01-06 (Positive)

Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
2026-01-06	Conference presentation	Positive	+1.6%	J.P. Morgan Healthcare Conference presentation and webcast details.
2025-12-15	Partner regulatory update	Positive	+1.4%	Vanda BLA submission for imsidolimab with positive Phase 3 data.
2025-11-25	Investor conferences	Positive	+1.6%	Planned participation in multiple December investor conferences.
2025-11-21	Stock repurchase plan	Positive	+5.2%	Announcement of amended <b>$100.0 million</b> stock repurchase plan.
2025-11-21	Litigation initiation	Neutral	+5.2%	Company initiated litigation against Tesaro, a GSK subsidiary.

Pattern Detected

Recent company- and partner-related headlines have generally aligned with positive price reactions, notably around capital return and strategic updates.

Recent Company History

Over recent months, ANAB news has centered on investor outreach, capital return, and its GSK/Tesaro relationship. Conference participation on 2026-01-06 and 2025-11-25 was followed by modest gains. A major catalyst came on 2025-11-21 with a $100.0 million stock repurchase expansion, coinciding with a 5.18% rise and an 8-K confirming the authorization. The same day, ANAB also initiated litigation against Tesaro, directly connected to today’s motion to dismiss and the broader Jemperli royalty dispute.

Market Pulse Summary

This announcement highlights progression in Anaptys’ legal dispute with Tesaro and GSK over the Jemp...

Analysis

This announcement highlights progression in Anaptys’ legal dispute with Tesaro and GSK over the Jemperli Collaboration Agreement, including a Motion to Dismiss and the application of Delaware’s anti-SLAPP law. The scheduled July 14–17, 2026 trial and an expected hearing by early March frame a clear litigation timeline. Investors may watch for further court filings, any discovery developments, and updates in SEC reports that clarify potential impacts on royalty revenue and overall strategy.

Key Terms

anticipatory breach of contract, motion to dismiss, anti-slapp law, tortiously interfered

4 terms

anticipatory breach of contract regulatory

"filed a partial motion to dismiss Tesaro’s anticipatory breach of contract claim"

When one party clearly indicates—by words or actions—that they will not fulfill their future contractual promises, the other party can treat the contract as broken immediately; this is an anticipatory breach of contract. For investors, it matters because such a declaration can wipe out expected revenue, trigger early legal claims or cancellations, and quickly change the outlook for a company’s cash flow and credit, much like a business partner announcing they won’t show up for a planned project.

motion to dismiss regulatory

"Anaptys filed a Motion to Dismiss Tesaro’s anticipatory breach of contract claim"

A motion to dismiss is a court filing asking a judge to throw out a lawsuit before it goes to full trial by arguing the complaint fails to state a legal claim or lacks necessary facts. For investors, it matters because a successful motion can end litigation quickly, reducing legal costs and uncertainty—like removing a cloud over a stock—while a denied motion means the case proceeds and may increase potential financial risk or distraction for a company.

anti-slapp law regulatory

"Anaptys’ motion also explains why Delaware’s anti-SLAPP law applies"

A law that lets judges quickly reject lawsuits that are filed mainly to intimidate or silence people who speak on public issues, such as critics, journalists, or shareholders. Think of it as a fast-track “get out of court” rule to stop bullying legal claims that waste time and money. For investors, these laws matter because they can reduce litigation risk and costs for companies, affect how freely people discuss corporate behavior, and influence stock volatility and governance outcomes.

tortiously interfered regulatory

"GSK, Tesaro’s corporate parent, has tortiously interfered with the Collaboration Agreement"

Tortiously interfered describes when a third party unlawfully or improperly causes a company to lose a contract, customer, or business opportunity by wrongful acts, such as false statements, threats, or other deliberate disruption. For investors, it matters because such interference can reduce revenue, damage reputation, and trigger lawsuits or remedies; think of it like someone sneaking in to pull a key customer away, harming the business and its future cash flow.

AI-generated analysis. Not financial advice.

• Trial to resolve all claims in the Anaptys and Tesaro/GSK dispute is scheduled for July 14-17, 2026
  

SAN DIEGO, Jan. 08, 2026 (GLOBE NEWSWIRE) -- AnaptysBio, Inc. (Nasdaq: ANAB), a clinical-stage biotechnology company focused on delivering innovative immunology therapeutics, filed a partial motion to dismiss Tesaro’s anticipatory breach of contract claim in Delaware Chancery Court related to pending litigation between Anaptys, GSK, and TESARO, Inc. (“Tesaro”) regarding their Collaboration and Exclusive License Agreement (“Collaboration Agreement”), which entitles Anaptys to receive royalties upon sales of Jemperli.

As previously disclosed, Anaptys approached Tesaro to engage in good faith discussions to potentially resolve Anaptys’ claims that Tesaro and GSK had breached the Collaboration Agreement. On Nov. 20, 2025, Tesaro, without notice to Anaptys and with discussions ongoing, initiated a lawsuit against Anaptys, claiming that Anaptys had repudiated the Collaboration Agreement and seeking a declaration that Tesaro had not breached.

In response, Anaptys filed its own Complaint in Delaware Chancery Court, requesting a court declaration that Tesaro has materially breached the parties’ Collaboration Agreement and that GSK, Tesaro’s corporate parent, has tortiously interfered with the Collaboration Agreement.

Further, on Dec. 30, 2025, Anaptys filed a Motion to Dismiss Tesaro’s anticipatory breach of contract claim in the same court. The motion, unsealed on Jan. 8, 2026, explains why, as a matter of law, Anaptys has never repudiated the Collaboration Agreement and how Anaptys has only sought to vindicate its contract rights (which cannot be a repudiation). Anaptys’ motion also explains why Delaware’s anti-SLAPP law applies, as the law exists to prevent strategic lawsuits aimed at deterring good‑faith efforts to assert legal rights, such as Tesaro’s lawsuit.

Tesaro and GSK contend that Anaptys’ Motion to Dismiss stays all discovery, a contention that Anaptys strongly opposes as the two companies work toward the scheduled July 14-17 trial date. The court is expected to hear Anaptys’ Motion to Dismiss by early March pursuant to Delaware’s anti-SLAPP law.

About Anaptys’ Collaboration and Exclusive License Agreement with Tesaro (an affiliate of GSK)

In March 2014, Anaptys entered into the Collaboration Agreement with Tesaro, an oncology-focused biopharmaceutical company now a part of GSK. Currently, under the Collaboration Agreement, Tesaro is developing Jemperli (dostarlimab) as a monotherapy, and in combination with additional therapies, for various solid tumor indications.

Anaptys is eligible to receive royalties upon sales of Jemperli, equal to 8% of net sales below $1.0 billion, 12% of net sales between $1.0 billion and $1.5 billion, 20% of net sales between $1.5 billion and $2.5 billion and 25% of net sales above $2.5 billion.

The royalty term under this collaboration extends at least through expiration of composition of matter coverage on the molecule which expires in 2035 in the U.S. and in 2036 in the EU.

About Anaptys

Anaptys is a clinical-stage biotechnology company focused on delivering innovative immunology therapeutics for autoimmune and inflammatory diseases. The company’s pipeline includes rosnilimab, a pathogenic T cell depleter, which has completed a Phase 2b trial for rheumatoid arthritis; ANB033, a CD122 antagonist, in a Phase 1b trial for celiac disease with plans to expand development into an additional indication; and ANB101, a BDCA2 modulator, in a Phase 1a trial. Anaptys has also discovered and out-licensed in financial collaborations multiple therapeutic antibodies, including a PD-1 antagonist (Jemperli (dostarlimab-gxly)) to GSK and an IL-36R antagonist (imsidolimab) to Vanda Pharmaceuticals. To learn more, visit www.AnaptysBio.com or follow us on LinkedIn.

Anaptys recently announced the intent to separate its biopharma operations from its substantial royalty assets by year-end 2026, enabling investors to align their investment philosophies and portfolio allocation with the strategic opportunities and financial objectives of each company. Learn more here.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995, including, but not limited to: the timing and potential outcome of proceedings in Delaware Chancery Court between Anaptys, Tesaro, and GSK, including the Court’s decision on the filed motion to dismiss, the nature of the remedies either party may seek or obtain in such proceedings, and the timing or amount of royalties from the sales of Jemperli. Statements including words such as “plan,” “continue,” “expect,” or “ongoing” and statements in the future tense are forward-looking statements. These forward-looking statements involve risks and uncertainties, as well as assumptions, which, if they do not fully materialize or prove incorrect, could cause its results to differ materially from those expressed or implied by such forward-looking statements. Forward-looking statements are subject to risks and uncertainties that may cause the company’s actual activities or results to differ significantly from those expressed in any forward-looking statement, including risks and uncertainties related to the company’s ability to advance its product candidates, obtain regulatory approval of and ultimately commercialize its product candidates, the timing and results of preclinical and clinical trials, the company’s ability to fund development activities and achieve development goals, the company’s ability to protect intellectual property and other risks and uncertainties described under the heading “Risk Factors” in documents the company files from time to time with the Securities and Exchange Commission. These forward-looking statements speak only as of the date of this press release, and the company undertakes no obligation to revise or update any forward-looking statements to reflect events or circumstances after the date hereof.

Contact:
Nick Montemarano
Executive Director, Investor Relations
858.732.0178
investors@anaptysbio.com