Las implicaciones legales y financieras de la solicitud de AnaptysBio para desestimar el caso relativo a las regalías de Jemperli con respecto a Tesaro de GSK

The legal battle between AnaptysBio and GSK over the royalty terms for Jemperli, a key oncology drug, has escalated into a high-stakes clash with profound implications for biotech royalty agreements. At the heart of the dispute lies a 2014 collaboration and license agreement between AnaptysBio and Tesaro (acquired by GSK in 2018), which grants AnaptysBio tiered royalties on Jemperli sales-ranging from 8% to 25%-through 2035 in the U.S. and 2036 in the EU. GSK alleges that AnaptysBio breached the contract by threatening to revoke the license, while AnaptysBio counters that GSK violated exclusivity terms by testing Jemperli alongside competing PD-1 inhibitors like Keytruda. The Delaware Chancery Court's ruling on AnaptysBio's motion to dismiss, expected by early March 2026, could reshape the financial and strategic landscape for both parties.

Legal Arguments and Strategic Risks

AnaptysBio's motion to dismiss focuses on repudiating GSK's claim of an anticipatory breach, asserting that its actions were merely the exercise of legal rights under the agreement. This argument hinges on the interpretation of contractual language regarding exclusivity and commercialization obligations. If successful, the motion could limit GSK's ability to assert claims of breach, preserving AnaptysBio's royalty entitlements. Conversely, a ruling in GSK's favor might allow the pharmaceutical giant to renegotiate terms including a potential 50% reduction in royalties and perpetual rights to Jemperli. Such an outcome would not only erode AnaptysBio's revenue stream but also jeopardize its $675 million debt to Sagard Healthcare Royalty Partners, which is secured against a portion of these royalties.

The case underscores the fragility of biotech royalty agreements, particularly in fast-evolving therapeutic areas like oncology. Unlike traditional licensing models, Jemperli's success depends on dynamic factors such as label expansions, competitive positioning, and clinical trial outcomes. GSK's alleged use of competing therapies in trials-while potentially boosting Jemperli's market share-risks triggering exclusivity disputes, as seen here. This highlights a broader trend: as biotech firms increasingly rely on collaborative R&D, conflicts over commercialization strategies and exclusivity are likely to intensify.

Financial Stakes and Market Performance

Jemperli's commercial performance has been robust, with $785 million in sales during the first nine months of 2025 and a 16% quarterly growth rate. Analysts project global sales to reach $2.56 billion by 2030, driven by label expansions and differentiation in overall survival data compared to rivals. However, recent clinical trials for first-line advanced ovarian cancer showed only a statistically significant but clinically modest progression-free survival benefit without an improvement in overall survival. This duality-strong sales versus mixed clinical data-creates valuation uncertainty, particularly if litigation disrupts the drug's commercial trajectory.

The financial implications of the dispute are magnified by AnaptysBio's reliance on Jemperli royalties. The company's debt to Sagard, secured against a portion of these royalties, introduces a secondary risk: if GSK's claims succeed, Sagard's collateral could shrink, forcing AnaptysBio to renegotiate terms or face liquidity constraints. This interplay between litigation outcomes and debt obligations is a critical consideration for investors, as it illustrates how biotech royalty streams can become entangled with third-party financial interests.

Valuation Implications and Investor Considerations

The litigation's impact on valuation hinges on three factors: the likelihood of a favorable ruling for AnaptysBio, the potential reduction in royalty rates, and the drug's long-term commercial viability. A March 2026 ruling favoring AnaptysBio would likely stabilize its royalty stream, reinforcing its valuation as a royalty-focused entity. Conversely, a partial dismissal or adverse ruling could depress its market value, particularly if GSK secures perpetual rights or a discounted royalty rate.

For investors, the case exemplifies the volatility inherent in biotech royalty agreements. Unlike tangible assets, royalty streams are contingent on complex legal and commercial variables, making them susceptible to litigation-driven revaluations. This volatility is compounded by the lack of clear precedents in biotech royalty disputes, as noted in the absence of comparable case studies. The AnaptysBio-GSK case may thus set a precedent for how courts adjudicate exclusivity and commercialization obligations in collaborative drug development.

Conclusion

The AnaptysBio-GSK dispute over Jemperli royalties is a microcosm of the challenges facing biotech firms navigating collaborative innovation. While Jemperli's commercial success has insulated AnaptysBio from immediate financial distress, the litigation threatens to upend its long-term revenue model. Investors must weigh the legal risks against the drug's market potential, recognizing that the outcome of the motion to dismiss in March 2026 will be a pivotal inflection point. As the trial approaches in July 2026, the case serves as a cautionary tale about the strategic and financial vulnerabilities of biotech royalty agreements in an era of rapid therapeutic innovation.