Esperion Sues Daiichi Sankyo Over $300M Milestone Payment


Disputes over milestone payments in the pharmaceutical industry are not uncommon, and the recent lawsuit filed by Esperion against Daiichi Sankyo highlights the intricacies of such agreements. With $300 million at stake, this legal showdown raises questions about contractual obligations, milestone achievements, and the potential impact on both companies. In this blog post, we will examine the key points surrounding the lawsuit, shedding light on the complexities of milestone payments in the pharmaceutical world.

Key Points:

1. Milestone Payments:

Milestone payments are commonly used in the pharmaceutical industry as a way to incentivize and reward companies for achieving specific goals in drug development or commercialization. These payments, often sizable sums, are typically laid out in contractual agreements between partnering companies. They serve as a crucial aspect of collaborations and provide financial support necessary for the advancement of research and development efforts.

2. The Dispute:

Esperion and Daiichi Sankyo entered into a collaboration agreement in 2019 to jointly develop and commercialize a cardiovascular drug. As part of the agreement, Daiichi Sankyo was required to make a $300 million milestone payment to Esperion upon the attainment of certain commercial milestones. However, Esperion filed a lawsuit, contending that Daiichi Sankyo failed to fulfill these contractual obligations.

3. Ensuring Milestone Achievement:

Milestone payments are typically tied to specific achievements, such as the successful completion of clinical trials, regulatory approvals, or commercial sales thresholds. Contracts governing these payments often include strict criteria and timelines to ensure that both parties are aligned on the expectations and obligations tied to the milestones. Any discrepancies or disagreements in the interpretation or attainment of these milestones can lead to legal disputes.

4. Potential Impact on Companies:

The outcome of the lawsuit holds significant implications for both Esperion and Daiichi Sankyo. If Esperion is successful and the milestone payment is awarded, it could provide a significant financial boost to the company’s ongoing research and development efforts. On the other hand, if Daiichi Sankyo prevails, it may avoid the substantial financial impact of the milestone payment, potentially reallocating those resources for other strategic purposes.

5. The Legal Process:

Resolving disputes over milestone payments typically involves a legal process that can be lengthy and complex. Both companies will have the opportunity to present their arguments and evidence in court, with the final decision resting in the hands of the judicial system. The outcome may rely on a thorough examination of the collaboration agreement, the milestones specified, and any supporting documentation that may shed light on whether the specified milestones were indeed achieved.

6. Broader Implications:

The lawsuit between Esperion and Daiichi Sankyo not only has implications for the two companies directly involved but also serves as a stark reminder of the importance of clear and comprehensive contractual agreements in the pharmaceutical industry. It underscores the need for meticulous attention to detail when drafting milestone payment clauses to avoid potential disputes and confusion down the line. Such legal conflicts can also impact the reputation and investor confidence in the companies involved.


The lawsuit filed by Esperion against Daiichi Sankyo over a $300 million milestone payment serves as a reminder of the complexities and potential pitfalls associated with financial agreements in the pharmaceutical industry. As the legal process unfolds, the outcome will not only impact the two companies involved but also offer valuable lessons for future collaborations. Clarity, transparency, and understanding of contractual agreements are crucial to avoid such disputes and maintain the harmony necessary for successful partnerships and advances in pharmaceutical research and development.