A federal jury in the US District Court for the Eastern District of Texas has ruled that Daiichi Sankyo and AstraZeneca's breakthrough breast cancer therapy Enhertu infringes on Seagen's intellectual property, awarding the biotech company $42 million in damages for past royalties.
The lawsuit centered on Patent No. 10,808,039, which covers antibody-drug conjugate (ADC) technology utilizing auristatin compounds linked to antibodies. The jury determined that the infringement was willful, potentially opening the door for enhanced damages.
Patent Implications and Next Steps
Seagen will now pursue royalties on all future US sales of Enhertu through November 2024, when the patent expires. This could represent substantial compensation given Enhertu's growing commercial success and expanding market potential.
Daiichi Sankyo has expressed disagreement with the verdict and is exploring several options, including post-trial motions and an appeal. The company noted that the US Patent and Trademark Office has granted a request to review the patent's validity, suggesting prolonged legal proceedings may lie ahead.
Commercial Impact and Market Potential
The financial stakes are significant, as Enhertu has shown remarkable commercial growth. AstraZeneca reported $426 million in Enhertu revenues for the previous year, more than doubling from the year before. This revenue stems from both direct sales and profit-sharing arrangements under the $6.9 billion licensing agreement between AstraZeneca and Daiichi Sankyo established in 2019.
Enhertu's market potential appears particularly promising following recent clinical successes. The drug achieved a significant milestone in February with positive Phase 3 results in HER2-low breast cancer through the DESTINY-Breast04 trial. Analysts at Credit Suisse project this expansion could generate an additional $3 billion in sales.
Current Therapeutic Applications
The drug is currently approved as a third-line treatment for both HER2-positive breast cancer and gastric cancer. Its potential expansion into earlier treatment lines and HER2-low expressions could significantly broaden its therapeutic reach. While HER2-positive breast cancer affects 20-25% of patients, the HER2-low category encompasses approximately 55% of breast cancer cases.
Seagen's ADC Leadership
Seagen has established itself as a pioneer in ADC development, with Clay Siegall, the company's CEO, emphasizing the importance of protecting their intellectual property to continue innovative cancer therapy development. The company's ADC portfolio includes several approved therapies:
- Adcetris (brentuximab vedotin) for classical Hodgkin lymphoma and ALCL (2011)
- Padcev (enfortumab vedotin) for metastatic urothelial cancers (2019)
- Tivdak (tisotumab vedotin) for cervical cancer (2021)
