KalVista Pharmaceuticals Strikes $22M Deal with Kaken for Japanese Rights to HAE Drug

KalVista Pharmaceuticals has entered into a licensing agreement with Kaken Pharmaceutical for the Japanese rights to sebetralstat, its oral plasma kallikrein inhibitor for hereditary angioedema (HAE). The deal, announced on April 8, 2025, comes as KalVista awaits an FDA decision on the drug's approval in the United States.

Deal Structure and Financial Terms

Under the terms of the agreement, Tokyo-based Kaken will pay KalVista $11 million upfront, with an additional $11 million contingent upon achieving a regulatory milestone in 2026. The deal also includes undisclosed commercial milestone payments and royalties based on the drug's price in Japan. KalVista stated that the royalty rate would be "approximately in the mid-twenties" as a percentage of sales.

Sebetralstat's Potential Impact on HAE Treatment

Sebetralstat is positioned to become the first oral on-demand treatment for HAE available in Japan, pending regulatory approval. The drug, designed to treat acute HAE attacks in patients aged 12 and older, has shown promising results in clinical trials.

KalVista CEO Ben Palleiko commented on the partnership, stating, "We are pleased to partner with Kaken, whose expertise and demonstrated success in the region make them well-suited to work alongside our exceptional team to bring sebetralstat to the HAE community in Japan."

Regulatory Landscape and Competition

The FDA is expected to make a decision on sebetralstat's approval in the United States by June 2025. The application is based on a successful phase 3 study conducted in 2024, which demonstrated that patients receiving either 300-mg or 600-mg doses of sebetralstat experienced symptom relief approximately four hours faster than those on placebo.

However, sebetralstat may face competition in the HAE market. Ionis Pharmaceuticals' donidalorsen, an RNA-targeted medicine for preventing HAE attacks, is anticipating an FDA decision in August 2025. Additionally, CSL recently secured EU approval for its prophylactic HAE drug garadacimab in February 2025, while Intellia Therapeutics is developing a CRISPR-based gene editing candidate for HAE treatment.

As the pharmaceutical industry continues to advance treatments for rare diseases like HAE, the success of sebetralstat and its competitors could significantly impact patient care and market dynamics in the coming years.