Sebetralstat Shows Promise, May Become First Oral Acute Treatment for Hereditary Angioedema


The findings in a recent phase 3 clinical study may allow Kalvista Pharma to seek FDA approval for this potential hereditary angioedema treatment option.

A recent announcement by KalVista Pharmaceuticals suggests their newly-developed oral treatment known as sebetralstat—for hereditary angioedema (HAE)—may allow for relief from symptoms within a timeframe comparable to current injectable treatments, according to phase 3 findings.1

HAE is known to be a more rare condition, with an impact of around 1 in 50,000 individuals around the world. Despite this fact, the condition can be debilitating and lead to swelling attacks continuing on for days if it remains untreated.

To address HAE, this newly-developed, experimental, oral treatment for the condition could represent a major breakthrough if approved by the US Food and Drug Administration (FDA), given the availability of primarily injectable treatments as the most efficient manner of addressing swelling attacks from HAE.

“We set a high bar for an oral therapy to deliver on the efficacy that is seen with approved injectable products, while also improving on the side-effect profile and treatment burden associated with injectables,” Andrew Crockett, KalVista CEO, said in a statement. “These Phase 3 data delivered on that promise, and in many ways surpassed it.”

The currently available medications often come with limitations, according to the announcement by KalVista, with acute options such as icatibant injection (Firazyr) and conestat alfa (Ruconest) requiring multiple injections during each HAE episode. Other more preventative treatment options are also suggested not to provide total protection.

The lack of effective oral therapies for HAE led to the search for such options by several different companies.

The initial findings from a mid-stage study published in The Lancet in 2021 suggested that sebetralstat could offer swelling relief for HAE patients within 1.5 to 2 hours. More recent findings summarized in the announcement have continued to be encouraging for the investigators, as the treatment was well tolerated and allowed for faster relief from HAE symptoms compared to placebo.2

There were 44 HAE specialists who were surveyed and expressed a desire for an oral medication which could lead to relief of HAE symptoms within less than 2.5 hours.1 Additionally, there were many of such experts who also expressed willingness to switch patients to the is new drug if its efficacy matches that of icatibant injection.

While new phase 3 data is still slated to be released, KalVista has plans to file for FDA approval within the initial half of 2024 and later in the year in Japan and Europe.


  1. B Fidler. Kalvista pill succeeds in late-stage study for rare swelling disorder. Biopharma Dive. February 13, 2024. Date accessed: February 13, 2024.
  2. Aygören-Pürsün E, Zanichelli A, Cohn DM, et al. An investigational oral plasma kallikrein inhibitor for on-demand treatment of hereditary angioedema: a two-part, randomised, double-blind, placebo-controlled, crossover phase 2 trial. Lancet. 2023;401(10375):458-469. doi:10.1016/S0140-6736(22)02406-0.
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