2-year Extension Study Launched of Sebetralstat for HAE Attacks

Data expected late 2023, with approval request planned for 2024

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by Steve Bryson, PhD |

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OLE of sebetralstat for HAE attacks launches | Angioedema News | new in the news illustration

KalVista Pharmaceuticals has launched a two-year open-label extension (OLE) study, dubbed KONFIDENT-S, to test the long-term safety of oral sebetralstat (formerly known as KVD900) as an on-demand treatment for swelling attacks caused by hereditary angioedema (HAE).

The study follows the ongoing Phase 3 KONFIDENT clinical trial, involving adults and adolescents with HAE — with new data from both expected in the second half of 2023.

Plans for the OLE were set in motion following the submission of key toxicology data to the U.S. Food and Drug Administration (FDA), intended to support an eventual approval request for sebetralstat. That request now is planned for 2024.

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KalVista’s HAE Treatment KVD900 Now Called Sebetralstat

“Initiating this treatment extension represents another significant step in advancing sebetralstat towards an intended FDA filing following completion of the ongoing KONFIDENT Phase 3 trial in the second half of 2023,” Andrew Crockett, CEO of KalVista, said in a press release.

“We can now provide participating patients with up to two additional years of therapy with what we expect will be the first oral, on-demand treatment for HAE attacks,” Crockett added.

In HAE, swelling attacks occur when bradykinin, a molecule that promotes blood vessel widening, is overactivated in the lower layers of the skin. Given as an oral tablet, sebetralstat is designed to block the action of a bradykinin precursor molecule called plasma kallikrein.

Data from a now completed Phase 2 trial (NCT04208412), which enrolled 68 HAE adults who regularly experienced swelling attacks, showed on-demand treatment with sebetralstat led to rapid relief of abdominal and peripheral attacks.

The Phase 3 KONFIDENT trial (NCT05259917), started earlier this year, is evaluating the therapy for the same indication. That trial, expected to enroll around 114 patients with types 1 and 2 HAE, is still recruiting participants.

Being held at sites across the U.S., Europe, Canada, and other countries, that trial includes both adults and adolescents, ages 12 and older.

The KONFIDENT-S OLE study (NCT05505916) will be open to adolescents and adults who complete KONFIDENT, and is expected to involve approximately 150 patients altogether.

Its primary goal is to record the proportion of adolescents and adults who experienced at least one adverse event for up to two years. It also will evaluate the treatment’s impact on attack resolution within 1224 hours of the initial dose, and explore sebetralstat’s therapeutic potential as a short-term option to prevent attacks before medical procedures.

“The data we collect in this trial will help us better understand the long-term safety profile of sebetralstat and may also inform future trials in younger patients,” Crockett said.