The U.S. Food and Drug Administration has extended its review of KalVista Pharmaceuticals' sebetralstat, a potential breakthrough oral treatment for hereditary angioedema, citing heavy workload and limited resources. The agency notified KalVista on Thursday that it would be unable to issue a decision by the original June 17 target action date, with a new timeline of approximately four weeks.
First Direct Resource-Related Delay
This delay marks the first instance where the FDA has explicitly attributed a missed deadline to resource constraints following the Trump administration's restructuring of federal health agencies. According to Leerink Partners analyst Joseph Schwartz, "this situation with [KalVista] is the first instance that we are aware of that is directly related to resource constraints at the FDA."
The FDA division reviewing sebetralstat has been under particularly heavy workload, having also missed a deadline for GSK's lung disease drug Nucala earlier this year while simultaneously reviewing a different hereditary angioedema drug from CSL with the same June 17 decision deadline.
Clinical Significance and Market Potential
If approved, sebetralstat would become the first on-demand oral treatment for hereditary angioedema, a life-threatening condition that causes sudden, dangerous swelling in the body, including the skin, digestive tract and upper respiratory system, due to deficiency in a protein known as C1 inhibitor. The drug would offer a convenient alternative to the injectable treatments currently used to manage the condition's hallmark swelling attacks.
In clinical testing, sebetralstat demonstrated comparable symptom relief to existing injectable therapies. Analysts at Stifel have estimated that the drug could generate $600 million in annual U.S. sales at its peak.
Regulatory Status and Company Confidence
KalVista emphasized that the delay is not related to any clinical or safety concerns. The FDA has not requested additional data or studies and has not raised any concerns regarding the safety, efficacy or approvability of sebetralstat. According to the company, it has addressed all prior information requests in a timely manner, and the only remaining item under FDA review is the finalization of the packaging insert.
"We remain confident in the potential for near-term approval of sebetralstat," KalVista told Reuters in an email statement. Analyst Joseph Schwartz echoed this sentiment, stating his team is "confident in the eventual approval" of the drug.
Broader FDA Context
The delay comes amid concerns about the FDA's capacity following dramatic downsizing earlier this year under the Trump administration. While drug reviewers were supposed to be spared from agency layoffs, many supporting employees and teams have been cut. FDA Commissioner Martin Makary has maintained that drug evaluations aren't being compromised, testifying at a Senate hearing that "the trains are running on time."
Several other companies, including Novavax, GSK, Stealth Biotherapeutics and Vanda Pharmaceuticals, have reported unexpected delays in agency decision-making, though KalVista is the first to be explicitly told that limited agency resources were the cause.
