KalVista Pharmaceuticals Presents New Data Highlighting High Patient Satisfaction and Evolving Treatment Trends with EKTERLY® (sebetralstat)

Key Terms

hereditary angioedema medical

A rare inherited disorder that causes sudden, painful swelling under the skin or in internal tissues, including the airway, because a natural blood‑control protein is missing or not working. Attacks can be unpredictable and sometimes life‑threatening, so people often need ongoing medication or emergency treatment. For investors, hereditary angioedema represents a niche but stable market for specialized therapies, diagnostics, and emergency care solutions.

open-label extension medical

An open-label extension is a continuation of a clinical trial where all participants and researchers know which treatment is being given, often after an initial blinded phase. It allows further study of a drug's long-term safety and effectiveness. For investors, it can indicate ongoing interest and confidence in a product's potential, influencing perceptions of its future value.

on-demand treatment medical

A treatment taken only when symptoms appear or when a specific need arises rather than on a fixed schedule; think of it like using an umbrella only when it starts to rain instead of carrying it every day. For investors, on-demand use affects how often patients buy or use a product, influences pricing and revenue predictability, and shapes market size and adoption patterns because demand can be sporadic and tied to acute events or seasonal trends.

on-demand therapy medical

On-demand therapy is a medical treatment or product designed to be used only when symptoms appear or when the patient chooses, rather than on a fixed daily schedule; it can be a pill, device, or digital intervention that is activated as needed. For investors, this affects how often customers buy or use the therapy, the predictability of revenue, regulatory and reimbursement pathways, and competitive positioning—think of it like pay-as-you-go versus a subscription service.

placebo-controlled medical

"Placebo-controlled" describes a testing method where one group receives the actual treatment or intervention, while another group receives a harmless, inactive version called a placebo. This approach helps determine whether the real treatment has genuine effects beyond psychological expectations. For investors, understanding this ensures confidence that reported benefits are real and not influenced by bias or false perceptions.

Presentations highlight patient preference for sebetralstat, early treatment as the strongest driver of response, and sustained effectiveness with use in clinical trials

FRAMINGHAM, Mass. & SALISBURY, England--(BUSINESS WIRE)-- KalVista Pharmaceuticals, Inc. (Nasdaq: KALV) today announced new data from its sebetralstat clinical trial program presented at the 2026 American Academy of Allergy, Asthma & Immunology (AAAAI) Annual Meeting and the Western Society of Allergy, Asthma & Immunology (WSAAI) 63rd Annual Scientific Session. The presentations demonstrate a significant shift in how patients manage hereditary angioedema (HAE) attacks when provided with access to sebetralstat, a safe and effective oral on-demand treatment. By reducing barriers to treatment, sebetralstat enabled early intervention which was associated with an improved treatment response. Collectively, the results highlight the potential of oral sebetralstat to help patients treat more attacks, earlier, with sustained efficacy and high satisfaction.

“The data presented at AAAAI and WSAAI reinforce the importance of treating HAE attacks early, which is consistently associated with improved outcomes,” said Ben Palleiko, CEO of KalVista. “In the KONFIDENT-S open-label extension, we are observing sustained effectiveness and high patient satisfaction with repeated use of sebetralstat, along with meaningful changes in treatment behavior, including treating the majority of attacks, early intervention, and preference for an oral option. Together, these findings support our belief that EKTERLY has the potential to transform how HAE is managed and deliver sustained real-world benefit for people living with HAE.”

Patterns Associated with Repeated Treatment with Sebetralstat for Multiple HAE Attacks in the KONFIDENT-S Open-Label Study was presented at WSAAI by Marc Riedl, MD, Professor of Medicine and Clinical Director, US Hereditary Angioedema Association Center at the University of California, San Diego, and an investigator for the KONFIDENT phase 3 trial.

• As of July 9, 2025, 2,464 HAE attacks were treated with sebetralstat. Across the first 30 attacks for participants:
  • The use of a second dose occurred in 19.3% of attacks and showed a decreasing trend from the first through the 30th attack.
  • The use of conventional injectable treatments within 12 hours occurred in only 5.1% of attacks and also showed a decreasing trend with repeated sebetralstat use.
• Patient satisfaction remained consistently high throughout the study, with 83.1% of sebetralstat-treated attacks rated as satisfied or better on a 7-point scale (ranging from -3 extremely dissatisfied to +3 extremely satisfied).

On-demand Treatment Patterns of Hereditary Angioedema (HAE) Attacks with Sebetralstat in the KONFIDENT-S Study was presented at AAAAI by Dr. Riedl.

• Across a total of 2,077 HAE attacks reported as of September 14, 2024, 98.1% were treated using either oral sebetralstat (82.1%) or conventional injectable on-demand treatment (16%). Only 1.9% of attacks were left untreated.
• Participants chose to treat the majority of attacks (82.1%) with sebetralstat, indicating strong preference regardless of attack severity or location.
• Nearly all reported attacks were treated (98.1%), a markedly higher rate than typically observed in real-world HAE studies, suggesting that access to an oral treatment option may increase willingness to treat, including mild attacks.
• Use of conventional on-demand treatments decreased from 21% to 13% across the first five attacks treated by participants, while sebetralstat use increased from 76% to 85%, indicating a growing shift and preference for oral sebetralstat despite having access to injectable options.

“The longitudinal data from KONFIDENT-S show a meaningful shift in HAE management by patients,” said Dr. Riedl. “With oral on-demand therapy, barriers to treatment of attacks are reduced, including challenges that may exist with injectable medications, potentially facilitating treatment of more attacks. What is also encouraging is that as patients gained treatment experience, we observed a decreasing trend in the need for both second doses and conventional injectable on-demand therapies. This change in treatment patterns occurred with high levels of patient satisfaction, which was durable over the large number of attacks treated. Overall, these trends suggest that sebetralstat may offer an on-demand treatment option that could empower patients to treat disabling HAE symptoms more frequently, and potentially more efficiently, over time.”

Response Drivers in Sebetralstat Placebo-controlled Clinical Trials was presented at AAAAI by Jonathan Bernstein, MD, FAAAAI, Professor of Clinical Medicine in the Department of Internal Medicine, Division of Allergy and Immunology at the University of Cincinnati College of Medicine, Partner at Bernstein Allergy Group and Clinical Research Center.

• Across analyses, treating HAE attacks within 30 minutes of onset was the strongest predictor of achieving earlier symptom relief with sebetralstat.
• Factors such as attack location, baseline severity and dose did not meaningfully improve the predictive model as significantly as time to treatment.
• Simulations suggested that early use of oral sebetralstat (within 30 minutes) could provide symptom relief for nearly 90% of subjects within 12 hours.

“The findings from our modeling and simulation analysis reinforce that time to treatment is the most robust driver of clinical success in HAE,” said Dr. Bernstein. “When patients are able to administer an oral dose of sebetralstat within 30 minutes of an attack, the probability of achieving symptom relief within 12 hours is nearly 90%. What is particularly striking is that early intervention proved more predictive of success than the location or severity of the attack. These data emphasize that an oral on-demand therapy like sebetralstat doesn’t just offer convenience, it provides a clinical advantage by allowing patients to treat early and consistently to achieve better outcomes.”

About Hereditary Angioedema

Hereditary angioedema (HAE) is a rare genetic disease resulting in deficiency or dysfunction in the C1 esterase inhibitor (C1INH) protein and subsequent uncontrolled activation of the kallikrein-kinin system. People living with HAE experience painful and debilitating attacks of tissue swelling in various locations of the body that can be life-threatening depending on the area affected. Treatment guidelines recommend treating attacks as early as possible to prevent progression of swelling and shorten the time to attack resolution, and to consider treatment for all attacks, regardless of anatomic location or severity.

About EKTERLY^® (sebetralstat)

EKTERLY (sebetralstat) is a novel plasma kallikrein inhibitor approved in the United States, European Union, United Kingdom, Switzerland, Australia, Singapore and Japan for the treatment of acute attacks of hereditary angioedema (HAE) in people 12 years of age and older. EKTERLY is the first and only oral on-demand treatment for HAE, offering efficacious and safe treatment of attacks without the burden of injections. With a US regulatory filing planned for 2026 to expand use to children aged 2–11, and additional filings anticipated in key global markets, EKTERLY has the potential to become the foundational therapy for HAE management worldwide. For more information, including the full US Prescribing Information, visit EKTERLY.com.

About KalVista Pharmaceuticals, Inc.

KalVista is a global pharmaceutical company dedicated to delivering life-changing oral therapies for individuals affected by rare diseases with significant unmet needs. The KalVista team discovered and developed EKTERLY^®—the first and only oral on-demand treatment for hereditary angioedema (HAE)—and continues to work closely with the global HAE community to improve treatment and care for this disease around the world. For more information about KalVista, please visit www.kalvista.com and follow us on LinkedIn, X, Facebook and Instagram.

Forward-Looking Statements

This press release contains "forward-looking" statements within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words such as: "anticipate," "intend," "plan," "goal," "seek," "believe," "project," "estimate," "expect," "position," "strategy," "future," "likely," "may," "should," "will" and similar references to future periods. These statements are subject to numerous risks and uncertainties that could cause actual results to differ materially from what we expect. Examples of forward-looking statements include, among others, information relating to our business and business plans, the success of our efforts to commercialize EKTERLY^® (sebetralstat), our ability to successfully obtain foreign regulatory approvals for sebetralstat, our expectations about the safety and efficacy of sebetralstat, the timing of clinical trials and their results, our ability to commence clinical studies or complete ongoing clinical studies, including our KONFIDENT-S and KONFIDENT-KID trials, and the ability of EKTERLY to treat HAE. Further information on potential risk factors that could affect our business and financial results are detailed in our filings with the Securities and Exchange Commission, including in our annual report on Form 10-K for the year ended April 30, 2025, our quarterly reports on Form 10-Q, and our other reports that we may make from time to time with the Securities and Exchange Commission. We undertake no obligation to publicly update any forward-looking statement, whether written or oral, that may be made from time to time, whether as a result of new information, future developments or otherwise.

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Ryan Baker

Head, Investor Relations

(617) 771-5001

ryan.baker@kalvista.com

Molly Cameron

Senior Director, Corporate Communications

(978) 339-3378

molly.cameron@kalvista.com

Source: KalVista Pharmaceuticals, Inc.