KalVista Pharmaceuticals Presents New Data at the European Academy of Allergy and Clinical Immunology Congress 2025 on the Efficacy of Sebetralstat for the On-demand Treatment of HAE Attacks Among Patients Receiving Long-Term Prophylaxis

–Real-world data highlight significant challenges with LTP adherence, and ongoing reliance on on-demand medications–

–In KONFIDENT-S, oral sebetralstat delivered rapid, consistent relief for breakthrough attacks, regardless of long-term prophylaxis mechanism of action–

CAMBRIDGE, Mass. & SALISBURY, England--(BUSINESS WIRE)-- KalVista Pharmaceuticals, Inc. (Nasdaq: KALV) today announced the presentation of new data at the European Academy of Allergy and Clinical Immunology (EAACI) Congress 2025 in Glasgow, United Kingdom that underscores the critical role of effective on-demand (OD) treatment for HAE attacks among patients receiving long-term prophylaxis (LTP).

Sebetralstat for Treatment of HAE Attacks in Patients Receiving Berotralstat, Lanadelumab, or C1 Inhibitor for Long-term Prophylaxis: Interim Analysis from KONFIDENT-S was presented by Marc A. Riedl, MD, Professor of Medicine and Clinical Director of the US Hereditary Angioedema Association Center at the University of California, San Diego.

• The KONFIDENT-S interim analysis, involving 35 participants receiving berotralstat, lanadelumab, or C1 inhibitor (C1-INH), treated 382 attacks with sebetralstat
• Median time to treatment was 6 minutes overall, ranging from 1 minute (C1-INH) to 20 minutes (berotralstat)
• One-third of attacks were still mild at time of sebetralstat use
• Median time to beginning of symptom relief was 1.3 hours

"Even with advancements in HAE long-term prophylactic treatments, attacks still occur, highlighting the critical need for easily administered, fast-acting, effective on-demand options," said Dr. Riedl. "These data from KONFIDENT-S show the promise of sebetralstat as an effective oral on-demand option that can complement all major long-term prophylaxis treatments, including those acting through plasma kallikrein inhibition, like lanadelumab and berotralstat.”

Adherence to Long-Term Prophylaxis for Hereditary Angioedema and the Impact on On-demand Treatment Claims in the US was presented by Daniel Soteres, MD, MPH, Asthma and Allergy Associates and Research Center, Colorado.

• Less than half (44%) of HAE patients using LTP were adherent based on refill data over 12 months
• No reduction in OD claims was observed in non-adherent patients (18 pre- and post-LTP; p=0.769)
• Over 12 months, greater than 20% discontinued their LTP, while 17% switched LTP

"The real-world data suggest that despite the effectiveness of long-term prophylactic therapies in clinical trials, maintaining adherence may be a significant hurdle for many HAE patients," said Dr. Soteres. "Refill gaps correlated with a greater number of on-demand treatment claims, indicating that patients may be experiencing more frequent attacks than expected. This underscores the importance of actively discussing LTP adherence with patients and having a reliable, efficacious on-demand treatment to manage breakthrough attacks.”

“These data reinforce what we hear from patients and clinicians on an ongoing basis; long-term prophylaxis plays an essential role in HAE management, but it’s not the full story,” said Paul Audhya, M.D., MBA, Chief Medical Officer of KalVista. “Attacks still occur, and adherence remains a real-world challenge. Sebetralstat is designed to meet this need: a rapid, reliable oral treatment that empowers patients to act the moment symptoms begin, regardless of their background therapy.”

Links to all presentations can be found on the KalVista website under Publications.

About Sebetralstat

Sebetralstat is an investigational, novel oral plasma kallikrein inhibitor for the treatment of hereditary angioedema (HAE). We have filed multiple regulatory applications seeking approval of sebetralstat as the first oral, on-demand treatment for HAE in individuals aged 12 and older, with ongoing studies exploring its use in children aged 2 to 11. If approved, sebetralstat has the potential to become the foundational therapy for HAE management worldwide.

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. All currently approved on-demand treatment options require either intravenous or subcutaneous administration.

About KalVista Pharmaceuticals, Inc.

KalVista Pharmaceuticals, Inc., is a global biopharmaceutical company dedicated to developing and delivering life-changing oral therapies for individuals affected by rare diseases with significant unmet needs. Our lead investigational product is sebetralstat, a novel, oral, on-demand treatment for hereditary angioedema (HAE). Sebetralstat is under regulatory review by the U.S. FDA. In addition, we have completed Marketing Authorization Applications for sebetralstat to the European Medicines Agency and multiple other global regulatory authorities.

For more information about KalVista, please visit www.kalvista.com or follow us on social media at @KalVista and LinkedIn.

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," "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, timing or outcomes of communications with the FDA, our expectations about safety and efficacy of our product candidates and timing of clinical trials and its results, our ability to commence clinical studies or complete ongoing clinical studies, including our KONFIDENT-S and KONFIDENT-KID trials, and to obtain regulatory approvals for sebetralstat and other candidates in development, the success of any efforts to commercialize sebetralstat, the ability of sebetralstat and other candidates in development to treat HAE or other diseases, and the future progress and potential success of our oral Factor XIIa program. 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, 2024, 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

Director, Corporate Communications

(978) 339-3378

molly.cameron@kalvista.com

Source: KalVista Pharmaceuticals, Inc.