Phenytoin

February 25, 2026 12:37 pm EST DOR/ISL is the first non-INSTI, two-drug regimen to demonstrate non-inferiority and a similar safety profile at Week 48 to BIC/FTC/TAF in adults living with HIV-1 who had not previously received antiretroviral treatment DOR/ISL maintained virologic suppression at Week 96 in adults with virologically suppressed HIV-1 who switched from other oral antiretroviral therapies, including BIC/FTC/TAF RAHWAY, N.J.--(BUSINESS WIRE)-- Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced the presentation of results from three pivotal Phase 3 trials evaluating the investigational, once-daily, oral, two-drug regimen of doravirine/islatravir [DOR/ISL (100 mg/0.25 mg), (MK-8591A)] in adults with HIV-1. The findings were shared in late-breaking presentations at the 33rd Conference on Retroviruses and Opportunistic Infections (CROI) being held in Denver. “We are proud to continue building on our 40-year history of HIV research with the presentation of compelling new data from our HIV pipeline at CROI this year,” said Dr. Eliav Barr, senior vice president, head of global clinical development and chief medical officer, Merck Research Laboratories. “Islatravir blocks HIV-1 replication through multiple mechanisms, including reverse transcriptase translocation inhibition, and could serve as the anchor for a series of two-drug, non-INSTI, daily and weekly treatment regimens. If approved, DOR/ISL will be the first of these regimens in our portfolio and may provide an important new option to help meet the evolving treatment needs of people living with HIV.” The Phase 3, double-blind, clinical trial MK-8591A-053 evaluating DOR/ISL versus bictegravir/emtricitabine/tenofovir alafenamidei [(50 mg/200 mg/25 mg),(BIC/FTC/TAF)] in adults living with HIV-1 who had not previously received antiretroviral treatment (treatment-naïve), met its primary efficacy endpoint of percentage of participants achieving viral suppression (HIV-1 RNA <50 copies/mL), demonstrating non-inferiority for DOR/ISL compared to BIC/FTC/TAF at Week 48, 91.8% and 90.6% respectively (treatment difference 1.2%, 95% CI: -3.7, 6.2, p<0.001). The safety profile was similar between both treatment groups and consistent with that observed in previous studies. Drug-related adverse events (AEs) and discontinuations due to drug-related AEs were similar between groups (14% for DOR/ISL and 18% for BIC/FTC/TAF; 1.1% for DOR/ISL and 2.2% for BIC/FTC/TAF, respectively). These data, which are being published simultaneously in The Lancet HIV, build on the previously reported Phase 3 data in adults with virologically suppressed HIV-1 and will form the basis of future regulatory applications. “These new Phase 3 results are meaningful, showing that an investigational two-drug regimen without an INSTI demonstrated non-inferior efficacy and a comparable safety profile versus BIC/FTC/TAF in previously untreated adults with HIV-1, including those with advanced disease,” said Dr. Jürgen K. Rockstroh, professor of medicine, head of the HIV Outpatient Clinic at the University of Bonn. “This study evaluated a diverse, global population, and included a significant proportion of participants with high viral loads and low CD4 counts. These findings add to the growing evidence supporting the potential role of DOR/ISL in HIV care.” New 96-week data from the Phase 3 MK-8591A-052 and MK-8591A-051 trials evaluating DOR/ISL vs. BIC/FTC/TAF or baseline antiretroviral therapy (bART), in participants with virologically suppressed HIV-1 and who were switched to DOR/ISL, were also presented. In both trials, DOR/ISL maintained high rates of viral suppression at Week 96 and had a similar safety profile to BIC/FTC/TAF and bART. The 48-week data from these trials supported the initial New Drug Application (NDA) for DOR/ISL for the treatment of HIV-1 infection in adults who are virologically-suppressed on a stable antiretroviral regimen; the U.S. FDA has set a target action date of April 28, 2026 for the application under the Prescription Drug User Fee Act (PDUFA). In the U.S., doravirine is approved for the treatment of adults with HIV-1 in combination with other antiretrovirals as a single agent (PIFELTRO) and a component of a single-tablet regimen [DELSTRIGO; doravirine, lamivudine, and tenofovir disoproxil fumarate (DOR/3TC/TDF)]. “As people living with HIV age, managing other health conditions becomes a reality for many, making it especially important to have treatment options that can help meet each person’s unique health needs,” said Dr. Amy Colson, director of research at Community Resource Initiative, Cambridge, Massachusetts. “Over time, people may need to adjust their HIV treatment regimens because of comorbidities, concerns about toxicities, tolerability challenges, or a desire for regimens with fewer medications. These 96-week data are encouraging, showing a non-INSTI option like investigational DOR/ISL could offer an important alternative.” About the Phase 3 data from MK-8591A-053 MK-8591A-053 is an ongoing Phase 3 randomized, active-controlled, double-blind, clinical trial evaluating the efficacy and safety of investigational, once-daily DOR/ISL (100 mg/0.25 mg) versus BIC/FTC/TAF in adults living with HIV-1 infection who had not previously received antiretroviral treatment. Participants were randomized 1:1 to DOR/ISL (n=269) or BIC/FTC/TAF (with matching placebos) (n=267), stratified by screening CD4+ T-cell count (<200 cells/mm³) and HIV-1 RNA (>100,000 copies/mL). The primary efficacy endpoint was the percentage of participants with HIV-1 RNA <50 copies/mL at Week 48 (non-inferiority margin 10%). Of the total participants enrolled in the trial, 36.8% had baseline HIV-1 RNA >100,000 copies/mL, 10.3% had HIV-1 RNA >500,000 copies/mL and 17.2% had baseline CD4+ T-cell count <200 cells/mm3. At Week 48, virological efficacy as measured by the percentage of participants with HIV-1 RNA levels < 50 copies/mL, was comparable in participants on DOR/ISL versus BIC/FTC/TAF with screening HIV-1 RNA >100,000 copies/mL (94.0% vs 87.6%, respectively) and >500,000 copies/mL (90.3% vs 84.4%, respectively). Drug-related AEs were reported in 14.1% of participants on DOR/ISL and 18.0% on BIC/FTC/TAF and discontinuations due to AEs (1.1% vs. 2.2%) were similar in both groups. Immune reconstitution was similar in DOR/ISL vs. comparator with no between-group differences in mean increases in CD4+ T-cell counts or total lymphocyte counts (TLC). About the Phase 3 data from MK-8591A-052 MK-8591A-052 is a Phase 3, randomized, active-controlled, double-blind, clinical trial to evaluate the efficacy and safety of a switch to investigational, once-daily DOR/ISL (100 mg/0.25 mg) in adults with HIV-1 infection that has been virologically suppressed on BIC/FTC/TAF (50 mg/200 mg/25 mg). In this trial, 513 adults with HIV-1 who had virologic suppression for three months or more on BIC/FTC/TAF, no history of treatment failure and no known resistance to DOR were randomized (2:1) and switched to DOR/ISL (n= 342) or continued treatment with BIC/FTC/TAF (n=171). The primary efficacy endpoint, the percentage of participants with HIV-1 RNA ≥50 copies/mL at Week 48 (non-inferiority margin 4%), was met, demonstrating non-inferiority to BIC/FTC/TAF; 1.5% of participants who switched to DOR/ISL had a viral load of ≥50 copies/mL at Week 48, compared to 0.6% on BIC/FTC/TAF (treatment difference 0.9%, 95% CI -1.9, 2.9). Results at Week 48 were recently published in The Lancet. At Week 96, DOR/ISL continued to demonstrate similar efficacy compared to BIC/FTC/TAF; 1.5% of participants on DOR/ISL had a viral load of ≥50 copies/mL compared to 1.2% of participants on BIC/FTC/TAF (treatment difference 0.3%, 95% CI -2.8, 2.4); 88.9% of participants on DOR/ISL maintained virologic suppression (HIV-1 RNA <50 copies/mL) compared to 90.1% of participants continuing BIC/FTC/TAF (treatment difference -1.2%, 95% CI -6.5, 5.0). No hypothesis testing was performed for these secondary endpoints. The safety profile for DOR/ISL at Week 96 continued to be similar to BIC/FTC/TAF with no new safety findings. No additional drug-related serious adverse events were reported in any group between Week 48 and Week 96. At Week 96, rates of discontinuation due to AEs were similar for both groups (3.2% vs. 2.9%). There were no differences between trial arms in CD4+ T-cell count or TLC changes through Week 96. About the Phase 3 data from MK-8591A-051 MK-8591A-051 is a Phase 3, open-label randomized, active-controlled, clinical trial to evaluate the efficacy and safety of a switch to investigational, once-daily DOR/ISL (100 mg/0.25 mg) in adults with HIV-1 infection that has been virologically suppressed using bART. In this trial, 551 adults with HIV-1 RNA <50 copies/mL for three months or more on oral 2- or 3-drug ART, with no history of treatment failure and no known virologic resistance to DOR, were randomized 2:1 and switched to DOR/ISL (n= 366) or continued bART (n=185), stratified by bART regimen. The primary efficacy endpoint, percentage of participants with HIV-1 RNA ≥50 copies/mL at Week 48 (non-inferiority margin 4%), was met, demonstrating DOR/ISL to be non-inferior to bART; 1.4% of participants who received DOR/ISL had a viral load of ≥50 copies/mL at Week 48, compared to 4.9% on bART (treatment difference -3.6%, 95% CI -7.8, -0.8). After Week 48 of the comparative portion of the study, all participants received open-label DOR/ISL through Week 144. Results at Week 48 were recently published in The Lancet. At Week 96, 1.9% of participants who continued on DOR/ISL for 96 weeks had HIV-1 RNA ≥50 copies/mL and 1.1% of participants who switched from bART to DOR/ISL at Week 48. Additionally, 92.6% of participants who were on DOR/ISL through 96 weeks and 96.6% of participants who switched to DOR/ISL at Week 48 maintained virologic suppression (HIV-1 RNA <50 copies/mL) at Week 96. At Week 96, there were similar rates of drug-related AEs between those who continued on DOR/ISL (13.7%) for 96 weeks and for those who switched from bART to DOR/ISL at Week 48 (11.3%) and rates of discontinuations due to AEs for those on DOR/ISL for 96 weeks (1.1%) and for those who switched from bART to DOR/ISL at Week 48 (0.6%) were similar. The mean percent change in total lymphocyte and CD4 counts were similar for participants who continued on DOR/ISL and switched from bART to DOR/ISL. No participants discontinued treatment due to decreased CD4+ T-cell count or TLC. About Islatravir (MK-8591) and Merck’s HIV Research Islatravir (MK-8591) is Merck’s investigational nucleoside analog that blocks HIV-1 replication by multiple mechanisms including inhibition of reverse transcriptase translocation, resulting in immediate chain termination and induction of structural changes in the viral DNA. Islatravir is under evaluation in multiple ongoing early and late-stage clinical trials in combination with other antiretrovirals for potential daily and once-weekly treatments for HIV-1, with islatravir serving as the anchor medicine in these two-drug regimens. Islatravir in combination with Gilead’s lenacapavir is in Phase 3 development as a novel oral once-weekly treatment for HIV-1 [ISLEND-1 (NCT06630286) and ISLEND-2 (NCT06630299)], and islatravir in combination with our company’s investigational non-nucleoside reverse transcriptase inhibitor (NNRTI) ulonivirine (MK-8507) is in Phase 2b development (MK-8591B-060, NCT06891066 and MK-8591B-062, NCT07266831) as an oral once-weekly treatment. MK-8527 is the company’s investigational, novel, once-monthly, oral candidate for pre-exposure prophylaxis (PrEP) for HIV-1. The Phase 3 EXPrESSIVE-11 (MK-8527-011, NCT07044297) trial is evaluating the safety and efficacy of MK-8527 as PrEP to reduce the risk of sexually acquired HIV-1 infection among people likely to be exposed to HIV-1 in 16 countries. The Phase 3 EXPrESSIVE-10 (MK-8527-010, NCT07071623) trial is evaluating the safety and efficacy of MK-8527 as PrEP to reduce the risk of sexually acquired HIV-1 infection among women and adolescent girls in sub-Saharan Africa. Both trials are now enrolling. For an overview of Merck’s HIV treatment and prevention clinical development program, please click here. Indications and usage for PIFELTRO® (doravirine) and DELSTRIGO® (doravirine, lamivudine, and tenofovir disoproxil fumarate) in the U.S. PIFELTRO is indicated in combination with other antiretroviral (ARV) agents for the treatment of HIV-1 infection in adult patients with no prior ARV treatment history or to replace the current ARV regimen in those who are virologically suppressed (HIV-1 RNA less than 50 copies per mL) on a stable ARV regimen with no history of treatment failure and no known substitutions associated with resistance to doravirine. DELSTRIGO is indicated as a complete regimen for the treatment of HIV-1 infection in adult patients with no prior ARV treatment history or to replace the current ARV regimen in those who are virologically suppressed (HIV-1 RNA less than 50 copies per mL) on a stable ARV regimen with no history of treatment failure and no known substitutions associated with resistance to the individual components of DELSTRIGO. Selected Safety Information Warning: Posttreatment Acute Exacerbation of Hepatitis B Virus (HBV) for DELSTRIGO All patients with HIV-1 should be tested for the presence of HBV before initiating ARV therapy. Severe acute exacerbations of HBV have been reported in people with concomitant HIV-1 and HBV who have discontinued products containing lamivudine or tenofovir disoproxil fumarate (TDF), which are components of DELSTRIGO. Patients coinfected with HIV-1 and HBV who discontinue DELSTRIGO should be monitored with both clinical and laboratory follow-up for at least several months after stopping DELSTRIGO. If appropriate, initiation of anti-HBV therapy may be warranted. Contraindications PIFELTRO and DELSTRIGO are contraindicated when coadministered with drugs that are strong cytochrome P450 (CYP)3A enzyme inducers (including the anticonvulsants carbamazepine, oxcarbazepine, phenobarbital, and phenytoin; the androgen receptor inhibitor enzalutamide; the antimycobacterials rifampin and rifapentine; the cytotoxic agent mitotane; and the herbal product St. John’s wort (Hypericum perforatum)), as significant decreases in doravirine plasma concentrations may occur, which may decrease the effectiveness of DELSTRIGO and PIFELTRO. DELSTRIGO is contraindicated in patients with a previous hypersensitivity reaction to lamivudine. Warnings and Precautions Severe Skin Reactions Severe skin reactions, including Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN), have been reported during the postmarketing experience with doravirine-containing regimens. Discontinue PIFELTRO or DELSTRIGO, and other medications known to be associated with severe skin reactions, immediately if a painful rash with mucosal involvement or a progressive severe rash develops. Clinical status should be closely monitored, and appropriate therapy should be initiated. New or Worsening Renal Impairment Renal impairment, including cases of acute renal failure and Fanconi syndrome, have been reported with the use of TDF. DELSTRIGO should be avoided with concurrent or recent use of a nephrotoxic agent (e.g., high-dose or multiple NSAIDs). Cases of acute renal failure after initiation of high-dose or multiple NSAIDs have been reported in people living with HIV with risk factors for renal dysfunction who appeared stable on TDF. Prior to or when initiating DELSTRIGO, and during treatment, assess serum creatinine, estimated creatinine clearance, urine glucose, and urine protein in all patients. In patients with chronic kidney disease, also assess serum phosphorus. Discontinue DELSTRIGO in patients who develop clinically significant decreases in renal function or evidence of Fanconi syndrome. Discontinue DELSTRIGO if estimated creatinine clearance declines below 50 mL/min. Bone Loss and Mineralization Defects In clinical trials in adults living with HIV, TDF was associated with slightly greater decreases in bone mineral density (BMD) and increases in biochemical markers of bone metabolism. Serum parathyroid hormone levels and 1,25 Vitamin D levels were also higher. Cases of osteomalacia associated with proximal renal tubulopathy have been reported with the use of TDF. The effects of TDF-associated changes in BMD and biochemical markers on long-term bone health and future fracture risk in adults are unknown. Immune Reconstitution Syndrome Immune reconstitution syndrome can occur, including the occurrence of autoimmune disorders with variable time to onset, which may necessitate further evaluation and treatment. Drug Interactions Because DELSTRIGO is a complete regimen, coadministration with other antiretroviral medications for the treatment of HIV-1 infection is not recommended. Coadministration of PIFELTRO with efavirenz, etravirine, or nevirapine is not recommended. If DELSTRIGO is coadministered with rifabutin, take one tablet of DELSTRIGO once daily, followed by one tablet of doravirine (PIFELTRO) approximately 12 hours after the dose of DELSTRIGO. If PIFELTRO is coadministered with rifabutin, increase PIFELTRO dosage to one tablet twice daily (approximately 12 hours apart). Consult the full Prescribing Information prior to and during treatment for more information on potential drug-drug interactions. Dosage and Administration/Specific Populations Renal Impairment Because DELSTRIGO is a fixed-dose combination tablet and the dosage of lamivudine and TDF cannot be adjusted, DELSTRIGO is not recommended in patients with estimated creatinine clearance less than 50 mL/min. Adverse Reactions The most common adverse reactions with DELSTRIGO (incidence ≥5%, all intensities) were dizziness (7%), nausea (5%), and abnormal dreams (5%). The most common adverse reactions with PIFELTRO (incidence ≥5%, all intensities) were nausea (7%), dizziness (7%), headache (6%), fatigue (6%), diarrhea (6%), abdominal pain (5%), and abnormal dreams (5%). By week 96 in DRIVE-FORWARD, 2% of adult participants in the PIFELTRO group and 3% in the darunavir+ritonavir (DRV+r) group had adverse events leading to discontinuation of study medication. By week 96 in DRIVE-AHEAD, 3% of adult participants in the DELSTRIGO group and 7% in the efavirenz (EFV)/emtricitabine (FTC)/TDF group had adverse events leading to discontinuation of study medication. In DRIVE-FORWARD, mean changes from baseline at week 48 in LDL-cholesterol (LDL-C) and non-HDL-cholesterol (non-HDL-C) were pre-specified. LDL-C: -4.6 mg/dL in the PIFELTRO group vs 9.5 mg/dL in the DRV+r group. Non-HDL-C: -5.4 mg/dL in the PIFELTRO group vs 13.7 mg/dL in the DRV+r group. The clinical benefits of these findings have not been demonstrated. In DRIVE-AHEAD, mean changes from baseline at week 48 in LDL-C and non-HDL-C were pre-specified. LDL-C: -2.1 mg/dL in the DELSTRIGO group vs 8.3 mg/dL in the EFV/FTC/TDF group. Non-HDL-C: -4.1 mg/dL in the DELSTRIGO group vs 12.7 mg/dL in the EFV/FTC/TDF group. The clinical benefits of these findings have not been demonstrated. In DRIVE-SHIFT, mean changes from baseline at week 24 in LDL-C and non-HDL-C were pre-specified. LDL-C: -16.3 mg/dL in the DELSTRIGO group vs -2.6 mg/dL in the PI + ritonavir group. Non-HDL-C: -24.8 mg/dL in the DELSTRIGO group vs -2.1 mg/dL in the PI + ritonavir group. The clinical benefits of these findings have not been demonstrated. In DRIVE-AHEAD, neuropsychiatric adverse events were reported in the three pre-specified categories of sleep disorders and disturbances, dizziness, and altered sensorium. Twelve percent of adult participants in the DELSTRIGO group and 26% in the EFV/FTC/TDF group reported neuropsychiatric adverse events of sleep disorders and disturbances; 9% in the DELSTRIGO group and 37% in the EFV/FTC/TDF group reported dizziness; and 4% in the DELSTRIGO group and 8% in the EFV/FTC/TDF group reported altered sensorium. The safety of DELSTRIGO in virologically suppressed adults was based on week 48 data from participants in the DRIVE-SHIFT trial. Overall, the safety profile in virologically suppressed adult participants was similar to that in participants with no ARV treatment history. Serum ALT and AST Elevations: In the DRIVE-SHIFT trial, 22% and 16% of participants in the immediate switch group experienced ALT and AST elevations greater than 1.25 X ULN, respectively, through 48 weeks on DELSTRIGO. For these ALT and AST elevations, no apparent patterns with regard to time to onset relative to switch were observed. One percent of participants had ALT or AST elevations greater than 5 X ULN through 48 weeks on DELSTRIGO. The ALT and AST elevations were generally asymptomatic, and not associated with bilirubin elevations. In comparison, 4% and 4% of participants in the delayed switch group experienced ALT and AST elevations of greater than 1.25 X ULN through 24 weeks on their baseline regimen. Pregnancy/Breastfeeding There is a pregnancy exposure registry that monitors pregnancy outcomes in individuals exposed to PIFELTRO or DELSTRIGO during pregnancy. Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263. Inform individuals with HIV-1 infection of the potential risks of breastfeeding, including: (1) HIV-1 transmission (in HIV-1–negative infants), (2) developing viral resistance (in HIV-1–positive infants), and (3) serious adverse reactions in a breastfed infant similar to those seen in adults. Merck’s Commitment to HIV For 40 years, Merck has been committed to scientific research and discovery in HIV leading to scientific breakthroughs that have helped change HIV treatment. Our work has been pioneering in the development of new options across multiple drug classes to help those impacted by HIV. Today, we are developing a series of antiviral options designed to help people manage HIV and protect people from HIV. We are researching for real life and want to ensure people are not defined by HIV. Our work focuses on transformational innovations, collaborations with others in the global HIV community, and access initiatives aimed at the goal of helping to end the HIV epidemic for everyone. About Merck At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities. For more information, visit www.merck.com and connect with us on X (formerly Twitter), Facebook, Instagram, YouTube and LinkedIn. Forward-Looking Statement of Merck & Co., Inc., Rahway, N.J., USA This news release of Merck & Co., Inc., Rahway, N.J., USA (the “company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline candidates that the candidates will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements. Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions. The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company’s Annual Report on Form 10-K for the year ended December 31, 2025 and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov). Please see Prescribing Information for PIFELTRO (doravirine) at: https://www.merck.com/product/usa/pi_circulars/p/pifeltro/pifeltro_pi.pdf and Patient Information for PIFELTRO at: https://www.merck.com/product/usa/pi_circulars/p/pifeltro/pifeltro_ppi.pdf Please see Prescribing Information for DELSTRIGO (doravirine, lamivudine, and tenofovir disoproxil fumarate) at: https://www.merck.com/product/usa/pi_circulars/d/delstrigo/delstrigo_pi.pdf and Patient Information for DELSTRIGO at: https://www.merck.com/product/usa/pi_circulars/d/delstrigo/delstrigo_ppi.pdf _______________________ ibictegravir/emtricitabine/tenofovir alafenamide (BIKTARVY) is a registered trademark of Gilead Sciences, Inc. Media Contacts: Eilyn Segura (203) 940-6259 Deb Wambold (215) 779-2234 Investor Contacts: Peter Dannenbaum (732) 594-1579 Damini Chokshi (732) 594-1577

Guideline recommends ensuring on-demand treatment is available anytime, anywhere and prioritizes early intervention and rapid self-administration, reinforcing the unique value of EKTERLY FRAMINGHAM, Mass. & SALISBURY, England--(BUSINESS WIRE)-- KalVista Pharmaceuticals , Inc. (Nasdaq: KALV) today announced that the newly published International Guideline on the Diagnosis and Management of Pediatric Patients With Hereditary Angioedema recommends EKTERLY® (sebetralstat) as a first-line therapy for the acute treatment of hereditary angioedema (HAE) attacks in adolescents aged 12 years and older. 1 Based on robust, high-quality evidence, including clinical trial data demonstrating consistent efficacy, rapid symptom relief and a favorable safety profile, the guideline committee issued a strong recommendation for the first-line use of sebetralstat in adolescents 12 and older with HAE. The recommendation comes just months after the launch of EKTERLY in the US and Germany and follows seven global regulatory approvals received in 2025. EKTERLY is the first and only oral on-demand treatment for people 12 and older with HAE. “We are encouraged to see this international guideline reflect the progress the HAE community has made toward more patient-centered care, particularly for adolescents,” said Paul Audhya, MD, MBA, Chief Medical Officer of KalVista. “The first-line recommendation for EKTERLY so soon after becoming commercially available underscores the strength of our clinical data and reinforces the importance of ensuring patients have immediate access to effective on-demand therapy. As the first and only oral on-demand treatment for HAE, EKTERLY uniquely enables guideline-aligned care by supporting early intervention and simplifying self-administration, empowering adolescents 12 and older to treat at the earliest recognition of an attack.” The guideline emphasizes the importance of early intervention, noting that early treatment of attacks is associated with better outcomes and results in shorter, less severe episodes. However, real-world data show that adolescents with HAE have historically faced substantial delays administering treatment, waiting nearly eight hours on average to treat attacks due to the anxiety and challenges associated with injectable therapies. 2 To support early intervention, the guideline recommends ensuring pediatric patients have on-demand therapy available anytime, anywhere, consider treatment of all attacks, and have sufficient supply to treat at least two attacks, even when receiving long-term prophylaxis. In addition, it recommends having on-demand treatment available during potentially triggering events such as medical, dental and surgical procedures, while emphasizing that the activities and lifestyle of patients should be kept as normal as possible, provided they have rapid access to on-demand medication. “While general protocols have existed for many years, these new recommendations recognize that children require care tailored to their unique needs to manage this rare and potentially life-threatening genetic condition,” said Mauro Cancian, MD, PhD, Head of the Allergy Division at the University of Padua in Padova, Italy. “HAE presents distinct physiological and psychological hurdles, particularly in adolescents, from puberty-driven flare-ups to the trauma of frequent injections. By moving beyond a 'one-size-fits-all' approach, the guidelines provide a clear framework for care that supports not only rapid life-saving treatment, but also a child’s long-term health and emotional well-being.” EKTERLY is currently approved in the United States, European Union, United Kingdom, Switzerland, Australia, Singapore and Japan for the treatment of acute attacks of HAE in people 12 years of age and older. It is marketed in the US and Germany, with additional global launches anticipated in 2026 and beyond. KalVista continues to advance the KONFIDENT-KID trial—the fastest-enrolling pediatric HAE trial conducted to date—and is on track to submit a new drug application for sebetralstat in patients aged 2 to 11 in the third quarter of 2026. Developed by an International Steering Committee, Taskforce and the Hereditary Angioedema Working (HAWK) Group, the guideline was published in Allergy , the official journal of the European Academy of Allergy and Clinical Immunology (EAACI). 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 KONFIDENT-KID KONFIDENT-KID is an open label clinical trial of sebetralstat for on-demand treatment of HAE attacks in pediatric patients. Originally designed to enroll 24 pediatric patients, the trial was met with high demand and will ultimately enroll approximately 36 children aged two to 11 years across seven countries in North America, Europe and Asia. KONFIDENT-KID will collect safety, pharmacokinetic and efficacy data for each patient for up to one year and features a proprietary pediatric oral disintegrating tablet (ODT) formulation of sebetralstat. If approved, sebetralstat would be the first oral on-demand therapy for this age group, and only the second FDA-approved on-demand therapy of any type for this population. 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 and follow us on LinkedIn , X , Facebook and Instagram . INDICATION AND IMPORTANT SAFETY INFORMATION What is EKTERLY® (sebetralstat)? EKTERLY is a prescription medicine used to treat sudden (acute) attacks of hereditary angioedema (HAE) in adults and children aged 12 years of age and older. It is not known if EKTERLY is safe and effective in children under 12 years of age. IMPORTANT SAFETY INFORMATION Before taking EKTERLY, tell your healthcare provider about all of your medical conditions, including if you: Are pregnant or planning to become pregnant. It is not known if EKTERLY can harm your unborn baby. Are breastfeeding or plan to breastfeed. It is not known if EKTERLY passes into your breast milk. Talk to your healthcare provider about the best way to feed your baby while taking EKTERLY. Have liver problems. Tell your healthcare provider about all of the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Taking EKTERLY with certain other medicines can cause side effects or affect how well EKTERLY or the other medicines work. Especially tell your healthcare provider if you take any of the following, as their use with EKTERLY is not recommended: itraconazole, phenytoin, efavirenz. Know the medicines you take. Keep a list of them to show your healthcare provider or pharmacist when you get a new medicine. What are the possible side effects of EKTERLY? The most common side effects of EKTERLY include headache. For more information, ask your healthcare provider or pharmacist. Talk to your doctor for medical advice about side effects. You are encouraged to report side effects related to KalVista products by calling 1-855-258-4782. If you prefer, you may contact the U.S. Food and Drug Administration (FDA) directly. Visit or call 1-800-FDA-1088. Please click here for full Prescribing Information , including Patient Information. 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. 1 Farkas H., Martinez-Saguer I., Bork K., et al. International guideline on the diagnosis and management of pediatric patients with hereditary angioedema. Allergy. 2026;1–30. 2 Christiansen S, et al. Ann Allergy Asthma Immunol . 2025; doi:10.1016/j.anai.2024.12.012 Contacts Ryan Baker Head, Investor Relations (617) 771-5001 ryan.baker@kalvista.com Molly Cameron Director, Corporate Communications (978) 339-3378 molly.cameron@kalvista.com