Three new FDA-approved drugs now give people with hereditary angioedema powerful options to prevent the kind of severe swelling attacks that can turn fatal within hours. In a remarkable three-month stretch during the summer of 2025, the FDA cleared ANDEMBRY, EKTERLY, and DAWNZERA — each representing a genuine first in HAE treatment, from the only once-monthly preventive injection to the first oral on-demand pill to the first RNA-targeted therapy. For the estimated 1 in 50,000 people living with this rare genetic condition, these approvals represent the most significant expansion of treatment options in the disease’s history. Hereditary angioedema causes unpredictable episodes of severe swelling in the hands, feet, face, stomach, genitals, and — most dangerously — the throat, where a single attack can obstruct the airway.
Consider a patient who has spent years managing breakthrough attacks despite existing prophylactic therapy: clinical data from the OASIS-HAE trial showed that patients switching from prior treatments to DAWNZERA experienced an additional 62 percent improvement in monthly attack rates. That kind of incremental gain, layered on top of existing care, signals a real shift in what is achievable. This article examines each of the three new therapies in detail, compares their mechanisms and practical considerations, and explores what these advances mean for patients navigating life with HAE. As of 2026, there are now 12 FDA-approved products available to prevent or treat hereditary angioedema — a number that would have seemed improbable even a decade ago. What follows is a close look at each new drug, who stands to benefit most, and the tradeoffs worth understanding before starting any new treatment.
Table of Contents
- How Do New Hereditary Angioedema Drugs Prevent Life-Threatening Swelling Attacks?
- ANDEMBRY — The First Once-Monthly Preventive Treatment and What Sets It Apart
- EKTERLY — Why the First Oral On-Demand Treatment Changes the Equation for Acute Attacks
- DAWNZERA — Comparing RNA-Targeted Prevention to Existing Prophylactic Options
- When New Treatments May Not Be the Right Fit — Warnings and Limitations
- What the Switch Cohort Data Tells Us About Transitioning Between Therapies
- The Future of HAE Treatment and What These Approvals Signal
- Conclusion
- Frequently Asked Questions
How Do New Hereditary Angioedema Drugs Prevent Life-Threatening Swelling Attacks?
Each of the three drugs approved in 2025 attacks HAE through a different biological pathway, which matters because patients who do not respond well to one mechanism now have genuinely distinct alternatives. ANDEMBRY (garadacimab-gxii), developed by CSL Behring, is a first-in-class monoclonal antibody that targets Factor XIIa — a protein involved early in the cascade that ultimately produces the excess bradykinin responsible for swelling. By intervening upstream, ANDEMBRY aims to prevent attacks before the inflammatory chain reaction gains momentum. DAWNZERA (donidalorsen), from Ionis Pharmaceuticals, takes an entirely different approach as the first RNA-targeted prophylactic treatment, working at the genetic instruction level to reduce production of the proteins that drive swelling. EKTERLY (sebetralstat), made by KalVista Pharmaceuticals, is a plasma kallikrein inhibitor designed not for prevention but for stopping attacks already in progress — and it is the first oral option in that category. The practical difference is significant.
Before EKTERLY, every on-demand treatment for acute HAE attacks required either an injection or intravenous infusion, which meant patients needed training, supplies, and often the presence of a healthcare provider or caregiver to manage an emergency. A patient experiencing the early warning signs of throat swelling at a restaurant or in a meeting can now take two tablets rather than find a private space to self-inject. That shift from needle to pill may sound incremental on paper, but for the roughly 6,600 Americans living with HAE, it fundamentally changes how quickly and discreetly they can respond to a crisis. It is worth noting that these drugs are not interchangeable. ANDEMBRY and DAWNZERA are prophylactic — taken on a schedule to reduce the frequency of attacks over time. EKTERLY is reactive, taken only when an attack begins. Many patients will use a prophylactic drug as their baseline and keep EKTERLY available for breakthrough attacks, creating a layered defense that was not previously possible with this combination of options.
ANDEMBRY — The First Once-Monthly Preventive Treatment and What Sets It Apart
ANDEMBRY earned FDA approval on June 16, 2025, for prophylaxis in adults and pediatric patients aged 12 and older. Its standout feature is straightforward: it is the only preventive HAE treatment that offers once-monthly dosing from the start for all patients, with no loading dose, titration period, or transition schedule. The subcutaneous self-injection autoinjector delivers the dose in 15 seconds or less, which compares favorably to other injectable prophylactics that may require longer administration times or more frequent dosing schedules. The clinical evidence behind ANDEMBRY comes from the VANGUARD trial, and the numbers are striking. Sixty-two percent of patients remained completely attack-free during treatment — a result that means more than statistical significance for someone who previously experienced multiple swelling episodes per month.
Across the trial population, HAE attacks were reduced by a median of greater than 99 percent and a least squares mean of 89.2 percent compared to placebo. Attacks requiring on-demand therapy dropped by approximately 88 percent, and moderate-to-severe attacks fell by roughly 90 percent. The most common side effects were nasopharyngitis and abdominal pain, each occurring in 7 percent or more of patients. However, a 62 percent complete attack-free rate also means that 38 percent of patients still experienced at least one breakthrough attack during the trial period. ANDEMBRY does not eliminate risk entirely, and patients should not discontinue their on-demand rescue medications. The monthly dosing convenience also assumes reliable adherence — missing a dose leaves a patient without protection for a longer window than they would face with a more frequently dosed therapy, where a single missed dose represents a smaller gap in coverage. For patients with irregular schedules or difficulty maintaining monthly routines, this tradeoff deserves an honest conversation with their care team.
EKTERLY — Why the First Oral On-Demand Treatment Changes the Equation for Acute Attacks
EKTERLY received FDA approval on July 7, 2025, marking a watershed moment for acute HAE management. Every previously approved on-demand treatment — including icatibant, ecallantide, and C1-esterase inhibitor concentrates — required subcutaneous injection or intravenous infusion. For patients experiencing an attack, particularly one involving the face or throat, the fine motor coordination and preparation time needed for self-injection added stress and delay to an already frightening situation. EKTERLY replaces that process with a 600-milligram oral dose (two tablets) taken at the earliest recognition of an attack, with a second dose permitted after three hours if needed, up to a maximum of 1,200 milligrams in 24 hours. The KONFIDENT trial program, which was the largest clinical trial program ever conducted in HAE, demonstrated significantly faster symptom relief and attack resolution compared to placebo. The safety profile was similar to placebo, meaning the drug did not introduce new side effect concerns that would give patients or physicians pause about keeping it on hand.
For a parent of a teenager with HAE, or for an adult who travels frequently, the ability to carry a blister pack of tablets instead of injection supplies and sharps containers represents a meaningful reduction in the daily burden of the disease. One important limitation: EKTERLY is not a preventive therapy. It will not reduce the frequency of attacks. A patient relying solely on EKTERLY without prophylactic treatment would still experience the same underlying attack rate and would simply be managing each episode as it arises. For patients with frequent attacks — some experience several per month — this reactive-only approach would be insufficient. EKTERLY works best as a complement to prophylactic therapy, serving as a safety net for breakthrough episodes rather than a standalone solution.
DAWNZERA — Comparing RNA-Targeted Prevention to Existing Prophylactic Options
DAWNZERA, approved on August 21, 2025, represents an entirely new class of HAE prophylactic as the first and only RNA-targeted treatment for the condition. Developed by Ionis Pharmaceuticals, it works by targeting prekallikrein messenger RNA to reduce production of the protein that drives the inflammatory cascade behind HAE attacks. It is approved for adults and pediatric patients aged 12 and older and has also received approval in the European Union, making it accessible to a broader patient population. The OASIS-HAE trial enrolled 90 patients in a randomized, double-blind study that tested two dosing intervals. Patients receiving DAWNZERA every four weeks saw an 81 percent reduction in monthly attack rate compared to placebo, and from the second dose onward, that figure climbed to 87 percent. Moderate-to-severe attacks dropped by approximately 90 percent over 24 weeks. An every-eight-week dosing arm showed a 55 percent reduction — still meaningful, but substantially less than the four-week schedule.
Long-term data over one year showed patients achieving a 94 percent mean reduction in HAE attack rates from their baseline. The most common side effects included injection site reactions, upper respiratory tract infection, urinary tract infection, and abdominal discomfort, each occurring in 5 percent or more of patients. The tradeoff between dosing frequency and efficacy is worth weighing carefully. DAWNZERA’s every-four-week schedule delivers strong attack reduction but requires more frequent injections than ANDEMBRY’s once-monthly autoinjector. The eight-week option offers greater convenience but at a meaningful cost in efficacy — a 55 percent reduction versus 81 percent is the difference between cutting attacks roughly in half versus eliminating the vast majority. Compare this to ANDEMBRY’s 89.2 percent least squares mean reduction with monthly dosing, and the practical calculus becomes patient-specific. Someone who tolerates injections well and values maximum reduction might prefer ANDEMBRY’s monthly profile, while a patient interested in an RNA-based mechanism — perhaps due to inadequate response to antibody therapies — may find DAWNZERA’s four-week schedule the right fit.
When New Treatments May Not Be the Right Fit — Warnings and Limitations
Not every patient with HAE will be a candidate for these new therapies, and the clinical trial populations highlight some important gaps. All three drugs are approved for adults and pediatric patients aged 12 and older, meaning children under 12 with HAE still lack access to these specific options. Pediatric HAE can be particularly difficult to manage because attacks may be misdiagnosed as allergic reactions or gastrointestinal problems, and the absence of newer prophylactics for younger children remains a genuine unmet need. Patients with significant comorbidities — particularly those affecting liver function, immune response, or coagulation — should approach these drugs with extra caution and thorough discussion with their specialists. ANDEMBRY’s mechanism of targeting Factor XIIa raises theoretical questions about coagulation effects, though the VANGUARD trial did not identify clinically significant bleeding events.
DAWNZERA’s RNA-based approach carries the general class considerations of antisense oligonucleotide therapies, including injection site reactions and the potential for effects on liver or kidney function over extended use. Long-term safety data beyond the trial periods remains limited for all three drugs, which is an inherent constraint of recently approved therapies. There is also the practical reality of drug access and cost. Rare disease treatments frequently carry annual price tags exceeding six figures, and insurance coverage, prior authorization requirements, and specialty pharmacy logistics can delay treatment initiation by weeks or months. A patient whose HAE is reasonably well-controlled on an existing prophylactic may face a difficult decision about whether the incremental benefit of switching justifies the administrative burden and potential coverage disruptions. The decision to switch therapies should be driven by clinical need — breakthrough attacks, side effect burden, or quality-of-life impact — rather than novelty alone.
What the Switch Cohort Data Tells Us About Transitioning Between Therapies
One of the most valuable pieces of real-world evidence from the DAWNZERA trials came from the switch cohort — patients who transitioned from prior HAE prophylactic therapies to DAWNZERA. These patients saw an additional 62 percent improvement in monthly attack rates after switching, which is a meaningful data point for the many HAE patients who are currently on older therapies and wondering whether a change is worthwhile.
This cohort matters because it addresses a question that clinical trials against placebo cannot fully answer: does a new drug work better than what patients are already taking? A 62 percent improvement over prior therapy is not the same as a 62 percent improvement over no treatment, and the distinction is critical for clinical decision-making. It suggests that for patients experiencing residual disease activity on existing prophylactics, DAWNZERA’s RNA-targeted mechanism may offer suppression that prior approaches did not achieve. That said, the switch cohort was not randomized against specific comparator drugs, so the data should be interpreted as encouraging rather than definitive proof of superiority over any particular existing treatment.
The Future of HAE Treatment and What These Approvals Signal
The approval of three distinct HAE therapies within three months during 2025 reflects a broader acceleration in rare disease drug development, driven in part by advances in biologics, RNA therapeutics, and regulatory pathways that incentivize orphan drug development. With 12 FDA-approved products now available for HAE prevention and treatment, the condition has moved from a space of limited options to one where patients and physicians can meaningfully tailor therapy based on mechanism, dosing preference, and individual response. Looking ahead, the pipeline suggests continued innovation.
Gene therapy approaches for HAE are in early-stage development, and the success of DAWNZERA’s RNA-targeting platform opens the door for similar strategies in other bradykinin-mediated conditions. For patients and families affected by HAE, the immediate takeaway is that 2025 reshaped the treatment landscape in ways that were not possible even two years ago — and the pace of progress shows no signs of slowing. The most important next step for anyone living with HAE is a candid conversation with a specialist about whether their current regimen reflects the full range of options now available.
Conclusion
The FDA’s approval of ANDEMBRY, EKTERLY, and DAWNZERA in rapid succession during 2025 gave people with hereditary angioedema three genuinely new tools — a once-monthly preventive injection, the first oral on-demand treatment, and the first RNA-targeted prophylactic. Each addresses a different aspect of disease management, and together they allow for layered treatment strategies that can reduce attack frequency by 89 to 94 percent while providing a fast, needle-free option for breakthrough episodes. The clinical trial results, particularly the VANGUARD trial’s 62 percent complete attack-free rate and the OASIS-HAE long-term data showing 94 percent attack reduction, represent the strongest efficacy outcomes HAE patients have seen.
For patients, caregivers, and the physicians who manage this rare condition, the priority now is translating these approvals into accessible care. That means working with specialty pharmacies and insurers to navigate coverage, discussing with HAE specialists whether current treatment plans should be revisited, and ensuring that on-demand options like EKTERLY are prescribed alongside prophylactic therapies for comprehensive protection. Hereditary angioedema remains a serious, lifelong condition — but the gap between what the disease can do and what medicine can prevent has never been narrower.
Frequently Asked Questions
What is hereditary angioedema and how common is it?
Hereditary angioedema is a rare genetic condition affecting approximately 1 in 50,000 people. It causes recurrent episodes of severe swelling in the hands, feet, face, stomach, genitals, and throat. Throat swelling can be life-threatening if untreated, as it may obstruct the airway.
What is the difference between prophylactic and on-demand HAE treatments?
Prophylactic treatments like ANDEMBRY and DAWNZERA are taken on a regular schedule to prevent attacks from occurring. On-demand treatments like EKTERLY are taken only when an attack begins, to reduce its severity and duration. Most specialists recommend using both types together for comprehensive protection.
Is EKTERLY really the first oral treatment for HAE attacks?
Yes. Prior to EKTERLY’s FDA approval on July 7, 2025, every available on-demand treatment for acute HAE attacks required either subcutaneous injection or intravenous infusion. EKTERLY is taken as two tablets (600 mg) at the first sign of an attack, with a second dose allowed after three hours if needed.
How often do patients need to take ANDEMBRY?
ANDEMBRY is a once-monthly subcutaneous self-injection from the start for all patients, with no loading dose or titration period required. The autoinjector delivers the dose in 15 seconds or less.
Can children under 12 use these new HAE drugs?
Currently, all three drugs approved in 2025 — ANDEMBRY, EKTERLY, and DAWNZERA — are approved for adults and pediatric patients aged 12 and older. Children under 12 do not yet have access to these specific treatments and must rely on previously approved therapies.
What were the main side effects seen in clinical trials?
Side effects varied by drug. ANDEMBRY’s most common were nasopharyngitis and abdominal pain. EKTERLY had a safety profile similar to placebo, meaning minimal additional side effects. DAWNZERA’s most common side effects included injection site reactions, upper respiratory tract infection, urinary tract infection, and abdominal discomfort.
