For the first time, there is a drug that works.
For the roughly one in 3,800 people living with hereditary hemorrhagic telangiectasia, a condition that quietly erodes life through relentless bleeding and the threat of stroke or heart failure, medicine has long offered little more than management of symptoms. Now, a clinical trial published in the New England Journal of Medicine suggests that engasertib — an oral drug targeting the molecular root of the disease — can meaningfully reduce nosebleed frequency and improve patients' sense of wellbeing. The finding does not yet constitute a cure, nor a regulatory approval, but it marks the first time a targeted therapy has demonstrated measurable effect against a disorder that has gone molecularly untreated for generations.
- HHT silently threatens its carriers with stroke, heart failure, and brain hemorrhage, yet no FDA-approved treatment has ever existed to address its underlying cause.
- A 12-week trial at Mass General Brigham enrolled 75 patients and pitted two doses of engasertib against placebo, creating the first rigorous test of a drug designed to correct the ALK1 pathway malfunction at the heart of the disease.
- The higher-dose group saw 61% of patients report significant improvement versus just 27% in the placebo group — a gap wide enough to signal that something real is happening.
- Side effects were mild and reversible, and serious adverse events were evenly distributed across groups, giving researchers confidence that the drug's safety profile is manageable.
- The trial's small size and short duration mean the work is far from finished — larger, longer studies must now confirm whether the benefit holds and whether rare risks emerge over time.
- For patients who have lived with chronic bleeding and no molecular recourse, the result is neither a resolution nor a false promise — it is, carefully, a first foothold.
Hereditary hemorrhagic telangiectasia — HHT — is the second most common inherited bleeding disorder in the world, affecting roughly one in 3,800 people. It announces itself through relentless nosebleeds, but its deeper danger lies in the abnormal blood vessels it spawns in the brain, lungs, and liver, leaving patients vulnerable to stroke, heart failure, and hemorrhage. Until now, no FDA-approved drug has existed to treat it at its source.
The disease corrupts a signaling pathway called ALK1, which governs how the body builds and maintains blood vessels. Researchers at Mass General Brigham set out to test whether engasertib — a once-daily oral drug that inhibits the AKT protein accumulating when ALK1 goes wrong — could interrupt that process. Seventy-five HHT patients were divided into three groups receiving either 30 milligrams, 40 milligrams, or a placebo daily for 12 weeks.
The results, published in the New England Journal of Medicine, were notable. Patients on engasertib experienced fewer and shorter nosebleeds than those on placebo. Among those taking the higher dose, 61 percent reported feeling significantly better by week 12, compared to 27 percent in the placebo group. The drug's safety profile was reassuring — the most common side effect was a mild, reversible rash, and serious adverse events occurred at similar rates across all groups.
Hematologist Hanny Al-Samkari, who led the trial, called it evidence that a targeted drug can reduce bleeding and improve quality of life for HHT patients — a first at the molecular level. The trial was sponsored by Vaderis Therapeutics, the drug's developer, though its double-blind, placebo-controlled design upholds the standard expected of rigorous clinical research.
What remains is the longer road. A 12-week study in 75 people is a promising opening, not a conclusion. Larger trials over extended periods will be required before regulators consider approval. For patients who have spent years managing a condition medicine could not yet touch, the wait is not over — but for the first time, there is something real to wait for.
Hereditary hemorrhagic telangiectasia is not a household name, but it shapes the lives of roughly one in every 3,800 people on earth. The condition—HHT for short—is the second most common inherited bleeding disorder worldwide, and it announces itself most visibly through relentless nosebleeds. But the real danger lives deeper. The disease mutates a pathway called ALK1, which normally tells the body how to build and maintain blood vessels. Without proper control, abnormal vessels sprout in the brain, lungs, and liver. Patients face the constant threat of stroke, heart failure, brain hemorrhage. Until now, there has been no FDA-approved drug to treat it.
A team at Mass General Brigham decided to test whether a new compound called engasertib could change that equation. The drug works by inhibiting a protein called AKT, which accumulates when the ALK1 pathway goes wrong. Engasertib is taken once daily by mouth—simple enough for a patient to manage. The researchers enrolled 75 people with HHT and split them into three groups: one received 30 milligrams of engasertib daily, another received 40 milligrams, and the third received placebo. For 12 weeks, they tracked what happened.
The results, published in the New England Journal of Medicine, showed something worth attention. Patients on engasertib had fewer nosebleeds and shorter episodes when they did occur, compared to those on placebo. More than that, 61 percent of people taking the higher dose reported feeling "much better" by week 12. In the placebo group, only 27 percent said the same. The drug proved safe. The most common side effect was a mild, reversible rash. Serious adverse events occurred at similar rates across all groups.
Hanny Al-Samkari, a hematologist at Massachusetts General Hospital and co-director of the hospital's Hereditary Hemorrhagic Telangiectasia Center of Excellence, led the trial. He emphasized what the finding means: for the first time, there is evidence that a targeted drug can reduce bleeding in HHT patients and improve how they feel. "This is a step toward a better life," he said, noting that HHT's vascular abnormalities have long gone untreated at the molecular level.
The trial was sponsored by Vaderis Therapeutics, the company that developed engasertib, and designed in collaboration with the research team. That partnership structure is standard in drug development but worth noting—the company had skin in the outcome. Still, the double-blind, placebo-controlled design is the gold standard for testing whether a treatment actually works.
What comes next is the harder part. A 12-week trial in 75 people is a beginning, not an ending. Larger studies over longer periods will be needed to confirm these findings, to understand how long the benefit lasts, and to catch any rare side effects that a small trial might miss. Regulators will want to see sustained improvement before they consider approving engasertib for widespread use. For patients living with chronic nosebleeds and the fear of internal bleeding, the wait continues. But for the first time, there is a drug that works.
Notable Quotes
HHT causes serious vascular abnormalities throughout the body, often leading to dangerous, abnormal blood vessels in the brain, lungs, and liver, which bring with them major complications including stroke, heart failure, and brain hemorrhage—yet an FDA-approved treatment doesn't exist.— Dr. Hanny Al-Samkari, Mass General Brigham hematologist
The Hearth Conversation Another angle on the story
Why does HHT cause so much internal bleeding if the main symptom people notice is nosebleeds?
The nosebleeds are just the visible part. The same mutation that breaks blood vessel control happens throughout the body. Abnormal vessels in the lungs or liver can bleed silently, or a malformed vessel in the brain can rupture without warning. The nosebleeds are the canary in the coal mine.
So engasertib doesn't cure HHT—it just manages the bleeding?
Right. It's not a cure. The mutation is still there. But by blocking the AKT protein, the drug seems to help the body maintain better control over the abnormal vessels it already has. That's why you see fewer and shorter nosebleeds, and why people report feeling better.
The trial was only 12 weeks. Why is that enough to publish in a major journal?
It's not enough to declare victory. But it's enough to show the drug is safe and that the signal is real—that something is actually happening. The journal publishes it because the question matters and the answer is promising. But you're right to be cautious. Longer studies will tell us if the benefit holds up over months or years.
What happens to the 75 people in the trial now?
That depends on the trial design and the company's next steps. Some may continue on the drug if there's an open-label extension. Others may cycle off. But all of them now have data showing engasertib works. That changes the conversation with their doctors.
If this drug works, how long until patients can actually get it?
Years, probably. The company needs to run larger trials, submit the data to the FDA, and wait for review. If all goes well, maybe three to five years. For patients who've had no treatment options, that's both hopeful and frustratingly slow.