Tipp didn’t just have an unusually bad allergic reaction. In just a few months, she learned that she was among approximately 32,000 American adults with systemic mastocytosis, or MS. A rare blood and immune disease resulting from a genetic mutation, it causes life-threatening allergic reactions to ordinary things, a whiff of perfume, the taste of a tomato seed, an elevated heart rate due to jogging.
On Monday, the Food and Drug Administration approved Ayvakit, a drug to treat a wide range of MS patients.
Produced by Cambridge biotech Blueprint Medicines, the medicine was approved in 2021 for only a few thousand patients with an advanced form of the disease. This has left most MS patients without medication to prevent frequent and unpredictable allergic reactions.
Some had to hold an EpiPen to deliver a dose of epinephrine at arm’s length at all times. Others regularly took antihistamines and steroids to gain weight. Some rarely left their homes, leading to depression.
I’ve waited 25 years for this drug to happen, said Dr. Mariana Castells, director of the Mastocytosis Center at Brigham and Women’s Hospital, who was principal investigator on a clinical trial of the drug.
The drug comes as a 25-milligram pill and should be taken daily. Ayvakit has a monthly wholesale cost of $37,111, which Blueprint intends to maintain with expanded use. Blueprint says it plans to market it to the 7,500 patients diagnosed with moderate to severe cases of MS.
Kate Haviland, chief executive officer of Blueprints, told analysts the company expects sales to peak at $1.5 billion annually, meaning about half of the 7,500 patients in the target market would take it every day. A prescription drug that generates $1 billion in sales is considered a blockbuster. Ayvakit generated $111 million in sales last year.
MS is a deeply debilitating and complex disease that severely impacts patients’ ability to live their own lives, Haviland said. This time of year, most of us are making plans to see family and friends. We are attending graduations and planning summer vacations. These are the kinds of things people live with [the disease] lose because they are afraid.
The unpredictable and life-threatening allergic reactions of MS result from an overactive type of white blood cell called mast cells.
These cells play an important role in managing immune responses, and the human body typically has millions of them, Castells said. People with MS have 10 to 100 times the normal amount and it builds up in parts of the body, such as the skin, heart, intestines, bones and other organs. The cells are easily activated, triggering inflammation where there is no problem.
Tipp, who was stung by the wasp in 2018, said she never had allergies until earlier that year, when she was 35. Suddenly, she started breaking out in hives. They were so itchy that she started scratching them in the middle of the night until they bled. Over-the-counter antihistamines didn’t help. The hives eventually left brown spots all over her skin.
A few months later, he started noticing the metallic taste in his mouth and started suffering from gastrointestinal problems, like when he took a sip of red wine. One whiff from someone wearing deodorant in the supermarket would trigger allergic reactions. She had to give herself an EpiPen at least once a week, and sometimes up to eight times. She eventually couldn’t leave the house because she was afraid of suffering an anaphylactic shock that could constrict her airways and kill her.
A doctor at the MD Anderson Cancer Center in Houston eventually diagnosed her with MS. In July 2021, she entered a clinical trial at the University of Alabama at Birmingham to test the Blueprints drug. She takes it every night. She rarely has allergic reactions, she said, and she hasn’t used an EpiPen in three months. Most importantly, she said, she feels comfortable leaving her house, and on Monday she was excited to attend her eighth-grade son’s graduation.
It changed my life, said Tipp, now 41. I felt like I was living in a bubble.
Castells, Brigham’s researcher, said the drug works by reducing the number of mutated mast cells by 70 to 80 percent. The genetic mutation is not hereditary, he added, but it does occur at some point in people’s lives.
Ayvakit is one of two drugs that Blueprint has on the market. It was originally approved in 2020 for an ultra-rare gastrointestinal cancer afflicting hundreds of US patients. The mutated proteins that are the underlying causes of MS and gastrointestinal cancers are similar in structure, according to the company.
Salveen Richter, an analyst at Goldman Sachs, said in a note to investors Monday night that Blueprint is an attractive target for mergers and acquisitions, with a broad pipeline, including potential treatments for multiple forms of cancer.
Jonathan Saltzman can be reached at jonathan.saltzman@globe.com.
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