Novartis Spent $12B on Avidity. The Leftovers Just Raised $270M.
Novartis paid $12 billion for Avidity Biosciences but left the cardiology programs on the table. Those "leftovers" just launched as Atrium Therapeutics with $270 million and two preclinical heart disease drugs. Sometimes the best biotechs are built from what big pharma didn't want.
When Novartis dropped $12 billion to buy Avidity Biosciences, they wanted three late-stage muscular dystrophy programs. They did not want the early-stage heart stuff.
So what happens to the assets a mega-pharma leaves on the table? Apparently, they become a whole new company.
Meet Atrium Therapeutics
Atrium Therapeutics launched on February 27, 2026, with roughly $270 million in cash and a mission to develop RNA medicines for rare genetic heart diseases. The company didn't emerge from a garage or an academic lab. It was spun directly out of the Novartis-Avidity deal, carrying two preclinical drug candidates that Novartis politely declined to keep.
Think of it like a restaurant buyout. A big chain acquires your favorite bistro for the brunch menu and the liquor license. But the original chef takes the secret dessert recipes, a pile of cash, and opens a new spot across town. That's basically what happened here.
Leading the charge is Kathleen Gallagher, who served as chief program officer at Avidity before the acquisition. She's now CEO of Atrium, and she brought Avidity's precision cardiology playbook with her. Sarah Boyce, Avidity's former CEO, will chair Atrium's board.
The Deal Behind the Deal
To understand Atrium, you need to understand the Novartis-Avidity transaction. Novartis paid $72 per share in an all-cash deal, a premium of roughly 46% over Avidity's pre-announcement price. The prize? Avidity's Antibody Oligonucleotide Conjugate (AOC) platform, which delivers RNA therapies directly to muscle tissue, plus three late-stage programs for Duchenne muscular dystrophy, myotonic dystrophy type 1, and facioscapulohumeral muscular dystrophy.
But Avidity also had early-stage cardiology programs and a collaboration with Bristol Myers Squibb. Novartis wasn't interested in those. Rather than let them die on the vine, Avidity structured a spin-off before the deal closed. Eligible shareholders received one Atrium share for every 10 Avidity shares they held, and the new entity walked away with $270 million to fund its pipeline.
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It's a playbook we've seen before in big pharma M&A. When the acquirer only wants part of the menu, the rest gets packaged into a standalone company. The result: shareholders get value from both sides of the deal, and promising science doesn't end up in a filing cabinet.
Two Drugs, Two Deadly Diseases, Zero Approved Treatments
Atrium's pipeline is focused on rare genetic cardiomyopathies (heart muscle diseases caused by inherited gene mutations). Both conditions are progressive, life-threatening, and currently have no approved therapies that address the underlying genetic cause.
The first candidate, ATR 1072, targets PRKAG2 syndrome, a rare condition that causes dangerous heart rhythm problems and abnormal thickening of the heart muscle. Chemistry, manufacturing, and IND-enabling studies are already underway. Gallagher's team is targeting an IND filing (the FDA application that lets you start testing in humans) in the second half of 2026.
The second candidate, ATR 1086, goes after phospholamban (PLN) cardiomyopathy. In this disease, a defective protein disrupts calcium regulation in heart cells, eventually leading to heart failure. Manufacturing work is planned for 2026, with an IND submission targeted for 2027.
Both drugs use small interfering RNA, or siRNA: tiny molecules designed to silence the specific genes causing these diseases. If DNA is the blueprint and proteins are the building, siRNA is like crossing out one line on the blueprint before construction begins. The faulty protein never gets made.
Atrium also has two undisclosed research-stage programs in rare cardiomyopathies, giving the company four shots on goal from a single platform.
The Hard Part: Getting RNA Into the Heart
siRNA has already proven it can work in the liver. Alnylam's patisiran (for a rare nerve disease) was approved back in 2018, and Novartis sells inclisiran (for cholesterol) as an siRNA injectable. But the heart is a different beast entirely.
Delivering RNA specifically to heart muscle cells, without it getting gobbled up by the liver or scattered everywhere else, is one of the hardest problems in the field. Atrium's platform builds on Avidity's targeted, non-viral delivery technology, originally developed for skeletal muscle. The bet is that lessons learned from getting RNA into muscle tissue can translate to cardiac muscle.
Atrium isn't the only group chasing this idea. Soufflé Therapeutics partnered with Bayer to develop cell-selective siRNA for dilated cardiomyopathy. PLaN Therapeutics licensed technology from UMass Chan to target the same PLN mutation that Atrium's ATR 1086 addresses. And RiboCure Pharmaceuticals has several cardiovascular siRNA programs in clinical trials, though those focus on cholesterol and clotting rather than genetic cardiomyopathies.
The competitive landscape is filling up, but nobody has cracked targeted cardiac siRNA delivery in the clinic yet. Whoever gets there first owns the category.
Why This Matters Beyond Atrium
The bigger story here isn't just one new biotech. It's what Atrium represents about how mega-M&A deals are reshaping the industry.
When Novartis writes a $12 billion check, it's buying specific assets that fit its commercial strategy: late-stage programs it can launch before 2030 to hit its 5-6% annual sales growth target. Everything else is a distraction. But "distraction" doesn't mean "worthless." It often means "too early for big pharma's timeline."
The spin-off model solves this elegantly. The acquirer gets focus. The early-stage science gets dedicated funding and leadership. Shareholders get exposure to both. And the biotech ecosystem gets a new, well-capitalized company that might not have existed otherwise.
Atrium launched with $270 million, a seasoned leadership team, existing pharma collaborations, and a clear path to the clinic. Most startups would kill for one of those things.
The Bottom Line
Novartis bought the steak. Atrium got the sizzle.
Whether Gallagher's team can actually deliver siRNA to the heart in a way that treats disease safely and effectively remains an open question. The science is promising but unproven in humans, and the technical barriers are real. Getting to Phase 1 trials by late 2026 and 2027 would be a meaningful milestone.
But with $270 million in the bank, no debt, and two shots at diseases with zero approved treatments, Atrium has the resources and the runway to find out. In biotech, sometimes the best companies are built from what someone else left behind.
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