▌ TODAY’S CHALLENGE: (1) How many times does your heart beat a day: 10,000, 100,000 or 1 million? (2) Lifetime risk of heart failure for U.S. adults: 1 in 50, 1 in 10 or about 1 in 4? (3) Miles of blood vessels: 600, 6,000 or 60,000? Answers at the bottom.
“The future cannot be predicted, but futures can be invented.” Dennis Gabor, Nobel Prize in Physics
Heart disease was the leading cause of death in the U.S. in 2024 (CDC), and about 7.7 million U.S. adults live with heart failure (HF STATS 2026). The catch: heart muscle barely regrows, about 1% of cells a year at age 25 and under 0.5% by 75 (Science, 2009). So companies are racing to rebuild the muscle or replace the whole heart. Here is who is closest.
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Companies, Milestones & What To Watch Next For Heart Repair And Replacement
Mesoblast (Australia, public: MESO)
Donor cells injected into the heart muscle for heart failure. Best result so far: in its 537-patient randomized DREAM-HF trial, one injection cut heart attacks and strokes by 60% (5% vs 13%) over about 30 months. It filed with the FDA in June 2026 for end-stage patients on an LVAD pump, and the FDA said a follow-up trial must cover the much larger group with milder heart failure. CEO Silviu Itescu already won FDA approval for Ryoncil in 2024. Cash about $99M (Sept 30, 2026). Market data (Oct 26 close): $12.39, market cap about $1.64B. Why it matters: the strongest outcome data in this group. Next: completing the FDA filing; no decision date yet.
Heartseed (Japan, public: 219A)
Tiny balls of lab-grown (iPS) heart muscle, injected during bypass surgery. Best result so far: in 10 patients with no comparison group, heart pumping (LVEF) rose from 23.8% to 31.1%, and 6 of 9 tested walked farther at one year (company data). It starts with bypass patients, but its catheter version aims at the wider group with severe heart failure. Cash ¥6.34B (about $40.3M), roughly three years at its forecast loss (our estimate). Market data (Oct 26): ¥2,703 (about $17.20), market cap about ¥62.0B (about $395M). Why it matters: some of the strongest early signs that lost heart muscle can be rebuilt. Next: Japan approval filing, targeted within 2026.
Cuorips (Japan, public: 4894)
Thin sheets of lab-grown (iPS) heart muscle laid on the heart. In March 2026, Japan gave it conditional approval, the world’s first iPS heart therapy, priced at ¥53.2M (about $339,000) per treatment (company). Best result so far: in an 8-patient Osaka study with no comparison group, all 8 had fewer symptoms and 4 had better heart function. Cash ¥3.04B (about $19.3M). Market data (Oct 26 close): ¥6,490 (about $41.30), market cap about ¥57.7B (about $367M). Why it matters: first to market, but the approval can be withdrawn if follow-up data disappoint. Next: more commercial patients; the first was treated September 29, 2026.
▌ DID YOU KNOW? About 1 in 6 U.S. adults with high blood pressure do not know they have it (CDC). In 123 trials, every 10-point drop in the top number cut heart failure by 28% (Lancet, 2016). A cuff check is the easiest win.
United Therapeutics (US, public: UTHR)
Gene-edited pig hearts with 10 edits. The FDA cleared its first pig-heart trial on May 15, 2026, starting with up to 2 patients (company). Best result so far: two earlier compassionate-use patients lived about 2 months and 40 days, versus about 80% five-year survival with a human donor heart. Founder Martine Rothblatt says the goal is an unlimited supply of transplantable organs. Cash $3.8B (June 30, 2026). Market data (Oct 23 close): $587.50, market cap about $25.2B. Why it matters: the only cleared pig-heart trial, paid for by a profitable drug business. Next: first trial transplant, date not disclosed.
BiVACOR (US and Australia, private)
A titanium artificial heart whose single disc floats on magnets, replacing both pumping chambers. Best result so far: all 5 first U.S. patients reached a donor heart, and an Australian man lived at home 105 days on it before his transplant. It starts as a bridge to transplant, but the company says it is designed as a long-term replacement. Backers: Cormorant Asset Management, OneVentures, plus Australian government and NIH grants. Why it matters: it could someday help people who never get a donor heart. Next: its expanded U.S. study is recruiting (NCT06174103).
▌ BAD JOKE BREAK: My heart and I have a wonderful relationship. We have been going steady for years.
Lexeo Therapeutics (US, public: LXEO)
A one-time gene therapy for the heart disease of Friedreich ataxia, a rare inherited condition. Best result so far: in small early studies with no comparison group, all 6 patients with thickened heart muscle reached the normal range (a biomarker), and coordination scores improved across 16 patients. It starts here, but its pipeline includes a gene therapy for Alzheimer’s in people with two APOE4 genes, which the company estimates affects about 900,000 Americans with Alzheimer’s. Cash $234.2M, which it says lasts into 2028. Market data (Oct 23 close): $2.80, market cap about $229.7M. Why it matters: a one-dose fix could become a template for diseases of aging. Next: pivotal data in late 2027.
Also watching: Capricor (CAPR: $5.74, market cap about $334M, cash $237.9M) gets an FDA decision on its Duchenne cell therapy on November 22, after advisers voted 9 to 3 against. Tenaya (TNYA: $0.41, about $92M, cash $78.1M) saw 5 of 6 gene therapy patients improve to the mildest heart failure class and plans a pill for the stiff-heart failure common in older adults. Rocket (RCKT: $2.28, about $250M, cash $283.7M) reports all 6 early patients alive without a transplant at up to 5 years.
Startups And Patent Watch
Repairon (Germany, private): its lab-grown heart patch lasted up to 6 months and improved pumping in 20 monkeys, and showed new heart muscle in its first human patient (Nature, 2025). It is now in a Phase 1/2 trial.
Secretome Therapeutics (US, private): raised $30M from RA Capital in May 2026. No human results yet; the company says animal studies showed better pumping, and it is in early trials for the stiff-heart failure common in older adults.
New patent application (Oct 8, 2026): a lab method to mature 3D lab-grown heart tissue, shown in lab cells only (US 20260308527).
Challenge answers: (1) About 100,000 beats a day. (2) About 1 in 4. (3) About 60,000 miles (Cleveland Clinic, HFSA). How many did you get?
Educational research, not investment advice. Prices are the latest closes found; currency conversions use October 26, 2026 exchange rates.
