Novartis had a very bad Tuesday. Shares of the Swiss pharmaceutical giant fell roughly 9% in Zurich, wiping about 24 billion Swiss francs, or approximately $30 billion, from its market value after del-desiran failed the primary endpoint of the Phase III HARBOR study in myotonic dystrophy type 1. The setback came just days after another closely watched Novartis program, pelacarsen, failed a pivotal cardiovascular study, compounding concerns about a pipeline the company needs to deliver substantial new growth over the remainder of the decade.
Neither failure has anything to do with nuclear medicine. But for radiopharma, what happened to Novartis this week matters because every major pipeline disappointment changes the relative value of the assets that are working. And Pluvicto is working.
Del-desiran was not a minor experimental asset buried deep inside Novartis' pipeline. The company acquired the drug as part of its approximately $12 billion acquisition of Avidity Biosciences, making the program an important test of the acquisition strategy CEO Vas Narasimhan has used to rebuild the company's growth pipeline.
The Phase III HARBOR study evaluated del-desiran in approximately 150 people with myotonic dystrophy type 1, a progressive neuromuscular disease with no approved treatments. Novartis said Tuesday that the trial did not demonstrate a statistically significant improvement over placebo on its primary endpoint, although the company observed evidence of clinical activity across some secondary endpoints and exploratory analyses. Novartis is continuing to analyze the data and plans to discuss the program's future with regulators.
The market reaction reflected more than disappointment about one drug. Del-desiran followed the failure of the company's Phase III pelacarsen cardiovascular program, while Novartis has also halted eight of ten studies involving its experimental rap-cel cell therapy following patient deaths. Investors had been counting on several of these pipeline assets to help sustain growth as older products decline and major patent expirations approach.
Novartis continues to stand behind its financial outlook. The company reiterated Tuesday that it expects sales to grow at a compound annual rate of 5% to 6% from 2025 through 2030. The challenge is that every major late-stage failure removes another potential contributor to that growth and places more pressure on the products and pipeline assets that remain.
That makes radioligand therapy increasingly difficult to view as a niche part of the portfolio.
Pluvicto generated $651 million in second-quarter 2026 sales, up 43% at constant currencies from the same period a year earlier. First-half sales reached nearly $1.3 billion, representing 55% constant-currency growth. Lutathera added another $225 million during the second quarter and $436 million during the first half.
Those numbers put Novartis' radioligand therapy franchise on a very different footing than it occupied only a few years ago.
Pluvicto is no longer simply evidence that radiopharmaceutical therapy can become commercially successful. It is becoming one of the growth products Novartis can point to while some of the company's older franchises decline. The contrast with Entresto is particularly striking: second-quarter Entresto sales fell 51% at constant currencies, while Pluvicto grew 43%.
The opportunity also expanded considerably this summer. The FDA approved Pluvicto in combination with an androgen receptor pathway inhibitor for PSMA-positive metastatic hormone-sensitive prostate cancer in July, moving the therapy earlier in the disease and substantially increasing the potential patient population.
For Novartis, that makes execution around Pluvicto increasingly important. Manufacturing capacity, treatment-center adoption, PSMA PET access and the ability to reliably deliver doses are no longer supporting functions around an experimental new modality. They are infrastructure around one of the company's meaningful growth franchises.
Novartis was one of the first major pharmaceutical companies to make a large strategic commitment to radioligand therapy, beginning with its acquisitions of Advanced Accelerator Applications and Endocyte. At the time, those transactions looked like bets on an emerging oncology modality.
They look different now.
Pluvicto and Lutathera have created a commercial radiopharmaceutical franchise, and Novartis has continued investing around it through manufacturing expansion and next-generation development. The company's pipeline includes additional radioligand programs across targets and isotopes, including actinium-225, as it attempts to extend its lead into the next generation of targeted radiation.
That strategy matters even more when conventional pharmaceutical bets stumble.
Drug development is inherently risky, and a failed trial does not mean Novartis suddenly becomes a radiopharmaceutical company. Its portfolio remains broad, with major growth products including Kisqali, Kesimpta, Scemblix and Leqvio. Kisqali alone generated nearly $1.7 billion during the second quarter and grew 43% at constant currencies.
But portfolio strategy is partly about reducing dependence on any single scientific bet. Radioligand therapy has now advanced far enough commercially that it can absorb some of the growth burden when other pipeline assets fail.
That is a significant change from where radiopharma stood when Novartis first began acquiring its way into the field.
Today's selloff also raises a broader question for the radiopharmaceutical industry: what happens when one of Big Pharma's most successful emerging growth platforms is radiopharma at the same time other expensive development programs are failing?
Capital tends to follow evidence.
Novartis has already invested heavily in radioligand manufacturing, clinical development and commercial infrastructure. Continued growth from Pluvicto gives management a tangible return on that investment while also strengthening the argument for additional spending on next-generation radiopharmaceuticals.
That doesn't mean every RLT acquisition or internal program will succeed. Radiopharma carries its own considerable clinical, manufacturing and commercial risks. But the strategic comparison changes when one platform is producing rapidly growing commercial revenue while a $12 billion acquisition produces a late-stage clinical disappointment.
The implications could extend beyond Novartis. Other pharmaceutical companies watching the company's experience can see both sides of modern drug development at once: enormous amounts of capital can disappear when a pivotal study fails, while an emerging modality that successfully reaches commercialization can become a meaningful growth engine surprisingly quickly.
That is one reason Big Pharma's interest in radiopharmaceuticals is unlikely to be measured solely by the performance of individual clinical programs. Companies are increasingly evaluating the modality as a platform capable of producing multiple drugs, targets and generations of therapies.
Novartis still has plenty of growth engines outside nuclear medicine, and it would be an overstatement to suggest that this week's failures fundamentally change the company's strategy overnight. The company continues to project mid-single-digit sales growth through 2030, and several major products are performing strongly.
What the setbacks do change is the pressure on the portfolio.
Every multibillion-dollar drug candidate that disappears from future forecasts increases the importance of the products already demonstrating that they can grow. Pluvicto has moved firmly into that category, with nearly $1.3 billion in sales during the first six months of this year and another major indication now opening a substantially larger patient population.
For years, radiopharma advocates argued that targeted radiation could become an important part of Big Pharma's future. Novartis was one of the companies willing to make that bet early and invest heavily enough to test it.
This week's events don't prove that radiopharma will replace the growth lost elsewhere in the company's pipeline. They do demonstrate something more consequential for the Nuclear Medicine Economy: when other major pharmaceutical bets fail, the radiopharmaceutical business Novartis spent years building suddenly becomes that much more valuable.
