Novartis Shares Plunge as Second Phase III Trial Fails in Two Days

Shares of Novartis tumbled 10.3% to CHF 112.60 after the Swiss drugmaker disclosed that the Phase III HARBOR study evaluating del-desiran for myotonic dystrophy type 1 (DM1) had failed to meet its primary endpoint—a second consecutive setback for its clinical pipeline in less than 48 hours.

The international trial, which enrolled roughly 150 patients and ran for 54 weeks, did not show a statistically significant improvement over placebo in video hand opening time—a key measure of hand muscle stiffness in DM1, a progressive neuromuscular condition with no currently approved therapies.

Monday’s separate failure intensified today’s selloff: the Phase III Lp(a)HORIZON trial of pelacarsen, a cardiovascular drug developed in partnership with Ionis Pharmaceuticals, also missed its primary endpoint of reducing major adverse cardiovascular events.

Together, these represent the company’s third clinical-trial setback within a single week. The stakes were especially high for del-desiran: Novartis’s chief executive had previously described the drug as having peak sales potential exceeding $5 billion, and the asset was acquired through the purchase of Avidity Biosciences.

Although del-desiran showed signals of activity on secondary endpoints, the failure on the primary measure casts uncertainty over its near-term regulatory pathway. Novartis did, however, reaffirm its five-year sales compound annual growth rate guidance of 5–6% for 2025–2030.

The broader market backdrop offered little support for Novartis today. European equities were already under pressure—with the pan-European STOXX 600 down 0.2%—as rising oil prices, driven by geopolitical tensions in the Strait of Hormuz, stoked inflation concerns ahead of the European Central Bank’s rate decision scheduled for September 10.

The Swiss Market Index, in which Novartis holds heavy weight, was dragged lower partly by the company’s outsized losses. U.S. markets were similarly subdued, with the S&P 500 slipping 0.4% and the Dow Jones losing 1.0%.

The combination of a high-profile, back-to-back pipeline collapse and a risk-off macro environment proved overwhelming for Novartis shares during today’s trading.

While reaffirmed guidance and the remaining pipeline—including other AOC-platform drugs advancing toward FDA review—offer some longer-term reassurance, the immediate loss of expected peak-sales value from two failed late-stage programs has prompted investors to reassess the near-term growth story, pushing the stock to its lowest intraday level in several months.

This article was generated with the support of AI and reviewed by an editor. For more information, see our Terms & Conditions.